Development of minimum quality requirements for water reuse in agricultural irrigation and

aquifer recharge

Draft V.3.1October 2016

This document has been established for information purposes only. It has not been adopted or in any way approved by the European Commission.

The European Commission does not guarantee the accuracy of the information provided, nor does it accept responsibility for any use made thereof. Users should therefore take all necessary precautions before using this information, which they use entirely at their own risk.

This document has no formal legal status and in the event of a dispute, ultimate responsibility for the interpretation of the law lies with the Court of Justice.

NOTEThis document is a living document and will be updated to take account of experiences and information from the Member States, from MS competent authorities, and other stakeholders.

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Table of ContentsAbbreviations and Acronyms.......................................................................................................2Glossary...................................................................................................................................... 41 Introduction.........................................................................................................................6

1.1 Background...................................................................................................................61.2 Scope of the document..................................................................................................71.3 Reference documents....................................................................................................8

1.3.1 Source of wastewater...........................................................................................102 Framework for reclaimed water management...................................................................10

2.1 Risk assessment..........................................................................................................112.2 Preventive measures and multiple barrier approach...................................................152.3 Monitoring...................................................................................................................16

3 Categories of use...............................................................................................................173.1 Categories of use for agricultural irrigation.................................................................173.2 Categories of use for aquifer recharge........................................................................17

4 Health and environmental risks of agricultural irrigation with reclaimed water.................185 Health and environmental risks of aquifer recharge with reclaimed water........................206 Preventive measures.........................................................................................................21

6.1 Preventive measures for agricultural irrigation............................................................216.2 Preventive measures for aquifer recharge...................................................................22

7 Tolerable risk.....................................................................................................................238 Reclaimed water monitoring..............................................................................................23

8.1 Microbiological parameters..........................................................................................238.1.1 Reference pathogens............................................................................................238.1.2 Indicator microorganisms.....................................................................................27

8.2 Physico-chemical parameters......................................................................................298.2.1 Physico-chemical parameters for agricultural irrigation monitoring......................308.2.2 Physico-chemical parameters for aquifer recharge monitoring.............................31

8.3 Contaminants of emerging concern (CECs) in reclaimed water for aquifer recharge...338.3.1 Source control program for CECs..........................................................................33

9 Reclaimed water quality criteria........................................................................................349.1 Reclaimed water quality criteria for agricultural irrigation...........................................359.2 Reclaimed water quality for aquifer recharge..............................................................38

9.2.1 Monitoring requirements for CECs in aquifer recharge.........................................409.2.2 Bioassays and assessment of risk of mixtures of pollutants in reclaimed water for aquifer recharge................................................................................................................43

9.3 Operational monitoring for agricultural irrigation and aquifer recharge......................469.4 Antimicrobial resistances and antibiotic resistance genes (AMR/ARG).........................47

10 Additional consideration on monitoring of environmental matrices...................................49References................................................................................................................................50References from CECs and ARM/ARG sections..........................................................................55

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ANNEX I..................................................................................................................................... 60ANNEX II....................................................................................................................................63

List of TablesTable 1 Evaluation of enteric bacteria for selecting a reference pathogen at EU level..............24

Table 2 Evaluation of enteric viruses for selecting a reference pathogen at EU level................25

Table 3 Evaluation of enteric protozoa for selecting a reference pathogen at EU level.............26

Table 4 List of CECs to monitor the suitability of wastewater for water reclamation via groundwater recharge...............................................................................................................34

Table 5 Performance targets for validation monitoring of agricultural irrigation with reclaimed water.........................................................................................................................................35

Table 6 Minimum reclaimed water quality criteria for verification monitoring and specified technology targets for agricultural irrigation.............................................................................37

Table 7 Verification monitoring frequency of analytical parameters for agricultural irrigation.. 38

Table 8 Minimum reclaimed water quality criteria for verification monitoring for aquifer recharge (modified from USEPA, 2012; Directive 98/83 EC)......................................................39

Table 9 Verification monitoring frequency of analytical parameters for aquifer recharge.........40

Table 10 Proposed list of initial CECs to be included in monitoring programs of indirect potable reuse projects leading to aquifer recharge................................................................................42

Table 11 Overview of recommended in vitro bioassays to detect activity towards selected endpoints relevant for drinking water.......................................................................................44

Table 12 Trigger values for estrogenic (ERα), androgenic (AR), progestagenic (PR), and glucocorticoid (GR) activities in reclaimed water used for recharge of potable aquifers...........45

Table 13 Recommended operational monitoring for some common treatment processes (NRMMC–EPHC–AHMC, 2006; WHO, 2006 and 2016).................................................................47

Table 14 Optional AMR reclaimed water quality criteria for agricultural irrigation for routinely monitoring.................................................................................................................................48

Table 15 Optional AMR reclaimed water quality parameters for aquifer recharge.....................48

List of FiguresFigure 1 Conceptional schematic of groundwater recharge practices considered by the Commission and point of compliance (a. surface spreading; b. direct injection)......................41

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Abbreviations and Acronyms (abbreviations and acronyms from CECs and AMR/ARG sections are not included)

AHMC Australian Health Ministers’ Conference

ANZECC Australian and New Zealand Environment and Conservation Council (Note: in 2001, the

functions of ARMCANZ and ANZECC were taken up by the Environment Protection and

Heritage Council and the Natural Resource Management Ministerial Council)

APHA American Public Health Association

ARMCANZ Agricultural and Resource Management Council of Australia and New Zealand (Note: in

2001, the functions of ARMCANZ and ANZECC were taken up by the Environment

Protection and Heritage Council and the Natural Resource Management Ministerial

Council)

bdl Below Detection Limit

BOD5 5 day Biochemical Oxygen Demand

CAC Codex Alimentarius Commission

CCR California Code of Regulations

CDPH California Department of Public Health

CECs Compounds of Emerging Concern

CEN European Committee for Standardization

cfu colony forming unit

CIS Common Implementation Strategy

COD Chemical Oxygen Demand

COM Communication from the Commission

DALYs Disability Adjusted Life Years

DG ENV Directorate General Environment (European Commission)

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DWD Drinking Water Directive

EC European Commission

EDC Endocrine Disrupting Compound

EDCs Endocrine Disrupting Compounds

EEA European Environment Agency

EPHC Environment Protection and Heritage Council

EQSD Environmental Quality Standards Directive

EU European Union

FAO Food and Agriculture Organization

GWD Groundwater Directive

HACCP Hazard Analysis and Critical Control Points

ISO International Organization for Standardization

JRC Joint Research Centre (European Commission)

MS Member States

NHMRC National Health and Medical Research Council

NRC National Research Council

NRMMC Natural Resource Management Ministerial Council

NTU Nefelometric Turbidity Unit

no Number

NWRI National Water Research Institute of the United States

PDT Pressure Decay Test

p.e. Population Equivalent

pfu plaque forming unit

QMRA Quantitative Microbial Risk Assessment

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SAR Sodium Adsorption Ratio

SCHEER Scientific Committee on Health, Environmental and Emerging Risks

SSP Sanitation Safety Planning

TOC Total Organic Carbon

TSS Total Suspended Solids

USEPA United States Environmental Protection Agency

UV Ultraviolet

UWWTD Urban Wastewater Treatment Directive

WFD Water Framework Directive

WHO World Health Organization

WSP Water Safety Plans

WWTP Wastewater Treatment Plant

Glossary

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Barrier a part of the treatment, conveyance, transport, or handling chain that substantially reduces the number of microorganisms, chemical and physical contaminants along a pathway.

Ct the product of residual disinfectant concentration (C) in milligrams per litre and the corresponding disinfectant contact time (t) in minutes.

Domestic wastewater wastewater from residential settlements and services which originates predominantly from the human metabolism and from household activities (according to Directive 91/271/EEC).

Dose–response the quantitative relationship between the dose of an agent and aneffect caused by the agent.

Exposure assessment the estimation (qualitative or quantitative) of the magnitude, frequency, duration, route and extent of exposure to one or more contaminated media.

Hazard a biological, chemical, physical or radiological agent that has the potential to cause harm.

Indirect potable reuse discharge of reclaimed water directly into a suitable environmental buffer (groundwater or surface water) with the intent of augmenting drinking water supplies, thus preceding drinking water treatment.

Industrial wastewater any wastewater which is discharged from premises used for carrying on any trade or industry, other than domestic wastewater and run-off rain water (according to Directive 91/271/EEC).

Log10 removal used in reference to the physical-chemical treatment of water to remove, kill, or inactivate microorganisms such as bacteria, protozoa and viruses (1 log10 removal = 90% reduction in density of the target organism, 2 log10 removal = 99% reduction, 3 log10 removal = 99.9% reduction, etc).

Population equivalent the organic biodegradable load having a five-day biochemical oxygen demand (BOD5) of 60 g of oxygen per day.

Primary treatment treatment of urban wastewater by a physical and/or chemical process involving settlement of suspended solids or other processes in which the BOD5 of the incoming wastewater is reduced by at least 20% before discharge and the total suspended solids of the incoming wastewater are reduced by at least 50% (according to Directive 91/271/EEC).

Raw wastewater wastewater that has not undergone any treatment, or the wastewater entering the first treatment process of a wastewater treatment plant.

Reclaimed water urban wastewater that has been treated to meet specific water quality criteria with the intent of being used for a range of purposes. Synonymous with recycled water.

Risk the likelihood of identified hazards causing harm in a specified timeframe, including the severity of the consequences.

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Secondary treatment treatment of urban wastewater by a process generally involving biological treatment with a secondary settlement or other process in which the requirements established in Table 1 of Annex I of Directive 91/271/EEC are respected.

More stringent treatment includes treatment beyond secondary treatment processes (N- and/or P-removal) for discharges from urban waste water treatment plants to sensitive areas which are subject to eutrophication. One or both parameters may be applied depending on the local situation (according to Directive 91/271/EEC).

Further treatment treatment processes, beyond secondary or biological processes, which further improve effluent quality, such as filtration and disinfection processes.

Urban wastewater domestic wastewater or the mixture of domestic wastewater with industrial wastewater and/or run-off rain water (according to Directive 91/271/EEC).

Water reuse use of treated wastewater for beneficial use. Synonymous with water recycling.

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1 Introduction1.1 BackgroundEurope's water resources are increasingly coming under stress, leading to water scarcity and quality deterioration. Pressures from climate change, drought and urban development have put a significant strain on freshwater supplies (EEA, 2012). In this context, Europe’s ability to respond to the increasing risks to water resources could be enhanced by wider reuse of treated wastewater. As stated in COM (2015)614: “Closing the loop – An EU action plan for the circular economy” the Commission will take a series of actions to promote the reuse of treated wastewaters, including development of a regulatory instrument on minimum quality requirements for water reuse in agricultural irrigation and aquifer recharge.

All information sources agree on the significant potential for further development of water reuse projects in the EU (BIO, 2015). By providing an additional source of water, water reuse can help lower the pressure on freshwater resources. Other benefits include decreasing wastewater discharges and reducing and preventing pollution. In addition, development of reuse in the EU is a market opportunity for the water industry with a strong eco-innovation potential in terms of technologies and services around water recycling in industry, agriculture and domestic water systems. It will provide new and significant opportunities for Europe to become a global market leader in water-related innovation and technology.

Water reuse needs to be considered as a measure within the context of the water policy hierarchy. The EC Communication on Water Scarcity and Droughts (COM (2007)414) sets out the water hierarchy of measures that Member States (MS) should consider in managing water scarcity and droughts. This communication states that water saving must become the priority and all possibilities to improve water efficiency must therefore be explored. Policy making should be based on a clear water hierarchy. Additional water supply infrastructures should be considered as an option when other options have been exhausted, including effective water pricing policy and cost-effective alternatives. Water uses should also be prioritised: it is clear that public water supply should always be the overriding priority to ensure access to adequate water provision. It also states that in regions where all prevention measures have been implemented according to the water hierarchy (from water saving to water pricing policy and alternative solutions) and taking due account of the cost-benefit dimension, and where demand still exceeds water availability, additional water supply infrastructure can in some circumstances be identified as a possible other way of mitigating the impacts of severe drought.

There are several possible ways of developing additional water infrastructures, such as storage of surface or groundwaters, water transfers, or use of alternative sources. Alternative options like desalination or water reuse are increasingly considered as potential solutions across Europe. The applicability of these options will have to be based on further work on risk and impact assessment, taking into account the specific bio-geographical circumstances of MS and regions (COM (2007)414).

Although the reuse of reclaimed water is an accepted practice in several EU countries experiencing water scarcity issues (e.g. Cyprus, Greece, Italy, Malta, Portugal, Spain), where it has become a component of long-term water resources management, overall a small proportion of reclaimed water is currently reused in the EU, even in those countries. Hence, there is significant potential for increased uptake of water reuse solutions in countries with several regions of water scarcity (Hochstrat et al., 2005).

One of the main barriers identified is the lack of harmonization in the regulatory framework to manage health and environmental risks related to water reuse at the EU level, and thus a lack of confidence in the health and environmental safety of water reuse practices.

The health and environmental safety conditions under which wastewater may be reused are not specifically regulated at the EU level. There are no guidelines or regulations at European Union (EU) level on water quality for water reuse purposes. In the Water Framework Directive

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(WFD) (2000/60/EC), reuse of water is mentioned as one of the possible measures to achieve the Directive’s quality goals: Part B of Annex VI refers to reuse as one of the “supplementary measures which Member States within each river basin district may choose to adopt as part of the programme of measures required under Article 11(4). Besides that, Article 12 (4) of the Urban Wastewater Treatment Directive (91/271/EEC) concerning the reuse of treated wastewater states that “treated wastewater shall be reused whenever appropriate”.

Despite the lack of common water reuse criteria at the EU level, several Member States (MS) have issued their own legislative frameworks, regulations, or guidelines for different water reuse applications. However, after an evaluation carried out by the EC on the water reuse standards of several MS it was concluded that they differ in their approach (JRC, 2014). There are important divergences among the different standards regarding the permitted uses, the parameters to be monitored, and the limiting values allowed. This lack of harmonization among water reuse standards within the EU put environmental and health safety at risk and might create some trade barriers for agricultural goods irrigated with reclaimed water. Once on the common market, the level of safety in the producing MS may not be considered as sufficient by the importing countries.

The relevance of EU action on water reuse was identified in the Impact Assessment of the “Blueprint to Safeguard Europe's Water Resources” published in November 2012. The Blueprint made clear that one alternative supply option- water reuse for irrigation or industrial purposes- has emerged as an issue requiring EU attention (COM(2012)673). Reuse of water (e.g. from wastewater treatment or industrial installations) is considered to have a lower environmental impact than other alternative water supplies (e.g. water transfers or desalination), but it is only used to a limited extent in the EU. This appears to be due to the lack of common EU environmental/health standards for water reuse and the potential obstacles to the free movement of agricultural products irrigated with reclaimed water (COM(2012)673).

After the 2015 Communication “Closing the loop - An EU action plan for the Circular Economy” the Commission published in April 2016 an Inception Impact Assessment on “Minimum quality requirements for reused water in the EU (new EU legislation)” stating that the initiative of a regulation on minimum quality requirements for reused water in agricultural irrigation and aquifer recharge will encourage efficient resource use and reduce pressures on the water environment, provide clarity, coherence and predictability to market operators, and complement the existing EU water policy, notably the Water Framework Directive and the Urban Wastewater Treatment Directive.

In the framework of the Common Implementation Strategy (CIS) for the implementation of the Water Framework Directive the EC (DG ENV) asked the JRC to develop the minimum quality requirements for water reuse in agricultural irrigation and aquifer recharge.

Considering the sensitivity of the health issue and public confidence in water reuse practice, the opinion of the independent Scientific Committee on Health, Environmental and Emerging Risks (SCHEER)1 has been requested and taken into consideration for the final document.

1.2 Scope of the documentThe scope of this document is to propose minimum quality requirements for water reuse for two specific water reuse applications: agricultural irrigation and aquifer recharge. These requirements should ensure adequate health and environmental protection, feasibility, and increase public confidence, in order to enhance water reuse practices at EU level.

This report is a technical document that includes specifications of the categories of use according to the type of crop that can be irrigated and the type of groundwater recharge; the water quality parameters to be monitored and the quality limits; the preventive measures for

1 The SCHEER Committee provides opinions on health and environmental risks related to pollutants in the environmental media and other biological and physical factors or changing physical conditions which may have a negative impact on health and the environment (e.g. in relation to air quality, waters, waste and soils). It also provides opinions on life cycle environmental assessment. It shall also address health and safety issues related to the toxicity and eco-toxicity of biocides.

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minimizing health and environmental risks as well as the monitoring requirements. This document is expected to support the proposal of EU legislation on water reuse.

In addition to human health protection, protection of environmental matrices (e.g. soil, biota, surface water, groundwater) is within the priorities of the concept of this technical document and is thoroughly considered, taking into account existing relevant EU legislation.

The minimum quality requirements have been derived from worldwide reference guidelines and regulations that have become a global reference for reuse guidance on water reuse, MS water reuse legislation and guidelines in place, scientific literature, and the existing EU regulatory framework on water, health and environmental protection, along with relevant experts’ consultation. It is obvious that the practice of water reuse, and specifically the development of minimum quality requirements for agricultural irrigation and aquifer recharge with reclaimed water in MS, has to be in compliance with the related EU legislation.

1.3 Reference documents For the purposes of developing the present work, the main documents consulted were the following, among others that were considered relevant for the matter and are cited along the text:

European Directives:

91/271/EEC-Urban Wastewater Treatment Directive (UWWTD) 91/676/EEC-Nitrates Directive 98/83/EC-Drinking Water Directive (DWD) 2000/60/EC-Water Framework Directive (WFD) 2006/118/EC-Groundwater Directive (GWD) 2008/105/EC as amended by 2013/39/EU-Environmental Quality Standards Directive

(EQSD)

Legislation and guidelines on water reuse from MS:

CyprusLaw 106 (l) 2002 Water and Soil pollution control and associated regulations KDP 269/2005 (KDP, 2005).

FranceJORF num.0153, Order of 2014, related to the use of water from treated urban wastewater for irrigation of crops and green areas (JORF, 2014).

GreeceCMD No 145116 2011 Measures, limits and procedures for reuse of treated wastewater (CMD, 2011).

ItalyDM 185/2003 Technical measures for reuse of wastewater (DM, 2003).

PortugalNP 4434 2005 Reuse of reclaimed urban water for irrigation (NP, 2005). (Guideline, not legislation).

SpainRD 1620/2007 Legal framework for the reuse of treated wastewater (RD, 2007).

The standards of Cyprus, France, Greece, Italy and Spain are included as regulations in the national legislation. In Portugal, the standards on water reuse are guidelines, but they are taken into consideration by the national government when issuing any water reuse permits in the country.

Worldwide reference guidelines and regulations:

International Organization for Standardization Guidelines for Treated Wastewater Use for Irrigation Projects (ISO, 2015): these guidelines provide guidance for healthy,

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environmentally and hydrologically good operation, monitoring, and maintenance of water reuse projects for unrestricted and restricted irrigation of agricultural crops, gardens, and landscape areas using treated wastewater. The guidelines are divided into three parts: The basis of a reuse project for irrigation, that considers climate, soils, design, materials, construction, and performance (Part 1); Development of the project (Part 2) that includes water quality requirements like microbiological and chemical parameters, potential barriers and potential corresponding water treatments; and Components of a reuse project for irrigation (Part 3) that includes recommendations for irrigation systems, and distribution and storage facilities. A fourth part will be published regarding monitoring considerations.

World Health Organization Guidelines for the Safe Use of Wastewater, Excreta and Greywater (WHO, 2006): the guidelines are divided into four volumes, devoted to different topics: Volume I, Policy and regulatory aspects; Volume II, Wastewater use in agriculture; Volume III, Wastewater and excreta use in aquaculture; and Volume IV, Excreta and greywater use in agriculture. This WHO guidelines deal with water reuse for agriculture, while other uses are not considered. The guidelines are designed to protect human health of workers and consumers when crops are irrigated with reclaimed water. They also include protection of crops and soils, but they are more devoted to preserve the public health.

The WHO is currently developing potable water reuse guidelines (WHO, 2016) and the last unpublished draft of these guidelines has been consulted. The aim of the WHO potable reuse guidelines is to supplement the advice provided in the WHO Guidelines for Drinking-water Quality (WHO, 2011) with information on specific issues associated with potable reuse including the quality of the source water, types of treatment processes, additional monitoring requirements, potential use of environmental buffers and engineered storages and public acceptance.

Australian Government Australian Guidelines for Water Recycling: these guidelines provide a generic framework for management of reclaimed water quality and use that applies to all combinations of reclaimed water and end uses, including agricultural irrigation and aquifer recharge. It provides guidance on safe use of reclaimed water focusing on health and environmental risks. These guidelines are developed in two phases. Phase I document (NRMMC-EPHC-AHMC, 2006) provides the scientific basis to assist and manage health and environmental risks. The three Phase II documents cover the specialized requirements for augmentation of drinking water supplies (NRMMC-EPHC-NHMRC, 2008), storm water harvesting and reuse, and managed aquifer recharge (NRMMC-EPHC–NHMRC, 2009). These guidelines are not legally binding, which would require the states and territories to adopt them in state-specific regulations.

