Development of an advanced, innovative, desalination ...solbrine.uest.gr/uploads/files/deliverable_5.2.pdf · Deliverable 5.2 Report on LCA of the brine treatment system Action 5

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LIFE+ Environment project: LIFE09 ENV/GR/000299

Development of an advanced, innovative, energy autonomous system for the treatment of brine from seawater

desalination plants

SOL-BRINE

Deliverable 5.2 Report on LCA of the brine treatment system

Action 5 Design of an innovative, pilot-scale, energy autonomous brine treatment system

Prepared by

Tinos

NTUA

1st Revisions

ATHENS, December 2015

Acknowledgements

This report was produced under co-finance of the European financial instrument for the Environment (LIFE+) as the second deliverable (D5.2) of the fifth Action of Project “SOL-BRINE” (LIFE 09 ENV/GR/000299) entitled “Design of an innovative, pilot-scale, energy autonomous brine treatment system”.

SOL-BRINE team would like to acknowledge the European financial instrument for the Environment (LIFE+) for the financial support. The authors can be contacted for enquiries, corrections or other remarks1.

Disclaimer The information included herein is legal and true to the best possible knowledge of the authors, as it is the product of the utilization and synthesis of the referenced sources, for which the authors cannot be held accountable.

1 Email: [email protected]

mailto:[email protected]

Deliverable 5.2: Report on LCA of the brine treatment system

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Contents 1 INTRODUCTION ........................................................................................................................ 9

1.1 BACKGROUND INFORMATION ........................................................................................................ 9 1.2 AIM AND OBJECTIVES................................................................................................................. 10 1.3 LIFE CYCLE ASSESSMENT ............................................................................................................. 11

1.3.1 General Information ........................................................................................................ 11 1.3.2 LCA tool ............................................................................................................................ 11 1.3.3 Assumptions and limitations ............................................................................................ 11

2 GOAL AND SCOPE DEFINITION ................................................................................................ 13

2.1 INTRODUCTION ......................................................................................................................... 13 2.1.1 General information ........................................................................................................ 13 2.1.2 Short description of SimaPro ........................................................................................... 14

2.2 IMPACT ASSESSMENT METHOD ................................................................................................... 15 2.2.1 CML 2 Baseline 2000 ........................................................................................................ 15 2.2.2 Characterization and Normalization ................................................................................ 15

2.3 SYSTEM BOUNDARIES ................................................................................................................ 16 2.4 DATA INPUT ............................................................................................................................. 19

3 INVENTORY ANALYSIS ............................................................................................................ 20

3.1 SYSTEM DESCRIPTION ................................................................................................................. 20 3.1.1 Feed water tank ............................................................................................................... 20 3.1.2 Evaporator unit ................................................................................................................ 20 3.1.3 Crystallizer ....................................................................................................................... 23 3.1.4 Dryer ................................................................................................................................ 24 3.1.5 Solar Energy System ......................................................................................................... 24 3.1.6 Transportation ................................................................................................................. 26 3.1.7 Installation ....................................................................................................................... 26 3.1.8 Resources / materials ...................................................................................................... 27

3.2 FINAL INVENTORY ..................................................................................................................... 29

4 IMPACT ASSESSMENT ............................................................................................................. 31

4.1 BASIC RESULTS .......................................................................................................................... 31 4.2 BENEFITS FROM THE UTILISATION OF THE PRODUCED SALT ................................................................. 57 4.3 ECO-BURDENS FROM BRINE DISPOSAL INTO THE OCEAN .................................................................... 70 4.4 COMPARISON WITH CONVENTIONAL SOURCES OF ELECTRICITY / HEAT .................................................. 71

5 REFERENCES ........................................................................................................................... 78


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List of figures Figure 1-1: SOL-BRINE concept ................................................................................................................ 9 Figure 2-1: SOL-BRINE flow process diagram ........................................................................................ 13 Figure 2-2: Mass balance of the pilot brine treatment system. ............................................................ 18 Figure 3-1: Raw materials (Super Duplex tubes and plates) .................................................................. 21 Figure 3-2: Photos from the construction of the evaporator unit ......................................................... 22 Figure 3-3: Evaporator unit.................................................................................................................... 22 Figure 3-4: Crystallizer unit .................................................................................................................... 23 Figure 3-5: Installation of the dryer ....................................................................................................... 24 Figure 3-6: Solar energy system ............................................................................................................ 25 Figure 3-7: Installation of the pilot brine treatment system ................................................................. 27 Figure 4-1: The basic model of the PV (not all products are visible) ..................................................... 32 Figure 4-2: Characterised results from the PV module ......................................................................... 33 Figure 4-3: Analysis of the characterised results from the PV module ................................................. 34 Figure 4-4: The basic model of the ETC (not all products are visible) ................................................... 36 Figure 4-5: Characterised results from the ETC module ........................................................................ 37 Figure 4-6: Analysis of the characterised results from the ETC module ................................................ 38 Figure 4-7: The basic model of the Feed Water Tank ............................................................................ 40 Figure 4-8: Characterised results from the Feed Water Tank module .................................................. 41 Figure 4-9: The basic model of the Evaporator (not all products are visible) ....................................... 43 Figure 4-10: Anasysis of the characterised results from the Evaporator module ................................. 44 Figure 4-11: The basic model of the Crystallizer (not all products are visible) ...................................... 46 Figure 4-12: Analysis of the characterised results from the Crystallizer module .................................. 47 Figure 4-13: The basic model of the Dryer (not all products are visible) .............................................. 49 Figure 4-14: Analysis fo the characterised results from the Dryer module ........................................... 50 Figure 4-15: The basic model of the System (not all products are visible) ............................................ 52 Figure 4-16: Characterised results of the System .................................................................................. 53 Figure 4-17: Normalised results of the System ..................................................................................... 55 Figure 4-18: Analysis fo the characterised results from the salt production (1 kg) ............................... 58 Figure 4-19: Summary of the characterised results of the System, taking into consideration benefits from salt utilisation ............................................................................................................................... 60 Figure 4-20: Global Warming characterised results of the System, taking into consideration benefits from salt utilisation ............................................................................................................................... 61 Figure 4-21: Acidification characterised results of the System, taking into consideration benefits from salt utilisation ........................................................................................................................................ 62 Figure 4-22: Eutrophication characterised results of the System, taking into consideration benefits from salt utilisation ............................................................................................................................... 63 Figure 4-23: Human toxicity characterised results of the System, taking into consideration benefits from salt utilisation ............................................................................................................................... 64 Figure 4-24: Marine aquatic ecotoxicity characterised results of the System, taking into consideration benefits from salt utilisation ................................................................................................................. 65 Figure 4-25: Photochemical oxidation characterised results of the System, taking into consideration benefits from salt utilisation ................................................................................................................. 66 Figure 4-26: Summary of the normalised results of the System, taking into consideration benefits from salt utilisation ............................................................................................................................... 68 Figure 4-27: Characterised results of the System (CER) ........................................................................ 72 Figure 4-28: Normalised results of the System (CER) ............................................................................ 73


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Figure 4-29: Comparison of characterized results of each system ........................................................ 75 Figure 4-30: Comparison of normalized results of each system ........................................................... 76


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List of drawings Drawing 3-1: Mass and energy balances during the system's operation .............................................. 30


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List of tables Table 4-1: Characterised results of the System ..................................................................................... 54 Table 4-2: Normalised results of the System (1/year) ........................................................................... 56 Table 4-3: Characterised and normalised results of salt production (1 kg) ........................................... 57 Table 4-4: Characterised results of the System (with salt benefit) ....................................................... 59 Table 4-5: Normalised results of the System (with salt benefit) (1/year) ............................................. 67 Table 4-6: Characterised results of the System (CER) ........................................................................... 74 Table 4-7: Normalised results of the System (CER) (1/year) ................................................................. 74


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1 Introduction

1.1 Background information

Main goal of SOL-BRINE project is the design, development, test, demonstration, optimization and evaluation of an innovative pilot scale energy autonomous brine treatment system for water recovery and production of a dry salt with potential market value. The system is expected to eliminate brine produced by desalination units, in line with the Zero Liquid Discharge concept and the objectives of Water Framework Directive (2000/60/EC) by significantly contributing to the protection of inland surface waters, transitional waters, coastal waters and groundwater (see Figure 1-1).

