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EG105GUIDE
WATER USE IN THE MANUFACTURE OF SPECIALITY CHEMICALS
AN ENVIRONMENTAL PERFORMANCE GUIDE: The benchmark for profitable environmental improvement
© Crown copyright. First printed November 1997.
This material may be freely reproduced except for sale or advertising purposes.
Printed on paper containing 75% post-consumer waste.
WATER USE IN THEMANUFACTURE OF SPECIALITY CHEMICALS
This Environmental Performance Guide was produced by
the Environmental Technology Best Practice Programme
Prepared with assistance from:
ECOTEC Research and Consulting Ltd
British Association of Chemical Specialities (BACS)
Specialised Organic Chemical Sector Association (SOCSA)
Water is essential in the production of all speciality chemicals. It is used as a raw material forreactions and in blending, dilution, steam production, cooling, vacuum system, vessel washing andgeneral cleaning operations. Traditionally, water has been considered a low-cost resource,particularly in relation to the high product values typical of the speciality chemicals sector. As aresult, there has been little financial incentive to improve the efficiency of water use.
This situation is now changing. Water supply charges are rising significantly, and many companiesrecognise that the ‘true’ cost of water includes the often high costs incurred during on-site watertreatment, water distribution and effluent treatment and/or discharge, in addition to the value ofany product or raw material that is ‘lost’ in the effluent stream. The economic and environmentalcase for rational water use is now convincing.
Specific water consumption in the speciality chemicals sector ranges from less than 1 m3/tonne ofproduct to more than 100 m3/tonne, depending on product range, processes used and theefficiency with which water is managed. Companies with high levels of specific water consumptionalso have high effluent discharge rates and, effectively, pay twice for not managing water use moreefficiently. The costs of water supply and effluent discharge also vary widely, as the Figs show.
This Guide is designed to help companies in the speciality chemicals sector save money and achieve environmental improvements by managing their use of water more effectively. It providesguidance on:
■ typical levels of water use within the speciality chemicals sector;
■ water supply and effluent discharge costs;
■ the techniques and technical options available for managing the use of water moreefficiently;
■ the cost savings that have been achieved by companies adopting these measures;
■ ways to overcome the barriers to improvement.
Using the information contained in this Guide and the Action Plan framework provided, each sitewill be able to assess its own water management performance relative to that of its competitors.The Action Plan framework will also help companies identify the most appropriate techniques fortheir site.
S U M M A R Y
Mains water supply costs/tonne of product Effluent discharge costs/tonne of product
30
25
20
15
10
5
0less than
0.50.5 - 2 2 - 5 5 - 10 10 - 100 100+
Costs/tonne of product (£)
Perc
enta
ge
of
site
s p
rovi
din
g d
ata
30
25
20
15
10
5
0less than 1 1 - 2 2 - 5 5 - 10 10 - 50 50+
Costs/tonne of product (£)
Perc
enta
ge
of
site
s p
rovi
din
g d
ata
Section Page
1 Why worry about water? 1
1.1 The cost incentive 1
1.2 Environmental and regulatory pressures 2
1.3 Long-term availability of water 4
1.4 How this Guide can help 4
2 Survey methodology and response profile 5
2.1 Survey methodology 5
2.2 Survey response profile 5
3 Water consumption and effluent discharge 7
3.1 Uses of water 7
3.2 Specific water consumption 8
3.3 Effluent discharge rates 9
4 The cost of water use 11
4.1 Calculating the costs 11
4.2 Water supply costs 11
4.3 Effluent discharge costs 13
4.4 Water costs as a proportion of site production costs 15
5 Improving the efficiency of water use 16
5.1 Demonstrated achievements 16
5.2 Water measurement systems 18
5.3 Good housekeeping measures 19
5.4 Plant and process modifications 20
6 Overcoming the remaining obstacles 22
6.1 Obstacles to progress 22
6.2 Overcoming the barriers 22
7 Water minimisation Action Plan 25
7.1 Ensure commitment to action 25
7.2 Organise for action 26
7.3 Audit and review water use 26
7.4 Identify options for improvement 27
7.5 Implement the selected options 27
7.6 Ensure feedback through a measuring to manage programme 27
7.7 Disseminate successes achieved 28
Appendix The Mogden Formula and UK trade effluent charges 29
C O N T E N T S
Water is essential to the production of all speciality chemicals. It is used in many different ways:
■ within the product as a raw material, eg for blending and dilution;
■ within the manufacturing process, eg for heating, cooling and vacuum systems;
■ outside the manufacturing process, eg for vessel washing and more general cleaning.
Water has traditionally been regarded as a low-cost resource, particularly in the production of thehigher-value speciality chemicals. As a result, economic incentives for companies to manage watermore efficiently have been limited.
This situation is now changing. The ‘true’ cost of water supply and effluent disposal is rising rapidly.Companies are becoming increasingly concerned, not only about the economic implications but alsoabout associated environmental issues. In some cases, companies have concerns about theavailability of the water that is crucial to their process. The various ‘drivers’ (Fig 1) are encouragingthe manufacturers of speciality chemicals to give greater priority to more efficient management oftheir water use.
1.1 THE COST INCENTIVE
The true cost of water includes more than the purchase price of water supplied to the site. Only asmall proportion of the water evaporates or leaves the site as part of the product. The rest will be:
■ returned to the water source from where it was extracted;
■ disposed of to sewer as trade effluent;
■ sent for landfill or treatment as a solid/sludge/liquid waste.
None of these services is free, and the associated charges have increased significantly in recent years.Unit costs for effluent discharge are already substantially higher than those for water supply, while thecosts of off-site landfill disposal are higher still, particularly since the introduction of the landfill tax.
The importance of cost as a driver for more efficient water use reflects the rising charges levied bywater companies for water supply and for trade effluent discharges. Fig 2 shows that average
1
W H Y W O R R Y A B O U T W AT E R ?1
section
1
Fig 1 Drivers for more efficient water use
0 20 40 60 80 100
Percentage of sites providing data
Cost pressures
Regulation
Increasing discharge costs
Corporate environmental policy
Supply restrictions
charges to industrial users between 1991 and 1995 increased by about 44% for trade effluentdischarge and by 31% for mains water supply. This trend continued during 1996 with the cost ofwater supply to UK industry rising by 4.9%, more than twice the rate of inflation. Predictionsindicate that water supply costs will continue to rise in the future.
The speciality chemicals sector has experienced similar cost increases. Of the companies providingdata for this Guide, 30% reported increases significantly greater than those associated with inflation.
The pressures of increasing costs are encouraging many companies to examine the true costs ofwater use (see Section 4), to manage their use of water more efficiently, and even to explore possiblealternatives to mains water, eg borehole water.
Many speciality chemicals manufacturers have now introduced at least one water managementmeasure, often achieving substantial reductions in water use and cost. The measures introducedinclude good housekeeping and a range of management techniques such as water use audits,improved monitoring and metering, water pinch analysis, greater re-use and recycling, and changesto production scheduling. There has also been some investment in technical options such astriggered hoses, improved pipework, cooling towers and vessel washing systems.