United States Environmental Protection Agency (USEPA, 2012) Guidelines for Water Reuse: these guidelines include an updated discussion on water reuse. Their primary purpose is to facilitate further development of water reuse by serving as an authoritative reference on water reuse practices, including establishing a comprehensive set of water quality targets for a wide range of reuse applications, (e.g. agricultural irrigation and aquifer recharge), as well as guidance on treatment options, risk management, and public engagement measures. These guidelines are not legally binding, as actual regulation of water resources occurs primarily at state level. A general description of the existing water reuse regulations at state level is also included in the USEPA guidelines.

California State Water Resources Control Board – Division of Drinking Water Regulations related to recycled water (CDPH, 2014): the State of California regulatory approach on water reuse is based on treatment technology with specific performance requirements. Statutes and regulations related to water reuse in California are included in the California Health and Safety Code, the California Water Code, and the California Code of Regulations. In the last update of the regulations on water reuse, the Division of Drinking Water (DDW) (formerly known as CDPH) included a regulation on aquifer recharge with reclaimed water (CDPH, 2014).

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1.3.1 Source of wastewaterThe source of wastewater considered in this document is only the wastewater covered by the Urban Wastewater Treatment Directive (91/271/EEC). Thus, the wastewater considered is

Urban wastewater Industrial wastewater from the industrial sectors listed in Annex III of the UWWTD.

This document does not deal with reclaimed water from other industrial sources: industrial wastewaters may have very particular characteristics in relation to quality and they may require specific quality criteria.

2 Framework for reclaimed water managementThe World Health Organization in order to tackle the health and environmental risks caused by microbiological and chemical contaminants potentially present in water, recommends to implement the principles of a risk management system (WHO, 2001). The WHO suggests that a risk management approach should be applied to drinking water, reclaimed water, and recreational water. A risk management approach provides the conceptual framework for the WHO Guidelines for Drinking Water Quality (WHO, 2004 and 2011), the Guidelines for the Safe use of Wastewater, Excreta and Greywater (WHO, 2006), in which water reuse for agriculture irrigation is described. In addition, the unpublished draft of the WHO potable water reuse guidelines (WHO, 2016) also adopts the same risk management framework as the other WHO guidelines.

Concurring with the development of the WHO guidelines and following the risk management approach, the Australian government developed the Australian Guidelines for Water Recycling (NRMMC-EPHC-AHMC, 2006) and the Australian Drinking Water Guidelines (NHMRC-NRMMC, 2011). It is to note that the Australian Guidelines for Water Recycling are currently under a review that will draw on the advances and implementation of water recycling schemes.

The comprehensive risk management approach in the WHO Guidelines for Drinking Water Quality is termed “Water Safety Plan (WSP)” (WHO, 2009). The elements of a WSP build on many of the principles and concepts from other systematic risk management approaches, in particular the multiple-barrier approach and the hazard analysis and critical control points (HACCP) system (WHO, 2011). The HACCP system was developed in the US in 1959 for food safety in the aerospace industry and has been widely adopted by the food and beverage industries worldwide. The application of the HACCP has received increasing recognition due to the many parallel issues in food and drinking water supply.

A risk management framework involves, as a first step, the development of a risk assessment, from which to identify those hazards, and characterize the risks that could affect human or environmental health for the proposed end use. The next step is to establish controls or preventive measures (barriers), according to the multiple barrier approach, that will reduce, prevent or eliminate the identified hazards, and to implement critical control points and monitoring programs to ensure that the preventive measures operate effectively. The final step is to verify that the management system consistently provides reclaimed water of a quality that is fit for the intended use (i.e. “fit-for-purpose”) (NRMMC–EPHC–AHMC, 2006; WHO, 2006).

The WHO and Australian guidelines approach implies the implementation of a risk management plan including a risk assessment for water reuse schemes. For this purpose, the WHO has launched a Sanitation Safety Planning (SSP) manual as guidance on implementation of the WHO guidelines for water reuse (WHO, 2015). A SSP is a step-by-step health risk based approach for managing, monitoring and improving sanitation systems. The SSP is in line with the concept of the WSPs manual issued for drinking water supply systems (WHO, 2009).

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The USEPA guidelines for water reuse are using the same approach described in the WHO and the Australian guidelines for controlling health and environmental risks (USEPA, 2012). They are based mainly on stringent design and control of water reclamation facilities and water quality monitoring Water quality targets have been validated by quantitative risk assessments and environmental and agronomic impact assessments within comprehensive research programs

The International Organization for Standardization (ISO) recently published the Guidelines for treated wastewater use for irrigation projects, including agricultural irrigation (ISO, 2015). These guidelines consider the risk management approach to assure health and environmental safety of water reuse projects in irrigation, thus taking into account the WHO, the Australian and the USEPA recommendations.

The State of California has been a pioneer in issuing water reuse regulations and the water quality requirements that California establishes have become a global benchmark, and they have provided a basis for the development of water reuse regulations worldwide. The last update of the water reuse regulations (CDPH, 2014) include also indirect potable reuse considering aquifer replenishment by surface and subsurface application. The regulatory approach is based on stringent treatment technology targets with specific performance requirements for several uses, including also agricultural irrigation.

In the context of the framework described above, this document establishes minimum quality requirements for the safe use of reclaimed water for agricultural irrigation and aquifer recharge taking into consideration elements of a risk management approach, including the multiple-barrier approach, and type of health-based targets described. The monitoring principles included in a risk management framework are the base for the monitoring established in this document for agricultural irrigation and aquifer recharge. The existing MS regulations on water reuse are also reflected in the minimum quality requirements. The EU legislation, especially for environmental protection, overarches the minimum quality requirements defined. The environmental risks that may arise while using reclaimed water are considered taking into account the environmental risk assessments recommended in several guidelines (i.e. WHO and Australian guidelines) and required by the relevant EU legislation (e.g. WFD, GWD).

2.1 Risk assessmentEffective risk management requires the performance of a risk assessment, which can be defined as a qualitative or quantitative characterization and estimation of potential adverse effects on human health and environmental matrices associated with the intended use of reclaimed water (Asano et al., 2007).

Different approaches to risk assessment are proposed in water reuse guidelines with varying degrees of complexity and data requirements. The risk assessment process can involve a quantitative or semi-quantitative approach, comprising estimation of likelihood/frequency and severity/consequence, or a simplified qualitative approach based on expert judgment (NRMMC–EPHC–AHMC, 2006; WHO, 2009 and 2015).

The quantitative risk assessment methodology (e.g. Quantitative Microbial Risk Assessment-QMRA) is a tool applied in recent years to assess the risks associated with water reuse practices, mainly for agricultural irrigation and also aquifer recharge (van Ginneken and Oron, 2000; Petterson and Ashbolt, 2001; Westrell et al., 2004; Hamilton et al., 2006; Mara et al., 2007; Bastos et al., 2008; Page et al., 2010; Toze et al., 2010; Ayuso-Gabella et al., 2011; Navarro and Jiménez, 2011). QMRA can be used as a tool to measure the impact of interventions and identify the best policies and practices to protect public health and safety (Haas et al., 2014).

Comprehensive application of health quantitative risk assessment procedures always includes the following steps (WHO, 2006):

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Hazard identification: identification of hazards that might be present and the associated effects on human health; this step also includes consideration of variability in hazard concentrations.

Dose-response: establishment of the relationship between the dose of the hazard and the incidence or likelihood of illness.

Exposure assessment: determination of the size and nature of the population exposed to the hazard, and the route, amount and duration of exposure.

Risk characterisation: integration of data on hazard presence, dose-response and exposure, obtained in the first three steps.

In this context:

A hazard is a biological, chemical, physical or radiological agent that has the potential to cause harm.

A hazardous event is an incident or situation that can lead to the presence of a hazard. Risk is the likelihood of identified hazards causing harm in a specified timeframe,

including the severity of the consequences.

Distinction between hazard and risk is important: attention and resources need to be directed to actions selected primarily on the basis of level of risk, rather than just the existence of a hazard. Realistic expectations of hazard identification and risk assessment are important. Rarely will enough knowledge be available to complete a detailed quantitative risk assessment. Given these inherent uncertainties, the risk manager should have a realistic understanding of the limitations, and this should also be conveyed to the public, in order to enhance public involvement and acceptance of water reuse schemes (WHO, 2006).

Wastewater can contain a large variety of waterborne pathogens and chemical hazards that may pose a risk to human and environmental health.

As analytical techniques have improved, a number of chemical compounds that are not commonly regulated have been detected in drinking water, wastewater, or the aquatic environment, generally at very low levels. This broad group of chemicals is termed Compounds of Emerging Concern (CECs) (or emerging pollutants), and includes compounds from most use categories but especially micropollutants (see above). They are sometimes grouped by their environmental and human-health effects (e.g., hormonally active agents or endocrine disrupting compounds [EDCs]), or by the type of compound (e.g. antibiotics), and may include transformation products resulting from various biotic and abiotic processes.

Residual antibiotics and metabolites are released into the environment through treated wastewater effluents. This may lead to proliferation of antibiotic resistance in pathogenic or nonpathogenic environmental microorganisms. However, the proliferation of antibiotic resistance is not limited to the environment and may actually occur during therapeutic use, during which intestinal flora are exposed to high concentrations of antibiotics, or during wastewater treatment, particularly secondary biological processes (USEPA, 2012). To reduce the potential for AR proliferation, future research should target identification of the major source(s) of antibiotic resistance (i.e., raw sewage, biosolids, or treated effluent), determine treatment conditions that promote AR development, and characterize the persistence of antibiotic resistance in the environment. Ultimately, this knowledge will assist in developing mitigation strategies and alleviating environmental and public health concerns (USEPA, 2012).

Frequent monitoring for every potential chemical substance is neither feasible nor plausible. Research is focusing on the development of a science-based framework to guide the identification of CECs that should be monitored or otherwise regulated, including the context of reclaimed water use, especially for potable use (Drewes et al., 2013). A sound selection framework is needed that can provide a short list of meaningful indicator measurements that can address both human health relevance and assurance of proper performance of water treatment processes in addition to routine monitoring for compliance with guidelines and/or regulations.

The EU Technical Report on aquatic effect-based monitoring tools (EC, 2014b) presents, in the context of the WFD, a range of effect-based tools (e.g. biomarkers, bioassays) that could be

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used in the context of different monitoring programmes, and that might be able to take account of the presence of several known and unknown compounds with similar effects.

Effect-based tools could be used as a screening and prioritisation tool for subsequent chemical analysis (EPHC-NHMRC-NRMMC, 2008). Nevertheless, there is still significant uncertainty regarding the role of effect-based tools in a regulatory context and developments in bioanalytical science should be examined to identify validated bioassay candidates (WHO, 2016).

Considering health risks, risk assessment is one of the tools that permits health-based targets to be set in order to reduce to a tolerable or acceptable level the potential health risks associated with water reuse practices. Health-based targets are measurable health, water quality, performance, or specified technology objectives that are established based on a judgement of safety and on risk assessments of waterborne hazards. To ensure effective health protection, targets need to be based on scientific data, measurable, realistic, and relevant to local conditions (including economic, environmental, social and cultural conditions). Health-based targets can be translated into different forms (WHO, 2006; WHO, 2011):

Health outcome target: determined by epidemiological studies, public health surveillance or QMRA (i.e. defined tolerable burden of disease for microbiological hazards and “no adverse effect or negligible risk” for chemical hazards). It is used to derive the other remaining targets, water quality, performance and specified technology targets.

Water quality target: guideline values (concentrations) for microbiological or chemical hazards. Targets based on QMRA, individual chemical risk assessment and health outcome target.

Performance target: specified removal of microbiological (expressed as log10 removal/reduction or percentage removal) or chemical (expressed as percentage removal) hazards based on source water quality. Targets based on QMRA, chemical risk assessment and health outcome target.

Specified technology target: defined combination of treatment processes or technologies to control microbiological and chemical hazards, either in general or with reference to specific circumstances of use. Targets based on assessment of source water quality, frequently underpinned by established or validated performance of specific technology.

Health outcome targets are based on a defined tolerable burden of disease or level of risk that is considered acceptable. Disability Adjusted Life Years (DALYs) are a measure of burden of disease that is used mainly for microbiological hazards. For chemical hazards, the health outcome target is based on no-observed-adverse-effect levels derived from international chemical risk assessments. Although the application of DALYs to chemical parameters is likely to expand, however, unlike pathogens, there are insufficient data to develop DALYs for most chemical hazards, thus expressing health-based targets for chemical hazards using the DALYs approach has been limited in practice (WHO, 2011).

The WHO Guidelines for Drinking Water Quality (WHO, 2004 and 2011) and the Australian Drinking Water Quality Guidelines (NHMRC-NRMMC, 2004 and 2011) establish the tolerable burden of disease (caused by either a chemical or an infectious agent) as an upper limit of 10–6

DALYs per person per year. This upper limit DALY is approximately equivalent to a 10−5 excess lifetime risk of cancer (i.e. 1 excess case of cancer per 100 000 people ingesting drinking-water at the water quality target daily over a 70-year period), which is the risk level used in the WHO Guidelines to determine guideline values for genotoxic carcinogens.

In the context of reclaimed water use, the WHO Guidelines for the Safe Use of Wastewater, Excreta and Greywater (WHO, 2006) and the Australian Guidelines for Water Recycling (NRMMC–EPHC–AHMC, 2006) also recommend a tolerable level of risk of 10–6 DALYs. The USEPA guidelines (USEPA, 2004 and 2012) for water reuse assumed a tolerable risk of infection (instead of disease burden) of 10-4 per person per year, which may be considered equivalent to

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10–6 DALYs per person per year. It is worth noting that the unpublished draft of the WHO potable water reuse guidelines also adopts a tolerable level of risk of 10–6 DALYs (WHO, 2016).

The most frequent form of health-based targets for microbiological hazards are performance targets, and specified technology targets. Water quality targets are typically not developed for pathogens, because monitoring reclaimed water for them is not considered a feasible or cost-effective option, due to the low content of pathogens and high cost and time-consuming analytical techniques. Specified technology targets are recommended in water reuse guidelines (NRMMC–EPHC–AHMC, 2006; WHO, 2006; USEPA, 2012; ISO, 2015).

The most common application of performance targets is in identifying appropriate combinations of treatment processes to reduce pathogen concentrations in source water to a level that will meet health outcome targets. The derivation of performance targets requires the integration of factors such as tolerable disease burden (acceptable risk), and QMRA. It is impractical, and there are insufficient data, to set performance targets for all waterborne pathogens potentially present in wastewater, particularly since this would require information on concentrations, dose-response relationships, and disease burdens that is often not available. A more practical approach is to identify reference pathogens that represent groups of pathogens taking into account variations in characteristics, behaviours and susceptibilities of each group to different treatment processes. Typically, different reference pathogens will be identified to represent bacteria, viruses, protozoa and helminths (NRMMC-EPHC-AMHC, 2006; WHO, 2006; USEPA, 2012). The WHO (2011) establishes selection criteria for reference pathogens. These criteria may lead to different reference pathogens for different countries and regions because it should take into account local conditions (e.g. incidence of the pathogen, and prevalence of waterborne disease). However, the range of potential reference pathogens is limited by data availability. The WHO and the Australian guidelines for water reuse recommend the establishment of performance targets (log10 removals) for reference pathogens depending on their assumed or measured concentrations in source water (raw wastewater) to ensure a tolerable health risk of 10–6 DALYs per person per year.

Water reuse guidelines include also water quality criteria for indicator microorganisms (i.e. E. coli) to be used as a verification and validation tool to determine whether or not the required performance target for reference pathogens is being achieved by the treatment system. The concept of using indicator microorganisms is a well-established practice in the assessment of drinking water and water reuse schemes. There is a specific criteria for selecting appropriate indicator microorganisms (e.g. not to be pathogens themselves) and they are used, in water reuse systems, as indicators of treatment/process effectiveness (WHO, 2006). It is important to indicate that measurements of indicator organisms do not represent a risk-based water quality target (WHO, 2011).

For chemical hazards, most frequently, health-based targets are water quality targets, taking the form of chemical guideline values. A chemical guideline value is the concentration of a water quality chemical component that, over a lifetime of consumption, will not lead to more than 10–6 DALYs per person per year.

Another form of health-based targets are the specified technology targets which represent recommended combinations of treatment processes that can achieve safety based on assessments of source water quality. These technology targets are embedded in some water reuse regulations and guidelines.

In terms of environmental health, the different uses of reclaimed water lead to different pathways by which reclaimed water enters the environment. In assessing environmental risk, a number of endpoints must be considered (i.e. soil, surface water, groundwater, biota). The development of an environmental risk assessment is similar to the health risk assessment but taking into account the environmental endpoints that may be affected adversely by reclaimed water pollutants.

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The Australian guidelines include a method for assessing environmental risks associated with the use of reclaimed water, based on a qualitative or semi-quantitative risk assessment. In place of DALYS and the other health-based targets, environmental guideline values are used; these are guideline values that relate to the impacts on specific endpoints or receptors within the environment (NRMMC–EPHC–AHMC, 2006).

2.2 Preventive measures and multiple barrier approachSafe use of reclaimed water requires preventive measures to reduce exposure to hazards by:

preventing hazards from entering reclaimed water removing them using treatment processes reducing exposure, either by using preventive measures at the site of use or by

restricting uses

Preventive measures (or barriers) are any action and activity that can be used to prevent or eliminate a health and environmental hazard, or reduce it to an acceptable level. They are used to protect the public as well as to reduce occupational exposures associated with the use of reclaimed water.

According to the risk management framework, identification and implementation of preventive measures should be based on the multiple barrier approach. In this approach, multiple preventive measures or barriers are used to control the risks posed by different hazards, thus making the process more reliable.

The strength of this approach is that a failure of one barrier may be compensated by effective operation of the remaining barriers, thus minimizing the likelihood of contaminants passing through the entire system and being present in sufficient amounts to cause any harm to human health or environmental matrices. Many control measures may contribute to control more than one hazard, whereas some hazards may require more than one control measure (WHO, 2011).

The multiple barrier approach is universally recognized as the foundation for ensuring safe drinking water. No single barrier is effective against all conceivable sources of contamination, is effective all of the time or constantly functions at maximum efficiency. The multiple barrier approach, used in the management of drinking water quality, has been also adopted in the management of reclaimed water schemes and is principally endorsed by WHO, Australia, and USEPA guidelines. This approach allows achievement of the tolerable risk of 10-6 DALYs not only relying on the wastewater treatment but also considering the use of additional preventive measures as barriers for health and environmental protection.

Water treatment processes prevent or reduce the concentration of hazards in the reclaimed water effluent and are the most important barrier to eliminate or minimize health and environmental risks of water reuse practices. Each treatment technology has its own characteristics and it is usually necessary to use a combination of two or more technologies to achieve the required water quality levels. The selection of the treatment technology must take into account several premises such as the quality and the quantity of the water to be treated, the final quality required for the specific use, the economic cost, and the environmental impact.

On-site controls are additional preventive measures that can prevent or minimise public exposure to hazards and can also minimise the impact on receiving environments.

2.3 MonitoringMonitoring is an integral part and forms a central component of the risk management framework and regular monitoring is essential to ensure that the water reuse scheme functions effectively. The general principles of monitoring programs in relation to reclaimed water are outlined in all reference water reuse guidelines (NRMMC–EPHC–AHMC, 2006; WHO, 2006;

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USEPA, 2012). Water sanitation plans require a comprehensive monitoring and control system measuring appropriate water quality and operational parameters throughout a treatment train, and a comprehensive sampling of finished reclaimed water to determine overall performance and compliance with regulatory requirements.

Monitoring of reclaimed water schemes has to be consistent with the operation of conventional wastewater and drinking water treatment systems. A high standard of reliability is required at wastewater reclamation plants. The need for reclamation facilities to reliably and consistently produce and distribute reclaimed water of adequate quality and quantity is essential and dictates that careful attention to be given to reliability features during the design, construction, and operation of the facilities (WHO, 2006).

According to risk management systems, monitoring has three different purposes: validation, or proving that the system is capable of meeting its design requirements; operational monitoring, which provides information regarding the functioning of individual components of the preventive measures in place; and verification, which usually takes place at the end of the process to assure that the reclamation system is achieving its specific targets (WHO, 2006 and 2011). Microbiological and physico-chemical parameters are used for monitoring purposes to provide assurance that risks are properly managed. The principal types of monitoring according to a risk management approach are defined as follow:

Validation monitoring: it should be conducted when a reclamation system is established (commissioned) and put in operation, when equipment is upgraded or new equipment or processes are added. Once the setup of the whole reclamation system has been validated, it is generally sufficient with the operational and verification monitoring. Full validation is usually only performed once for each reclamation system configuration, thus, it should be thorough. One of the objectives of validation monitoring is to prove that the reclamation system delivers the expected water quality specified for the intended use. Therefore, validation monitoring includes also operational and verification monitoring parameters, discussed below. Pathogens are often monitored as part of validation to demonstrate removal or inactivation of pathogenic bacteria, viruses, and protozoa. More commonly, indicator microorganisms are used. The microorganisms monitored are dependent of the sensitivity of the intended use (i.e. high-exposure or low-exposure uses).