The system’s structural components have been determined in activity 2(a). For each system’s component (process unit) a mathematical model have been also developed, based on mass and energy balances and on the equations used for sizing and designing purposes. These models were used for the development of a simulator which was built in Visual Basic Environment and can be run as an Excel application

Within the framework of Action 3, the engineering, construction and installation of the pilot-scale, energy-autonomous, brine treatment system took place. The system was constructed according to the engineering drawings that were produced during the design stage (Action 2) of the project implementation. The reader can find more information regarding the design of the prototype system at: http://uest.ntua.gr/solbrine.

Figure 1-1: SOL-BRINE concept

http://uest.ntua.gr/solbrine


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1.2 Aim and Objectives

The overall aim of this technical report is to assess the environmental performance of the system, by conducting a Life Cycle Assessment (LCA).

LCA has become a well-known and commonly used method which finds extended application in water management systems or subsystems (e.g. Nessi et al, 2012, Amores et al, 2013, Risch et al, 2014, Fantin et al, 2014). Assessing the environmental performance of the brine treatment system using LCA, is expected to lead to a comprehensive evaluation of the system under examination, and possible in the future to provide results for comparison with other water management systems or subsystems.

During Action 2, a preliminary LCA of the system was performed. More specifically, in Deliverable 2.3, by using the process simulator developed during Activity 2(b), different scenarios (processes and design parameters) were developed and evaluated in order to achieve increasing environmental and economic performance of the innovative brine treatment system. In brief, the main area affected by the system production in any scenario was marine eco-toxicity.

Furthermore, environmental impacts of the second scenario that involved a thermal and mechanical compressor decrease in comparison to any other alternative. The use of the thermal compressor for the compression of the vapors of the evaporator (MED) unit (third effect) results to energy savings and to minimal energy requirements, as the energy content of the vapors is recovered. The same energy recovery was achieved with the use of the vapor compressor in the crystallizer unit. However it is very important to be noted that these results could only be used for comparative purposes, since the system boundaries were very narrow.

Further to the preliminary study, here the total environmental performance of the system is assessed, based on real operating data. In order to capture the minimum benefits of its operation, LCA is conducted for the system without taking into consideration possible benefits from utilisation of salt, as well as for not disposing brine into the ocean. Regarding the first (salt utilisation), since the possess produces salt that can be used in numerous applications, an off-set benefit could be allocated in order to take into consideration impacts that can be avoided from average salt production. This benefit however is calculated separately, since it can be considered time and location dependant. Regarding brine disposing into the ocean, LCA studies cannot quantify its aquatic eco-toxic potential mainly due to the limitation of current life cycle impact assessment (LCIA) approaches. Thus, a separate benefit is estimated, based on various local and case-specific assumptions.

Finally, a comparison of the original system was performed with one that uses conventional sources of electricity and heat, instead of Photovoltaic units (PV) and Evacuated tube collectors (ETC).


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1.3 Life Cycle Assessment

1.3.1 General Information

LCA in general, is a systematic way of evaluating the environmental impact of products or activities by following a ‘cradle to grave’ approach. This approach implies the identification and quantification of emissions and energy as well as material consumption which affects the environment at all stages of the entire product of life cycle (ISO 14044, 2006]. Thus for each process within the life cycle, detailed inventories of the material and energy inputs and outputs are produced. In this way a life cycle inventory (LCI) is compiled which accounts for the total inputs and outputs of all energy and material flows attributable to the provision of a particular service or product (ISO 14040, 2006). The goal of LCA is to compare the full range of environmental effects assignable to products and services in order to improve processes, support policy and provide a sound basis for informed decisions. Final, it must be noted that the procedures of LCA are part of the ISO 14000 environmental management standards: in ISO 14040:2006 and 14044:2006.

1.3.2 LCA tool

As the LCA modelling and analysis tool, the software SimaPro 7 (System for Integrated environMental Assessment of PROducts), developed by the Dutch PRé Consultants (www.pre.nl), will be used.

At this point must be noted that the brine treatment system is powered exclusively by solar energy, demonstrating a highly innovative and environmental friendly character.

Moreover, as no energy requirements is covered by the use of fossil fuels or the electrical grid, the system is regarded as energy-autonomous application. Thus, there no negative impacts from its operation and focus have been given on infrastructure, design parameters and actual performance (activity data).

1.3.3 Assumptions and limitations

Finally, it is important to make some reservations regarding further implication of results of the LCA method outside the actual case. First of all, LCA typically does not address the economic or social aspects of a product. Moreover, LCA addresses potential and not actual environmental impacts and does not predict absolute or precise environmental impacts due to the relative expression of potential environmental impacts to a reference unit, the integration of environmental data over space and time, and the inherent uncertainty in modeling of environmental impacts (ISO 14040, 2006).

Furthermore, LCA is not a complete assessment of all environmental issues of the product system under study, since it addresses only the environmental issues that are specified in


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the narrow goal and scope of the study, within limited system boundaries, for comparison reasons.

Thus it cannot always demonstrate significant differences between impact categories and the related indicator results of alternative systems, while the results are dependent on the common-basis assumptions.


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2 Goal and Scope definition

2.1 Introduction

2.1.1 General information

As defined in an earlier stage of the project, the system comprises by the following main structural components (Figure 2-1, A):

• a: Feed water tank • b: Evaporator • c: Crystallizer • d: Dryer

Figure 2-1: SOL-BRINE flow process diagram

As illustrated in Figure 2-1 (B), the brine treatment system is provided with energy by renewable energy sources and in particular solar energy. The devices used are for captivating solar energy are the following:

• e: Evacuated tube collectors (ETC) • f: Photovoltaic units (PV)

Feedstock was a small portion of the brine rejected from Tinos seawater desalination plant (~500 kg/day). The brine treatment system is fed with brine at 7% (measured at normal operating conditions) from the existing desalination plant situated in Agios Fokas. The salt concentration of the brine introduced in the evaporator unit was measured at 7%. This


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means that theoretically, some 35 kg of salt shall be produced by the pilot unit per day of operation.

Due to the fact that energy requirements is covered by renewable sources (hence there no negative impacts from its operation), LCA was used to calculate total potential impacts from its construction. As previously mentioned, it is highly recommended not to compare the results with other systems, since the boundaries are very narrow and the data very time and local specific. Nevertheless, results could be used for comparative reasons if divided with total amount of brine treated to calculate potential impacts from the treatment of 1m3 of brine 7%.

2.1.2 Short description of SimaPro

As mentioned, the software SimaPro 7 developed by the Dutch PRé Consultants (PRé, 2010), will be used as the LCA modelling and analysis tool.

SimaPro is a well-known, internationally accepted and validated tool and since its development in 1990 has been used in a large number of LCA studies (SimaPro is used in more than 80 countries serviced by our global partner network – Pre, 2011). The software allows to model and analyse complex life cycles in a systematic and transparent way, following the recommendations of the ISO 14040 and 140444 (2006) series of standards.

Included in the software are several inventory databases (libraries) with a range of data on most commonly used materials and processes, such as steel manufacture, electricity production, transportation etc and materials such as plastics, chemicals, electronics, ferro and non ferro metals etc, which can be used for background data in the study.