1.2 ENVIRONMENTAL AND REGULATORY PRESSURES
Fig 1 shows that regulation is an important driver, encouraging companies within the specialitychemicals sector to manage their use of water more efficiently. In addition, a significant number offirms have implemented corporate environmental policies.
The environmental regulation with which the industry has to comply is becoming more extensive andstringent. In the past, most of this regulation related to one specific environmental ‘medium’, eg airpollution, liquid effluent discharges or waste management/disposal. The introduction of IntegratedPollution Control (IPC) means that individual media can no longer be considered in isolation, and theeffective management of water (and effluent) has become just one component of a company’sresponse to IPC.
2
section
1
Fig 2 The rising costs of trade effluent discharge and mains water supply: industrial users
0
10
20
30
40
50
60
70
80
90
100
1991 1992 1993 1994 1995
Un
it c
ost
s (p
ence
/m3 )
Year
Average mains water supply charge
Average trade effluent discharge charge
Source: OFWAT 1995/1996: Report on Tariff Structure and Charges
The emphasis on ‘economic instruments’ as a means of meeting environmental policy objectives islikely to be much greater in the future. Rising water and effluent charges, together with the landfilltax, are examples of economic instruments that are already having an impact on the specialitychemicals sector. Furthermore, although the distinction between cost pressures and regulation willprobably become more blurred in future, the overall impact of these two main drivers is unlikely todecline.
The other significant environmental driver for more efficient water use is company commitment tothe environment. This commitment may, in part, reflect the expectations of customers and otherstakeholders. It is also a recognition of the fact that good environmental management is part ofgood business management and can cut costs and improve competitiveness.
Responses from the companies providing data for this Guide ranked efficient management of waterresources alongside effective management of waste as a priority area for achieving cost-effectiveimprovements in environmental performance (Fig 3). Only air pollution comes close to these twoissues in terms of their importance to the companies in the sector.
Many speciality chemicals firms have signed up to the chemical industry’s Responsible Careprogramme. This programme publicly commits companies to continued improvements in all aspectsof health, safety and the environment. The efficient management of water resources is a keycomponent in the initiative. Furthermore, Responsible Care requires companies to:
■ involve all staff in their improvement programmes;
■ establish procedures for measuring actual progress;
■ maintain an ongoing dialogue with the public.
Many companies in the speciality chemicals sector are also carrying out waste minimisation projectsand implementing environmental management systems as a means of controlling theirenvironmental impact and potential liabilities. As these management systems become more widelyestablished, data relating to environmental parameters, such as water consumption, should becomemore readily available.
3
section
1
Fig 3 Environmental priorities of speciality chemicals manufacturers
Many speciality chemicals manufacturers use processes defined as Part A processes under theIPC regime established by the Environmental Protection Act 1990. These manufacturers arerequired to demonstrate that they use Best Available Techniques Not Entailing Excessive Cost(BATNEEC) to prevent the release of prescribed substances. Where this is not practicable, theymust minimise the release of these substances to air, water and land (as waste) and renderthem harmless. They must also record the associated process emissions and discharges.
0 10 20 30
Waste issues
Water and effluent
Air pollution issues
Product stewardship
Energy
Noise or nuisance
Non-routine events
Land contamination
Number of times mentioned by sites providing data
1st priority
2nd priority
3rd priority
1.3 LONG-TERM AVAILABILITY OF WATER
Most manufacturers already face absolute limits on the quantity and quality of the effluent they candischarge. These limits are likely to become more stringent as the water companies seek to meetthe standards imposed on the volume and composition of their own discharges to watercourses.However, even companies that are concerned about the rising costs of water supply and disposaltend to take the availability of water for granted.
There is growing evidence that this perception may be misplaced, and that manufacturers could facereductions in the quantity and quality of water supplied. This is a matter of extreme concern. Whilethere is generally an engineering solution to more stringent discharge controls, reducing or cuttingoff the water supply would prejudice the viability of the manufacturing operation and make itnecessary to obtain water from other sources. This would almost certainly be more expensive.
Water quality is also a major issue for companies relying on high quality water for their production;there is no certainty that the quality of any alternative supply will be acceptable.
Concerns about water supply and quality cannot be regarded as simply theoretical. Recent droughtconditions have led the Environment Agency to impose tighter controls on the quantities of waterthat water companies and industry can extract from inland sources. Water companies, in turn, areplacing greater emphasis on water conservation, both in their own activities and in those of theindustries they supply. One water company, to safeguard its reserves, has even threatened 24-hourcuts in water supply.
1.4 HOW THIS GUIDE CAN HELP
This Environmental Performance Guide allows those responsible for water consumption on specialitychemicals manufacturing sites to assess the efficiency of their water use in relation to the industryas a whole. It also assesses the extent to which the various water minimisation technologies andtechniques currently available to the industry have been adopted, and examines how the barriers totake-up can be overcome. Finally, it provides the framework for developing a water minimisationAction Plan.
The questions at the end of each Section or Sub-section are designed to promoteinvestigation and, ultimately, action.
4
section
1
■ Do you know the ‘true’ costs of your site’s water use?
■ Are these costs increasing? If so, how fast?
■ How could efficient water management help you to meet your environmental targets?
■ Do future water resource limitations pose a threat to your company’s business?
This Environmental Performance Guide has been prepared with the help of industry representativesand individual speciality chemicals manufacturers. It is based on the findings of two recent wateruse surveys and provides the most complete picture to date of water use within the specialitychemicals industry.
2.1 SURVEY METHODOLOGY
The first survey was predominantly qualitative and was intended to identify the attitudes ofrespondents to water-related issues and the extent to which these had influenced managementpractices and/or investment. The second survey sought more detailed, quantitative informationabout water consumption and about the costs and benefits of any measures that had beenimplemented to manage water more efficiently.
2.2 SURVEY RESPONSE PROFILE
Forty-seven operational sites responded to the initial (qualitative) survey. This represented aresponse rate of 21% based on the 220 questionnaires distributed. Twenty of the 47 sites provideddetailed quantitative information. Responses from sites involved solely in operations such asblending and/or packaging were excluded.
Sites varied widely in terms of staff numbers (Fig 4) and turnover (Fig 5). The largest sites had morethan 250 staff and an annual turnover in excess of £40 million: the smallest had fewer than 25 staffand an annual turnover between £1 - 10 million.
There was also considerable variation in the types of product manufactured, production processesused and the different types of plant (Fig 6). Less than 20% of sites used any form of continuousplant, while 75% used multi-product batch plant (ie batch plant using the same basic process tomake several different products as opposed to batch plant dedicated to a single product or batchplant used for several different processes).