Operational monitoring: it is the monitoring of control parameters to assess and confirm that the performance of preventive measures, including treatment process, ensures reclaimed water of an appropriate quality to be consistently provided (NRMMC–EPHC–AHMC, 2006; WHO, 2011). This monitoring provides a high level of assurance that reclaimed water will meet all regulatory standards and provide a degree of redundancy in the multiple barrier approach. Furthermore, appropriate operational monitoring is key for ensuring safety of reclamation systems. Operational parameters should be selected that reflect the effectiveness of each process or activity, and provide an immediate indication of performance. Typically, operational monitoring should focus on parameters that can be readily measured and enable a rapid response. The most widely used operational parameter of microbial quality management are disinfectant residuals and other related disinfection-related parameters, filtration performance as measured by turbidity or particle counts. Other operational parameters specific to process performances include ultraviolet light transmission and parameters for membrane performance tests.

Verification monitoring: it is the use of methods, procedures or tests, in addition to those used in operational monitoring, to assess the overall performance of the treatment system, the compliance with guideline values and regulatory requirements of the ultimate quality of the final effluent of reclaimed water being supplied, and the quality of the receiving environment. For microbial water quality, verification monitoring is likely to be based on the analysis of indicator microorganisms (e.g. E. coli) according to the water quality criteria established for the intended use. As for validation, the group of microorganisms monitored are likely to vary, according to the sensitivity of the intended use.

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E. coli is the default indicator microorganisms for monitoring purposes, but water reuse guidelines state that it may be desirable to include more resistant microorganisms, such as bacteriophages and/or bacterial spores, as additional indicators of persistent microbial hazards (NRMMC–EPHC–AHMC, 2006; WHO, 2006).

3 Categories of useThe reclaimed water uses considered in this document are agricultural irrigation and aquifer recharge. For these uses, specific categories of use are established.

3.1 Categories of use for agricultural irrigationThe categories of use defined for the application of agricultural irrigation are the following:

Food crops consumed raw : crops which are intended for human consumption to be eaten raw or unprocessed.

Processed and other food crops : crops which are intended for human consumption not to be eaten raw but after a treatment process (i.e. pilled, cooked, industrially processed), as well as orchards and vineyards.

Non-food crops : crops which are not intended for human consumption (e.g. pastures, forage, fiber, ornamental, seed, forest, energy and turf crops).

These definitions are based on the ISO guidelines (ISO, 2015) and are also in line with the categories considered in other reference guidelines and some MS legislations (NRMMC-EPHC-AMHC, 2006; WHO, 2006; USEPA, 2012; JRC, 2014). Definitions included in EC food safety regulations 178/2002 and 852/2004 also apply to these categories of use.

3.2 Categories of use for aquifer rechargeThe categories of use defined for aquifer recharge are the following:

Aquifer recharge by surface spreading for non-drinking water purposes at the present and medium future

Aquifer recharge by direct injection for non-drinking water purposes at the present and medium future

Aquifer recharge by surface spreading for drinking water purposes or intended for such future use (indirect potable reuse)

Aquifer recharge by direct injection for drinking water purposes or intended for such future use (indirect potable reuse)

The categories of use for aquifer recharge make a distinction between aquifers that are used for the abstraction of drinking water at the present or intended for such future uses and aquifers that are not used for such uses at the present, and will unlikely be used for those uses in the medium future, including those aquifers that presumably will never be able to be used for drinking water abstraction due to its level of contamination.

Most of MS national regulations for water reuse do not include (or specifically prohibit) recharge of aquifers used for the abstraction of drinking water or intended for such future uses and only few MS include aquifer recharge for non-drinking water uses in their national regulations (i.e. Cyprus, Greece, Spain). However, the USEPA and the Australian guidelines, and California regulations include indirect potable reuse as a regular practice. In order to be aligned with the latest developments in aquifer recharge with reclaimed water, this document includes indirect potable reuse as a potential use.

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The methods for aquifer recharge considered are surface spreading and direct injection. These are the most commonly types of aquifer recharge employed with reclaimed water (NRMMC-EPHC–NHMRC, 2009; USEPA, 2012; CDPH, 2014). MS regulations on water reuse for aquifer recharge make the distinction between surface spreading and direct injection, in line with water reuse guidelines (JRC, 2014).

Surface spreading is a method of recharge whereby the water moves from the land surface to the aquifer by infiltration and percolation through the vadose zone (Regnery et al., 2013).

Direct injection recharge is achieved when water is pumped directly into the groundwater zone (i.e. saturated zone), usually into a well-confined aquifer (USEPA, 2012).

Aquifer recharge by surface spreading may provide added benefits to reclaimed water quality that direct injection is unable to, due to the natural attenuation capacity of the vadose zone. Surface spreading makes reclaimed water to pass through the vadose zone (i.e. unsaturated zone), hence allowing mechanisms as filtration, adsorption, precipitation, volatilisation, biodegradation, and microbial assimilation to take place (NRMMC-EPHC–NHMRC, 2009). Processes in the vadose zone that result in attenuation or degradation of substances are to be taken into account when establishing water quality criteria.

4 Health and environmental risks of agricultural irrigation with reclaimed water

The risks associated with the use of reclaimed water for agricultural irrigation have to consider pathogens and chemical compounds that may harm human health and the environment. For agricultural irrigation, health risks are established considering the routes of exposure that are recommended to be evaluated by WHO and Australian Guidelines (NRMMC–EPHC–AHMC, 2006; WHO, 2006).

It has to be considered that some pathogens may survive for long periods of time on crop surfaces and soils with the potential to be transmitted to humans or animals (WHO, 2006). However, natural die-off due to adverse environmental conditions also occurs.

The main route of exposure to microbial or chemical hazards from reclaimed water is ingestion, including ingestion of contaminated crops, or ingestion of droplets or aerosols by agricultural workers, or inhabitants of nearby communities. Some microorganisms found in reclaimed water have the potential to cause respiratory illness (e.g. certain types of adenoviruses and enteroviruses, Legionella) and, for these organisms, inhalation of fine aerosols may be a source of infection. Dermal exposure to microorganisms is also possible, but there is a lack of evidence of health impacts through this route and it is considered unlikely to cause significant levels of infection or illness in the normal population (NRMMC–EPHC–AHMC, 2006). Accidental ingestion of soil particles by agricultural workers or children is a route of exposure that has been considered under the tolerable risk applying water reuse guidelines limit values (WHO, 2006; Mara et al., 2007).

The irrigation of pastures and fodder crops with reclaimed water may potentially pose a risk to the health of both livestock and humans through the consumption of animal products. These risks have been considered in water reuse guidelines and water quality targets and specific preventive measures are set (NRMMC–EPHC–AHMC, 2006; USEPA, 2012). In addition, when these health risks were evaluated in a recent study, none of the animals showed signs of infection or of disease (Bevilacqua et al., 2014). There was no evidence to suggest any resulting health risk to humans from the consumption of milk from animals fed with reclaimed-water-irrigated forage crops.

Agricultural irrigation with reclaimed water may pose risks to soils, plants, other aquatic and terrestrial biota, surface and groundwaters. The following risks are considered in this document

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according to the risk assessment approaches recommended in several guidelines (FAO, 1985; NRMMC–EPHC–AHMC, 2006; WHO, 2006).

Salinity: the presence of soluble salts in reclaimed water may lead to accumulation of salts in soils (especially in dry climates), the release of cadmium from soils due to increased chlorine content, reduced rates of plant growth and productivity, and water stress due to plants' susceptibility to osmotic effects, and changes in native vegetation, groundwater salination affecting dependent ecosystems, and increased salinity in surface water aquatic systems.

Sodicity: the presence of a high proportion of sodium (Na+) ions relative to calcium (Ca2+) and magnesium (Mg2+) ions in soil or water could degrade soil structure by breaking down clay aggregates, which makes the soil more erodible, causing surface sealing and preventing the movement of water (permeability) and air (anoxia) through the soil, and reducing plant growth.

Toxicity: the effect of specific toxicity of certain ions to plants (e.g. chloride, boron, sodium, and some trace elements) may lead to reduced crop yields. Some ions may prejudice the microbial activity of the soil, and aquatic biota.

Nutrients imbalance: unbalanced supply of nutrients may result in crop deficiencies and toxicities. Macronutrients like nitrogen, phosphorus and potassium in reclaimed water may be higher than the needs of the crop, or not supplied at an optimal rate for the crop. Excess of nutrients may lead to groundwater deterioration, and surface waters eutrophication.

Micropollutants: micropollutants present in reclaimed water can pass through the soil, can accumulate there or/and reach groundwater or surface water bodies.

It worth mentioning that biofouling and scaling of the distribution system and irrigation equipment may occur due to inappropriate characteristics of the reclaimed water (e.g. high suspended matter concentrations) and that this risk has to be taken into account.

5 Health and environmental risks of aquifer recharge with reclaimed water

The practice of aquifer recharge using reclaimed water may have several purposes, and thus, it can be performed to:

establish saltwater intrusion barriers in coastal aquifers, provide further treatment for future reuse, augment aquifers for non-drinking and drinking water purposes, provide storage of reclaimed water for subsequent retrieval and reuse, maintain groundwater dependent terrestrial and aquatic ecosystems, dilute saline aquifers, control or prevent ground subsidence, or ensure water supply.

Pathogen survival in groundwater is highly variable and is affected by physical, chemical and biological processes. However, pathogens can also vary in their environmental stability (e.g. between different locations), depending on local groundwater conditions. In general, enteric viruses and protozoa have been found to be the most resistant of the pathogens (Toze 2004).

Aquifer recharge, including aquifer recharge with reclaimed water, may affect groundwater dependent ecosystems and may cause leaching to surface waters. Health and environmental risks can arise from reactions that may occur between the recharge water and the existing (in place) groundwater conditions (e.g. pH, redox state, minerals, organic matter, microbial activity), and between the recharge water and the aquifer material (e.g. heavy metals

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mobilization from aquifer material), thus leading to change water quality and aquifer permeability (NRMMC-EPHC–NHMRC, 2009).

Groundwater protection is the overarching concern when aquifer recharge is performed. In this regard, the Groundwater Directive 2006/118/EC (GWD) (amended by Directive 2014/80/EC) complements the WFD and its objective is to protect groundwater against pollution and deterioration through the establishment of specific measures to prevent and control groundwater pollution, as provided for in Article 17 of the WFD. These measures include in particular (Article 1) “criteria for the assessment of good groundwater chemical status; and criteria for the identification and reversal of significant and sustained upward trends and for the definition of starting points of trend reversals”. Good groundwater chemical status is the chemical status of a body of groundwater, which meets all the conditions set out in Section 2.3.2 of Annex V of the WFD.

Considering the risks from chemical substances, the GWD (Article 6) demands establishment of measures to prevent or limit inputs of pollutants into groundwater. These measures have to prevent inputs of any hazardous substances, in particular taking into account hazardous substances belonging to the families or groups of pollutants referred to in points 1 to 9 of Annex VIII of the WFD, where these are considered to be hazardous (including priority hazardous substances of the EQSD). The measures also have to limit inputs of pollutants from Annex VIII of the WFD which are not considered hazardous and any other non-hazardous substances not listed in Annex VIII considered to present an existing or potential risk of pollution, so as to ensure that such inputs do not cause deterioration or significant and sustained upward trend in the concentration of pollutants in groundwater.

6 Preventive measures Considering the health and environmental risks described in previous sections, appropriate preventive measures, according to the multiple barrier approach, are to be applied to reduce exposure and minimise the impact on receiving environments when using reclaimed water for agricultural irrigation and aquifer recharge (NRMMC-EPHC-AHMC, 2006; WHO, 2006; USEPA, 2012; ISO, 2015):

Common preventive measures in reclaimed water schemes are the following:

Wastewater source control: it is necessary to establish source control programs and oversight of industrial and commercial discharges to the sewer systems connected to a wastewater treatment plant.

Wastewater treatment: wastewater is usually treated by a combination of at least primary and secondary treatment, and more stringent treatment in sensitive areas. Further treatment such as filtration and disinfection is generally added to meet reclaimed water quality criteria. There is an ever-increasing range of treatment options. Selection and control of appropriate treatment technologies is essential to consistently deliver reclaimed water with the required quality.

Education and training: education and training of workers and managers involved in agricultural irrigation and aquifer recharge are of principal importance as components of implementing and maintaining preventive measures. Personnel should be kept fully informed on the use of reclaimed water. Agricultural workers are especially vulnerable, and a range of human exposure measures (e.g. personal protective equipment, handwashing and personal hygiene) are also recommended.

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6.1 Preventive measures for agricultural irrigation

Specific preventive measures for agricultural irrigation are the following: Control of application methods: appropriate selection of the irrigation method (e.g.

spray, flood, drip or subsurface irrigation) must be made. The nature of food crops needs to be considered in selecting agricultural irrigation methods.

Surface irrigation involves less investment than other types of irrigation but exposes agricultural workers to the greatest health risk. Subsurface and drip irrigation can provide the highest degree of health protection, as well as using water more efficiently and often producing higher crop yields. However, a high degree of reliable treatment is required to prevent clogging of emitters. Risks associated with sprinkler irrigation are influenced by type of equipment and local weather conditions (e.g. higher risks in windy conditions). Irrigation systems should be installed and operated to minimise surface ponding and to control surface runoff.

Control of application rates: application rates need to be controlled so that irrigation provides maximum benefit, while minimising impacts on receiving environments (including soils, groundwater and surface water). Soil characteristics (e.g. texture, pH, organic matter content, hydraulic conductivity, water retention capacity), water requirements and nutrient balances need to be considered to minimize risks such as salinity and sodicity. As soil retention capacities differ, a proper assessment of soil characteristics (e.g. permeability, drainage, salinity, sodicity) is necessary to assess the possibility of nutrients, chemicals or pathogens accumulating or leaching to the groundwater or surface water bodies. The behaviour of substances in soils is strongly affected by soils conditions, rainfall and evaporation that may vary widely in response to climate. It is necessary to assess irrigation related parameters (e.g. evapotranspiration, precipitation) to be controlled according to climatic conditions. Proper use of fertilizers is to be evaluated.

Crop selection: selection of crops has to be made according to crop tolerance (e.g. salt and specific ion tolerance) and reclaimed water quality should be established to produce satisfactory yields.

Control of the distribution system: within the distribution system, that may include storage (open and closed reservoirs), reclaimed water for irrigation may suffer changes that affect its chemical and biological quality (e.g. microbial regrowth, nitrification, algae growth, natural decay of microorganisms). Thus, management strategies have to be undertaken in order to prevent deterioration of reclaimed water quality. Maintaining good water quality in the distribution system will depend on the design and operation of the system and on maintenance and survey procedures to prevent contamination. Control of short-circuiting and prevention of stagnation in both storage and distribution, including use of backflow prevention devices, maintaining positive pressure throughout the system and implementation of efficient maintenance procedures are strategies to maintain the quality of reclaimed water within the distribution system. Some of these management strategies are included in the ISO guidelines (ISO, 2015).

Water sources protection: hydrogeological vulnerability has to be assessed to determine the risk of infiltration and percolation of reclaimed water to surface water and groundwater. According to the WFD (Article 7) waters used for the abstraction of drinking water, or intended for such use, shall ensure the necessary protection with the aim of avoiding deterioration in their quality, establishing safeguard zones for those bodies of water, if necessary.

Control of access and buffer zones: buffer zones might be used as a mechanism to reduce human and environmental exposure. Buffer zones apply from the edge of wetted areas to the nearest point of public access, and to receiving environments of concern.

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6.2 Preventive measures for aquifer recharge

Specific preventive measures for aquifer recharge are the following: Aquifer characterisation: it is paramount to undergo a comprehensive preliminary

aquifer characterisation, including hydrogeological and hydraulic studies, to estimate the aquifer behaviour, and the potential to affect groundwater quality, groundwater dependent ecosystems or surface waters. Advanced modelling tools are advised to be used. The characterization should be performed in accordance with Article 5 of the WFD.

Guidance documents and technical reports have been produced by the CIS of the WFD to assist MS to implement the WFD, and some of them support aquifer characterisation as they provide guidance on, for instance, establishing groundwater monitoring programmes for status and trend assessment (EC, 2007a; EC, 2007b; EC, 2009). Guidance documents are intended to provide an overall methodological approach, but these need to be tailored to specific circumstances of each MS.

Furthermore, the Environmental Impact Assessment Directive (2014/52/EU) (amending Directive 2011/92/EU) requires that artificial aquifer recharge schemes where the annual volume of water recharged is equivalent to or exceeds 10 million m3 have to undergo an environmental impact assessment.

Due to the range of aquifer characteristics that come into play, it is difficult to use performance at one aquifer recharge site to predict performance at another. Therefore, a site-by-site approach will be necessary until the knowledge base has extended sufficiently to make predictions more reliable.

Attenuation capacity of the saturated zone: after aquifer recharge is performed, water can be recovered after a certain period of time, and can be reused. The saturated zone may be considered as another barrier by which the water quality can be improved, thus reducing the pollutants and pathogens presence. Residence time in the aquifer induce an attenuation of human pathogens and selected organic chemicals. Therefore, the system needs to provide required residence time; recovery rate is restricted to ensure adequate time between recharge and recovery. Removals in aquifers are primarily related to the residence time of the recharge water, the activity of the indigenous groundwater microorganisms, the redox state of the aquifer, and the temperature. However, there are considerable challenges in validating and continually demonstrating the attenuation of pathogens in aquifers. The scientific literature demonstrating the removal of pathogens in managed aquifer recharge is limited, only a few pathogens have been studied, and in many cases these are not the worst-case target pathogen (NRMMC-EPHC–NHMRC, 2009; USEPA, 2012). Furthermore, this data is aquifer-specific and not transferable. Therefore, an evaluation of residence time between recharge and recovery is deemed necessary on a case-by-case basis.

Control of groundwater quality: the installation of monitoring wells is essential to follow the evolution of groundwater levels and quality and also for warning of treatment effectiveness to allow recharge interruption.

7 Tolerable risk The tolerable health risk adopted in this document for water reuse in agricultural irrigation and aquifer recharge is the one recommended by WHO and Australian guidelines that establish a tolerable burden of disease of 10–6 DALYs per person per year equivalent to a tolerable health risk of 10−5 excess lifetime risk of cancer.

It should be noted that the Drinking Water Directive (98/83/EC) considers as tolerable health risk a 10−6 excess lifetime risk of cancer, thus applying a stricter approach than the WHO

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guidelines. Therefore, when DWD is considered for water quality criteria, the associated tolerable health risk will be more stringent.

8 Reclaimed water monitoring Microbiological and physico-chemical parameters are selected for monitoring purposes of reclaimed water schemes for agricultural irrigation and aquifer recharge.

8.1 Microbiological parametersMicrobiological parameters include the selection of reference pathogens and indicator microorganisms.

8.1.1 Reference pathogensReference pathogens are to be applied to establish performance targets as health-based targets and for validation monitoring of water reuse schemes in agricultural irrigation and aquifer recharge.

The selection of reference pathogens is important because controlling reference pathogens implies controlling all pathogen risks that are covered by the reference pathogens. Therefore, reference pathogens at EU level will be identified following the selection criteria established by WHO (2011). Information on waterborne disease from EU countries has been considered whenever possible.

Selection criteria for reference pathogens is described in water reuse guidelines and includes all of the following elements (WHO, 2011):

waterborne transmission established as a route of infection; sufficient data available to enable a QMRA to be performed; occurrence in source waters; persistence in the environment; sensitivity to removal or inactivation by treatment processes; infectivity, incidence and severity of disease.

This document considers urban wastewater as the main source water for reclaimed water, thus the focus is on pathogens of fecal origin. Considering reuse of wastewater in agricultural irrigation and aquifer recharge, the most important human health risks are associated with irrigation of food crops and use of recharged groundwater for drinking water.

Information has been gathered considering the scope of this document, and the scientific evidence, and reference pathogens have been selected accordingly. Only enteric pathogens for which waterborne transmission is conclusively established are taken into account. Reference pathogens are considered for each group of microorganisms (i.e. bacteria, viruses, protozoa and helminths).

There are a number of enteric bacteria that are candidates for reference pathogen, including Vibrio, Campylobacter, E. coli O157, Salmonella and Shigella, and they are evaluated against the criteria (Table 1). Compared with other bacterial pathogens, Campylobacter has a relatively low infective dose and is relatively common, and waterborne outbreaks have been recorded. Therefore, Campylobacter is selected as the reference pathogen for bacteria.

This selection is in agreement with the bacterial reference pathogens recommended by the WHO, and the Australian guidelines for water reuse and drinking-water (NRMMC–EPHC–AHMC, 2006; NHMRC-NRMMC, 2011, WHO, 2006 and 2011).

Table 1 Evaluation of enteric bacteria for selecting a reference pathogen at EU level.24

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Path

ogen

Suffi

cien

t in

form

atio

n

Occ

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nce

in E

U

dom

esti

c w

aste

wat

er

Pers

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nce

in

wat

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oil

Rem

oval

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trea

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t

Infe

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ity,

in

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nce,

bur

den

of d

isea

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Campylobacter

Enteropathogenic E. coli

Enterohemorrhagic E. coli (O157)

Salmonella

Salmonella typhi

Shigella

Vibrio cholerae

There is a range of enteric viruses for which waterborne transmission is established. Presence of sufficient information in the EU context is focused on information on occurrence of infectious viruses in wastewater. Many recent studies on virus occurrence use molecular detection methods that detect virus particles. Only a small fraction of these particles is infectious. Therefore, information on the occurrence of infectious viruses (using cell culture methods) in the EU context is mostly used in Table 2. On the basis of these data, cultivable enteroviruses are selected as reference pathogens for enteric viruses at EU level.