SimaPro distinguishes five process types (materials, energy, transport, processing, use, waste scenario and waste treatment) each of which can be either a unit process, i.e. describing a single operation or a process system describing a set of unit processes as if it is one process. All process types are used to quantify the flows of resources, products and emissions in and out of the system and the main purpose of process classification is to facilitate model building (Goedkoop et al., 2010).

Product stages describe the way a product is produced, used and disposed of and they have links to processes, which contain the flow data. SimaPro by default has five product stages (Goedkoop et al., 2010):

1. an assembly, which defines the production stage of the product studied

2. the life cycle stage, which describes the total life cycle and therefore links to the assembly and disposal stages, as well as any processes during the use of the product.

3. a disposal scenario, which describes the end of life scenario for the product if disassembled or reused,


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4. a disassembly scenario, which describes what parts of a product are being disassembled and where the disassembled parts and the remaining parts are going,

5. a reuse stage, which describes the processes needed to reuse a product or a disassembled part and

At this stage the basic model of the system life cycle is built by creating the unit processes and interconnecting them into an assembly network through products and co-products, depending on the scenario.

Subsequently, data were collected and collated based on the data collection plan defined in section 2.2. Furthermore, both inventory analysis and impact assessment steps were undertaken using SimaPro software.

2.2 Impact Assessment Method

2.2.1 CML 2 Baseline 2000

The results of the present LCA have been analyzed following the CML 2 Baseline 2000 method (CML, 2010). The CML 2 Baseline 2000 Impact Assessment method is based on the classic midpoint indicators. The CML 2 Baseline 2000 Impact Assessment method. Ten indicators are given to characterize environmental impacts, namely abiotic depletion, global warming (GWP 100), photochemical oxidation, ozone layer depletion (ODP), human toxicity, fresh water aquatic ecotoxicity, marine aquatic ecotoxicity, terrestrial ecotoxicity, acidification and eutrophication. As mentioned in preliminary LCA (Activity 2(b) - Deliverable 2.3), by using a mid-point method, a number of problems and complexities associated with damage methods are avoided. The distinction between mid-point and end-point methods is based on the cause-effect chain or environmental mechanism of environmental problems. The cause-effect chain starts with some activities which lead to what can be seen as primary changes in the environment. These primary changes lead to secondary and tertiary changes etc. Earlier in the cause-effect chain are often chemical and physical changes, for example changes in concentrations in the atmosphere. Further down the cause-effect chain can be biological changes, for example changes in ecosystems or human health. Ideally, all of the impact pathways that lead from mid to end points would be proven and quantified. However, some impact pathways are extremely complex, and for this reason, midpoints have often been chosen at a point at which further modelling is considered to become too uncertain.

2.2.2 Characterization and Normalization

As mentioned in Deliverable 2.3, during characterization phase, each emission is multiplied by the relevant impact category characterization factor given by the CML 2 Baseline 2000


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Impact Assessment method. In this way, the relative contribution of the different pollutants in each category is identified. The normalization phase was used to compare the different impact categories in absolute numbers, using the average global emissions per capita. Each value is divided by the average worldwide emission of that substance per total world population. Noted that before the normalization stage, the results cannot be plotted on a scale; they are essentially dimensionless without the normalization stage and difficult to conceptualize for those without more than a passing knowledge of LCA. During normalization step, a calculation of average global emissions of each substance is divided by the total world population sourced from the CML 2 Baseline 2000 Impact Assessment method (1995 World Total indicators), which is then used as a reference and each of the results of the characterization stage is divided by this value.

2.3 System Boundaries

As previously mentioned, the system can be regarded as energy-autonomous application, thus, impacts from its operation are not expected, and focus will be given on infrastructure and design parameters.

The life cycle of the system in general comprises of the following stages (based on guidelines from SETAC, 2002):

• Raw material extraction: The life cycle of its component (evaporator, crystallizer etc) starts with the extraction of the raw materials. Each component is made of a large variety of materials and substances. This phase includes both the production of raw material and the use of these raw materials to produce other materials and substances. The environmental aspects and impacts from this phase arise from the mining operations, refining of ores, and manufacturing of materials and substances.

• Components manufacture: This phase covers the manufacturing of the components used in the system. The components manufacture is characterised by several environmental aspects main among them being energy consumption and use of materials with various properties. The role of component manufacturers is crucial to reduce the environmental impacts from this phase.

• Components transportation: The environmental impacts in this phase mainly arise from the energy consumption of the carriers.

• Demolition - Final Disposal/Recycle/Waste management stage: Begins after the system has served its intended purpose and includes the mainly the solid waste management system.


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As previously mentioned, there are no negative impacts from its operation, since it utilises solar power.

Next, a mass balance of the pilot brine treatment system is presented.


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Figure 2-2: Mass balance of the pilot brine treatment system2.

2 The quantities of distilled water produced are marked in pink, while the salt in blue color.

500kg/day

(465kg H2O/day) (35kg Salt/day)

330kg H2O/day

170kg/day

105kg H2O/day

30kg H2O/day

35kg Salt/day

65kg/day


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2.4 Data Input

The following data were used:

Data from the system construction: data regarding the construction of the system was sourced from all the companies involved into the manufacturing process.

Results from the system operation: The pilot system was operated for a sustained period of time (>12 months) and the collected samples were analyzed in the laboratory facilities of NTUA.


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3 Inventory Analysis

3.1 System description

In order to achieve Zero Liquid Discharge, all the amount of water must be gradually removed from the brine effluent until solid salt crystals are obtained. As previously mentioned, in order for this to be achieved the following units are employed:

• Feed water tank • Evaporator unit • Crystallizer unit • Dryer • Solar system (Evacuated tube collectors and Photovoltaic units)

Following, a brief description of the process involved within each of these units is discussed. The reader can find more details at the relevant report on the results of the design stage (Deliverable 2.4).

3.1.1 Feed water tank

Feed water tank3 is made by Polyethylene (PE) which is one of the most versatile thermoplastic in use today. It is used extensively in all walks of life, from food packaging to home construction and has an excellent strength-to-weight ratio and superior flame resistance. The total volume of the tank is 1 m3, and for its construction was used around 25 kg Polyethylene (PE).

3.1.2 Evaporator unit

The evaporator unit is consisted of two (2) consecutive effects operated at decreasing levels of pressure. In each of the evaporator effects, the brine is evaporated and two subsequent streams are produced: a water vapor stream, which is subsequently condensed and recovered as fresh

water, and a more concentrated brine stream, which is driven to the subsequent treatment

stage.

3 Impacts from feed water tank are taken into consideration, although during the system operation water tank was by-passed because the water flow from the desalination plant was perfectly controlled.


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The vapor stream of the first effect is used for heating the concentrated brine produced which is sprayed on the top of the bundle and runs down from tube to tube by gravity. This way, the required latent heat for the vaporization of the brine in the second effect is provided by internal heat gain (heating steam from the first effect) and thus energy recovery is achieved. The vapor stream produced by the second effect is used for pre-heating purposes. More pertinently, the vapor is passed through and condensed in a plate heat exchanger, transferring its thermal energy to the inlet feed brine stream. Thus, thermal energy and fresh water is recovered to the best possible extent.

The concentrated stream produced by the second effect is then passed to the crystallizer unit where it is further concentrated. The concentration of the evaporator exit stream is designed to be near saturation point.

The unit was constructed in workshop facilities of Thermossol Company in Athens, Greece. The actual construction schedule deviated from the original plan due to complications with the acquisition of certain raw materials, namely austenitic-ferritic stainless steel of special grade (Stainless Steel Super Duplex / EN 1.4410 / UNS S32750). Even though sophisticated materials such as titanium and zirconium exhibit very good corrosion resistance behavior, they induced high cost burden to the acquisition and processing of the materials, and thus were avoided.

Following photos from the construction of the prototype are provided.