5
section
2
S U R V E Y M E T H O D O L O G Y A N DR E S P O N S E P R O F I L E
2
Fig 4 Site size: staff numbers Fig 5 Site size: turnover (£ million)
51 - 100
101 - 250
morethan 250
lessthan 25
26 - 50 10 - 20
20 - 40
morethan 40
1 - 10
Production operations used at different sites also varied significantly (Fig 7). Apart from materialshandling, the most common production operations were packaging, blending and chemicalreaction. More specialised operations such as liquid-liquid extraction, crystallisation, refrigerationand centrifugation were less frequently used.
6
section
2
Fig 6 Types of plant used by speciality chemicals sites
0 20 40 60 80
Percentage of sites providing data
Multi-product batch plant
Dedicated batch plant
Multi-purpose batch plant
Continuous plant
Fig 7 Production operations of speciality chemicals sites
0 20 40 60 80 100
Percentage of sites undertaking operations
Materials handling
Packaging
Blending
Reactions
Mixing
Filtration
Distillation
Drying
Centrifugation
Refrigeration
Crystallisation
Liquid-liquid extraction
3.1 USES OF WATER
The production of speciality chemicals uses water for many purposes. Fig 8 summarises the surveyfindings. The most common uses identified were for cooling, as a raw material and for steamproduction. Other widespread uses included effluent dilution and air pollution control to meetenvironmental regulatory requirements.
Fig 9 shows the percentage of sites using water for each of the purposes identified above. It alsoindicates approximate consumption levels in each case. These are rated as high, medium or low,depending on a site’s own perception of its relative consumption. The three uses with the largestpercentage in the ‘high’ consumption category are for cooling, as a raw material and for steamproduction. The three uses with the widest application across the sector are plant and vesselwashing, domestic uses and housekeeping.
7
section
3
W AT E R C O N S U M P T I O N A N DE F F L U E N T D I S C H A R G E
3
Fig 8 Uses of water in the speciality chemicals sector
Cooling
Vacuum systems
Effluent dilution
Steam production
Air pollutioncontrol
Domestic uses
Plant andvessel washing
Housekeeping
Product washing
Raw material
Fig 9 Water use and relative consumption levels in the speciality chemicals sector
Cooling (product/processes)
Raw material
Steam production
Plant and vessel washing
Product washing
Air pollution control
Vacuum systems
Domestic uses
Housekeeping
Effluent dilution
0 20 40 60 80 100
Percentage of sites providing data
High usageMedium usageLow usage
There are opportunities for improving the efficiency of water management and reducing costs in eachwater-use category, without adversely affecting production levels or product quality. Some companieshave, for instance, reduced the volume of cooling water used by up to 50% (see Section 5).
3.2 SPECIFIC WATER CONSUMPTION
Specific water consumption (m3/tonne of product) in the speciality chemicals sector variedenormously. Reported values ranged from less than 1 m3/tonne of product to more than 100 m3/tonne (Fig 10), with about 80% of the sites providing data using less than 10 m3/tonne.These differences reflect the wide variation in processes, products and plant operations that existswithin the industry. They also reflect differing levels of efficiency in water management, particularlythe degree to which measures have been implemented to reduce water consumption.
Table 1 details the product types associated with the different levels of specific water consumptionreported. This shows that low rates of water use are often associated with products requiring littlewater as a product ingredient or for cooling or steam production.
8
section
3
Fig 10 Specific water consumption of survey respondents
Table 1 Products associated with different specific water consumptions
0
5
10
15
20
25
less than 1 1 - 2 2 - 5 5 - 10 10 - 50 50 - 100 100+
Perc
enta
ge
of
site
s p
rovi
din
g d
ata
m3/tonne of product
less than 1 1 - 2 5 - 102 - 5 10 - 50 50 - 100 100+
Pro
du
ct t
ypes
Specific water consumption (m3/tonne of product)
Resins,adhesives,
detergents,disinfectants,photographic
solutions,betaines.
Sulphonic acids,
detergents,rubbers,resins,
pigments,salts.
Silicones,polyacrylics,
water treatment chemicals, chelating agents,
surfactants, amine
products, synthetic organic
polymers,sulphonic
acids,esters,imides,
anhydrides,quaternaries,alkyl ethers,
salts,soaps.
Brighteningagents,dyes,
biocides,herbicides,insecticides,phosphates,
pharmaceutical intermediates,
polyacrylics, amine
products,esters,soaps.
Esters,biocides,fungicide
intermediates,mercaptan gas
odorants,carbonates,
thioglycollates,thioureas.
Pharmaceutical intermediates,
acrylates,amine
products.
Liquid crystals, buffer
solutions,pigments,
chlorine and bromine products.
3.3 EFFLUENT DISCHARGE RATES
Any water that is not included in the finished product or passed to atmosphere as steam or watervapour will either be discharged as effluent to sewer or watercourse or be tankered away fortreatment and disposal.
Effluent discharge rates were found to vary significantly (Fig 11), again reflecting the wide range ofprocesses and product types associated with the speciality chemicals sector and also the differinglevels of efficiency in water management. Table 2 indicates the product types associated withdifferent levels of effluent discharge.
Companies with high levels of specific water consumption invariably have high effluent dischargerates and, effectively, pay twice for not managing their use of water more efficiently. It is thereforeimportant to reduce both the volume of water supplied and, by recognising opportunities forrecirculation and re-use, the quantities disposed of as effluent.
9
section
3
Fig 11 Effluent discharge rates in the speciality chemicals sector
0
5
10
15
20
25
30
35
40
less than 1 1 - 5 5 - 20 20 - 50 50 - 100 100+
Perc
enta
ge
of
site
s p
rovi
din
g d
ata
m3/tonne of product
Table 2 Products associated with different effluent discharge rates
Soaps,sulphonic
acids,salts,
acrylates,detergents,
disinfectants,photographic
solutions,resins,
adhesives,pigments.
Water treatment chemicals,
surfactants,amine
products,polyacrylics,
chelating agents,
synthetic organic
polymers,acrylates,
herbicides,phosphates,
esters,sulphonic
acids, silicones.
Brightening agents,dyes,
esters,betaines,biocides,fungicide
intermediates,rubbers,resins.
Salts,esters,imides,
anhydrides,dyes,
biocides,pharmaceutical intermediates,
herbicides,insecticides.
Acrylates,amine
products.
Liquid crystals, buffer
solutions,pigments,
chlorine and bromine products.
less than 1 1 - 5 5 - 20 20 - 50 50 - 100 100+
Pro
du
ct t
ypes
Effluent discharge rate (m3/tonne of product)
Because the speciality chemicals sector is a major user of water, there is significant scope for moreefficient water management. Improvements can be achieved by all companies in the sector,irrespective of size. Section 4 outlines the costs of water to the speciality chemicals sector, whileSection 5 provides examples and handy hints for reducing these costs.
10
section
3
Has your company worked out its specific water consumption?
How does your company’s specific water consumption compare with the rates identified in thesurvey?
Does your effluent discharge rate reflect your water consumption?
Is there scope for improving your management of water and effluent?