However, it is worth noting that, although enteroviruses are always mentioned as one of the suitable candidates, the reference pathogen for viruses used in the WHO and the Australian guidelines for water reuse and for drinking water (NHMRC-NRMMC, 2011; WHO 2006 and 2011) are rotaviruses. However, the use of rotavirus has been complicated by the development and use of a rotavirus vaccine that over time will change the incidence and severity of disease outcomes from this pathogen (Gibney et al., 2014). On this basis, norovirus has been selected instead of rotavirus as reference pathogen in the draft guidelines for potable reuse from the WHO (WHO, 2016) and the unpublished draft new revision of the Australian Guidelines for Water Recycling (NRMMC–EPHC–AHMC, 2016) as reference pathogen. A dose response model has been published for norovirus (Teunis et al., 2008) and a disease burden has been determined (Gibney et al., 2014). However, no culture-based method for norovirus is available.

Table 2 Evaluation of enteric viruses for selecting a reference pathogen at EU level.

Path

ogen

Suffi

cien

t in

form

atio

n

Occ

urre

nce

in E

U

dom

esti

c w

aste

wat

er

Pers

iste

nce

in

wat

er/s

oil

Rem

oval

by

trea

tmen

t

Infe

ctiv

ity,

in

cide

nce,

bur

den

of d

isea

se

Enteroviruses

Adenoviruses 1 ()2

Noroviruses 1

Astroviruses 1

Hepatitis A virus 1

Hepatitis E virus 1

Rotaviruses 1

Sapoviruses ?

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1 Mainly based on molecular methods2 Adenovirus is very resistant to UV

Enteric protozoa for which waterborne transmission is established and sufficient information is available in the EU are Cryptosporidium and Giardia intestinalis. Cyclospora cayetanensis and Entamoeba histolytica are other enteric protozoa for which waterborne transmission is established, but for these there is limited information about occurrence, fate and removal. In addition, the disease burden in the EU is higher for Cryptosporidium and Giardia. Other enteric protozoa for which waterborne transmission is inconclusive are Balatidium coli, Blastocystis hominis, Microsporidia, Isospora belli and Toxoplasma gondii. Cryptosporidium oocysts are smaller than Giardia cysts and hence more difficult to remove by physical processes; it is also more resistant to oxidizing disinfectants, and there is some evidence that it survives longer in water environments (WHO, 2011). It is very likely that these protozoa are sufficiently controlled when Cryptosporidium is used as the reference for targeting control measures in the irrigation of food crops and in aquifer recharge for potable use. Evaluating these protozoa against the criteria (Table 3), Cryptosporidium is selected as reference pathogen for enteric protozoa at EU level.

This selection is in agreement with the protozoa reference pathogen recommended by the WHO, and the Australian guidelines for water reuse and drinking-water (NRMMC–EPHC–AHMC, 2006; NHMRC-NRMMC, 2011; WHO, 2006 and 2011). Table 3 Evaluation of enteric protozoa for selecting a reference pathogen at EU level.

Path

ogen

Suffi

cien

t in

form

atio

n

Occ

urre

nce

in E

U

dom

esti

c w

aste

wat

er

Pers

iste

nce

in

wat

er/s

oil

Rem

oval

by

trea

tmen

t

Infe

ctiv

ity,

in

cide

nce,

bur

den

of d

isea

se

Cryptosporidium

Giardia intestinalis

Entamoeba histolytica

Cyclospora cayetanensis

No reference pathogen from the group of helminths is selected, since it is very likely that adequate control of the reference pathogens for the other pathogen groups will protect against health risks from helminths which are more readily removed by wastewater treatment processes and soil passage. For protection of human health, the protozoan reference pathogen can be used as a reference for helminths. Helminths are likely to be present in lower numbers than protozoa in sources of reclaimed water, and they will be removed more readily by physical treatment processes as they are much larger than protozoa (NRMMC–EPHC–AHMC, 2006). In addition, helminth infections are not endemic in EU countries, there is limited information on occurrence in wastewater and there is no human dose-response model.

Helminth reference pathogens are recommended by WHO guidelines, but this is due to the fact that these guidelines are mostly addressed to developing countries, where helminth infections may be endemic in some regions. Australian guidelines do not recommend any helminth reference pathogen (NRMMC–EPHC–AHMC, 2006).

Therefore, the reference pathogens selected to be applied at EU level are Campylobacter for bacteria, enterovirus for viruses and Cryptosporidium for protozoa. These reference pathogens are used for risk assessment evaluations to determine performance targets, and may be used by MS to develop specific risk assessments for water reuse projects. Reference pathogens are

26

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also included as an option for validation monitoring of treatment processes and overall treatment trains. In addition, MS may select a different reference pathogen if there are specific local conditions that may suggest that another reference pathogen would be more suitable to evaluate the risk posed by a reclaimed water use.

Considering additional pathogens, Legionella pneumophila is a non-conventional opportunistic waterborne pathogen, as it is not transmitted orally. Transmission is through mechanical means, which generate aerosols including sprinklers. Legionella pneumophila is on the (USEPA) Candidate Contaminant list (CCL) for drinking water purposes as an important pathogen. It is commonly encountered in freshwater environments and in wastewater and there is a potential of growth in distribution systems of reclaimed water in warm climates where suitable temperatures and conditions for their multiplication may be provided (Jjemba et al., 2015). No legionellosis outbreak has been linked to reclaimed water yet, but it is recommended as a reference pathogen for pathogens able to grow in water distribution systems in the revision of Annex I of the DWD performed by the WHO (WHO, 2016b), although no recommendations for monitoring are made. The ISO guidelines recommend monitoring of Legionella spp. only for green houses irrigation with risk of aerosolization (ISO, 2015). Legionella spp. is only recommended for verification monitoring of agricultural irrigation practices in the Spanish regulations. This document follows the ISO recommendations regarding Legionella monitoring.

8.1.2 Indicator microorganismsSelection of indicator microorganisms is made to identify the microbiological parameters to be used for validation and/or verification monitoring for agricultural irrigation and aquifer recharge. The following indicator microorganisms are selected, presented for each group of microorganisms:

Bacteria

Escherichia coli (E. coli) is the most suitable indicator of faecal contamination, and it is a traditional bacterial indicator for monitoring purposes in water treatment. Although some guidelines and regulations utilize thermotolerant (faecal) or total coliforms as bacterial indicators for agricultural irrigation (WHO, 2006; USEPA, 2012; CDPH, 2014), E. coli is considered more specific of fecal contamination and reflects better the behaviour of the pathogenic enteric bacteria (Ashbolt et al., 2001; NRMMC–EPHC–AHMC, 2006). E. coli is the first organism of choice in monitoring programmes including surveillance of drinking-water quality (WHO, 2011), as well as the most commonly used bacterial indicator in national water reuse legislations of MS (JRC, 2014). In addition, E. coli is considered an appropriate indicator for the presence/absence of Campylobacter in drinking water systems (WHO, 2016b). The ISO guidelines establish that E. coli and thermotolerant coliforms can be both used for water quality monitoring as the difference in values is not considered significant (ISO, 2015).

E. coli is requested for validation and verification monitoring for all agricultural irrigation and aquifer recharge uses defined in this document.

Viruses

Generally, viruses are more resistant to environmental conditions and treatment technologies, including filtration and disinfection, than bacteria (WHO, 2011). Enteric viruses usually have a great persistence in groundwater (Toze, 2004). Therefore, due to the limitations of bacterial indicators, there has been significant research into determining a viral indicator that may be adopted for water quality monitoring (USEPA, 2012). Coliphages, a type of bacteriophages, are being considered as viral indicators for pathogenic viruses as they share many properties with human viruses, notably composition, morphology, structure and mode of replication (Grabow, 2001; WHO, 2011). Usually, somatic coliphages and F-RNA coliphages are the major groups investigated for water quality assessment.

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Somatic coliphages monitoring is considered more conservative than F-RNA coliphages monitoring. The greater potential for somatic coliphages to multiply in sewage means that they can provide some additional conservatism. F-RNA coliphages are less prevalent in human faeces than somatic coliphages, but they provide a more specific indicator of fecal pollution. In addition, F-RNA coliphages are considered better indicators of the behaviour of enteric viruses in water environments and their response to treatment and disinfection processes than are somatic coliphages (WHO, 2011).

However, there are shortcomings and conflicting data that need to be resolved, and the extent to which coliphages can be applied in practice as indicators for pathogenic viruses remains to be elucidated and it is currently an area of debate and ongoing research (WHO, 2011; USEPA, 2012). Furthermore, there have been no documented cases based on limited epidemiological studies of viral disease resulting from water reuse practices (USEPA, 2012).

Coliphages (i.e. somatic coliphages) are recommended for verification monitoring of high-exposure water reuse schemes in the Australian guidelines, and the WHO guidelines stay that, under certain circumstances, bacteriophages may be included in verification monitoring to overcome E. coli limitations as indicator (NRMMC–EPHC–AHMC, 2006; WHO, 2006).

The USEPA guidelines recognize that alternative indicators to E. coli may be adopted in the future for water quality monitoring (e.g. bacteriophages), but they do not include any specific viral indicator in their recommendations (USEPA, 2012). However, regarding indirect potable reuse for surface spreading or direct injection, the USEPA guidelines state that log10 removal credits for viruses can be based on challenge tests (spiking) or the sum of log10 removal credits allowed for individual treatment processes, although monitoring for these pathogens is not required.

According to an unpublished draft from the WHO on the revision of Annex I of the DWD (WHO, 2016b), owing the limitations of coliphages, they are not recommended for verification monitoring of drinking water, but possibly for validation testing.

California regulations include F-RNA bacteriophages as a performance target (e.g. 99.999% removal/inactivation of F-RNA bacteriophages) for food crops irrigation, and for indirect potable reuse (aquifer recharge) adopt a 12 log10 removal (from raw wastewater) of enteric viruses (CDPH, 2014). In addition, US state regulations of North Carolina adopt coliphages as water quality target for irrigation of food crops not processed, and Texas regulations include 8 log10 removal of enteric viruses for indirect potable reuse (USEPA, 2012).

MS regulations for agricultural irrigation and aquifer recharge do not include coliphages, or any viral indicator, for monitoring, with the exception of the French regulation that includes F-RNA coliphages as performance target for verification monitoring in agricultural irrigation (JORF, 2014). Coliphages (somatic coliphages/F-RNA coliphages) are requested for validation monitoring in agricultural irrigation and aquifer recharge uses, and for verification monitoring in high-exposure uses of agricultural irrigation (i.e. food crops eaten raw).

Protozoa:

There has been considerable interest in recent years regarding the occurrence and significance of Giardia and Cryptosporidium in water reuse schemes because Giardia cysts and Cryptosporidium oocysts have been found in reclaimed water (Huffman et al., 2006; USEPA, 2012).

E. coli is more readily removed by disinfection methods than protozoa, which are mainly removed by filtration systems. Protozoa also survive longer than bacteria in groundwater. Clostridium perfringens spores have been suggested as indicators of

28

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protozoan removal and effectiveness of filtration processes. Clostridium perfringens spores have an exceptional resistance to disinfection processes and other unfavourable environmental conditions, its spores are smaller than protozoan (oo) cysts, and hence more difficult to remove by physical processes (NRMMC–EPHC–AHMC, 2006; WHO, 2006; WHO, 2011).

Protozoan indicators (i.e. Clostridium perfringens spores) are recommended for verification monitoring of high-exposure water reuse schemes in the Australian guidelines, and the WHO guidelines stay that, under certain circumstances, additional indicators may be included in verification monitoring (NRMMC–EPHC–AHMC, 2006; WHO, 2006). The unpublished draft from the WHO on the revision of Annex I of the DWD recommend Clostridium perfringens spores monitoring for verification of treatment control for disinfection-resistant pathogens such as Cryptosporidium (WHO, 2016b).

The USEPA guidelines do not include any specific protozoan indicator in their recommendations (USEPA, 2012). As regards of aquifer recharge for potable uses (indirect potable reuse) using surface spreading or direct injection, the USEPA guidelines state that log10 removal credits for Giardia and Cryptosporidium can be based on challenge tests ( spiking) or the sum of log10 removal credits allowed for individual treatment processes, although monitoring for these pathogens is not required (USEPA, 2012).

California regulations for indirect potable reuse include a 10 log10 removal (from raw wastewater) of Giardia cysts and Cryptosporidium oocysts for aquifer recharge through surface spreading or direct injection (CDPH, 2014). Furthermore, US state regulations of North Carolina have specific water quality limits for Clostridium for non-processed food crops, and Florida requires monitoring of Giardia and Cryptosporidium for food crops irrigation and for indirect potable reuse (aquifer recharge) (USEPA, 2012). MS regulations for agricultural irrigation and aquifer recharge do not include protozoan indicator for monitoring, with the exception of the French regulation that requests monitoring of spores of sulphite-reducing bacteria as performance target for verification in agricultural irrigation (JORF, 2014).

Clostridium perfringens spores are requested for validation monitoring in agricultural irrigation and aquifer recharge uses, and for verification monitoring in high-exposure uses of agricultural irrigation (i.e. food crops eaten raw).

8.2 Physico-chemical parametersSeveral physico-chemical parameters are selected for monitoring purposes to assure that health and environmental risks are properly coped. Common physico-chemical parameters selected for verification and/or operational monitoring for agricultural irrigation and aquifer recharge schemes are the following:

Total suspended solids (TSS): this parameter indicates effectiveness of sedimentation and it is also related with filtration and disinfection efficacy. The removal of suspended matter is linked to pathogen removal, as many pathogens are particulate-associated, and both bacteria and viruses can be shielded from disinfectants such as chlorine and UV. Also, organic matter consumes chlorine, thus making less of the disinfectant available for disinfection. There is general agreement that particulate matter should be reduced to low levels prior to disinfection to ensure reliable destruction of pathogenic microorganisms during the disinfection process. Furthermore, materials in suspension are listed as pollutants which input has to be limited in Annex VIII of the WFD.

The USEPA guidelines do not include TSS for aquifer recharge. However, TSS is included for verification monitoring of processed food crops and non-food crops irrigation (USEPA,

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DRAFT

2012). The Australian guidelines follow a similar pattern (NRMMC–EPHC–AHMC, 2006). ISO guidelines include TSS for agricultural irrigation monitoring (ISO, 2015).

MS regulations include TSS for agricultural irrigation, and they are also included in some MS regulations that allow aquifer recharge (Cyprus, and Spain).

However, these guidelines and regulations apply TSS values usually in the range of the requirements of the UWWTD, with more stringent requirements only for some uses, like irrigation of food crops eaten raw and direct aquifer recharge.

TSS is requested for verification monitoring for some of the categories of use defined for agricultural irrigation and aquifer recharge.

Turbidity: it is a traditionally used parameter to indicate filtration effectiveness and suitability for disinfection, and can be a surrogate for protozoa removal, and viruses. Turbidity is an important factor in achieving the microbial inactivation requirements.

Turbidity appears in the USEPA guidelines for food crops eaten raw and aquifer recharge, similarly to the Australian guidelines (NRMMC–EPHC–AHMC, 2006; USEPA, 2012). The ISO guidelines only include turbidity for irrigation of food crops eaten raw (ISO, 2015). Turbidity is included in the Greek and Spanish water reuse legislations for specific categories of use of agricultural irrigation and aquifer recharge.

Turbidity is requested for verification and operational monitoring some of the categories of use defined for agricultural irrigation and aquifer recharge practices.

Other operational parameters: additionally to turbidity, there are other parameters that are to be included in operational monitoring that have to reflect the effectiveness of preventive measures, provide a timely indication of performance, be readily measured and provide the opportunity for an appropriate response. These parameters are dependent on the specificities of each water reuse scheme, and for treatment processes may include several parameters (e.g. disinfectant concentration and contact time, ultraviolet intensity, pH, light absorbency, membrane integrity, flow rate, transmembrane pressure and temperature). For distribution systems, operational parameters typically include pressure measurements, and residual disinfectant content. Operational monitoring include also observational monitoring that usually involves checking the system integrity (e.g. pipes, sprinklers). Indicative operational parameters for treatment technologies are shown in Table 13. BOD and TOC may be used for operational monitoring of specific treatment processes (Table 13).

8.2.1 Physico-chemical parameters for agricultural irrigation monitoring

The following specific physico-chemical parameters are requested for verification monitoring of agricultural irrigation:

Biochemical Oxygen Demand (BOD5): this parameter acts as an indication of biological treatment effectiveness and indirect potential for bacterial regrowth in distribution systems. BOD5 can be considered a surrogate for performance related to pathogen reduction (NRMMC–EPHC–AHMC, 2006). However, this parameter presents the disadvantage of the time needed to obtain a result (5 days).

BOD5 appears in the Australian and USEPA guidelines for agricultural irrigation, as well as in the ISO guidelines (NRMMC–EPHC–AHMC, 2006; USEPA, 2012; ISO, 2015). Some MS include BOD5 in their water reuse legislations for agricultural irrigation (Cyprus, Greece and Italy).

Chemical Oxygen Demand (COD): this parameter accounts as an aggregate measure of organic matter (like BOD5) and indicates treatment efficiency. Some MS water reuse legislations include COD alone (France), or both BOD5 and COD (Cyprus, and Italy), or

30

DRAFT

none (Spain). COD does not appear in any water reuse guideline, although it appears in some US regulations (USEPA, 2012). The ISO recommendations stay that COD can be used as an additional parameter. COD is also a compulsory parameter included in the UWWTD (Directive 91/271/EEC). Nevertheless, the chemical analysis of COD incorporates some toxic substances such as mercury and potassium dichromate, which are potentially harmful to the environment. Due to its toxicity the EU will enforce a ban in September 2017 on the application of potassium dichromate (Annex XIV of Regulation (EC) No 1907/2006 REACH regulation (Commission Regulation No 348/2013 of 17 April 2013 amending Annex XIV to REACH)).(Not included in tables, to be discussed as substitute to BOD or be rejected)

Agronomic parameters: monitoring of these is compulsory in order to control environmental risks to soils, plants, surface waters and groundwaters, associated with reclaimed water use for agricultural irrigation (e.g. salinity, phytoxicity).

Agronomic parameters are included in all guidelines for water reuse (WHO, 2006; NRMMC–EPHC–AHMC, 2006; USEPA, 2012; ISO, 2015) and also in most of the MS water reuse regulations. The specific agronomic parameters and the associated limit values comprised in guidelines and regulations are adapted from the recommendations made by the Food and Agriculture Organization of the United Nations (FAO) (FAO, 1985). The FAO recommendations (Annex I) are a worldwide reference document that provides a guide to making an initial assessment of agronomic parameters for application of reclaimed water in agriculture. They emphasize the long-term influence of water quality on crop production, soil properties and farm management.

However, almost all water reuse guidelines and regulations have applied some modifications to the FAO recommendations due to their basic assumptions and comments and the number of variables that are site-specific when establishing agronomic parameters and values (e.g. soil characteristics, climate conditions, crop variety, cultivation practices (i.e. irrigation method, hydraulic loading)).

In this regard, due to the variety of local conditions in MS, the agronomic parameters and limit values of FAO recommendations are required to be adopted for verification monitoring, and modified, if necessary, by MS to take into account site specific conditions and related national regulations in place (e.g. soil protection regulations).

Other chemical parameters: additional chemical parameters may be requested for verification monitoring when EU Directives and other regulations in place are to be considered for agricultural irrigation.

The Directive 86/78/EEC (Sludge Directive) on the protection of the environment, and in particular of the soil, when sewage sludge is used in agriculture establishes limit values for heavy metals in soils, and the maximum limit values of heavy metals amounts which may be added annually to agricultural land based on a 10 year average (Annex I A and C of Directive 86/78/EEC). These values have to be taken into account in order to do not damage the soil quality. The Portuguese water reuse guidelines include the values from the Sludge Directive. However, since the adoption of the Directive 86/78/EEC, several MS have enacted and implemented stricter limit values for heavy metals and set requirements for other contaminants. Therefore, the Sludge Directive is now under a revision process and any update should be also reflected accordingly when soils analysis are carried out in irrigation with reclaimed water schemes.

Environmental risks from agricultural irrigation with reclaimed water are in great part to be controlled and reduced by MS implementing a code or codes of good agricultural practice which must contain provisions covering the items mentioned in Annex II of the Nitrates Directive (91/676/EEC). For instance, the fertilization plan should take into account the quantity of nutrients in reclaimed water used for irrigation. The nitrate vulnerable zones designated according to Article 3 of this Directive have to be taken into consideration to prevent nitrate pollution via run-off from agricultural irrigation.