Figure 3-1: Raw materials (Super Duplex tubes and plates)


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Figure 3-2: Photos from the construction of the evaporator unit

Figure 3-3: Evaporator unit


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In total, for the construction of the evaporator unit were used 390 kg of Stainless Steel Super Duplex, 25 kg of INOX Stainless Steel 316L, 80 kg of Steel ST52, 10 kg of Aluminum alloy (Al alloy), 10 kg of Copper (Cu) and 5 kg Polypropylene (PP). Energy consumption for welding was considered to be negligible.

3.1.3 Crystallizer

Crystallizer (as the evaporator unit) is based on the physical process of vacuum evaporation. The crystallizer is consisted of a single vessel maintained at lower levels of pressure. The crystallizer unit is equipped with scraping blades inside the boiling vessel for allowing high evaporation rates through cleaning of the heat transfer surfaces from the formed salt crystals and good agitation. The vacuum is maintained through the combined use of a pump and an ejector.

Its purpose is to crystallize the brine effluent, producing a slurry (magma) with humidity levels of approximately 50%. The whole process is characterized by energy efficiency through the combined use of vacuum technology and heat pump.

Figure 3-4: Crystallizer unit

The crystallizer unit was purchased ready-to-use, and it was mainly made of

ΙΝΟΧ Stainless steel 316L Stainless Steel Super Duplex Polypropylene (PP) Metal (Copper and Aluminum alloy)


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More specifically, for the construction of the Crystallizer were used in total 156 kg of ΙΝΟΧ 316L, 78 kg of Stainless Steel Super Duplex, 11 kg of PP, around 20 kg of Cu and 5 kg of Al alloy.

3.1.4 Dryer

The magma leaves the crystallizer with an amount of moisture. In order to obtain the dry salt products a solar dryer was employed. The dryer was constructed in situ, and for its construction, 100 kg of Galvanized steel, 15 kg Steel St52 and 10 kg of nylon were used.

Following photos from the construction of the dryer are provided.

Figure 3-5: Installation of the dryer

3.1.5 Solar Energy System

The energy requirements of the pilot brine treatment system were covered through the use of solar energy. The thermal requirements were supplied by concentrating evacuated tube


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collectors through hot water at 80oC, while the electrical requirements through the use of an autonomous photovoltaic generator.

Following photos from the solar energy system are provided.

Figure 3-6: Solar energy system

Photovoltaic (PV) Panels

Data for Photovoltaic Panels were sourced from Simapro (PV-module, monocrystalline, silicon). Included processes are production of the cell matrix, cutting of foils and washing of glass, production of laminate, isolation and aluminium frame of the panel. Disposal after end of life is also taken into consideration. Data for direct air and water emissions were not available, but it can be expected that small amount of non-methane volatile organic compounds (NMVOC) will be emitted from the lamination process. The data concern 1 m2 of PV panel, while cell size, amount and capacity might differ between different producers. Life cycles for batteries and convertors are proportionally included.

Concerning geographical issues, average data from several local to global sized companies were used (main focus is on Germany and Europe). Transportation within Europe is included (average values).

In total, 19,2 m2 of PV panels were used.

Evacuated Tube Collectors (ETC)

The area collector consists of an absorber, a covering (single glazing), an isolation, a casing and frame and a sealing. Absorber material is copper (gilled absorbers). Glazing materials is glass, isolation materials are mineral fibers, and the casing is made out of aluminium.


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Inventory data comprise materials and transport services required. Energy demand for manufacturing is not included except for the selective coatings (molybdenum, nickel-pigmented aluminiumoxide) and the storage tanks. NMVOC and particulates-emissions during manufacturing (from coatings and welding, respectively) are included. Land use of the collectors mounted on the roof is considered as well. End of life waste treatment processes of solar collectors are included, although based on assumptions due to little experience with existing equipment.

Concerning geographical issues, average data from several local to global sized companies were used (main focus is on Germany and Europe). Transportation within Europe is included (average values).

In total, 30 m2 of ETC were used.

3.1.6 Transportation

All materials were transported from Athens to Tinos by ferry. Since the trip was not dedicated to the transportation of the materials and their volume was relatively small, impacts from their transportation to Tinos was deemed to be negligible.

Finally, regarding materials, data sourced included transportation within Europe (see sector 3.1.8)

3.1.7 Installation

All system components were installed on the 110m2 concrete platform as shown in Figure 3-7. The installation of the system lasted nine (9) days, as follows:

• 2 days (from 26/09 to 27/09) for the solar system; • 2 days (from 12/10 to 13/10) for the dryer and; • 5 days (from 12/10 to 16/10) for the crystallizer and evaporator units.


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Legend

Evaporator

Crystallizer

Dryer

Solar system (concentrating evacuated tube collectors)

Figure 3-7: Installation of the pilot brine treatment system

During the installation, all impacts (mainly labor work and a brief use of a small forklift truck) were deemed to be negligible.

3.1.8 Resources / materials

Stainless Steel Super Duplex / ΙΝΟΧ Stainless steel 316L / Steel ST52 / Galvanized steel Data was sourced from ecoinvent (SCLCI, 2012) and IDEMAT (2001) and represent the European industry. The dataset used encompasses manufacturing processes to make a semi-manufactured product into a final product. It includes average values for the processing by machines as well as the factory infrastructure and operation. 1 kg of this process is needed to produce 1 kg of final product, while concerning geographical issues, average data from several local to global sized companies were used (main focus is on Germany and Europe). Transportation within Europe is included (average values) while infrastructure processes were excluded.

d

c

b

a

a b

d

c


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Polypropylene (PP) Data was sourced from ecoinvent (SCLCI, 2012) and represent Eco-profiles of the European plastics industry. The system’s boundaries do not include values reported for unspecified metal emission to air and to water, mercaptan emission to air, unspecified chlorofluorocarbon and hydrochlorofluorocarbon emission to air and dioxin to water. Recycling benefits and energy consumption during construction (thermoforming) are included. Finally, transportation within Europe is included (average values) while infrastructure processes were excluded.

Polyethylene Data was sourced from ecoinvent (SCLCI, 2012) and represent Eco-profiles of the European plastics industry (27 European production sites). The system’s boundaries do not include the values reported for wastes, amount of air / N2 / O2 consumed, unspecified metal emission to air and to water, mercaptan emission to air, unspecified CFC/HCFC emission to air and dioxin to water. The amount of "sulphur (bonded)" is assumed to be included into the amount of raw oil. Recycling benefits and energy consumption during construction (thermoforming) are included. Finally, transportation within Europe is included (average values) while infrastructure processes were excluded.

Nylon Data was sourced from ecoinvent (SCLCI, 2012) and represent Eco-profiles of the European plastics industry (3 European production sites - production by different ways out of caprolactam). The system’s boundaries do not include the values reported for wastes, amount of air / N2 / O2 consumed, unspecified metal emission to air and to water, mercaptan emission to air, unspecified CFC/HCFC emission to air and dioxin to water. The amount of "sulphur (bonded)" is assumed to be included into the amount of raw oil. Recycling benefits and energy consumption during construction (thermoforming) are included. Finally, transportation within Europe is included (average values) while infrastructure processes were excluded.

Metals Inventory data were sourced from ecoinvent database (SCLCI, 2012), and processes include production of alloys from primary metals. Infrastructure processes of metals were excluded from the scope of this study. In order to incorporate the benefits of recycling, primary Al, Cu and Ni was considered as avoided product, whereas old metal scrap was introduced as input material. Finally, transportation within Europe is included (average values) while infrastructure processes were excluded.


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3.2 Final Inventory

The following table presents a summary of the final inventory.