Water use imposes a cost burden. The most obvious components of this cost include charges forwater supply and effluent discharge and the cost of on-site water treatment - either to make itsuitable for site use or to ensure that discharges meet regulatory requirements. Other costs thatmay be incurred include off-site waste treatment and disposal charges, energy costs associated withwater heating, cooling or pumping, and the value of product or raw material that is ‘lost’ in theeffluent stream.
The total cost of water use varies significantly from site to site. It is determined not only by specificwater consumption (which, in turn, depends on the products manufactured, the processes used andstandards of water management), but also by unit costs and other charges levied by watercompanies and by other contractors and suppliers.
4.1 CALCULATING THE COSTS
A top priority for any company wishing to reduce its water supply and effluent disposal costs is toidentify the true cost associated with water use. In many cases these costs are unknown and,furthermore, are sometimes regarded - mistakenly - as being too low to be of concern.
The true cost of water use may be more than three times the total amount charged for water supplyand disposal - much more if staff time or production downtime due to water-use operations suchas vessel washing are included. Table 3 (overleaf) provides details of the eight main componentcosts and allows companies to calculate the true cost of water for their own site.
4.2 WATER SUPPLY COSTS
Water supply costs vary with the source of water used. Speciality chemicals manufacturers obtaintheir water from three main sources:
■ the mains supply system;
■ groundwater supplies, abstractedvia boreholes;
■ surface water supplies - rivers,lakes, canals and reservoirs.
All the sites providing data used mainswater supplies and, for 75% of them,this was their only source of water (Fig 12). The remainder, usually thelarger plants requiring substantialvolumes of water for cooling purposes,drew on groundwater or surface watersources in addition to mains water.Cooling water from these sources wasgenerally kept separate from processwater and was discharged as surfacewater after use.
11
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4
T H E C O S T O F W AT E R U S E4
Fig 12 Proportion of sites accessing the three
main sources of water
Mains water
Surface water Groundwater
75%
7% 15%
3%
0%
0% 0%
Cost component Comments Cost£/year
Supply Mains water supply, usually charged per m3 and invoiced monthly. Costs are currently set to increase at a rate above that of inflation. Details are available from water company invoices.
Cost of licences for surface water/groundwater abstraction.
Disposal Effluent discharge to sewer, charged per m3 and invoiced monthly. Costsare currently set to increase at a rate above that of inflation.
Trade effluent charges are usually levied to take account of effluent contamination levels, eg chemical oxygen demand (COD), suspended solidscontent. Charges are calculated according to the Mogden Formula (seeAppendix). The advent of direct toxicity assessment (DTA) may increaseeffluent charges significantly for some speciality chemicals companies.
Details are available from water company invoices.
Labour and Operators undertaking water-using tasks such as vessel washing incur plant downtime labour costs and reduce the production hours of the plant. Labour costs
may exceed £15/hour - much greater than the cost of the water itself - andevery minute of downtime means there is less time to produce a saleableproduct.
Avoiding or speeding up the water-using operation can result in substantial labour cost savings and reduced plant downtime.
Pumping Water distribution using pumps incurs electricity charges. Electricity use is a function of flow rate, distribution pressure and pumping efficiency.
Maintenance Maintenance costs associated with pumps, flow meters and thedeterioration of pipework and equipment through corrosion or deposition.
Capital Excess capital costs incurred if the water supply system is not optimisedduring the design stage for either a new supply or an extension of theexisting supply.
Capital costs also incurred for water treatment plant. These may be reduced by rational water use and lower effluent volumes.
Treatment Treatment costs associated with:
■ treatment prior to use;
■ treatment prior to discharge.
Costs may comprise operating costs (usually per m3) and depreciation oftreatment plant.
Materials Materials lost in effluent may include raw materials, products, by-products and treatment/cleaning chemicals. These can be valuable.
Table 3 True costs of water use
Annual water supply costs for the speciality chemicals sites providing data totalled approximately £6 million. The equivalent figure for the whole sector is estimated to be around £140 million/year.Water costs for an individual company depend on whether it uses mains water, surface water,groundwater or a combination of these. Although lower costs may be achieved by using surfaceand groundwater supplies, this option is not available to many sites. The cost of mains water supplyfor the companies providing data varied from less than £1/tonne of product to more than £50/tonne(Fig 13), with 30% of sites incurring costs greater than £5/tonne.
Mains water costs vary significantly between sites and regions. Some sites, for instance, may benefitfrom more favourable large-user tariffs, while the charges levied by the water companies varyregionally, with industrial users in the south and south-east paying up to twice the rate levied in theMidlands1. These regional disparities are likely to increase in the future with changes in the regionalavailability of water resources.
12
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4
1 Source: OFWAT 1997-1998: Report on Tariff Structure and Charges
Sites may have little scope for reducing the unit cost of water supplied by water companies. Forfirms that wish to cut costs, the most practicable option is to manage water use more efficiently.Section 5 explores the options available to speciality chemicals manufacturers.
4.3 EFFLUENT DISCHARGE COSTS
Most speciality chemicals companies discharge effluents to sewer, although some companies installand operate on-site plant to treat effluents prior to discharge. The water companies receiving theseeffluents then levy an appropriate charge based on the Mogden Formula (see Appendix) which takesinto account both the volume and the composition (strength) of the effluent. Whichever option ischosen, the discharging company meets the cost of effluent treatment.
Based on data from the survey, total annual effluent discharge costs for 38 speciality chemicals sites,excluding the costs of on-site treatment, were on average £410 500/site. For the sector, the cost islikely to be around £410 million/year, almost three times the cost of mains water supply.
For individual companies effluent discharge costs per tonne of product varied from less than 50 pence/tonne of product to more than £100/tonne of product (Fig 14). The actual figure isdetermined by product and process types, site effluent characteristics (which themselves reflect thedegree of on-site treatment), and the extent to which the water companies themselves need to treatthe effluent before its eventual disposal to a watercourse or the sea. Costs are also influenced bythe effectiveness of water management on the manufacturing site.
13
section
4
Fig 13 Mains water supply costs/tonne of product
30
25
20
15
10
5
0less than 1 1 - 2 2 - 5 5 - 10 10 - 50 50+
Costs/tonne of product (£)
Perc
enta
ge
of
site
s p
rovi
din
g d
ata
■ Do you know how much the water supplied to your site actually costs each year?
■ Is your company at a commercial disadvantage because of high water supply costs?
■ Can you draw on alternative, cheaper sources of supply?
■ Can you negotiate more favourable tariffs?
■ Can your profitability be enhanced by managing water use more efficiently?
There is a strong correlation between water supply costs and effluent discharge costs (Fig 15). Thishighlights the double cost benefit to be gained from more efficient water management and thereduction of water inputs. Furthermore, the scope for savings in effluent discharge costs are likelyto be greater than water supply cost savings.