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8.2.2 Physico-chemical parameters for aquifer recharge monitoringThe following specific physico-chemical parameters are requested for verification monitoring of some of the categories of use for aquifer recharge:

Total Organic Carbon (TOC): measurement of TOC in reclaimed water is a gross measure of the organic constituents of wastewater origin. TOC is also used as a surrogate for overall soil aquifer treatment operations, similarly to the use of turbidity for determining filter efficacy (NRMMC-EPHC–NHMRC, 2009). However, TOC is not included in any MS water reuse regulations for aquifer recharge (JRC, 2014).

For indirect potable reuse, TOC of wastewater origin appears in USEPA guidelines and California regulations (USEPA, 2012; CDPH, 2014).

Other chemical parameters: additional chemical parameters are requested for verification monitoring when EU Directives and other regulations in place are to be considered for aquifer recharge specific uses.

The USEPA guidelines recommend that for indirect potable reuse, reclaimed water has to comply with drinking water legislation at the point of injection for direct injection, and after the vadose zone for surface spreading (USEPA, 2012). One of the most relevant examples of indirect potable reuse in a MS is placed and legally allowed at the Torreele facility in Wulpen, Belgium, where since 2002 the effluent of the municipal WWTP is reclaimed for indirect potable reuse after artificial recharge of the dune aquifer of St-André, also, enhancing natural values with a sustainable groundwater management in the dunes (Van Houtte and Verbauwhede 2008). The recharge water is subject to stringent water quality standards due to the excellent existing groundwater quality and the sensitive environmental nature of the dune area. The health authorities established the specific parameters (e.g. organic contaminants, heavy metals, nutrients, electrical conductivity), limit values and monitoring program to be implemented. Limit values usually comply with the national drinking water regulation, although some values are more stringent and some others are less stringent. The plant applies an integrated membrane process: ultrafiltration and reverse osmosis.

For indirect potable reuse, conformity with the DWD (98/83/EC) is requested for direct injection at the point of injection, and for surface spreading after the vadose zone, acknowledging the additional barrier of the unsaturated zone. However, flexibility is also considered to allow MS to establish exceptions in some parameters without compromising health and environmental protection, in line with the amendment to the DWD (Commission Directive 2015/1787) that included an option for MS to apply the risk-based approach to ensure a high standard of health protection by allowing more flexibility in monitoring programmes and better adaptation to local conditions.

The USEPA guidelines do not specify reclaimed water quality criteria for aquifer recharge (excluding indirect potable reuse), being considered as site specific to be defined in a case-by-case basis (USEPA, 2012). MS regulations for aquifer recharge (excluding indirect potable reuse) do not specify priority substances analysis. Only the Greek regulation for water reuse includes a list of the priority substances from the EQSD, with some modifications, that has to be complied for all categories of use, including aquifer recharge.

According to the GWD (amended by Directive 2014/80/EC) MS have to establish threshold values for groundwater pollutants and indicators of pollution (e.g. nitrates, active substances in pesticides, conductivity, heavy metals) on a national, river basin or other appropriate level having regard dependent ecosystems and regional or even local conditions.

For aquifer recharge by surface spreading or direct injection for non-drinking water purposes at the present and medium future, following the GWD, MS have to set minimum quality requirements on a case-by-case basis, according to the existing

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groundwater quality of the aquifer to be recharged, and establish, if necessary, maximum limit values to be fulfilled by the reclaimed water quality and to be included for verification monitoring.

8.3 Contaminants of emerging concern (CECs) in reclaimed water for aquifer recharge

Besides already regulated pollutants, contaminants of emerging concern (CECs), including biocides, hormones, pharmaceuticals, personal care products, etc. and their transformation products raise increasing attention as they are regularly found both in treated urban wastewater and in the environment. A possibility of these substances having an impact on the environment due to their carcinogenic, teratogenic and/or mutagenic, endocrine disruption and other adverse effects cannot be neglected, since currently there is no comprehensive understanding of their fate and transport as well as their remaining biological potency on environmental and human health during reuse applications. Also, the mixture effects of pollutants are not well understood yet. Nevertheless, there is strong evidence of an increasing number of CECs present in the aquatic environment. The intentional recharge of potable aquifers is intended to augment drinking water supplies. Although, there might be dilution and additional attenuation of CECs occurring during retention in the subsurface and during post-treatment (after recovery of the recharged groundwater), there is a potential remaining risk to public health that needs to be properly assessed and managed. For agricultural irrigation with reclaimed water, providing best management practices are being followed (i.e., irrigation based on agronomic rate; no run-off), CEC exposure to humans which could result in health-relevant levels is not expected. For environmental health protection, exposure scenarios of CECs still being present in reclaimed water for soil organisms do not suggest a risk level that would justify regular monitoring of CECs for this water reuse practice providing best management practices are being followed. However, since the issue is of concern, ongoing collection of evidence should be considered by the European Commission in future revisions of the minimum requirements for agricultural irrigation.Groundwater recharge using reclaimed water via surface spreading operations or direct injection is being conducted to augment drinking water supplies. Thus, maximizing the recovery of this recharged groundwater resource and little - if any - discharge of this groundwater to surface water are assumed. Therefore, the exposure to aquatic life in surface waters is highly unlikely. In situations where there is evidence that more than 20 percent of the groundwater recharged with reclaimed water is exfiltrating into surface water, monitoring for reclaimed water needs to include also contaminants regulated in the WFD (2000/60/EC; priority substances and priority hazardous substances) listed in the Environmental Quality Standards Directive (2013/39/EU) including river basin specific pollutants as well as CECs. Since the reclaimed water intended for groundwater recharge is expected to meet core requirements of the GWD, there is also no concern regarding situations of elevated exposure to any chemical of concern to groundwater ecosystems.

8.3.1 Source control program for CECs

Any indirect potable reuse project requires a tailored source control program that includes regular monitoring requirements for commercial and industrial discharger to the public sewer system serving a potable water reuse project (Drewes and Khan, 2011). This source control program should specify monitoring requirements for dischargers, sampling locations and frequencies, as well as target inorganic and organic analytes. The source control program should be reviewed and approved by the local health regulators prior to start of an indirect potable reuse project. Where a new water reuse project is pursued for the first time, a one-time monitoring effort should be conducted in the raw sewage serving a water reclamation facility. This monitoring program should include parameters listed in the Urban Wastewater Treatment Directive (91/271/EEC) and a short-list of selected CECs which are of toxicological relevance (Table 4 List of CECs to monitor the suitability of wastewater for water reclamation viagroundwater recharge.Table 4). The presence of these chemicals at elevated concentrations represents a serious threat to groundwater recharge projects using reclaimed water. Thus, any detection of these CECs exceeding the health-relevant levels by a factor of 10 in the raw

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sewage are not compatible with a potable reuse practice and requires mitigation strategies at the point of discharge to the sewer system before a project can be pursued. In addition, prior to start an indirect potable reuse project, the chemicals used by companies connected to the sewer systems have to be collected and evaluated whether there are CECs in use that might be problematic for quality of groundwater and drinking water. Table 4 List of CECs to monitor the suitability of wastewater for water reclamation via groundwater recharge.

Target chemical Human health relevant level (HRL) (ng/L)

References

N-Nitrosodimethylamine 10 tba

PFOS 70 USEPA 2016

PFOA 70 USEPA 2016

1,4-Dioxane 1,000 tba

Tolylfluanide/DMSA 50 (tbc) Schmidt & Brauch, tba

MTBE 100 (tbc) tba

Glyphosate/AMPA 50 tba

9 Reclaimed water quality criteriaThis section provides the minimum quality requirements recommended for agricultural irrigation and aquifer recharge with reclaimed water. There are some common water quality criteria to both agricultural irrigation and aquifer recharge uses, and these are described below.

The Directive 91/271/EEC (UWWTD) that concerns the collection, treatment and discharge of urban wastewater, establishes quality requirements that have to be satisfied by discharges from urban wastewater treatment plants (UWWTP) including also specific requirements for discharges in sensitive areas (Annex I of UWWTD). Therefore, all treated wastewater potentially considered for reclamation and reuse (i.e. wastewater coming from a UWWTP) has to comply at least with the quality requirements of Annex I, table 1 of the Directive 91/271/EEC.

The Water Framework Directive 2000/60/EC (WFD) has to be considered when using reclaimed water for agricultural irrigation and aquifer recharge in order to prevent further deterioration of surface waters, groundwaters, and their related ecosystems. Therefore, it is necessary to take into account the EQSD 2008/105/EC (amended by Directive 2013/39/EU) on priority substances and certain other pollutants, and the pollutants identified by MS of regional or local importance (river basin specific pollutants).

As regards MS legislations, the Spanish water reuse legislation states that the use of reclaimed water for agricultural irrigation must respect the EQSD, and the Italian legislation includes some organic contaminants for verification monitoring in reclaimed water. The Greek regulation for water reuse includes a list of the priority substances from the EQSD, with some modifications, that has to be complied with for reclaimed water quality for all categories of use. Therefore, MS have to assure that the use of reclaimed water for agricultural irrigation and aquifer recharge does not compromise the fulfillment of the Directive 2008/105/EC, and specify, if necessary, minimum quality requirements on a case-by-case basis to be complied with by the reclaimed water quality and to be included for verification monitoring.

The point of compliance of the reclaimed water quality criteria is the final reclaimed water effluent after the adequate treatment, and this quality has to be complied also at the point of application (e.g. irrigation, surface spreading or direct injection), thus, the end-use point. This

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acknowledges the potential quality changes due to distribution and storage of the reclaimed water, and it is consistent with the risk-based management approach.

The frequencies established for each type of monitoring in the following sections are considered minimum requirements, however, these frequencies can be more stringent if a risk-based approach is performed in order to better adapt to specific site conditions. The range of parameters and the frequency of testing included in monitoring programs should be adapted to the local conditions, size of the reuse scheme, and the identified health and environmental risks associated with the end use. In many wastewater systems, flow volumes and composition entering a facility can change greatly across a single day and are often vary on weekends, and holidays. Thus, monitoring programs must be designed to determine the variability within the source water in order to better design and maintain a reuse treatment train.

Analytical methods used for monitoring shall conform to the international standards listed in related Directives (i.e. WFD (2000/60/EC), DWD (98/83/EC), GWD (2006/118/EC)) or such other national or international standards which will ensure the provision of data of an equivalent scientific quality and comparability. When the parameter to be monitored is not included in any EU Directive, the analytical method selected should conform to the latest available ISO/CEN standards or the Standard Methods for the Examination of Water and Wastewater (APHA, 2005).

9.1 Reclaimed water quality criteria for agricultural irrigationMinimum water quality criteria recommended for reclaimed water used for agricultural irrigation include performance targets for validation monitoring, and water quality targets for verification monitoring, as well as specified technology targets.

Performance targets (from raw wastewater) for the selected reference pathogens to meet the health-outcome target of 10–6 DALYs per person per year are established for the use of reclaimed water in agricultural irrigation (). The performance targets described are derived from the risk assessment performed in the Australian guidelines, assuming similar content of reference pathogens in MS raw wastewaters and acknowledging that the reference pathogen for virus in the Australian guidelines is an amalgam of adenovirus and rotavirus (NRMMC-EPHC-AMHC, 2006). Data on content of reference pathogens at EU level (from MS) needed.

Table 5 Performance targets for validation monitoring of agricultural irrigation with reclaimed water.

Category of use Performance targetsfor reference pathogens

(log10 removal)

Indicator microorganisms for validation of performance targets

(log10 removal)Food crops consumed raw

Campylobacter 5.0Enterovirus 6.0Cryptosporidium 5.0

E. coli 5.0Coliphages 6.0Clostridium perfringens spores 5.0

Processed and other food crops

Campylobacter 5.0Enterovirus 6.0Cryptosporidium 5.0

E. coli 5.0Coliphages 6.0Clostridium perfringens spores 5.0

Non-food crops Campylobacter 4.0Enterovirus 5.0Cryptosporidium 3.5

E. coli 4.0Coliphages 5.0Clostridium perfringens spores 3.5

Performance targets established are to be met by the preventive measures in place at the specific water reuse scheme. Most frequently, performance targets are applied to treatment performance, but there are other preventive measures that may contribute to reduce risks.

Water reuse scheme proponents must validate the treatment technologies for the specific log10 removals requested. This can be achieved by testing for reference pathogens or for the indicator microorganisms removal selected for validation monitoring. Indication of relative log10 removals of pathogens and indicator microorganisms reported in the literature for different treatment systems and additional preventive measures is shown in

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Annex II. The achievable ranges of pathogen reduction shown in Annex II are relatively broad because effectiveness will be influenced by design features. These log10 removals are typically based on removal efficiency demonstrated by challenge testing, and are intended to be informative.

The log10 removals are subject to compliance with defining design features and operational conditions (e.g. specified filtration design features, chlorine Ct, limits for turbidity, chlorine residual). In California regulations, for example, direct testing is generally not required for treatment meeting specified design criteria (CDPH, 2014). Treatment facilities that employ approved filtration or disinfection processes, or underground storage can obtain log10 removal credits for specific pathogens. Thus, use of proven, CDPH accepted technology/treatment processes reduces the burden on utilities to prove reduction of pathogens.

According to the performance targets established for each category of use, water quality targets are defined for verification monitoring (Table 6).

The verification monitoring frequencies for the final effluent of reclaimed water for agricultural irrigation are summarized in Table 7. Sampling frequency refers to the minimum frequency required, based on sampling frequency recommendations of Australian and USEPA guidelines, and MS water reuse legislations. The monitoring frequency of agronomic parameters should be adjusted to the project needs and the identified environmental risks. As a rule, higher monitoring frequency could be requested for salinity or boron (daily to monthly), moderate frequency for nutrients and sodium (once every 2 to 6 months) and low frequency for trace elements (once every 1 to 5 years).

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Table 6 Minimum reclaimed water quality criteria for verification monitoring and specified technology targets for agricultural irrigation.

Category of use

E. colia

(cfu/100 ml)

Coliphages (pfu/100 ml)

Clostridium perfringens

spores(num./100ml)

BOD5(mg/l)

TSS(mg/l)

Turbidity(NTU)

Agronomic parameters

Other criteria

Specified technology

targetb

Food crops consumed raw

100 1 1 10 10 5 Based on FAO recommendation

s modified by site conditions

Use of reclaimed water do not compromise fulfillment of Directive 2008/105/EC

Secondary treatment, filtration, and disinfection

Processed and other food crops

1,000 - - According to Directive 91/271/EEC

20 - Based on FAO recommendation

s modified by site conditions

Use of reclaimed water do not compromise fulfillment of Directive 2008/105/EC

Secondary treatment, and disinfection

Non-food cropsc

10,000 - - According to Directive 91/271/EEC

According to Directive 91/271/EEC

- Based on FAO recommendation

s modified by site conditions

Use of reclaimed water do not compromise fulfillment of Directive 2008/105/EC

Secondary treatment, and disinfection

NOTE: the limit values are maximum values. (to be defined the % of samples to compliance and maximum deviation limits).a: Legionella analysis have to be performed for greenhouses irrigation if there is risk of aerosolization (< 1,000 cfu/l).b: Filtration means the passing of wastewater through natural undisturbed soils or filter media such as sand and/or anthracite; or the passing of wastewater through microfilters or other membrane processes (USEPA, 2012). Disinfection means the destruction, inactivation, or removal of pathogenic microorganisms by chemical, physical, or biological means. Disinfection may be accomplished by chlorination, ozonation, other chemical disinfectants, UV, membrane processes, or other processes (USEPA, 2012).c: For pasture and fodder crop irrigation, animals must be prohibited from pasture for 5 days after irrigation. No public access during irrigation.

Limit values to be confirmed).

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Table 7 Verification monitoring frequency of analytical parameters for agricultural irrigation.

Analytical parameter

Reclaimed water quality category Comments

Food crops consumed raw

Processed and other food

crops

Non-food crops

E. coli (Legionella if applicable)

Twice aweek

Once aweek

Once every two

weeksColiphages Once a

weeks- -

Clostridium perfringens spores

Once aweeks

- -

BOD5 Twice aweek

Once aweek

Once every two

weeksTSS Twice a

weekOnce aweek

Once every two

weeksTurbidity Continuous

(Daily)- - Preferably in continuous, if

not feasible, daily

Agronomic parameters

Depending on each parameter and irrigation practices Electrical conductivity should be monitored in continuous if possible

9.2 Reclaimed water quality for aquifer rechargeThe minimum reclaimed water quality criteria for aquifer recharge include performance targets for validation monitoring, and water quality targets for verification monitoring, as well as specified technology targets.

Performance targets (from raw wastewater) for the selected reference pathogens are to be established for indirect potable reuse.

Water quality targets and specified technology targets for verification monitoring are shown in Table 8. Limit values for aquifer recharge for non-drinking water purposes are based on MS water reuse legislations that consider aquifer recharge for non-drinking water uses (Cyprus, Greece, and Spain). The USEPA guidelines do not establish any parameter or limit value stating that these are site specific and use dependent. Specified technology targets are based on Greece regulations. Indirect potable reuse is not contemplated in most of the MS water reuse regulations, and some limit values and parameters, as well as the specified technology targets, are based on the USEPA guidelines and California regulations (USEPA, 2012; CDPH, 2014).

A hydrogeological study has to be performed to characterize the aquifer, and the attenuation capacity of the vadose (unsaturated) zone and the aquifer (soil-aquifer treatment) has to be proved to establish less stringent water quality requirements for surface spreading.

Compliance with the GWD 2006/118/EC (amended by Directive 2014/80/EC) implies that MS have to set minimum quality requirements on a case-by-case basis, according to the existing groundwater quality of the aquifer to be recharged, and establish, if necessary, maximum limit values to be fulfilled by the reclaimed water quality.

Compliance with the DWD 98/83/EC implies that MS have to fulfill the DWD requirements, allowing MS to establish exceptions in some parameters without compromising health and environmental protection, in line with the amendment to the DWD (Commission Directive 2015/1787) that included an option for MS to apply the risk-based approach to ensure a high

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standard of health protection by allowing more flexibility in monitoring programmes and better adaptation to local conditions.

Table 8 Minimum reclaimed water quality criteria for verification monitoring for aquifer recharge (modified from USEPA, 2012; Directive 98/83 EC).

Category of use E. coli(cfu/100 ml)

TSS(mg/l)

Turbidity(NTU)

TOCa

(mg/l)Other

criteriaSpecified

technology targetb

Aquifer recharge by surface spreading for non-drinking water purposes at the present and medium future

1,000 According to Directive

91/271/EEC

- - Compliance with Directive 2006/118/EC on a case-by-

case basis

Secondary treatment,

and disinfection (advanced

water treatments if

needed)Aquifer recharge by direct injection for non-drinking water purposes at the present and medium future

10 10 2 - Compliance with Directive 2006/118/EC on a case-by-

case basis

Secondary treatment,

filtration, and disinfection(advanced

water treatments if

needed)Aquifer recharge by surface spreading for drinking water purposes or intended for such future use

b.d.l 2C 2 Compliance with Directive 98/83/EC with potential MS exceptions justified.

Secondary treatment, filtration,

disinfection, and advanced

water treatments

Aquifer recharge by direct injection for drinking water purposes or intended for such future use

b.d.l 2 C 2 Compliance with Directive 98/83/EC with potential MS exceptions justified.

Secondary treatment, filtration,

disinfection, and advanced

water treatments

NOTE: the limit values are maximum acceptable values (to be defined the % of samples to compliance and maximum deviation limits).b.d.l.: below detection limita: TOC of wastewater origin. Dilution of reclaimed water with waters of non-wastewater origin can be used to help meet the TOC limit (USEPA, 2012).b: Filtration means the passing of wastewater through natural undisturbed soils or filter media such as sand and/or anthracite; or the passing of wastewater through microfilters or other membrane processes. Disinfection means the destruction, inactivation, or removal of pathogenic microorganisms by chemical, physical, or biological means. Disinfection may be accomplished by chlorination, ozonation, other chemical disinfectants, UV, membrane processes, or other processes. Advanced water treatment processes may include chemical clarification, carbon adsorption, reverse osmosis and other membrane processes, advanced oxidation, air stripping, ultrafiltration, and ion exchange (USEPA, 2012).c: The average turbidity should be based on a 24-hour time period. The turbidity should not exceed 5 NTU at any time. If membranes are used as the filtration process, the turbidity should not exceed 0.2 NTU (USEPA, 2012).

The verification monitoring frequencies for the final effluent of reclaimed water for aquifer recharge are shown in Table 9. Sampling frequency refers to the minimum frequency required, based on sampling frequency recommendations of Australian and USEPA guidelines, and MS water reuse legislations.

Table 9 Verification monitoring frequency of analytical parameters for aquifer recharge.