Unit Material / Components Other

Feed water tank • 25 kg of PE

• Transportation within Europe is included

• Energy consumption during thermoforming is included

Evaporator unit

• 390 kg of Super Duplex • 25 kg INOX 316L • 80 kg Steel St52 • 10 kg Al alloy • 15 kg Cu • 5 kg of PP


• Impacts resulting from assembling was negligible

Crystallizer unit

• 156 kg of ΙΝΟΧ 316L • 78 kg Super Duplex • 11 kg of PP • 20 kg of Cu, • 5 kg of Al alloy


• Impacts resulting from assembling was negligible

Dryer • 100 kg of Galvanized steel • 10 kg of nylon • 15 kg Steel St52


• Energy consumption during thermoforming is included

• Impacts resulting from assembling were negligible

Solar Energy System • 19,2 m2 PV-module,

monocrystalline, silicon • 30m2 Evacuated tube

collectors


• Energy consumption during construction is included

System

• Feed water tank • Evaporator unit • Crystallizer unit • Dryer • Solar Energy System

• Impacts from transportation from Athens to Tinos was negligible

Furthermore, the following drawing presents mass and energy balances during the systems' operation.


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Drawing 3-1: Mass and energy balances during the system's operation

Legend

Mass

500 kg Brine/day (7 % w/w)

(465 kg water/day

35 kg Salt/day)

SYSTEM

35 kg Water/day (Vapors)

35 kg Salt/day

120 kwh TE/day

150 kwh EE/day

Energy TE: Thermal Energy EE: Electrical Energy

435 kg Water/day


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4 Impact Assessment

4.1 Basic results

The model network created with SimaPro, as well as the characterized and normalized results, are shown in the following figures and tables.


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Figure 4-1: The basic model of the PV (not all products are visible)


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Figure 4-2: Characterised results from the PV module


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Figure 4-3: Analysis of the characterised results from the PV module


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As presented above, impacts from transportation in case of PV are very small (Figure 4-2).

Production of single-silicon wafer accounts for the vast majority of impacts for all categories, apart from Ozone layer depletion, where fuel consumption is the major pollutant. All categories are also affected by electricity production.

A single-silicon wafer, is a thin slice of semiconductor single-silicon material, used for the fabrication of integrated circuits and wafer-based solar cells. The wafer serves as the substrate for microelectronic devices built in and over the wafer and undergoes many microfabrication process steps such as doping or ion implantation, etching, deposition of various materials, and photolithographic patterning.

In general, high efficiency PV panels are considered as the best available alternative to power the system under study, especially in countries with high sunshine duration such as Greece.


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Figure 4-4: The basic model of the ETC (not all products are visible)


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Figure 4-5: Characterised results from the ETC module


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Figure 4-6: Analysis of the characterised results from the ETC module


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As presented above, impacts from transportation in case of ETC are very small (Figure 4-5). Production of copper accounts for the vast majority of impacts for acidification, human toxicity and terrestrial ecotoxicity. Abiotic depletion, eutrofication, global warming and ozon layer depletion are mainly affected by glass production. Chromium production affects mainly human toxicity and water ecotoxicity.

In general, ETC modules are considered as the best available alternative to provide heat to the system under study, especially in countries with high sunshine duration such as Greece.


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Figure 4-7: The basic model of the Feed Water Tank


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Figure 4-8: Characterised results from the Feed Water Tank module


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Regarding feed water tank impacts from Polyethylene production, transformation and transportation are all relevant (Figure 4-8). However, it should be noted that even thought these materials are recyclable, recycling benefit has not taken into consideration, in order to capture the worst-case scenario.

Taking into consideration recycling benefit and the light weight of polyethylene, this type of tank is considered to be the best available alternative in terms of technical, economical and environmental viability.


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Figure 4-9: The basic model of the Evaporator (not all products are visible)


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Figure 4-10: Anasysis of the characterised results from the Evaporator module


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As presented above, in case of the Evaporator, production of aluminum account for the majority of the total emissions for human toxicity, aquatic ecotoxicity and terrestrial ecotoxicity, while production of steel plays an important role in all categories apart from ozone layer depletion, where transport affects the category by 90% (Figure 4-10).

Taking into consideration recycling benefit of aluminum (that has not been captured above) and its light weight, this type of evaporator is considered to be the best available alternative in terms of technical, economical and environmental viability.


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Figure 4-11: The basic model of the Crystallizer (not all products are visible)


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Figure 4-12: Analysis of the characterised results from the Crystallizer module


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Regarding the Crystallizer, production of steel accounts for the vast majority of impacts for abiotic depletion, acidification, eutrophication, global warming and photochemical oxidation. Human toxicity, aquatic ecotoxicity and terrestrial ecotoxicity are mainly affected by aluminum production, while ozone layer depletion is mainly affected by transport (~90%) (Figure 4-12).

Taking into consideration recycling benefit of aluminum and steel (that has not been captured above) and steel's necessary strength (for technical purposes), this type of crystallizer is considered to be the best available alternative, balancing technical needs, economical viability and environmental performance.


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Figure 4-13: The basic model of the Dryer (not all products are visible)


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Figure 4-14: Analysis fo the characterised results from the Dryer module


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In case of the Dryer, production of steel account for the vast majority of the total emissions for all the categories apart from aquatic ecotoxicity and ozone layer depletion. Both of them are mainly affected by transportation (Figure 4-14).

Taking into consideration recycling benefit of steel (that has not been captured above) and its necessary strength (for technical purposes), this dryer is considered to be the best available alternative, balancing technical needs, economical viability and environmental performance.


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Figure 4-15: The basic model of the System (not all products are visible)


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Figure 4-16: Characterised results of the System


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Table 4-1: Characterised results of the System

Impact category Unit Feed water tank Crystallizer Dryer Evaporator Photovoltaic

Panel

Evacuated tube

collectors Total

Abiotic depletion kg Sb eq 1,06E+00 6,49E+00 2,13E+00 8,62E+00 2,89E+01 8,57E+00 5,58E+01

Acidification kg SO2 eq 2,82E-01 2,78E+01 1,62E+00 1,03E+01 1,57E+01 8,34E+00 6,40E+01

Eutrophication kg PO4--- eq 2,60E-02 3,44E-01 1,65E-01 5,44E-01 2,28E+00 7,97E-01 4,16E+00 Global warming (GWP100) kg CO2 eq 7,68E+01 9,25E+02 2,77E+02 1,14E+03 3,88E+03 1,20E+03 7,50E+03

Ozone layer depletion (ODP) kg CFC-11 eq 2,81E-06 2,28E-05 1,00E-05 4,33E-05 8,67E-04 1,24E-04 1,07E-03

Human toxicity kg 1,4-DB eq 9,39E+00 1,35E+02 4,92E+01 2,77E+02 1,84E+03 5,91E+03 8,22E+03 Fresh water aquatic ecotox. kg 1,4-DB eq 2,95E+00 2,21E+01 4,66E+00 3,15E+01 3,50E+02 6,45E+02 1,06E+03

Marine aquatic ecotoxicity kg 1,4-DB eq 5,22E+03 3,02E+04 8,48E+03 4,76E+04 6,36E+05 6,71E+05 1,40E+06

Terrestrial ecotoxicity kg 1,4-DB eq 1,24E-01 8,55E-01 4,44E-01 1,81E+00 1,70E+01 1,67E+01 3,69E+01

Photochemical oxidation kg C2H4 2,04E-02 1,24E+00 1,57E-01 7,14E-01 7,94E-01 3,42E-01 3,26E+00

Table 4-1 and Figure 4-16 summarise the potential characterised impacts for entire life-cycle of the System. In general, all categories apart from acidification and photochemical oxidation are mostly affected by PV and ETC production. Regarding acidification and photochemical oxidation, production of the crystallizer is also a substantial contributor to the potential impacts.