14
section
4
Fig 14 Effluent discharge costs/tonne of product
30
25
20
15
10
5
0less than
0.50.5 - 2 2 - 5 5 - 10 10 - 100 100+
Costs/tonne of product (£)
Perc
enta
ge
of
site
s p
rovi
din
g d
ata
Fig 15 Correlation between water supply and effluent discharge costs
30
20
10
0 2 4 6 8 10
Water supply costs (£/tonne of product)
Effl
uen
t d
isch
arg
e co
sts
(£/t
on
ne
of
pro
du
ct)
■ Do you know your site’s annual on-site treatment and effluent discharge costs?
■ Is your company at a commercial disadvantage because of effluent treatment/dischargecosts?
■ Have you compared the costs of on-site treatment and discharging untreated effluent?
■ Do you have the data available to renegotiate your effluent charges?
■ Do you know how much reducing your water usage would cut your effluent charges?
4.4 WATER COSTS AS A PROPORTION OF SITE PRODUCTIONCOSTS
Fig 16 illustrates the relationship between water supply/effluent discharge costs and total siteproduction costs. Total water-related costs varied from under 1% to almost 10%, with a typicalvalue around 2%. While this may seem low when expressed in percentage terms, the monetaryvalue can be substantial (£20 000 - £40 000/year for a site with an annual turnover of £2 million).Furthermore, both water purchase and discharge costs are increasing at a rate above that forinflation. It must also be remembered that these figures only cover mains water supplies anddischarges to sewer. They do not include potentially substantial additional water-related costs suchas on-site treatment or production downtime for vessel washing.
Although water-related costs may be only a small proportion of total production costs, theirsignificance in relation to profits can be much greater. Reducing costs by improved watermanagement can, therefore, have an immediate and lasting effect on a company’s bottom line -enhancing profitability and competitiveness.
15
section
4
Fig 16 Water supply and effluent discharge costs as a percentage of site production costs
0 2 4 6 8 10
Ind
ivid
ual
sit
es
Percentage of site production costs
Water supply costs
Effluent discharge costs
■ What percentage of your total production costs do water-related costs represent?
■ How does this compare with your current and projected levels of profitability?
■ What would a 25% reduction in water-related costs represent in terms of improvedprofitability?
5.1 DEMONSTRATED ACHIEVEMENTS
Many of the companies providing data have achieved significant cost savings and environmentalimprovements by managing their water use more efficiently. They have shown that water costs arenot fixed costs. Furthermore, many of the measures used are applicable across the specialitychemicals sector, so there is clear potential for other sites to benefit similarly.
Fig 17 shows the extent to which speciality chemicals manufacturers have adopted different watermanagement measures. These measures are described briefly in Sections 5.2 - 5.4.
The most widely implemented measures to date have been cooling water recirculation, improvedmetering of water volumes, audits of water use, and water minimisation programmes. Othermeasures under active consideration or definitely planned included water recycling/re-use andalternative plant or vessel washing techniques.
Overall, more than one third of sites have reduced their water consumption by between 5% and50% (Table 4). These companies manufacture a very wide range of products using many differentprocesses. High percentage savings have been achieved using various measures - watermanagement techniques, ‘good housekeeping’ and investment in plant/process modifications.Although, in general, high cost savings (net of any capital and operating costs) were correlated withhigh percentage water savings, the highest cost saving was achieved through measures thatreduced water consumption by only 5%.
16
section
5
I M P R O V I N G T H E E F F I C I E N C Y O FW AT E R U S E
5
Fig 17 Take-up of water management measures
Recirculation of cooling water
Improved metering (quantity)
Audit of water use
Water minimisation programme
Re-negotiation of tariffs/consents
Improved monitoring (quality)
In-process water recycling/re-use
Triggered hoses
Leak detection programme
Staff awareness and training
Housekeeping to reduce cleaning
Production scheduling
Improved cooling towers/systems
Improved control system
Valve and pipe maintenance
'Clean-in-place' technologies
0 20 40 60 80
Percentage of sites providing data
UndertakenDefinitely plannedUnder consideration
Plant or vessel washing techniques
Upgrading vacuum systems
Measures introduced Reduction in Net cost saving water use (%) (£)
Water management techniques
Metering individual product areas and setting reduction targets 30 96 000
A package including production scheduling, improvements in 50 24 000plant wash-downs and the use of triggered hoses
Good housekeeping measures
Improved pipework to reduce leaks 10 6 000
Good housekeeping, taps on hoses, etc 8 3 400
Better housekeeping to avoid cleaning 3 1 000
Storm water prevented from entering effluent system 7 3 000
Leak detection and reduction 30 70 000
Flow restrictors on vessel cooling lines 5 5 000
Plant and process modifications
Cooling water re-use 21 8 400
Installation of cooling tower 50 30 000
Installation of cooling tower 23 3 000
Installation of improved cooling towers 50 30 000
Re-use of wash-water for batch dilution 25 29 000
Installation of pressure washers for cleaning blending tanks 5 1 000
Recirculation of water in liquid ring vacuum pumps 50 19 000
Replacement of water seal vacuum pumps with dry versions 24 6 300
Installation of air chillers 5 3 000
Reduction in process water wastage 5 70 000
Water minimisation project 20 20 000
A package of waste minimisation measures 65 (water) 135 000
50 (effluent) 80 000
Replacement of laboratory sample coolers with refrigerators 31 8 500
Modernisation of manufacturing facilities 38 45 000
Improvements in process efficiency 5 350 000
Table 4 Water use reductions and cost savings achieved
The individual measures identified are not mutually exclusive. Most companies had implemented atleast three of these measures, while more than 15% had implemented at least seven (Fig 18).
17
section
5
Fig 18 Number of water management measures implemented
None
1 - 2
3 - 4
5 - 6
7 - 8
9 - 10
0 5 10 15 20 25 30
Percentage of sites providing data
Nu
mb
er o
f w
ater
man
agem
ent
mea
sure
s im
ple
men
ted
Median = 3 measures adopted
There is scope for many more sites to adopt the cost-effective water reduction measures alreadydemonstrated successfully by some of their competitors within the sector. Furthermore, sites thathave already implemented measures should continue to consider opportunities for furtherimprovements.
5.2 WATER MEASUREMENT SYSTEMS
The old adage: ‘If you don’t measure it, you can’t manage it’, applies to every aspect ofmanagement. Measuring water consumption, effluent discharge and the associated costs istherefore crucial to the effective management of water as a resource.
Effective measurement requires the installation and use of appropriate water metering andmonitoring systems. These should be designed so that water-related costs can be allocated to keyproducts and processes where water consumption is estimated to be high. This eliminates theassumption that these costs are simply part of general site overheads. However, it is equallyimportant to avoid unnecessary metering as this is costly in terms of equipment, and also increasesthe staff time needed to record and analyse the information produced.