Analytical parameter

Categories of use

Aquifer recharge by surface

spreading for non-drinking

water purposes at

Aquifer recharge by direct

injection for non-drinking water purposes at the

Aquifer recharge by

surface spreading for drinking water

Aquifer recharge by direct injection for drinking

water purposes or intended for such future

use

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the present and medium future

present and medium future

purposes or intended for

such future useE. coli Twice

a weekThree times

a weekOnce a day

Once a day

TSS Oncea week

Once a day

Turbidity - Continuous(Daily)

Continuous Continuous

TOC - - Oncea week

Oncea week

Other criteria According to MS responsible authorities

9.2.1 Monitoring requirements for CECs in aquifer recharge

In addition to meeting core requirements of the GWD and to protect human health from CECs, monitoring of a selection of health-based indicator CECs and performance-based indicator chemicals and appropriate surrogates (such as bulk parameters) should be regulated at the EU level for monitoring of planned water reuse activities leading to aquifer recharge. For the determination of health-based indicator chemicals with available toxicological information, a de minimis risk approach can be used. To specify de minimis levels for these health-based contaminants, any of the following can be adopted and usually modified by a relative source contribution (e.g., 0.2) and used as a point of departure (POD) for estimating risks for carcinogens and non-carcinogens by applying appropriate uncertainty factors (Schwab et al., 2005; Snyder et al., 2008; WHO, 2010; Bull et al., 2011; Khan, 2013):

Acceptable daily intake (ADI). Reference dose (RfD) which is derived from a no-observed-adverse-effect-level (NOAEL)

or lowest-observed-adverse-effect-level (LOAEL) and applying several uncertainty factors depending upon the nature of the toxicological data.

Predicted no-effect concentration (PNEC) that expresses the toxicological potency of health-based contaminants.

Performance validation and verification of water reclamation treatment trains can be obtained through direct measurements of certain performance-based indicator contaminants that frequently occur in reclaimed water and correlate with core removal mechanisms (i.e., biotransformation, adsorption, size exclusion, chemical oxidation) of individual treatment processes (Drewes et al., 2008; Dickenson et al., 2009, 2011). The following factors must be considered for the selection of performance-based indicator contaminants to assess the treatment efficacy of potable reuse schemes (Drewes and Horstmeyer, 2016):

Target substances chosen to assess treatment performance must permanently occur at concentrations significantly above their analytical method detection limit (preferably, the ratio between the measured environmental concentration and the method detection limit should exceed at least 10).

Appropriate and commercially available analytical methods must exist to quantify the target contaminants in recycled water.

Performance-based indicator chemicals used for monitoring should broadly represent the range of physico-chemical and biological properties affecting their removals by the various treatment processes within an indirect potable reuse treatment train.

Substances with a high potential to contaminate groundwater and drinking water. Substances with toxicological relevance.

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Monitoring of health-based and performance-based indicator chemicals provides an additional safeguard for proper removal of CECs. However, the reliability of the treatment processes in properly removing microbial and chemical contaminants is assured by measuring bulk parameters (“surrogate parameters”) that correlate with the removal of CECs (Drewes et al., 2008; Dickenson et al., 2009; Wert et al., 2009). Examples of specific performance-based bulk measurements that can be monitored continuously include turbidity, electrical conductivity, UV absorbance, or TOC. Such surrogate parameters can also indicate out-of-specification performance or treatment process failure. Thus, the monitoring frequency of indicator chemicals can be much longer (e.g., semi-annual) and provides an additional check on proper operation of the overall treatment train in addition to continuous monitoring of surrogates. In principle, this concept is well established in conventional drinking water treatment to manage the risk from microbial contaminants, where treatment efficiency is assessed by measuring turbidity and residual chlorine levels online while monitoring indicator organisms occurs less frequently. The choice of appropriate surrogate parameter will depend on the treatment processes selected, which might differ from project to project. Thus, the selection of surrogate parameters and their expected removal efficiency (expressed as percent removal) should be specified during the start-up and validation monitoring phase of a treatment train (Drewes et al., 2010). Meeting the removal criteria for both the selected indicator chemicals and surrogate parameters can be accomplished by establishing multiple barriers within the overall water reuse project, which are obtained through the use of several different treatment processes operated in series to provide redundancy and robustness in the removal of both pathogens and unwanted chemicals and to ensure the failure of a single process does not render the system vulnerable to penetration by microbial or chemical contaminants that pose a significant risk to public health or the environment.While the requirements to meeting these standards for the two groundwater recharge practices (a. surface spreading; b. direct injection) are the same, the point of compliance differs since removal credit can be given to soil-aquifer treatment (SAT) resulting in additional attenuation of contaminants during vadose zone treatment (Figure 1). For surface spreading operations, the point of compliance is the uppermost groundwater downstream of the recharge facility, which can be monitored by lysimeters or groundwater monitoring wells (Figure 1a). For direct injection projects, all standards have to be met prior to injection (Figure 1b.).

Figure 1 Conceptional schematic of groundwater recharge practices considered by the Commission and point of compliance (a. surface spreading; b. direct injection).

Where groundwater aquifers are already severally compromised due to local environmental conditions (e.g., brackish groundwater; seawater intrusion; geologically-occurring arsenic), MS might define these aquifers as non-potable and specify less stringent water quality requirements.A minimum list of chemicals and appropriate surrogate parameters in reclaimed water used for groundwater recharge to potable aquifers and frequency of their monitoring should be established by the Commission. The Commission will be responsible for defining threshold values for the health-based indicator chemicals at the EU level, whereas MS can define more stringent threshold values at a national, river basin or other level addressing regional or local conditions. It is recommended that an initial list should contain approximately 10 substances and it should indicate the possible methods of analysis not entailing excessive costs for each substance. A mechanism for regular revision/update of the list of CECs each five years should be proposed by the Commission. A proposed list of initial CECs is provided in Table 10.

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Table 10 Proposed list of initial CECs to be included in monitoring programs of indirect potable reuse projects leading to aquifer recharge.

Indicator chemical Human health relevant level (HRL) (ng/L)

Frequency LOQ (ng/L)

References - analytical method

Biodegradable1

Acesulfam tba Every 6 months tba Loos et al., 2013 Benzotriazole tba Every 6 months tba Loos et al., 2013 Diclofenac 100 Every 6 months tba Loos et al., 2013 Gabapentin 1,000 Every 6 months tba Kasprzyk-Hordern et

al., 2008Trimethoprim tba Every 6 months tba Kostich et al., 2014Sulfamethoxazole 150 Every 6 months tba Göbel et al, Valsartanic acid 300 Every 6 months tba Schultz et al., 2010Oxypurinol tba Every 6 months tba Funke et al., 2015Not biodegradable, but oxidizable2

Carbamazepine 500 Every 6 months tba Loos et al., 2013 Difficult to degrade biologically; not amendable to chemical oxidation3

TCEP tba Every 6 months tba Loos et al., 2013Sucralose tba Every 6 months tba Loos et al., 2013

1 Biodegradable during biofiltration or soil-aquifer treatment.2 Not degradable during conventional activated sludge treatment, biofiltration or soil-aquifer treatment, but amendable to chemical oxidation.3 Not degradable during conventional activated sludge treatment, biofiltration or soil-aquifer treatment, not amendable to chemical oxidation.

Analytical methods used for monitoring must comply with the Commission Directive 2009/90/EC of 31 July 2009 laying down, pursuant to Directive 2000/60/EC of the European Parliament and of the Council, technical specifications for chemical analysis and monitoring of water status, which establishes minimum performance criteria for the analytical methods used in monitoring water status. Those criteria ensure meaningful and relevant monitoring information by requiring the use of analytical methods that are sensitive enough to ensure that any exceedance of a threshold value can be reliably detected and measured. Member States should be permitted to monitor in wastewater only if the analytical method used meets the minimum performance criteria set out in Article 4 of Directive 2009/90/EC.

An exceedance of any of the threshold values at the point of compliance (measured environmental concentration, MEC) and the recommended associated follow-up action is described in the following section. This guidance on thresholds for each of these tiers is based on conservative values because of the limited toxicological information available and the fact that the suggested point of compliance does not represent the point of exposure to public health. In indirect potable reuse projects, additional attenuation in the aquifer, dilution with native groundwater or other source waters after abstraction, as well as post-treatment will result in further reductions of contaminant concentrations. It is recommended that the agency responsible for the recharge project confer with the local health regulator to develop a response plan with specific actions to be implemented by the recharge agency as part of interpreting appropriate responses to the monitoring results.

If 1 <MEC/HRL< 10: quality check data, continue to monitor every three months, until 1 year and the MEC/HRL < 1 and preferably is consistently less than 5 times the ratio of MEC/HRL.

If 10 <MEC/HRL< 100: data check, immediate re-sampling and analysis to confirm MEC, also monitor at the point of abstraction. Continue to monitor every three months, until 1

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year and the MEC/HRL< 1 and preferably is consistently less than 5 times the ratio of MEC/HRL.

If 100 <MEC/HRL< 1,000: all of the above plus enhance source identification program. Also monitoring at a point of abstraction and in the distribution system closer to the point of exposure to confirm attenuation of CEC is occurring and to confirm the magnitude of assumed safety factors associated with removal efficiency, dilution and post-treatment.

MEC/HRL>1,000: all of the above plus immediately confer with the local health regulator to determine the required response action. Confirm plant corrective actions through additional monitoring that indicates the CEC levels are below at least an MEC/HRL of 100.

9.2.2 Bioassays and assessment of risk of mixtures of pollutants in reclaimed water for aquifer recharge

To address the issue of mixtures of pollutants a paradigm shift is suggested to employ low cost bioassays in combination with target analysis of the minimum list of pollutants (cf. Table 2 above). This allows to combine a higher level of protection with decreased economic burden caused by monitoring. The use of bioassays has reached sufficient level of maturity and accessibility on the market to include them now in the legislation.In addition to chemical methods which are intended to detect individual compounds, in vitro bioassays (also called bioanalytical tools or effect-based assays) are now recognized as sensitive monitoring tools to screen for contaminants based on their specific biological action (e.g. mutagenic and genotoxic effects). As the chemical composition of a sample is often unknown and mixture effects cannot be detected or predicted based on the results of the chemical analysis, in vitro bioassays are highly suitable tools to examine the presence of specific acting chemicals in complex mixtures (Escher and Leusch, 2012; Leusch et al., 2010; Van der Linden et al., 2008; Wernersson A-S. et al., 2015; Leusch and Snyder, 2015; Prasse et al., 2015).At present, the WHO, the US Environmental Protection Agency (US EPA) and health agencies in Europe have derived approximately 125 statutory guideline values for drinking water (US EPA, 2004, 2006; WHO, 2011; Schriks et al., 2010; Umweltbundesamt, 2003a, 2003b). The Australian drinking water guidelines contain 181 organic chemicals (NHMRC, 2011), most of which are a subset of the chemicals regulated in recycled water for indirect potable reuse (NRMMC, 2008). The scope of such evaluation is rather limited since many compounds that are present in the aquatic environment are not analysed and for the compounds that are analysed, toxicological information is often lacking or insufficient for hazard identification purposes.In addition, while drinking water sources (including potable groundwater) contain complex mixtures of chemicals, analytical chemistry does not account for combined effects. Smart combinations of chemical- and biological analytics therefore lead to reduced uncertainty in safety assessments at lower costs. To put bioassays into a regulatory context, a list of robust bioassays and bioassay threshold values (trigger values) are required. A list of criteria was developed in the DEMEAU project (DEMEAU Deliverable D41.1., 2015) to assess the suitability of effect-based assays to detect activity towards selected endpoints in drinking water. Applying the criteria a list of ready-to-use bioassays available on the market has been compiled (Table 11). A detailed definition of criteria for validation of the performance of the bioassays and validation of their fitness for purpose should still be a subject of further refinement.

Table 11 Overview of recommended in vitro bioassays to detect activity towards selected endpoints relevant for drinking water.

Toxicity endpoints relevant for monitoring of reclaimed water

quality

Specific pathway Most promising bioassay(s)

Xenobiotic metabolism PXR receptor agonists HG5LN PXR assay, PXR HepG2

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AhR receptor agonists assay DR CALUX, AhR-CALUX

Hormone-mediated mode of action

(anti)estrogenic activity(anti)androgenic activity (anti)glucocorticoid activity

ERα CALUX, YES assay, ERα Geneblazer, AR CALUX, AR-MDA-kb2, AR Geneblazer, GR CALUX, GR-MDA-kb2, GR-Geneblazer

Reactive mode of action Gene mutations Chromosomal mutations DNA damage response

Ames fluctuation assay, ToxTracker Micronucleus assay, ToxTracker UMUc assay, Vitotox, p53 CALUX, p53-Geneblazer, BlueScreen

Adaptive stress response Oxidative stress pathway Nrf2 CALUX, AREc32 assay, ARE-Geneblazer

Developmental toxicity Focus point endocrine disruption Various nuclear receptor activation assays, H295R assay

For monitoring of reclaimed water for groundwater recharge, a list of suitable bioassays covering four different toxicity endpoints with specific effect-based trigger values is proposed ((equivalents (eq)/L) for 17β-estradiol (E2), dihydrotestosterone (DHT), dexamethasone (DEX) and Org2058) (Error: Reference source not found). Recognised (i.e., defined by the FAO/WHO Joint Expert Committee on Food Additives (JECFA)) ADI values of specific reference compounds were chosen as point of departure for the derivation of the proposed trigger values. A mechanism for regular revision/update of the list of bioassays and their trigger values each five years should be proposed by the Commission.The trigger values are based on 1) acceptable or tolerable daily intake (ADI/TDI) values of specific compounds, 2) pharmacokinetic factors defining their bioavailability, 3) estimations of the bioavailability of unknown compounds with equivalent hormonal activity, 4) relative endocrine potencies, and 5) physiological, and drinking water allocation factors. Chemical (compound-directed) analysis provides a method of absolute quantification of certain compounds in water samples, but the toxicological properties of these compounds are not always known (Schriks et al., 2010a). Bioassays do not discriminate between different specific compounds but detect the total specific biological activity, and so the concentration of specific biological activity is expressed as an equivalent (eq) to a potent reference compound, e.g. 17β-estradiol (E2) for ERα-, dihydrotestosterone (DHT) for AR-, dexamethasone (DEX) for GR-, and Org2058 for PR-mediated activity (Sonneveld et al., 2005). By using in vitro bioassays, the combined biological activities of the mixture can be quantified and expressed as ng eq of a reference compound per L. This enables an assessment of the effect of unknown compounds by their activity and provides toxicological relevance of this mixture (i.e., specific endocrine activity). Given the sensitivity and robustness, these properties make the use of in vitro bioassays suitable as a screening tool for endocrine activity in water samples (Escher and Leusch, 2012; Schriks et al., 2010b; Van der Linden et al., 2008). A list of compounds with their relative potencies (to be compared to the trigger values) can be established for each bioassay. It is expected that the relative potency (Benchmark Quotient) will be determined for a large number of new substances identified as relevant in the reclaimed water allowing for risk assessment of mixtures of substances (Escher at al., 2015).The effect-based trigger values for the selected bioassays for agonistic and antiagonistic hormonal activities in the reclaimed water used to recharge potable aquifers define the level above which human health risk cannot be waived a priori and additional examination of specific endocrine activity may be warranted. Effect-based trigger values have already been proposed for drinking water for the CALUX series of bioassays (Brand et al., 2013). The derivation of safe level was based on acceptable effect levels in vivo translated to in vitro by extrapolation methods that took into account toxicokinetics.Another approach was used to proposed effect-based trigger values for recycled water by reading across from existing single chemical guideline values of the Australian Guidelines for Water Recycling and applying mixture toxicity considerations (Escher at al., 2015, 2013, Tang

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et al. 2013). The trigger values derived by these various approaches do not differ significantly and the methodology proposed by Brand et al. (2013) is followed in this document.The application of effect-based trigger values can help to decide whether further examination of specific endocrine activity followed by a subsequent safety evaluation may be warranted, or whether concentrations of such activity are of low priority with respect to health concerns in the human population. As limit values are aimed at the protection of human health in the finally produced drinking water, such limits should be sufficiently conservative to serve as a warning signal. On the other hand, such limits should not be too conservative, to avoid unnecessary and costly additional protection measures.The sample location and frequency for these bioassays should be linked to specified monitoring requirements for CECs (i.e., frequency of six months; collected at the point of compliance). Due to the limited sensitivity of the bioassays it is recommended to enrich the water via solid phase extraction prior to testing using appropriate solid phase materials. An exceedance of the trigger values listed in Table 12 should initiate the following actions:• If 1<MEC/HRL< 3: quality check data, continue to monitor every three months, until 1 year and the MEC/HRL < 1 and preferably is consistently less than 5 times the ratio of MEC/HRL.• If 3<MEC/HRL< 10: data check, immediate re-sampling and quantify specific target compounds which are known to cause the effects observed in the respective bioassay.

Table 12 Trigger values for estrogenic (ERα), androgenic (AR), progestagenic (PR), and glucocorticoid (GR) activities in reclaimed water used for recharge of potable aquifers.

Activity Trigger valuea

ERα 3.8 ng E2-eq/LAR 11 ng DHT-eq/LGR 21 ng DEX-eq/LPR 333 ng Org2058-eq/L

aBased on Acceptable Daily Intake (ADI) values reported by the JECFA (FAO/WHO, 1995, 2000). E2 = 17β-estradiol; eq = equivalent; DHT = dihydrotestosterone; DEX = dexamethasone; Org2058 = 16a-ethyl-21-hydroxy-19nor-4-pregnene-3,20-dione.

9.3 Operational monitoring for agricultural irrigation and aquifer recharge

The specified technology targets for agricultural irrigation and aquifer reuse include secondary treatment, filtration, disinfection or advanced wastewater treatments to meet the performance and water quality targets. Operational monitoring parameters, like disinfectant residuals and physical tests, have to be defined according to the specific treatment technologies employed in order to assure the appropriate performance of the water reuse scheme to deliver the requested reclaimed water quality. Operational parameters are used to assess not only pathogen removals but also chemical contaminants reduction, which generally occurs through biological transformation, chemical oxidation, and/or physical removal.

Recommended operational monitoring requirements for some of the most common water treatment processes are shown in Table 13. On-line monitoring with real-time data reporting is strongly recommended when technologically feasible, although frequent grab samples using

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rapid analytical procedures, such as turbidity, and chlorine residuals, are an appropriate alternative in some situations (NRMMC–EPHC–AHMC, 2006; WHO, 2016). According to the risk-based approach, it would be necessary to establish target limits at the different sampling points (e.g. filtration, disinfection) to detect variations of performance (exceeded target limits) and implement corrective actions in response to deviation from target limits.

Chemical disinfection processes have to be designed to achieve specified Ct values (product of concentration and contact time) for indicator microorganisms to achieve designated log10 removals of pathogens. Free and combined chlorine residuals can indicate control of bacteria and viruses, but not some protozoa. Turbidity measurements are an essential operational monitoring for demonstrating protozoan control.

Physical tests for operational monitoring may include several parameters. Electrical conductivity, representing total dissolved solids rejection, and TOC provide excellent information for monitoring the performance of high-pressure membranes (e.g. reverse osmosis, nanofiltration). Integrity of high and low-pressure membranes can be assessed by on-line turbidity measurements and periodic pressure decay tests (PDTs). UV lamp performance can be tracked by percent transmission.Operational monitoring should be established based on design and performance characteristics of the treatments used, following specifications according to the current practices and standardization of performance for wastewater treatment. As an example, the Ultraviolet Disinfection Guidelines for Drinking Water and Water Reuse published by the National Water Research Institute of US (NWRI, 2012) are intended to provide guidance to state and federal regulatory agencies who review applications for the use of ultraviolet (UV) disinfection systems in drinking water and water reuse, and to water utilities who are interested in using UV for disinfection purposes. They establish suggested UV design dosage considering the CDPH (2014) requirements for filtration and disinfection, which are similar to the ones required for agricultural irrigation of food crops (i.e. 5 log10 inactivation/removal of F-specific bacteriophages or poliovirus), and establishing other technical characteristics that has to be complied. They conclude that, when UV disinfection systems are used with granular medium filtration, the design UV dose of 100 mJ/cm2 is suggested; when using microfiltration or ultrafiltration systems, the suggested design UV dose is 80 mJ/cm2; when using reverse osmosis, the design UV dose is 50 mJ/cm2.

Table 13 Recommended operational monitoring for some common treatment processes (NRMMC–EPHC–AHMC, 2006; WHO, 2006 and 2016).

Treatment process Operational monitoring Frequency

Secondary treatment (activated sludge) Ammonia, nitrate/nitrite,BOD, suspended solids, dissolved oxygen,, mixed liquor suspended solids, hydraulic retention time, solids retention time, flow rate

Continuous (on-line) for dissolved oxygen, ammonia, flow rateWeekly for other parameters

Low-rate biological systems (stabilization ponds)

Flow rateBOD, dissolved oxygen (facultative and maturation ponds)

Continuous (on-line) for flow rate and dissolved oxygenWeekly for other parameters

Soil-aquifer treatment Flow rateTotal organic carbonTotal Nitrogen, Nitrate, Nitrite

Continuous (on-line)WeeklyQuarterly

Media filtration system Turbidity downstreamFlow rate

Continuous (on-line)

Membrane bioreactor (MBR) pH, bioreactor dissolved Continuous (on-line) for 46

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oxygen, solids retention time, hydraulic retention time, mixed liquor suspended solids, transmembrane pressureflux, turbidity

parameters such as pH, turbidity, dissolved oxygen, transmembrane pressureWeekly for other parameters

Membrane filtration technology Transmembrane pressureFluxTurbidityElectrical conductivity or TOC

Continuous (on-line)Daily

Ultraviolet light disinfection (UV) Turbidity upstreamUV intensity and/or calculated doseUV transmissivityFlow rate

Continuous (on-line)

Ozone Ozone CtTemperature

Continuous (on-line)

Chlorination Free chlorine residual, Ct pHTemperature

Continuous (on-line) or frequent grab samples

Common treatment combination: coagulation, flocculation, filtration, chlorination

TurbidityFree chlorine residual, Ct

Continuous (on-line)Continuous (on-line) or frequent grab samples

Ct: product of residual disinfectant content (mg/l) and disinfectant contact time (min).