More specifically, the potential impact in Global Warming over 100 years (GWP100) is estimated 7.497 kg CO2 eq. Regarding photovoltaic production (which is the major contributor in this category), apart from CO2, sulfur hexafluoride emissions is also emitted during construction. Although it is emitted in much smaller quantities, its global warming potential (GWP) is much higher than that of CO2, and therefore changes the GWP of the overall system.

The Human Toxicity Potential (HTP) is 8.224 kg 1,4-DB eq, Terrestrial Ecotoxicity Potential (TEP) 36,93 kg 1,4-DB eq, Freshwater Aquatic Ecotoxicity Potential (FAEP) is around 1.056 kg 1,4-DB eq, and Marine Aquatic Ecotoxicity Potential (MAEP) is 1.398.790 kg 1,4-DB eq.

The estimated Ozone Layer Depletion Potential (ODP) of 0,00012 kg CFC-11 eq (practically negligible) is caused mainly by the PV production. Regarding Acidification Potential (AP), 45% of 64 kg SO2 eq result from the crystallizer production. Eutrophication Potential (EP) is estimated at 4,16 kg PO4--- eq mainly because of the nitrogen oxides during PV production. Finally, the Photochemical Oxidation Potential (POP) is around 3,26 kg C2H4 eq. 40% of which is caused by the crystallizer production, while the main contributing burdens include carbon monoxide and sulfur dioxide emissions.


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Figure 4-17: Normalised results of the System


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Table 4-2: Normalised results of the System (1/year)

Impact category Feed water tank Crystallizer Dryer Evaporator Photovoltaic

Panel Evacuated tube

collectors Total

Abiotic depletion 6,8E-12 4,15E-11 1,36E-11 5,51E-11 1,85E-10 5,48E-11 3,56E-10

Acidification 8,79E-13 8,64E-11 5,03E-12 3,2E-11 4,89E-11 2,59E-11 1,99E-10

Eutrophication 1,96E-13 2,6E-12 1,25E-12 4,11E-12 1,72E-11 6,03E-12 3,14E-11 Global warming (GWP100) 1,85E-12 2,23E-11 6,69E-12 2,75E-11 9,35E-11 2,89E-11 1,81E-10

Ozone layer depletion (ODP) 5,46E-15 4,42E-14 1,94E-14 8,41E-14 1,68E-12 2,40E-13 2,07E-12

Human toxicity 1,64E-13 2,36E-12 8,61E-13 4,84E-12 3,23E-11 1,03E-10 1,44E-10 Fresh water aquatic ecotox. 1,45E-12 1,08E-11 2,28E-12 1,55E-11 1,72E-10 3,16E-10 5,18E-10

Marine aquatic ecotoxicity 1,02E-11 5,89E-11 1,65E-11 9,29E-11 1,24E-09 1,31E-09 2,73E-09

Terrestrial ecotoxicity 4,63E-13 3,18E-12 1,65E-12 6,74E-12 6,31E-11 6,22E-11 1,37E-10

Photochemical oxidation 2,13E-13 1,29E-11 1,63E-12 7,42E-12 8,25E-12 3,56E-12 3,40E-11

During normalisation, reference emissions from EU25+3 (in the year 1995) were used. As Figure 4-17 illustrates, the main area affected by the system production and use is marine aquatic ecotoxicity, while potential impacts on fresh aquatic ecotoxicity, abiotic depletion, human toxicity, global warming, and acidification are also considered to be relevant.

The major contributors of MAEP during PV and ETC production are emissions of barium, vanadium and barite. All aforementioned pollutants have extremely high characterisation factors for Marine Aquatic Ecotoxicity. At this point, it should be note that uncertainty issues relating to toxicity are very common (Hayea et al., 2007, Sleeswijk et al, 2008) mainly due to the lack of spatial differentiation between countries in toxicity characterisation factors (Sleeswijk A. W. and Heijungs R., 2010).

Nevertheless, high MAEP value appears to be a common result. Iriarte et al (2009) in particular, regarding collection of MSW in dense urban areas, report values of around 3.000.000 kg 1,4-DB eq / collection of 1.500 t MSW.


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4.2 Benefits from the utilisation of the produced salt

As previously mentioned, the system under study produces salt that can be used in numerous applications, instead of using salt (sodium chloride) that is produced from ocean or minerals. Hence, an off-set benefit could be allocated in order to take into consideration impacts that can be avoided from average salt production. This benefit however is calculated separately, since it can be considered time and location dependant. Sodium chloride (also known as salt or halite), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. Large quantities of sodium chloride are used in many industrial processes, and it is a major source of sodium and chlorine compounds used as feedstock for further chemical syntheses. A second major consumer of sodium chloride is de-icing of roadways in sub-freezing weather. The manufacture of salt is one of the oldest chemical industries. A major source of salt is seawater, which has a salinity of approximately 3.5%. The world's oceans are a virtually inexhaustible source of salt, and this abundance of supply means that reserves have not been calculated. The evaporation of seawater is the production method of choice in marine countries with high evaporation and low precipitation rates (such as Greece). Elsewhere, salt is extracted from the vast sedimentary deposits which have been laid down over the years from the evaporation of seas and lakes. These are either mined directly, producing rock salt, or are extracted in solution by pumping water into the deposit. In either case, the salt may be purified by mechanical evaporation (drying) of brine. In order to calculate average impacts from salt production, data was sourced from ecoinvent (SCLCI, 2012) and represent the European industry. Process includes the solution mining process of sodium chloride (thermo compressing technology), its cleaning form impurities, and the drying step. It is usually sold as bulk and therefore no packaging materials are included. Geography data represent the European mix of 40% solution mining and 60% rock salt. Characterized and normalized results from the production of 1 kg of salt, are shown in the following table.

Table 4-3: Characterised and normalised results of salt production (1 kg)

Impact category Characterised results normalised results (1/yr)

Abiotic depletion 0,001417 kg Sb eq 9,05E-15

Acidification 0,000966 kg SO2 eq 3,01E-15

Eutrophication 0,000158 kg PO4--- eq 1,20E-15

Global warming (GWP100) 0,202574 kg CO2 eq 4,88E-15

Ozone layer depletion (ODP) 1,17E-08 kg CFC-11 eq 2,27E-17

Human toxicity 0,237545 kg 1,4-DB eq 4,16E-15

Fresh water aquatic ecotox. 0,045595 kg 1,4-DB eq 2,23E-14

Marine aquatic ecotoxicity 58,48455 kg 1,4-DB eq 1,14E-13

Terrestrial ecotoxicity 0,001741 kg 1,4-DB eq 6,48E-15

Photochemical oxidation 5,40E-05 kg C2H4 5,62E-16


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Figure 4-18: Analysis fo the characterised results from the salt production (1 kg)


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Assuming that the systems could operate 6 days per week, 48 weeks per year for 15 years, and taking into consideration that can produce around 35 kg salt per day, we calculate that in total the system could produce 35 x 6 x 48 x 15 = 151.200 kg salt in its life cycle. Based on that, next the characterised results of the system are presented, taking into consideration environmental benefits from salt utilisation.

Table 4-4: Characterised results of the System (with salt benefit)

Impact category Unit Sol-brine system basic results

Environmental benefits from salt

utilisation Total

Abiotic depletion kg Sb eq 5,58E+01 -2,14E+02 -1,58E+02

Acidification kg SO2 eq 6,40E+01 -1,46E+02 -8,21E+01

Eutrophication kg PO4--- eq 4,16E+00 -2,40E+01 -1,98E+01

Global warming (GWP100) kg CO2 eq 7,50E+03 -3,06E+04 -2,31E+04 Ozone layer depletion (ODP) kg CFC-11 eq 1,07E-03 -1,77E-03 -7,01E-04

Human toxicity kg 1,4-DB eq 8,22E+03 -3,59E+04 -2,77E+04 Fresh water aquatic ecotox. kg 1,4-DB eq 1,06E+03 -6,89E+03 -5,83E+03

Marine aquatic ecotoxicity kg 1,4-DB eq 1,40E+06 -8,84E+06 -7,44E+06

Terrestrial ecotoxicity kg 1,4-DB eq 3,69E+01 -2,63E+02 -2,26E+02

Photochemical oxidation kg C2H4 3,26E+00 -8,16E+00 -4,90E+00

The results presented above, are also depict in the following figure.