An effective measurement system allows a company to:
■ measure water use on a frequent (daily or weekly) basis;
■ gain a clear picture of how much water is used and where;
■ establish a correlation between water use and operating costs on a process or product basis;
■ compare actual consumption with the quantities theoretically required for individual processesor plants;
■ identify the changes that need to be made to optimise water use in key processes and plants;
■ measure subsequent consumption and compare it with targets set.
Targets would normally be based on past experience of achievable consumption levels, whether onsite or elsewhere.
This approach encourages a critical examination of water use, rather than a simple acceptance ofconsumption on the basis that ‘it has always been like that’. The same principles can be applied towater quality, thereby helping to avoid over-specification.
All the sites providing data monitored their water use, although the frequency of monitoring variedsignificantly (Fig 19). Only 25% of sites kept records on a daily or more frequent basis, with somemonitoring the quantity and quality of their water intake every 20 seconds. In the case of effluentmonitoring, while more than 50% of sites recorded data on a daily or more frequent basis, almost25% did no monitoring at all of the volume and/or concentration of their effluent discharge (Fig 20).
18
section
5
■ Have any of the measures listed in Table 4 been implemented at your site?
■ Has your site achieved similar reductions in water use and costs?
■ Which of these measures do you believe might be appropriate for your site?
■ What levels of water use and cost savings do you think you might achieve?
5.3 GOOD HOUSEKEEPING MEASURES
Introducing simple, no-cost or low-cost good housekeeping measures is often one of the easiestways of reducing water use. Such measures can generate immediate savings, thereby raising staffawareness of the commercial importance of efficient water management and providing a strongincentive for the subsequent introduction of more capital-intensive measures. Fig 21 shows someof those that have been introduced in the speciality chemicals sector.
19
section
5
■ Do you routinely measure water supply and effluent discharge?
■ Are measurements made often enough so that short-term variations and problems canbe detected?
■ Are measurements detailed enough to identify the amount of water used by individualproducts and processes?
■ Do you allocate water costs to individual products and processes or simply treat them asa general overhead?
■ Do you set targets for water use and monitor performance against these targets on aregular basis?
Fig 19 Frequency of water monitoring (by volume) Fig 20 Frequency of effluent monitoring (by volume
and concentration)
Daily
Yearly
QuarterlyMonthly
Weekly
Percentage of surveyed sites
Daily
Never
Quarterly
Monthly
Weekly
Percentage of surveyed sites
Fig 21 Take-up of good housekeeping measures
Leak detection programme
Triggered hoses
Housekeeping to reduce cleaning
Valve and pipe maintenance
0 10 20 30 40 50
Percentage of sites providing data
Undertaken
Definitely planned
Under consideration
5.4 PLANT AND PROCESS MODIFICATIONS
As well as managing water more efficiently in existing plant and processes, there are opportunitiesfor introducing more fundamental modifications to reduce water consumption and costs. There is,for instance, a move away from traditional ‘end-of-pipe’ solutions with their reliance on largesettlers and holding tanks to even out flows and allow time for solids to settle. The modernapproach relies more on advanced engineering systems that are integrated into the process andlinked to effective, modern control technology.
The greatest opportunity for modification arises when sites are investing in new process plant andequipment: when efficient water management and environmental protection systems can beincorporated into the original design.
Fig 22 shows the extent to which these modifications have been adopted by sites in the specialitychemicals sector.
20
section
5
Fig 22 Take-up of plant and process modifications
Recirculation of cooling water
In-process water recycling/re-use
Improved cooling towers/systems
'Clean-in-place' technologies
Plant or vessel washing techniques
Upgrading vacuum systems
0 20 40 60 80
Percentage of sites providing data
Undertaken
Definitely planned
Under consideration
1, 2, 3* **
**
1*
* The following Environmental Technology Best Practice Programme publications give detailed information about theseareas. All are available free of charge through the Environmental Helpline on 0800 585794.
1 Reducing Vacuum Costs (GG101)
2 Cost-effective Separation Technologies for Minimising Wastes and Effluents (GG37)
3 Cost-effective Membrane Technologies for Minimising Wastes and Effluents (GG54)
** A Good Practice Guide on effective management of vessel washing is being prepared. It will be available free ofcharge through the Environmental Helpline in early 1998.
Fig 23 illustrates how it is possible to increase water re-use in speciality chemicals plant by cascadingwater from the cleanest to ‘dirtier’ uses.
21
section
5
Fig 23 Opportunities for cascading water to encourage re-use
Cleanest
Dirtiest
Process uses
Filter wash-water
Final wash
Second wash
First wash
Plant cleaning
Vessel washing
Final rinse
Displacement
Cascade
■ Have you done as much as your competitors to improve water management efficiency?
■ Are there (other) measures that you could implement immediately to bring about an improvement?
■ Are there (other) measures that you regard as high priorities for future action?
■ What additional support and information do you need to reach decisions on theseshort-term and medium-term options?
6.1 OBSTACLES TO PROGRESS
Many speciality chemicals companies are already achieving significant year-on-year cost savings andenvironmental improvements as a result of managing water more effectively (Section 5.1). However,many other companies have not installed water-saving measures and are therefore missing out onthe associated benefits.
Companies in the sector face a number of barriers to the introduction of more effective watermanagement (Fig 24). However, the number of sites that have reduced their water consumptionand costs demonstrates that these real or perceived barriers can be overcome. This requires a clearunderstanding of the associated cost benefits, a recognition of the senior management commitmentrequired, and an understanding of the necessary changes in staff attitudes and awareness.
6.2 OVERCOMING THE BARRIERS
Table 5 summarises the main ways in which companies are successfully overcoming the individualbarriers identified above.
22
O V E R C O M I N G T H E R E M A I N I N GO B S TA C L E S
6
Fig 24 Barriers to more efficient water management
Investment costs
Staff attitudes and awareness
Water is cheap, so waste it
Poor payback
Process and QA standards
Senior management inertia
Lack of staff skills
Concentration of effluent
Other environmental priorities
Time pressures
No responsibilities allocated
No measurement
0 10 20 30 40
Percentage of sites providing data
section
6
23
Barriers Factors that help to overcome the barriers
Lack of financial incentive Understanding of ‘true’ costs of water.
Low perceived cost of water Demonstration of net cost savings.
Savings achieved by other companies.
Limited resources for capital investment Low cost of many water management measures.
Net costs of water reduction measures Rapid payback on many projects requiring investment.
Other projects offer higher rates of return Recognition of water as a high-value resource.
Priority given to ‘mainstream’ improvement projects
Lack of schemes showing clear paybacks Initial focus on low-cost good housekeeping measures.
Systematic evaluation of investment opportunities.
Other environmental priorities Similar approaches to water and waste minimisation.
Integration of water management into widerenvironmental management systems (EMS).
Water as a component of Integrated Pollution Control (IPC).
Lack of information on water use/costs Evaluation of billing information for water supply andeffluent discharge.
Introduction of simple metering at critical points with highwater usage.
QA requirements for plant/vessel cleaning Avoiding projects that may jeopardise product quality.
Piloting and monitoring new measures.