9.4 Antimicrobial resistances and antibiotic resistance genes (AMR/ARG)Considering the threat posed by the spread of antibiotic resistant bacteria (ARB) and the multiple evidences that domestic wastewater is amongst their major environmental reservoirs, the issue of antimicrobial resistance (AMR) has to be addressed and not only in water re-use but in a general context of waste water sanitation. Such a measure if introduced only for water reuse applications favours for instance the discharge to surface water bodies rather than the reuse option. As a viable compromise it is suggested to introduce an optional parameter E.coli resistant to cefotaxime as a surrogate of a wider range of ARB (Table 14 and Table 15).

E.coli is a common harbour of acquired antibiotic resistance genes, therefore an adequate monitoring tool.Cefotaxime resistance is a good indicator for human sources of antibiotic resistance, is associated with a wide diversity of antibiotic resistance genes that are widespread in the environment and of great clinical concern, in particular with extended spectrum beta lactamases (ESBL). ESBL producing E.coli are widespread in the community and a potential source to human infections (e.g. Journal of Antimicrobial Chemotherapy (2006)).

This resistance category corresponds to distinct presumable sources of antibiotic resistant bacteria and may be good indicators of the antibiotic resistance level in the water. This parameter is favoured also due to an access to low cost and reliable measurement techniques. The introduction as 'optional' parameter gives MS an opportunity to regulate ARB at the national level while maintaining harmonised approach between MS.

The values proposed correspond to 10% of resistance prevalence – which is a compromise between adequacy to monitor wastewater resistance levels and the feasibility of analyses (volumes to filter, in particular). It is proposed that instead of accepting a single criterion for value of E.coli abundance, there would be two criteria to bind – e.g. if 100 CFU is the maximum value of E. coli in 100 ml, of those 100, no more than 10 could be resistant to cefotaxime.

Although the proposed values took into account practical issues related with the analytical procedure, they express also important facts related with the water quality and human health risks. Infective doses for some pathogenic E.coli or Shigella can be as low as 10-500 cells (PLoS Pathog, 2007). In addition, the potential of antibiotic resistant bacteria to propagate in the environment is widely documented (Woolhouse Phil. Trans. R. Soc. B 2015).

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Table 14 Optional AMR reclaimed water quality criteria for agricultural irrigation for routinely monitoring.

Category of use E. coli(cfu/100 ml)

Food crops consumed raw 10 cefotaxime resistant

Processed food crops and other food crops

100 cefotaxime resistant

Non-food crops 1000 cefotaxime resistant

Table 15 Optional AMR reclaimed water quality parameters for aquifer recharge.

Category of use E. coli(cfu/100 ml)

Aquifer recharge by surface spreading for non-drinking water purposes at the present and medium future

100 cefotaxime resistant

Aquifer recharge by direct injection for non-drinking water purposes at the present and medium future

1 cefotaxime resistant

Aquifer recharge by surface spreading for drinking water purposes or intended for such future use

1 cefotaxime resistant

Aquifer recharge by direct injection for drinking water purposes or intended for such future use

Cefotaxime resistant bdl in 1000 ml

10 Additional consideration on monitoring of environmental matrices

Verification monitoring requires monitoring of the environmental matrices that may be considered in risk due to reclaimed water use.

For agricultural irrigation, soil analysis is essential to verify that the soil continues to remain fit for its intended use, and that it is appropriate for sustainable land use. Soil sampling, handling and analysis must be conducted according to quality assured methodologies. Soil properties are inherently highly variable in space and time, so correct sampling procedures are crucial to provide samples for analysis that are representative of the sample area. The use of correct sample protocols will help to ensure that detrimental changes in the soil environment are identified at an early stage, thus minimising or preventing effects on vegetation, surface and groundwaters (NRMMC–EPHC–AHMC, 2006).

Surface waters and groundwater analysis have to be implemented for aquifer recharge and also for agricultural irrigation in order to ensure that surface waters and groundwaters will not be detrimentally affected by the use of reclaimed water, according to the main purpose of the WFD. Groundwater monitoring will involve monitoring wells (bores) to provide representative water level and water quality data of the aquifer system being recharged.

48

DRAFTReferencesANZECC-ARMCANZ (2000) Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Environment and Conservation Council, Agriculture and Resource Management Council of Australia and New Zealand, Canberra, Australia.

APHA (2005) Standard Methods for the examination of Water and Wastewater. American Public Health Association APHA, Washington, DC, USA.

Asano, T., Burton, F.L., Leverenz, H., Tsuchihashi, R. and Tchobanoglous, G. (2007) Water Reuse. Issues, Technologies and Applications. Metcalf & Eddy / AECOM. McGraw-Hill, New York, USA.

Ayuso-Gabella, N., Page, D., Masciopinto, C., Aharoni, A., Salgot, M., Wintgens, T. (2011) Quantifying the effect of Managed Aquifer Recharge on the microbiological human health risks of irrigating crops with recycled water. Agric. Water Manag. 99(1), 93-102.

Bastos, R.K.X., Bevilacqua, P.D., Silva, C.A.B., Silva, C.V. (2008) Wastewater irrigation of salad crops: further evidence for the evaluation of the WHO guidelines. Water Sci. Technol. 57 (8), 1213-1219.

Bevilacqua, P.D., Bastos, R.K.X., Mara, D.D (2014) An evaluation of microbial health risks to livestock fed with wastewater-irrigated forage crops. Zoonoses and Public Health, 61 (4), 242-249.

BIO (2015) Optimising water reuse in the EU. Final report - Part 1. EC/DG-ENV, 116. Paris: Bio by Deloitte, Paris, France.

49

DRAFT

CAC (Codex Alimentarius Commission) (2003) Hazard analysis and critical control point (HACCP) system and guidelines for its application. Annex to CAC/RCP 1–1969, Rev 4. FAO/WHO, Rome, Italy.

CMD (2011) CMD No 145116 2011 Measures, limits and procedures for reuse of treated wastewater. Government of Greece.

Commission Directive 2015/1787 of 6 October 2015 amending Annexes II and III to Council Directive 98/83/EC on the quality of water intended for human consumption. L 260/6, 7 October 2015.

COM (2007) 414 Addressing the challenge of water scarcity and droughts in the European Union. Communication from the Commission to the European Parliament, and the Council. European Commission, Brussels, Belgium.

CDPH (2014) Regulations related to recycled water. California Code of Regulations. California Department of Public Health, Sacramento, California, USA.

COM (2012) 673 A Blueprint to Safeguard Europe’s Water Resources. Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions. European Commission, Brussels, Belgium.

COM (2015) 614 Closing the loop- An EU action plan for the Circular Economy. Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions. European Commission, Brussels, Belgium.

Directive 79/409/EEC of 2 April 1979 on the conservation of wild birds. Official Journal. L 103/1, 25 April 1979.

Directive 91/676/EEC of the European Parliament and of the Council of 12 December 1991 concerning the protection of waters against pollution caused by nitrates from agricultural sources. Official Journal. L 375/1, 31 December 1991.

Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora. Official Journal. L 206, 22 July 1992.

Directive 2006/7/EC of the European Parliament and of the Council of 15 February 2006 concerning the management of bathing water quality and repealing. Official Journal. L 64/37, 4 March 2006.

Directive 2014/80/EU of 20 June 2014 amending Annex II to Directive 2006/118/EC of the European Parliament and of the Council on the protection of groundwater against pollution and deterioration. Official Journal. L 182/52, 21 June 2014.

DM (2003) DM185/2003 Technical measures for reuse of wastewater. D. Lgs 152/06 - art. 74, art.124 DGR 1053/03. Government of Italy.

Drewes, J. E., Anderson, P., Denslow, N., Olivieri, A., Schlenk, D., Snyder, S.A., Maruya, K.A. (2013) "Designing monitoring programs for chemicals of emerging concern in potable reuse - what to include and what not to include?" Water Science and Technology 67(2), 433-439.

EC (1986) Directive 86/278/EEC of 12 June 1986 on the protection of the environment, and in particular of the soil, when sewage sludge is used in agriculture. Official Journal. L 181/6, 4 July 1986.

EC (1998) Directive 98/83/EC of the European Parliament and of the Council of 12 December 1998 on the quality of water intended for human consumption. Official Journal. L 330/32, 5 December 1998.

50

DRAFT

EC (2000) Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for community action in the field of water policy. Official Journal. L 327, 22 December 2000.

EC (2002) Regulation No 178/2002 of the European Parliament and of the Council of 28 January2002 laying down the general principles and requirements of food law, establishing the European Food Safety Authority and laying down procedures in matters of food safety. Official Journal. L 31, 1 February 2002.

EC (2004) Regulation No 852/2004 of the European Parliament and of the Council of 28 January2002 on the hygiene of foodstuffs. Official Journal. L 139, 30 April 2004.

EC (2006) Directive 2006/118/EC of the European Parliament and of the Council of 12 December 2006 on the protection of groundwater against pollution and deterioration. Official Journal. L 372/19, 27 December 2006.

EC (2007a). Guidance on groundwater monitoring. Guidance Document No. 15. Technical Report 002-2007, Office for Official Publications of the European Communities. ISBN 92-79-04558-X.

EC (2007b). Guidance on preventing or limiting direct and indirect inputs in the context of the Groundwater Directive 2006/118/EC. Guidance Document No. 17. Technical Report 2007-012, Office for Official Publications of the European Communities. ISBN 978-92-79-06277-3.

EC (2008) Directive 2008/105/EC of the European Parliament and of the Council of 16 December 2008 on environmental quality standards in the field of water policy amending and subsequently repealing Council Directives 82/176/EEC, 83/513/EEC, 84/156/EEC, 84/491/EEC, 86/280/EEC and amending Directive 2000/60/EC of the European Parliament and of the Council. Official Journal. L 348/84, 24 December 2008.

EC (2009). Guidance on Groundwater Status and Trend Assessment. WFD CIS Working Group on Groundwater. Guidance Document No. 18.Technical Report -2009 - 026. Office for Official Publications of the European Communities. ISBN 978-92-79-11374-1.

EC (2013) Directive 2013/39/EU of the European Parliament and of the Council of 12 August 2013 amending Directives 2000/60/EC and 2008/105/EC as regards priority substances in the field of water policy. Official Journal. L 226/1, 24 August 2013.

EC (2014) Directive 2014/52/EU of the European Parliament and of the Council of 16 April 2014 amending Directive 2011/92/EU on the assessment of the effects of certain public and private projects on the environment. Official Journal. L 124/1, 25 April 2014.

EEA (2012) Towards efficient use of water resources in Europe. EEA report No 1/2012. European Environment Agency, Copenhagen, Denmark.

EC (2014b) Technical report on aquatic effect-based monitoring tools. Technical Report 2014-077. Office for Official Publications of the European Communities, ISBN 978-92-79-35787-9.

FAO (1985). Water Quality for Agriculture. FAO Irrigation and Drainage Paper 29, rev. 1. Food and Agriculture Organization of the United Nations, Rome, Italy.

Gibney, K.B., O’Toole, J., Sinclair, M., Leder, K. (2014) Disease burden of selected gastrointestinal pathogens in Australia. International Journal of Infectious Disease 28: 176-185.

Haas, C.N., Rose, J.B, Gerba, C.P. (2014) Quantitative Microbial Risk Assessment: Second edition. Wiley Blackwell, ISBN 9781118910030.

Hamilton, A.J., Stagnitti, F., Premier, R., Boland, A.-M., Hale, G. (2006) Quantitative microbial risk assessment models for consumption of raw vegetables irrigated with reclaimed water. Appl. Environ. Microbiol. 72 (5), 3284-3290.

51

DRAFT

Hochstrat, R., Wintgens, T., Melin, T., Jeffrey, P. (2005) Wastewater reclamation and reuse in Europe: a model-based potential estimation. Water Supply, 5(1), 67-75.

ISO 16075 (2015) Guidelines for Treated Wastewater Use for Irrigation Projects. International Organization for Standardization, Geneva, Switzerland.

JORF (2014) JORF num.0153, Order of 2014, related to the use of water from treated urban wastewater for irrigation of crops and green areas. Government of France.

JRC (2014) Water Reuse in Europe. Relevant guidelines, needs for and barriers to innovation. A synoptic overview. Joint Research Centre, European Commission Publications Office of the European Union. ISBN 978-92-79-44399-2.

KDP (2005) Law 106 (l) 2002 Water and Soil pollution control and associated regulations KDP 772/2003, KDP 269/2005, Government of Cyprus.

Mara, D.D., Sleigh, P.A., Blumenthal, U.J., Carr, R.M. (2007) Health risks in wastewater irrigation: comparing estimates from quantitative microbial risk analyses and epidemiological studies. J. Water Health 5 (1), 39-50.

Navarro, I., Jiménez, B. (2011) Evaluation of the WHO helminth eggs criteria using a QMRA approach for the safe reuse of wastewater and sludge in developing countries. Water Sci. Technol. 63(7), 1499-1505.

NHMRC-NRMMC (2004) Australian drinking water guidelines. Natural Resource Management Ministerial Council, National Health and Medical Research Council. Canberra, Australia.

NHMRC-NRMMC (2011) Australian drinking water guidelines. Natural Resource Management Ministerial Council, National Health and Medical Research Council Canberra, Australia.

NP (2005) NP 4434 2005 Guidelines for Reuse of reclaimed urban water for irrigation. Portugal Quality Institute.

NRMMC-EPHC-AHMC (2006) Australian guidelines for water recycling: managing health and environmental risks: Phase 1. National Water Quality Management Strategy. Natural Resource Management Ministerial Council, Environment Protection and Heritage Council, Australian Health Ministers’ Conference. Canberra, Australia.

NRMMC-EPHC-NHMRC (2008) Australian guidelines for water recycling: managing health and environmental risks: Phase 2. Augmentation of water drinking supply. National Water Quality Management Strategy. Natural Resource Management Ministerial Council, Environment Protection and Heritage Council, Australian Health Ministers’ Conference. Canberra, Australia.

NRMMC-EPHC-NHMRC (2009) Australian guidelines for water recycling: managing health and environmental risks: Phase 2c: Managed aquifer recharge. National Water Quality Management Strategy. NRMMC-EPHC-AHMC, Canberra, Australia.

NWRI (2012) Ultraviolet Disinfection Guidelines for Drinking Water and Water Reuse. NWRI-2012-04, National Water Research Institute, USA.

Page, D., Dillon, P., Toze, S., Bixio, D., Genthe, B., Jiménez Cisneros, B.E., Wintgens, T. (2010) Valuing the subsurface pathogen treatment barrier in water recycling via aquifers for drinking supplies. Water Res. 44 (6), 1841-1852.

Petterson, S.R., Ashbolt, N.J., Sharma, A. (2001) Microbial risks from wastewater irrigation of salad crops: a screening-level risk assessment. Water Environ. Res. 72, 667-672.

RD (2007) RD 1620/2007 Legal framework for the reuse of treated wastewater. Government of Spain.

52

DRAFT

Regnery, J., Lee, J., Kitanidis, P., Illangasekare, T., Sharp, J.O., Drewes, JE. (2013). Integration of Managed Aquifer Recharge for Impaired Water Sources in Urban Settings – Overcoming Current Limitations and Engineering Challenges. Environmental Engineering Science 30(8), 409-420.

Teunis, P.F.M., Moe, C.L., Liu, P., Miller, S.E., Lindesmith, L., Barie, R.S., Pendu, J. L., Calderon, R.L. (2008) Norwalk Virus: How Infectious is it? Journal of Medical Virology 80, 1468-1476.

Toze, S., Bekele, E., Page, D., Sidhu, J., Shackleton, M. (2010) Use of static quantitative microbial risk assessment to determine pathogen risks in an unconfined carbonate aquifer used for managed aquifer recharge. Water Res. 44 (4), 1038-1049.

USEPA (2004) Guidelines for water reuse. EPA/625/R-04/108. United States Environmental Protection Agency, Washington DC, USA.

USEPA (2009). National Primary Drinking Water Regulations. EPA 816-F-09-004. United States Environmental Protection Agency, Washington DC, USA.

USEPA (2012) Guidelines for water reuse. (EPA/600/R-12/618) United States Environmental Protection Agency, Washington DC, USA.

USEPA (2012) Guidelines for water reuse. (EPA/600/R-12/618) United States Environmental Protection Agency, Washington DC, USA.

Van Houtte, E., Verbauwhede, J. (2008) Operational experience with indirect potable reuse at the Flemish coast, Desalination 218, 198-207.

Van Ginneken, M., Oron, G. (2000) Risk assessment of consuming agricultural products irrigated with reclaimed wastewater: an exposure model. Water Resources Research 36 (9), 2691-2699.

Westrell, T., Schönning, C., Stenström, T.A., Ashbolt, N.J. (2004) QMRA (quantitative microbial risk assessment) and HACCP (hazard analysis and critical control points) for management of pathogens in wastewater and sewage sludge treatment and reuse. Water Science and Technology 50(2), 23-30.

WHO (2001) Water Quality: Guidelines, Standards and Health. Assessment of risk and risk management for water-related infectious disease. IWA Publishing, London, UK. ISBN: 1 900222 28 0.

WHO (2004) Guidelines for drinking-water quality. World Health Organization, Geneva, Switzerland.

WHO (2006) Guidelines for the safe use of wastewater, excreta and greywater. Volume 2: Wastewater use in agriculture. World Health Organization, Geneva, Switzerland.WHO (2009) Water safety plan manual: step-by-step risk management for drinking-water suppliers. World Health Organization, Geneva, Switzerland.

WHO (2011) Guidelines for drinking-water quality. World Health Organization, Geneva, Switzerland.

WHO (2015) Sanitation safety planning: manual for safe use and disposal of wastewater, greywater and excreta. World Health Organization.

WHO (2016) Potable Reuse Guidelines (unpublished draft). World Health Organization, Geneva, Switzerland.

WHO (2016b) Background paper on microbiologically safe water and microbiological parameters (unpublished draft). Revision of Annex I of the Council Directive on the Quality of Water Intended for Human Consumption (Drinking Water Directive). World Health Organization, Geneva, Switzerland.

53

DRAFT

References from CECs and ARM/ARG sections

Australian Guidelines for Water Recycling: Managing Health and Environmental Risks (Phase 1), 2006. Natural Resource Management Ministerial Council Environment Protection and Heritage Council Australian Health Ministers Conference. Web copy: ISBN 1 921173 06 8; Print copy: ISBN 1 921173 07 6, November 2006.

Becerra-Castro C, Lopes AR, Vaz-Moreira I, Silva EF, Manaia CM, Nunes OC., 2015. Wastewater reuse in irrigation: a microbiological perspective on implications in soil fertility and human and environmental health. Environment International 75C:117-135.

Brand, W., De Jongh, C.M., van Linden, S.C., Mennes, W., Puijker, L.M., van Leeuwen, C., van Wezel, A., Schriks, M. and Heringa, M., 2013. Trigger values for investigation of hormonal activity in drinking water and its sources using CALUX bioassays. Environment International, 55: 109-118.

Bull, R., J. Crook, M. Whittaker, and J. Cotruvo (2011). “ Therapeutic dose as the point of departure in assessing potential health hazards from drugs in recycled municipal wastewater.” Regulatory Toxicology and Pharmacology , 60(1): 1-19.California Code of Regulations, 2014, DPH-14-003E GW Replenishment Using RW, May 30, 2014.

California Department of Public Health, 2009, Regulations Related to Recycled Water, January 2009.

DEMEAU - Demonstration of promising technologies to address emerging pollutants in water and waste water, European Union Seventh Framework Programme (FP7/2007-2013) under Grant Agreement no. 308339; www.demeau-fp7.eu.

DEMEAU WA4 Deliverable D41.1., 2015 - Selection criteria to select in vitro bioassays for implementation and use, October 2015.

DEMEAU WA4 Deliverable D41.2., 2014 - Establishment of trigger values for effect-based water quality assessment, May 2014.

DEMEAU WA4 Deliverable D42.2., 2015 - Report on robustness of novel water treatment technologies as determined with bioassays in a novel testing framework, October 2015.

54

DRAFT

Dickenson, E.R.V., Drewes, J.E., Sedlak, D.L., Wert, E.C. and Snyder, S.A., 2009. Applying Surrogates and Indicators to Assess Removal Efficiency of Trace Organic Chemicals during Chemical Oxidation of Wastewaters. Environmental Science & Technology, 43(16): 6242-6247.

Dickenson, E.R.V., Snyder, S.A., Sedlak, D.L. and Drewes, J.E., 2011. Indicator compounds for assessment of wastewater effluent contributions to flow and water quality. Water Research, 45(3): 1199-1212.

Drewes, J.E. & Horstmeyer, N.,2016. Recent Developments in Potable Reuse. D. Fatta-Kassinos et al. (eds.), Advanced Treatment Technologies for Urban Wastewater Reuse, Hdb Env Chem 45: 269–290.