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Figure 4-19: Summary of the characterised results of the System, taking into consideration benefits from salt utilisation

-1,00E+07

-8,00E+06

-6,00E+06

-4,00E+06

-2,00E+06

0,00E+00

2,00E+06

Abiotic depletion

Acidification Eutrophication Global warming

(GWP100)

Ozone layer depletion

(ODP)

Human toxicity

Fresh water aquatic ecotox.

Marine aquatic

ecotoxicity

Terrestrial ecotoxicity

Photochemical oxidation

Sol-brine system basic results Environmental benefits from salt utilisation Total


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Figure 4-20: Global Warming characterised results of the System, taking into consideration benefits from salt utilisation

-3,50E+04

-3,00E+04

-2,50E+04

-2,00E+04

-1,50E+04

-1,00E+04

-5,00E+03

0,00E+00

5,00E+03

1,00E+04


Global warming -GWP100 (kg CO2 eq)


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Figure 4-21: Acidification characterised results of the System, taking into consideration benefits from salt utilisation

-2,00E+02

-1,50E+02

-1,00E+02

-5,00E+01

0,00E+00

5,00E+01

1,00E+02


Acidification (kg SO2 eq)


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Figure 4-22: Eutrophication characterised results of the System, taking into consideration benefits from salt utilisation

-3,00E+01

-2,50E+01

-2,00E+01

-1,50E+01

-1,00E+01

-5,00E+00

0,00E+00

5,00E+00

1,00E+01


Eutrophication (kg PO4--- eq)


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Figure 4-23: Human toxicity characterised results of the System, taking into consideration benefits from salt utilisation

-4,00E+04

-3,50E+04

-3,00E+04

-2,50E+04

-2,00E+04

-1,50E+04

-1,00E+04

-5,00E+03

0,00E+00

5,00E+03

1,00E+04

1,50E+04


Human toxicity (kg 1,4-DB eq)


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Figure 4-24: Marine aquatic ecotoxicity characterised results of the System, taking into consideration benefits from salt utilisation

-1,00E+07

-8,00E+06

-6,00E+06

-4,00E+06

-2,00E+06

0,00E+00

2,00E+06


Marine aquatic ecotoxicity (kg 1,4-DB eq)


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Figure 4-25: Photochemical oxidation characterised results of the System, taking into consideration benefits from salt utilisation

-1,00E+01

-8,00E+00

-6,00E+00

-4,00E+00

-2,00E+00

0,00E+00

2,00E+00

4,00E+00


Photochemical oxidation (kg C2H4)


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Moreover, next the normilised results of the system are presented, taking into consideration environmental benefits from salt utilisation.

Table 4-5: Normalised results of the System (with salt benefit) (1/year)

Impact category Sol-brine system basic results

Environmental benefits from salt

utilisation Total

Abiotic depletion 3,56E-10 -1,37E-09 -1,01E-09

Acidification 1,99E-10 -4,54E-10 -2,55E-10

Eutrophication 3,14E-11 -1,81E-10 -1,50E-10

Global warming (GWP100) 1,81E-10 -7,38E-10 -5,57E-10

Ozone layer depletion (ODP) 2,07E-12 -3,44E-12 -1,36E-12

Human toxicity 1,44E-10 -6,29E-10 -4,85E-10

Fresh water aquatic ecotox. 5,18E-10 -3,38E-09 -2,86E-09

Marine aquatic ecotoxicity 2,73E-09 -1,72E-08 -1,45E-08

Terrestrial ecotoxicity 1,37E-10 -9,79E-10 -8,42E-10

Photochemical oxidation 3,40E-11 -8,49E-11 -5,10E-11

The results presented above, are also depict in the following figure.


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Figure 4-26: Summary of the normalised results of the System, taking into consideration benefits from salt utilisation

-2,00E-08

-1,50E-08

-1,00E-08

-5,00E-09

0,00E+00

5,00E-09

Abiotic depletion

Acidification Eutrophication Global warming

(GWP100)

Ozone layer depletion

(ODP)

Human toxicity

Fresh water aquatic ecotox.

Marine aquatic

ecotoxicity

Terrestrial ecotoxicity

Photochemical oxidation



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All the above-mentioned Tables and Figures clearly show that when taking into consideration benefits from salt utilisation, the potential environmental impacts of the autonomous system for all categories are negative. Negative values are explained by the environmental off-set benefit from salt substitution, from the salt that is produced by the system under study as a by-product.

Based on the above we can conclude that in case salt can locally be used for a variety of industrial or other purposes (e.g. on roadways in sub-freezing weather), the Sol-Brine system presents a plethora of environmental benefits, without compromising its technical performance and economical viability.


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4.3 Eco-burdens from brine disposal into the ocean

As previously mentioned, LCA studies cannot quantify the aquatic eco-toxic potential of the brine disposal mainly due to the limitation of current life cycle impact assessment approaches. More specifically, according to Zhou et/ al, (2013) when brine is disposed into the ocean, the impact of extra salinity is not considered because the current life cycle impact assessment approach cannot translate the salt ions into aquatic eco-toxic impact. Moreover potential impacts are subject to local conditions, such as salt solubility. Thus, a separate and more abstract benefit is estimated, based on various local and case-specific assumptions.

At macro level, high salinity of seawater can accelerate the water cycle which can cause extreme weather events such as floods and drought. The salinity of the oceans is also connected to CO2, since waters with more saline can dilute less CO2. Finally, at micro level salt interacts with animals and plants in water, changing the ecological health of marine ecosystems. An thus increase salinity threats biodiversity and can lead to loss of habitat—both in water and on land.

Based on all the above it is shown that diversion of brine from ocean, even thought cannot be depicted in the results of the LCA, is clearly another benefit of Sol-Brine system.


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4.4 Comparison with conventional sources of electricity / heat

In order to provide a further insight of the potential environmental benefits of the autonomous system under examination, we analysed a similar system which however is fueled by Conventional Energy Sources (CER), i.e. electricity from the grid, and heat from a natural gas engine.

In order to capture the impacts from the worst case alternative scenario, benefit from salt utilisation is not taken into consideration, since it can be considered time and location dependant.

Next are presented the characterised results of the System (CER), as well as a comparison between the two systems. Note that in order for the results to be comparable, it was assumed that both systems had a life span of 15 years where the system with CER would consume around 657.000 kWh of thermal energy and 821.000 kWh of electric energy.