High process water requirements Recognition that opportunities for rationalising water usestill exist.
Consideration of water used for non-process purposes.
Lack of time Importance of team-working and sharing responsibilities.
Integration of water management into routine tasks andprocedures.
Senior management inertia Demonstration of the proven cost benefits of watermanagement.
Highlighting savings already being achieved by competitors.
No clear allocation of responsibilities Senior management take overall responsibility.
Allocating and delegating responsibilities to staff at everylevel.
Staff awareness Encouraging ‘ownership’ of water management measures.
Attitudes to water use Encouraging staff suggestions, providing feedback andgiving praise where it is due.
Prioritising the introduction of simple measures that haveclear financial benefits.
Staff turnover Integrating water management measures into normaloperator practices.
Documenting practices and procedures to facilitatehandover.
Customer demands for water-based products Potential increase in value of water savings achieved.
Uncertain where to start Following the Action Plan (Section 7).
Table 5 Ways of overcoming the barriers to more efficient water management
section
6
■ What barriers are preventing your site from reducing its water consumption?
■ What approaches can you adopt to overcome these barriers?
■ Does commitment to effective water management come from the top?
■ Are staff at all levels involved and aware of their responsibilities?
■ Is the case for investment being presented as effectively as possible, taking into accountall potential cost savings?
section
6
24
25
W AT E R M I N I M I S AT I O NA C T I O N P L A N
7
section
7
This Section provides a clearly-defined framework (Fig 25) that you can adapt and develop to meetthe specific characteristics of your own site and management structures. The key elements of theframework are described below.
7.1 ENSURE COMMITMENT TO ACTION
Your first step is to make the case for further action. Use this Guide to help you review your site’swater performance and the procedures used. Assess site circumstances and determine the need for,and likely benefits arising from, an improvement programme focusing on water use. Use thisinformation to gain the commitment of senior management to such a programme and therebysecure an appropriate allocation of staff and resources.
Fig 25 Framework for a water minimisation Action Plan
1. Commitment to actionSenior management
commitment
2. Organisation for actionAppoint a champion
Establish teams
3. Audit/reviewWater audit
4. Options for improvementTechnical feasibilityEconomic viability
Selection and prioritisation
6. Feedback on performanceThrough monitoring and
targeting and performancereviews
5. ActionImplementation of improvement plans
7. DisseminationPublicising success to all
stakeholders
The preparation
The journey
Commitment starts at the top - unless the most senior manager on the site is committed to theefficient management of water and to associated environmental issues, little will be achieved.
7.2 ORGANISE FOR ACTION
Establish an organisational structure that will allow you to proceed with the improvement plan, andallocate responsibilities accordingly. Where appropriate, appoint a champion for the programmeand form the necessary teams to secure its implementation2. These teams may consist of themanufacturing manager, chemists, chemical engineers and quality, health & safety supervisors.Involvement across the site may be essential, particularly when undertaking an audit or review.Identify and address any additional training needs. Remember that no-one understands the sitebetter than those who work in it, and no-one will, therefore, be better placed to ensure the successof measures implemented under the plan.
7.3 AUDIT AND REVIEW WATER USE
Use the teams or individuals responsible for different areas of the plant to undertake acomprehensive water audit of the site. This will establish where and how water is used and whereit ends up. Identify all points of water loss and, most importantly, identify the water-related costsassociated with each element of the process or flow. The scope of the review should cover:
■ water supply/abstraction;
■ incoming water treatment;
■ pumping and distribution;
■ process water uses;
■ ‘domestic’ water uses;
■ effluent treatment;
■ trade effluent discharge;
■ off-site liquid waste disposal;
■ energy, materials and product losses as a result of leaks and effluent discharge.
The end result should be a comprehensive water mass balance for the site and individual processes,together with an accurate characterisation of costs. This may require the installation of additionalmetering at key locations. Using the mass balance and water consumption data, critically compareactual water use in key processes and plant with theoretical water consumption.
26
section
7
Organisation is essential. If the efficient management of water is to become part of site‘culture’, everyone needs not only to be involved, but also to understand their own role andbe equipped to fulfil it.
The audit is not an end in itself, but a means to an end. As well as helping to identify areasin which savings might be achieved, it will allow water-related costs to be allocated toindividual products and processes, rather than to remain an ‘unavoidable overhead’ for the siteas a whole.
2 See Good Practice Guide (GG27), Saving Money Through Waste Minimisation: Teams and Champions. Copies can beobtained through the Environmental Helpline on freephone 0800 585794.
27
section
7
7.4 IDENTIFY OPTIONS FOR IMPROVEMENT
Having identified areas of high water usage, the next step is to identify and review the opportunitiesfor improvement.
■ Identify possible options for improvement and assess these in relation to processrequirements.
■ Hold brainstorming sessions involving operators who know the process best.
■ Consider a scheme for rewarding bright ideas.
■ Assess any technical or process implications of the proposed improvements.
■ Assess the economic feasibility of each option before prioritising options for implementation.
■ Give high priority to low-cost options that will provide clear and rapid benefits.
■ Where an option requires a capital input, make sure that the investment is supported by asound business case.
7.5 IMPLEMENT THE SELECTED OPTIONS
Having identified the appropriate measures, the next stage is to implement the processimprovements. Good housekeeping measures can often be integrated into establishedmanagement practices that are already in place for other reasons such as health and safety. Someof the management techniques will also be familiar - there are many parallels, for instance, in energymanagement.
7.6 ENSURE FEEDBACK THROUGH A MEASURING TO MANAGEPROGRAMME
Make sure that your staff are kept informed about, and involved in, the improvements being made.This will help to engender ‘ownership’ of the changes and make it much easier to integrate watermanagement into general management practices and operating procedures. Furthermore, the staffwho operate and know the processes are often the best sources of ideas for making practicalimprovements.
■ Implement a measuring to manage programme to provide feedback on the success ofmeasures carried out under the plan. Remember that measuring to manage is a means ofdriving improvement forward.
■ Identify areas where savings are still possible and suggest how they might be achieved.
■ Encourage staff to come forward with their own suggestions for improvement - they knowthe process best.
Costly, technical solutions are not always the answer. Consider management techniques andlow-cost or no-cost good housekeeping measures as well, but remember that even theseoptions will incur costs in some form, even if no capital investment is required.
Feedback is vital to long-term success. It helps to maintain staff interest and motivation.
7.7 DISSEMINATE SUCCESSES ACHIEVED
Disseminate the successes achieved as widely as possible within the site, using terms that people canrelate to and eye-catching charts to show the improvements. This will help you to maintain thecommitment of your staff. Presenting the results at board meetings will help to ensure thecontinued commitment of senior management. Consider awards for staff who have helped toidentify and achieve savings. Publicise and promote successes to stakeholders outside the company.This can generate widespread recognition of the company’s achievements. Improving the site’senvironmental credentials may generate additional cost benefits.