Drewes, J.E. and Khan, S.,2011. Water Reuse for Drinking Water Augmentation. J. Edzwald (ed.) Water Quality and Treatment, 6th Edition. 16.1-16.48. American Water Works Association. Denver, Colorado.

Drewes, J.E., Anderson, P., Denslow, N., Olivieri, A., Schlenk, D., Snyder, S.A. and Maruya, K.A., 2013. Designing monitoring programs for chemicals of emerging concern in potable reuse - what to include and what not to include? Water Science and Technology, 67(2): 433-439.

Drewes, J.E., Sedlak, D., Snyder, S. and Dickenson, E., 2008. Development of indicators and surrogates for chemical contaminant removal during wastewater treatment and reclamation., Alexandria, VA, USA.

Duirk, S. E.; Lindell, C.; Cornelison, C. C.; Kormos, J.; Ternes, T. A.; Attene-Ramos, M.; Osiol, J.; Wagner, E. D.; Plewa, M. J.; Richardson, S. D., 2011. Formation of Toxic Iodinated Disinfection By-Products from Compounds Used in Medical Imaging. Environmental Science & Technology 45 (16), 6845-6854.

Escher B, Leusch F. Bioanalytical tools in water quality assessment, 2012. With contributions by Heather Chapman and Anita Poulson. IWA Publishing, London, UK, 2012.

Escher BI et al., 2014. Benchmarking organic micropollutants in wastewater, recycled water and drinking water with in vitro bioassays. Environ Sci Technol 48(3):1940-56.

Escher, B.I., Neale, P.A. and Leusch, F.D.L., 2015. Effect-based trigger values for in vitro bioassays: Reading across from existing water quality guideline values. Water Research, 81(0): 137-148.

Escher, B.I., Van Daele, C., Dutt, M., Tang, J.Y.M., Altenburger, R., 2013. Most oxidative stress response in water samples comes from unknown chemicals: The need for effect-based water quality trigger values. Environ. Sci Technol. 47, 7002-7011.

Escher, B.I., van Daele, C., Dutt, M., Tang, J.Y.M. and Altenburger, R., 2013. Most oxidative stress response in water samples comes from unknown chemicals: the need for effect-based water quality trigger values. Environmental Science & Technology, 47(13): 7002-7011.

FAO/WHO, 2000. Evaluation of certain veterinary drug residues in food (Fifty-second report of the Joint FAO/WHO Expert Committee on Food Additives). WHO Technical Report Series 893, 2000.

FAO/WHO. Evaluation of certain veterinary drug residues in food (Forty-second report of the Joint FAO/WHO Expert Committee on Food Additives). WHO Technical Report Series 851, 1995.

Funke, J.; Prasse, C.; Lütke Eversloh, C.; Ternes, T. A. Oxypurinol – A novel marker for wastewater contamination of the aquatic environment. Water Res. 2015, 74, 257–265.

55

DRAFT

Kaiser, E.; Prasse, C.; Wagner, M.; Bröder, K.; Ternes, T. A. Transformation of oxcarbazepine and human metabolites of carbamazepine and oxcarbazepine in wastewater treatment and sand filters. Environ. Sci. Technol. 2014, 48 (17), 10208–10216.

Kasprzyk-Horderna, B., Dinsdaleb, R.M., Guwyb. A.J. The occurrence of pharmaceuticals, personal care products, endocrine disruptors and illicit drugs in surface water in South Wales, UK. 42 (13), 2008, 3498–3518.

Khan S.J. (2013) Drinking water through recycling. A report of a study by the Australian Academy of Technological Sciences and Engineering (ATSE). Melbourne, Australia.

Kormos, J. L.; Schulz, M.; Ternes, T. A. Occurrence of iodinated X-ray contrast media and their biotransformation products in the urban water cycle. Environ. Sci. Technol. 2011, 45 (20), 8723–8732.

Kostich, M. S.; Batt, A. L.; Lazorchak, J. M. Concentrations of prioritized pharmaceuticals in effluents from 50 large wastewater treatment plants in the US and implications for risk estimation. Environ. Pollut. 2014, 184, 354–359.

Leusch FDL, de Jager C, Levi Y, Lim R, Puijker L, Sacher F, et al., 2010. Comparison of five in vitro bioassays to measure estrogenic activity in environmental waters. Environ Sci Technol 2010;44: 3853-60.

Leusch, F.D.L. and Snyder, S.A., 2015. Bioanalytical tools: half a century of application for potable reuse. Environ. Sci.: Water Res. Technol., (1): 606-621.

Loos, R.; Carvalho, R.; António, D. C.; Comero, S.; Locoro, G.; Tavazzi, S.; Paracchini, B.; Ghiani, M.; Lettieri, T.; Blaha, L.; et al. EU-wide monitoring survey on emerging polar organic contaminants in wastewater treatment plant effluents. Water Res. 2013, 47 (17), 6475–6487.

Manaia, C. M., Macedo, G., Fatta-Kassinos, D., Nunes, O. C. (2016). Antibiotic resistance in urban aquatic environments: can it be controlled? Applied Microbiology and Biotechnology. In press.

NHMRC, 2011. Australian Drinking Water Guidelines Paper 6 National Water Quality Management Strategy. www.nhmrc.gov.au/guidelines/publications/eh34, National Health and Medical Research Council (NHMRC) and the Natural Resource Management Ministerial Council, Canberra, Australia.

NRMMC & EPHC & NHMRC, 2008. Australian guidelines for water recycling: managing health and environmental risks (phase 2). Augmentation of drinking water supplies, National Water Quality Management Strategy (NWQMS), Natural Resource Management Ministerial Council (NRMMC), Environment Protection and Heritage Council (EPHC) and National Health and Medical Research Council (NHRMC), Canberra, Australia. http://www.environment.gov.au/resource/national-water-quality-management-strategy-australian-guidelines-water-recycling-managing.

Prasse, C., Stalter, D., Schulte-Oehlmann, U., Oehlmann, J. Ternes, T.A:, 2015. Spoilt for choice: A critical review on the chemical and biological assessment of current wastewater treatment technologies. Water Research, 87: 237-270.

Prasse, C.; Wagner, M.; Schulz, R.; Ternes, T. A. Biotransformation of the Antiviral Drugs Acyclovir and Penciclovir in Activated Sludge Treatment - Environmental Science & Technology (ACS Publications). Environ. Sci. Technol. 2011, 45, 2761–2769.

56

DRAFT

Rizzo, L., Manaia, C.M., Merlin, C., Schwartz, T., Dagot, D., Ploy, M. C., Michael, I., Fatta-Kassinos, D., 2013. Urban wastewater treatment plants as hotspots for antibiotic resistant bacteria and genes spread into the environment: A review. Science of the Total Environment 447: 345–360.

Schriks M, Heringa MB, van der Kooi MME, de Voogt P, van Wezel AP, 2010. Toxicological relevance of emerging contaminants for drinking water quality. Water Res 2010a;44: 461-76.

Schriks M, van Leerdam JA, van der Linden SC, van der Burg B, van Wezel AP, de Voogt P., 2010. High-resolution mass spectrometric identification and quantification of glucocorticoid compounds in various wastewaters in the Netherlands. Environ Sci Technol 2010b;44: 4766-74.

Schultz, M. M.; Furlong, E. T.; Kolpin, D. W.; Werner, S. L.; Schoenfuss, H. L.; Barber, L. B.; Blazer, V. S.; Norris, D. O.; Vajda, A. M. Antidepressant pharmaceuticals in two U.S. effluent-impacted streams: Occurrence and fate in water and sediment and selective uptake in fish neural tissue. Environ. Sci. Technol. 2010, 44 (6), 1918–1925.

Schwab, B.W., E.P. Hayes, J.M. Fiori, F.J. Mastrocco, N.M. Roden, D., Cragin, R.D. Meyerhoff, V.J. D'Aco, and P.D. Anderson (2005). “ Human pharmaceuticals in US surface waters: A human health risk assessment.” Regul. Toxicol. Pharm ., 42(3): 296– 312.

Snyder, S.A., R. Trenholm, E.M. Snyder, G.M. Bruce, R.C. Pleus, and J.D. Hemming (2008). Toxicological Relevance of EDCs and Pharmaceuticals in Drinking Water. Awwa Research Foundation Report. Water Research Foundation, Denver, CO.

Sonneveld E, Jansen HJ, Riteco JAC, Brouwer A, van der Burg B., 2015. Development of androgen- and estrogenresponsive bioassays, members of a panel of human cell line-based highly selective steroid-responsive bioassays. Toxicol Sci 2005;83: 136-48.US EPA, 2006. Drinking Water Health Advisories 2006 Edition. http://water.epa.gov/action/advisories/drinking/dwstandards.cfm. Accessed September 2015.

Tang, J.Y.M., McCarty, S., Glenn, E., Neale, P.A., Warne, M.S. and Escher, B.I., 2013. Mixture effects of organic micropollutants present in water: towards the development of effect-based water quality trigger values for baseline toxicity. Water Research 47(10): 3300-3314.

U.S. Environmental Protection Agency, 2004. Guidelines for Water Reuse, EPA/625/R-04/108, September 2004.

Umweltbundesamt, 2003a. Bewertung der Anwesenheit teil- oder nicht bewertbarer Stoffe im Trinkwasser aus gesundheitlicher Sicht. Empfehlung des Umweltbundesamtes nach Anhörung der Trinkwasserkommission beim Umweltbundesamt (Evaluation from the health point of view of the presence in drinking water of substances that are not (yet) possible or only partially possible to evaluate. Guidance of the Federal Environment Agency after consultation with the Drinking Water Commission at the Federal Environment Agency). Bundesgesundheitsblatt– Gesundheitsforschung-Gesundheitsschutz 46: 46 249-251.

Umweltbundesamt,,2003b. Maßnahmewerte (MW) für Stoffe im Trinkwasser während befristeter Grenzwert-Überschreitungen gem. § 9 Abs. 6-8 TrinkwV 2001. Empfehlung des Umweltbundesamtes nach Anhörung der Trinkwasserkommission beim Umweltbundesamt (Action values for substances in drinking water during temporary limit value exceedances. Guidance of the Federal Environment Agency after consultation with the Drinking Water Commission at the Federal Environment Agency). Bundesgesundheitsblatt–GesundheitsforschungGesundheitsschutz 46: 46 707-710.

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van der Linden SC, Heringa MB, Man H-Y, Sonneveld E, Puijker LM, Brouwer A, van der Burg B., 2008. Detection of multiple hormonal activities in wastewater effluents and surface water, using a panel of steroid receptor CALUX bioassays. Environ Sci Technol 2008;42: 5814-20.

Varela, A.V. and Manaia, C.M., 2013. Human health implications of clinically-relevant bacteria in wastewater habitats. Environmental Science and Pollution Research. 20:3550–3569.

Wernersson A-S. et al., 2015. The European technical report on aquatic effect-based monitoring tools under the water framework directive, Environmental Sciences Europe, Bridging Science and Regulation at the Regional and European Level, 201527:7, DOI: 10.1186/s12302-015-0039-4.

WHO (2010). WHO Human Health Risk Assessment Toolkit: Chemical Hazards. World Health Organization, Geneva, Switzerland.

WHO (World Health Organization), 2011. Guidelines for drinking-water quality. WHO, Geneva, Switzerland.

WHO, 2014. Antimicrobial resistance: global report on surveillance.

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ANNEX I

Reference for agronomic parameters from FAO recommendations

Table A1.1 Guidelines for evaluation of water quality for irrigation (FAO, 1985).

Potential irrigation problem and selected parameters

Units Degree on restriction on irrigation

None Slight to moderate SevereSalinity

ECw1 dS/m < 0.7 0.7 - 3.0 > 3.0TDS mg/l < 450 450 - 2000 > 2000

Infiltration

SAR2

0-3and ECw =

> 0.7 0.7 - 0.2 < 0.23-6 > 1.2 1.2 - 0.3 < 0.36-12 > 1.9 1.9 - 0.5 < 0.512-20 > 2.9 2.9 - 1.3 < 1.320-40 > 5.0 5.0 - 2.9 < 2.9

Specific ion toxicity

Sodium (Na)3

surface irrigation SAR < 3 3 - 9 > 9sprinkler irrigation meq/l < 3 > 3Chloride (Cl)surface irrigation meq/l < 4 4 - 10 > 10sprinkler irrigation meq/l < 3 > 3Boron (B) mg/l < 0.7 0.7 - 3.0 > 3.0

Miscellaneous effects (affects susceptible crops)

Nitrate (NO3-N) mg/l < 5 5 - 30 > 30Bicarbonate (HCO3) meq/l < 1.5 1.5 - 8.5 > 8.5pH Normal range 6.5-8.4

1 ECw: electrical conductivity. Reported in dS/m at 25°C (dS/m) or in mmho/cm; both are equivalent.2 SAR: sodium adsorption ratio. At a given SAR, infiltration rate increases as water salinity increases. 3 For surface irrigation, most tree crops and woody plants are sensitive to sodium and chloride; most annual crops are not sensitive. With overhead sprinkler irrigation and low humidity (< 30 percent), sodium and chloride may be absorbed through the leaves of sensitive crops.

Table A1.2 Recommended maximum concentration of trace elements in irrigation water (FAO, 1985).

Constituent Maximum concentration for irrigation

(mg/l)

Remarks

Aluminium 5.0 Can cause non-productivity in acid soils (pH < 5.5), but more alkaline soils at pH > 7.0 will precipitate the ion and eliminate any toxicity.

Arsenic 0.10 Toxicity to plants varies widely, ranging from 12 mg/l for Sudan grass to less than 0.05 mg/l for rice.

Beryllium 0.10 Toxicity to plants varies widely, ranging from 5 mg/l for kale to 0.5 mg/l for bush beans.

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Constituent Maximum concentration for irrigation

(mg/l)

Remarks

Cadmium 0.01 Toxic to beans, beets and turnips at concentrations as low as 0.1 mg/l in nutrient solutions. Conservative limits recommended due to its potential for accumulation in plants and soils to concentrations that may be harmful to humans.

Cobalt 0.05 Toxic to tomato plants at 0.1 mg/l in nutrient solution. Tends to be inactivated by neutral and alkaline soils.

Chromium 0.10 Not generally recognized as an essential growth element. Conservative limits recommended due to lack of knowledge on its toxicity to plants.

Copper 0.20 Toxic to a number of plants at 0.1 to 1.0 mg/l in nutrient solutions.Fluoride 1.0 Inactivated by neutral and alkaline soils.Iron 5.0 Not toxic to plants in aerated soils, but can contribute to soil acidification

and loss of availability of essential phosphorus and molybdenum. Overhead sprinkling may result in unsightly deposits on plants, equipment and buildings.

Lithium 2.5 Tolerated by most crops up to 5 mg/l; mobile in soil. Toxic to citrus at low concentrations (<0.075 mg/l). Acts similarly to boron.

Manganese 0.20 Toxic to a number of crops at a few-tenths to a few mg/l, but usually only in acid soils.

Molybdenum

0.01 Not toxic to plants at normal concentrations in soil and water. Can be toxic to livestock if forage is grown in soils with high concentrations of available molybdenum.

Nickel 0.20 Toxic to a number of plants at 0.5 mg/l to 1.0 mg/l; reduced toxicity at neutral or alkaline pH.

Lead 5.0 Can inhibit plant cell growth at very high concentrations.Selenium 0.02 Toxic to plants at concentrations as low as 0.025 mg/l and toxic to

livestock if forage is grown in soils with relatively high levels of added selenium. As essential element to animals but in very low concentrations.

Tin, Tungsten and Titanium

- Effectively excluded by plants; specific tolerance unknown.

Vanadium 0.10 Toxic to many plants at relatively low concentrations.Zinc 2.0 Toxic to many plants at widely varying concentrations; reduced toxicity

at pH > 6.0 and in fine textured or organic soils.

Basic assumptions and comments from the FAO recommendations:

The FAO recommendations are intended to cover the wide range of conditions encountered in irrigated agriculture practices. Several basic assumptions were used to define their range of values (more detailed information is reported in FAO (1985)). Where sufficient experience, field trials, research or observations are available, the guidelines may be modified to fit local conditions more closely.The basic assumptions are the following (FAO, 1985, USEPA, 2012):Yield Potential: Full production capability of all crops, without the use of special practices, is assumed when the guidelines indicate no restrictions on use. A “restriction on use” indicates that choice of crop may be limited or that special management may be needed to maintain full production capability; it does not indicate that the water is unsuitable for use.Site Conditions: Soil texture ranges from sandy-loam to clay-loam with good internal drainage; the climate is semi-arid to arid, and rainfall is low. Rainfall does not play a significant role in meeting crop water demand or leaching requirement. Drainage is assumed to be good, with no uncontrolled shallow water table present within 2 meters of the surface.Method of Irrigation: Normal surface or sprinkler irrigation methods are used; water is applied infrequently, as needed, and the crop utilizes a considerable portion of the available stored soil-water (50 percent or more) before the next irrigation. At least 15 percent of the applied water percolates below the root zone. The guidelines are too restrictive for specialized irrigation methods, such as localized drip irrigation, which results in near daily or frequent irrigations, but are applicable for subsurface irrigation if surface-applied leaching satisfies the leaching requirements.

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Restriction on Use: The “Restriction on Use” is divided into three degree of severity: none, slight to moderate, and severe. The divisions are somewhat arbitrary because changes occur gradually, and there is no clear-cut breaking point. A change of 10 to 20 percent above or below a guideline value has little significance if considered in proper perspective with other factors affecting yield. Field studies, research trials and observations have led to these divisions, but management skill of the water user can alter the way in which the divisions are interpreted for a particular application. Values shown are applicable under normal field conditions prevailing in most irrigated areas in the arid and semi-arid regions of the world.The recommended maximum concentrations of trace elements and nutrients constituents in reclaimed water for “long-term continuous use on all soils” are set conservatively based on application to sandy soils that have adsorption capacity. These values have been established below the concentrations that produce toxicity when the most sensitive plants are grown in nutrient solutions or sand cultures to which the constituent has been added. Thus, if the suggested limit is exceeded, phytotoxicity will not necessarily occur; however, most of the elements are readily fixed or tied up in soil and accumulate with time such that repeated application in excess of suggested levels is likely to induce phytotoxicity (USEPA, 2012). There are also related effects of pH on plant growth, which are primarily related to its influence on metal toxicity, as a result, a pH range of 6-8 is recommended for reclaimed water used for irrigation.

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ANNEX IIReference for log10 removals of preventive measuresTable A2.1 Indicative log10 removals of pathogens and indicator microorganisms for several wastewater treatments (USEPA, 2012).

Pathogenic microorganisms Indicator microorganisms

Ente

ric

bact

eria

Ente

ric

viru

ses

Gia

rdia

lam

blia

Cryp

torp

orid

ium

par

vum

Esch

eric

hia

coli

Clos

trid

ium

pe

rfri

ngen

s

Bact

erio

phag

es

Type of wastewater treatment

Indicative log10 removals1

Secondary treatment

1.0-3.0 0.5-2.0 0.5-1.5 0.5-1.0 1.0-3.0 0.5-1.0 0.5-2.5

Dual media filtration2

0-1.0 0.5-3 1.0-3.0 1.5-2.5 0-1.0 0-1.0 1.0-4.0

Membrane filtration3

4.0->6.0 2.0->6.0 >6.0 >6.0 4.0->6.0 >6.0 2.0->6.0

Reservoir storage

1.0-5.0 1.0-4.0 3.0-4.0 1.0-3.5 1.0-5.0 N/A 1.0-4.0

Ozonation 2.0-6.0 3.0-6.0 2.0-4.0 1.0-2.0 2.0-6.0 0-0.5 2.0-6.0Ultraviolet disinfection

2.0->6.0 1.0->6.0 3.0-6.0 3.0-6.0 2.0->6.0 N/A 3.0->6.0

Advanced oxidation

>6.0 >6.0 >6.0 >6.0 >6.0 N/A >6.0

Chlorination 2.0->6.0 1.0-3.0 0.5-1.5 0-0.5 2.0->6.0 1.0-2.0 0-2.51: Reduction rates depend on specific operating conditions, such as retention times, contact times and concentrations of chemicals used, pore size, filter depths, pretreatment, and other factors. Ranges given should not be used as design or regulatory bases—they are meant to show relative comparisons only. 2: Including coagulation. 3: Removal rates vary dramatically depending on the installation and maintenance of the membranes. N/A = not available.

Table A2.2 Indicative types of on-site preventive measures and the provided pathogens exposure reduction for agricultural irrigation (NRMMC-EPHC-AHMC, 2006; WHO, 2006; USEPA, 2012 and ISO, 2015).

Type of preventive measure Pathogen exposure reduction

(log10 units)

Comments

On-site preventive measures

Drip irrigation of low-growing crops 2 Root crops and crops that grow just above, but partially in contact, with the soil.

Drip irrigation of high-growing crops 4 Crops the harvested parts of which are not in contact with the soil.

Sprinkler irrigation 1-2

Pathogen die-off (withholding periods)

0.5-2 per day

Die-off on crops that occurs between last irrigation cessation before harvest. The log unit reduction achieved depends on climate conditions, crop type.

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