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Figure 4-27: Characterised results of the System (CER)


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Figure 4-28: Normalised results of the System (CER)


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Table 4-6: Characterised results of the System (CER)

Impact category Unit Feed water tank Crystallizer Dryer Evaporator Heat

production Electricity

production Total

Abiotic depletion kg Sb eq 1,06E+00 6,49E+00 2,13E+00 8,62E+00 1,58E+03 9,28E+03 1,09E+04

Acidification kg SO2 eq 2,82E-01 2,78E+01 1,62E+00 1,03E+01 1,78E+02 5,91E+03 6,12E+03

Eutrophication kg PO4--- eq 2,60E-02 3,44E-01 1,65E-01 5,44E-01 1,62E+01 2,00E+02 2,17E+02 Global warming (GWP100) kg CO2 eq 7,68E+01 9,25E+02 2,77E+02 1,14E+03 1,92E+05 9,63E+05 1,16E+06

Ozone layer depletion (ODP) kg CFC-11 eq 2,81E-06 2,28E-05 1,00E-05 4,33E-05 2,50E-02 2,68E-02 5,19E-02

Human toxicity kg 1,4-DB eq 9,39E+00 1,35E+02 4,92E+01 2,77E+02 1,84E+04 3,74E+05 3,92E+05 Fresh water aquatic ecotox. kg 1,4-DB eq 2,95E+00 2,21E+01 4,66E+00 3,15E+01 5,64E+02 2,31E+05 2,31E+05

Marine aquatic ecotoxicity kg 1,4-DB eq 5,22E+03 3,02E+04 8,48E+03 4,76E+04 1,46E+06 5,90E+08 5,92E+08

Terrestrial ecotoxicity kg 1,4-DB eq 1,24E-01 8,55E-01 4,44E-01 1,81E+00 3,34E+01 1,15E+04 1,15E+04

Photochemical oxidation kg C2H4 2,04E-02 1,24E+00 1,57E-01 7,14E-01 2,18E+01 2,36E+02 2,60E+02

Table 4-7: Normalised results of the System (CER) (1/year) Impact category Feed water

tank Crystallizer Dryer Evaporator Heat production

Electricity production Total

Abiotic depletion 6,8E-12 4,15E-11 1,36E-11 5,51E-11 1,01104E-08 5,92818E-08 6,95E-08

Acidification 8,79E-13 8,64E-11 5,03E-12 3,2E-11 5,52186E-10 1,83677E-08 1,9E-08

Eutrophication 1,96E-13 2,6E-12 1,25E-12 4,11E-12 1,2213E-10 1,51156E-09 1,64E-09 Global warming (GWP100) 1,85E-12 2,23E-11 6,69E-12 2,75E-11 4,61952E-09 2,32161E-08 2,79E-08

Ozone layer depletion (ODP) 5,46E-15 4,42E-14 1,94E-14 8,41E-14 4,85024E-11 5,20871E-11 1,01E-10

Human toxicity 1,64E-13 2,36E-12 8,61E-13 4,84E-12 3,22066E-10 6,53822E-09 6,87E-09 Fresh water aquatic ecotox. 1,45E-12 1,08E-11 2,28E-12 1,55E-11 2,76488E-10 1,131E-07 1,13E-07

Marine aquatic ecotoxicity 1,02E-11 5,89E-11 1,65E-11 9,29E-11 2,8547E-09 1,15113E-06 1,15E-06

Terrestrial ecotoxicity 4,63E-13 3,18E-12 1,65E-12 6,74E-12 1,24361E-10 4,27638E-08 4,29E-08

Photochemical oxidation 2,13E-13 1,29E-11 1,63E-12 7,42E-12 2,26244E-10 2,4527E-09 2,7E-09

As shown in Figure 4-27 impacts for entire life-cycle of the System CER, are affected mainly by electricity consumption. In other words, operation of the conventional system dominates the potential environmental impacts, while emissions during construction of the system can be deemed negligible.

As in case of the autonomous system, the main area affected by the system production and use is marine aquatic ecotoxicity, while potential impacts on fresh aquatic ecotoxicity, abiotic depletion, terrestrial toxicity, global warming, and acidification are also considered to be relevant (Figure 4-28).

Next, a comparison of the two systems is presented.


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Figure 4-29: Comparison of characterized results of each system


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Figure 4-30: Comparison of normalized results of each system


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Figure 4-29 and Figure 4-30 clearly show that the environmental impacts of the autonomous system decrease significantly in comparison to the conventional system (CER), and especially in the case of MAEP, where in system CER is tremendously affected by emissions of chromium VI to soil during electricity production in Greece.

Based on the above we can conclude that even the PV and ETC construction affect greatly the system's environmental footprint, the fact that the system is autonomous and there is no electricity consumption from conventional sources (i.e. grid), results to an extremely environmental friendly system, with a plethora of ecological benefits.


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5 References

[1] Amores Maria José, Montse Meneses, Pasqualino Jorgelina, Antón Assumpció, Castella Francesca (2013) Environmental assessment of urban water cycle on Mediterranean conditions by LCA approach. Journal of Cleaner Production, Volume 43, March 2013, Pages 84–92

[2] Centre for Environmental Studies (CML) University of Leiden, Netherlands (2010) CML-IA Characterisation Factors Database

[3] Fantin Valentina, Scalbi Simona, Ottaviano Giuseppe, Masoni Paolo (2014) A method for improving reliability and relevance of LCA reviews: The case of life-cycle greenhouse gas emissions of tap and bottled water. Science of The Total Environment, Volumes 476–477, 1 April 2014, Pages 228–241

[4] Goedkoop Mark, Schryver An De, Michiel Oele, Douwe de Roest, Marisa Vieira and Sipke Durksz (2010) Simapro 7 tutorial.

[5] Hayea S, Slaveykovab V I, Payeta J (2007) Terrestrial ecotoxicity and effect factors of metals in life cycle assessment (LCA). Chemosphere Volume 68, Issue 8, July 2007, Pages 1489–1496

[6] Zhou Jin, Chang Victor, Fane Anthony (2013) An improved life cycle impact assessment (LCIA) approach for assessing aquatic eco-toxic impact of brine disposal from seawater desalination plants. Desalination 308 (2013) 233–241

[7] IDEMAT (2001) IDEMat inventory data of materials. Faculty of Industrial Design Engineering of Delft University of Technology, Delft, the Netherlands

[8] Iriarte A, Gabarrell X, Rieradevall J (2009) LCA of selective waste collection systems in dense urban areas. Waste Manage 29 (2009) 903–914

[9] ISO 14044 (2006), Environmental management – Life cycle assessment – Requirements and guidelines, International Organisation for Standardisation (ISO), Geneve

[10] ISO 14040 (2006), Environmental management – Life cycle assessment – Principles and framework, International Organisation for Standardisation (ISO), Geneve

[11] Nessi Simone, Rigamonti Lucia, Grosso Mario (2012) LCA of waste prevention activities: A case study for drinking water in Italy. Journal of Environmental Management, Volume 108, 15 October 2012, Pages 73–83.


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[12] Risch Eva, Loubeta Philippe, Núñezc Montserrat, Roux Philippe (2014) How environmentally significant is water consumption during wastewater treatment?: Application of recent developments in LCA to WWT technologies used at 3 contrasted geographical locations. Water Research, Volume 57, 15 June 2014, Pages 20–30

[13] SCLCI (Swiss Centre for Life Cycle Inventories) (2012) Ecoinvent v3 (www.ecoinvent.org/database)

[14] SETAC (2002), Life-Cycle Impact Assessment: Striving towards Best Practice, Society of Environmental Toxicology and Chemistry

[15] Sleeswijk, A. W., Van Oersc L., Guinéec J. B., Struijsd J., Huijbregtsb M. (2008) Normalisation in product life cycle assessment: An LCA of the global and European economic systems in the year 2000. Sci Total Environ, Volume 390, Issue 1, 1 February 2008, Pages 227–240

[16] Sleeswijk A. W., Heijungs R. (2010) GLOBOX: A spatially differentiated global fate, intake and effect model for toxicity assessment in LCA. Sci Total Environ, Volume 408 (14), 15/6/2010, Pages 2817–2832

Internet sites [1] PRé Consultants, 2011

http://www.pre.nl

[2] Water Framework Directive (2000/60/EC) - European Commission http://ec.europa.eu/environment/water/water-framework/index_en.html

http://www.pre.nl/

http://ec.europa.eu/environment/water/water-framework/index_en.html

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Sol – Brine

LIFE+-Environment project: LIFE 09 ENV/GR/000299

Documents

Development of an advanced, innovative, desalination ...solbrine.uest.gr/uploads/files/deliverable_5.2.pdf · Deliverable 5.2 Report on LCA of the brine treatment system Action 5