28
section
7
Publicising your successes ensures a wider recognition of the achievements and savings thathave been made. It is an important method of helping to maintain the commitment of seniormanagement.
Can the Environmental Technology Best Practice Programme provide any further help?
■ Speciality chemicals manufacturing sites with specific environmental queries can contactthe Environmental Helpline on 0800 585794.
■ Sites employing fewer than 250 people can ask for a counselling visit to advise on anyaspect of waste minimisation, including water use.
29
Water company charges for trade effluent discharged to sewer are based on the Mogden Formula.This formula attempts to link charges to trade effluent customers to the costs that they impose, ie,customers pay according to the volume and strength of the effluent they discharge.
The Mogden Formula is expressed as follows:
C = R + M + V + Bv + OtB + StSOs Ss
where:
C = Charges in pence/m3
R = Reception and conveyance
M = Treatment and disposal where effluent goes to a sea outfall (M for marine)
V = Primary treatment (V for volumetric)
Bv = Additional volume charge if biological treatment is required
Ot = Chemical oxygen demand (COD) of effluent after one hour quiescent settlement at pH 7
B = Biochemical oxygen demand of settled sewage
Os = COD of crude sewage after one hour quiescent settlement
St = Total suspended solids (mg/litre) of trade effluent at pH 7
S = Treatment and disposal of primary sludge
Ss = Settleable solids (mg/litre) - suspended solid after one hour quiescent settlement
Values for B and S may be corrected for average regional strength (B’ and S’):
B’ = B/Os
S’ = S/Ss
Charges for B’ and S’ are usually expressed in pence/m3 relative to standard strength (concentrationusually expressed in mg/litre). Standard strengths vary from company to company. To maintaincomparability, the charges shown in the following tables (B’ and S’) are corrected for standardstrength and shown as pence/kg.
The extent to which the Mogden Formula is applied depends on the degree of treatment providedby the water company receiving the effluent:
Discharge directly to a watercourse - site pays only the R component
Discharge via an effective sea outfall - site pays only R + M
Discharge receiving primary treatment only - site pays R + V + S
Discharge receiving full treatment - site pays R + V + S + B
The charges paid by sites for each m3 of effluent discharged will also vary because of variations inwater company charges and in the strengths discharged.
appx
A1
T H E M O G D E N F O R M U L A A N DU K T R A D E E F F L U E N T C H A R G E S
Appendix
Variations in water company/authority trade effluent charge factors for 1996/97 are shown in Table A1.
Regional Minimum strengths
charge R V Bv M B’ S’ Os Ss(£) p/m3 p/m3 p/m3 p/m3 p/kg p/kg mg/l mg/l
Anglian 108.00 9.38 14.68 2.84 7.27 34.70 19.63 447 403
Dwr Cymru 102.00 11.00 7.23 2.89 10.72 33.37 33.65 500 350
North West 99.00 10.00 8.00 1.10 7.40 22.34 25.73 367 237
Northumbrian 239.00 19.30 9.47 - - 37.30 39.05 386 187
Severn Trent 107.00 15.48 14.60 - - 24.90 19.00 351 343
Southern 110.00 19.73 14.41 2.32 2.54 42.01 26.39 452 512
South West 118.70 31.92 29.42 - - 69.64 63.26 744 489
Thames 70.00 6.53 8.03 - - 28.43 47.98 445 336
Wessex 160.00 12.75 12.60 0.50 - 30.50 41.92 802 313
Yorkshire 195.00 17.00 19.53 - - 21.19 36.09 926 339
E of Scotland1 110.00 7.89 6.63 - - 48.59 17.47 334 233
N of Scotland2 - 9.99 4.73 - - 27.89 20.48 350 250
W of Scotland 130.00 4.68 4.83 - - 23.25 18.00 240 155
N Ireland3 - 10.00 8.00 - - 20.83 16.67 480 340
1 Trade effluent data for the East of Scotland Water Authority were provided by Lothian Regional Council. Tayside RegionalCouncil has a flat rate charge of 23 p/m3.
2 Trade effluent data for the North of Scotland Water Authority were provided by Grampian Regional Council.3 Trade effluent data for Northern Ireland were provided by the Department of the Environment for Northern Ireland Water
Services Division. There is currently no minimum charge in place in Northern Ireland, although this may be introduced inthe future.
Table A1 Water company/authority trade effluent charge components 1996/97
Trade effluent charge calculation: a worked example.
Anglian Water Mogden Formula values:
R = 9.38 pence/m3
V = 14.68 pence/m3
Bv = 2.84 pence/m3
B’ = 34.70 pence/kg
S’ = 19.63 pence/kg
For 1 m3 of low-strength effluent (Ot = 200 mg/litre and St = 300 mg/litre), the volumetric chargeC can be calculated as follows:
C = R + V + Bv + B’ Ot + S’ St
= 9.38 + 14.68 + 2.84 + (34.7 x 0.200) + (19.63 x 0.300)
= 39.729 pence/cm3
= £0.397/m3
For a total discharge of 5 000 m3, the charge would be 5 000 m3 x £0.397
= £1 986
30
appx
A1
31
Table A2 shows the charge variations between water companies for 5 000 m3 of low-strengtheffluent and the same volume of a high-strength effluent.
Water and sewage Low-strength High-strength companies/authorities effluent (£) effluent (£)
Anglian 1 986 6 644
Dwr Cymru 1 894 6 910
North West 1 564 5 034
Northumbrian 2 397 8 054
Severn Trent 2 038 5 567
Southern 2 624 8 344
South West 4 712 14 935
Thames 1 732 6 681
Wessex 2 226 7 201
Yorkshire 2 580 6 280
E of Scotland 1 474 7 673
N of Scotland 1 322 5 246
W of Scotland 978 4 282
N Ireland 1 461 4 681
NB: All bills are shown rounded to the nearest £. Bills for full treatment of effluent are calculated according to the MogdenFormula where the effluent characteristics are:
Low strength: COD = 200 mg/litre and St = 300 mg/litre;
High strength: COD = 2 500 mg/litre and St = 1 000 mg/litre.
Table A2 Water company/authority charges for 5 000 m3 of low-strength and high-strength effluent
appx
A1
The Environmental Technology Best Practice Programme is a joint Department of Trade and Industry
and Department of the Environment, Transport and the Regions programme. It is managed by
AEA Technology plc through ETSU and the National Environmental Technology Centre.
The Programme offers free advice and information for UK businesses and promotes
environmental practices that:
■ increase profits for UK industry and commerce;
■ reduce waste and pollution at source.
To find out more about the Programme please call the Environmental Helpline on freephone
0800 585794. As well as giving information about the Programme, the Helpline has access to
a wide range of environmental information. It offers free advice to UK businesses on technical
matters, environmental legislation, conferences and promotional seminars. For smaller
companies, a free counselling service may be offered at the discretion of the Helpline Manager.
FOR FURTHER INFORMATION, PLEASE CONTACT THE ENVIRONMENTAL HELPLINE
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