Tracking Water Use to Cut Costs

Transcription

1 Business Resource Efficiency Guide Tracking Water Use to Cut Costs

2 WRAP Tracking Water Use to Cut Costs II Our vision is a world without waste, where resources are used sustainably. We work with businesses and individuals to help them reap the benefits of reducing waste, develop sustainable products and use resources in an efficient way. Find out more from the WRAP Resource Efficiency Helpline on or at Contents The true cost of water Understanding where costs arise What is a water balance? Why produce a water balance? How to use this guide 6 for constructing/using 8 a water balance 2.1 Step 1 Obtaining top-level commitment 8 and assessing the resources required 2.2 Step 2 A preliminary review Step 3 Drawing up a water balance Step 4 Adding detail to the water balance Step 5 Using the water balance to save 30 money 2.6 Step 6 Continuous improvement Gathering more data Finding out more about effluent flows Using the water balance to save money 40 4 Action plan 43 5 Further 44 Appendix A: UK charging schemes 46 Appendix B: Where do businesses use water? 58 Appendix C: Unit operations for a boiler and 64 cooling tower Appendix D: Example water balances 65 Appendix E: Producing and using site 70 drainage plans Appendix F: Calculating water flows for cooling 71 towers and steam relief valves Appendix G: Determining pollutant loads 73

3 WRAP Tracking Water Use to Cut Costs 1 Summary Adopting a systematic approach to water reduction can typically result in around 30% water savings if no measures have previously been implemented. A water balance is a management tool that provides managers with an overview of the major uses of water on their company s site, irrespective of the company s activity. When used to control water use and effluent generation, a water balance can help companies and organisations of all sizes and types to reduce water use, cut costs and increase profits. This guide describes a six-step for constructing a water balance and explains how this can help you to identify water and cost saving opportunities. The step-by-step approach to reducing water use described in this guide involves: 1. Obtaining commitment and resources. 2. A preliminary review. 3. Drawing up a water balance. 4. Adding detail to the water balance. 5. Using the water balance to save money. 6. Continuous improvement. Checklists and worksheets are provided to help you investigate your water use and effluent sources. Examples of cost savings already achieved by companies are given throughout the guide.

4 WRAP Tracking Water Use to Cut Costs 2 Companies that adopt a systematic approach to water reduction typically achieve a 30% decrease in the amount of water they use. Water is becoming an increasingly expensive resource with mains, sewerage and trade effluent charges rising. However, introducing water efficiency measures is one of the easiest and most inexpensive ways to achieve cost savings. Most companies and organisations know how much water they use, but may not always use this knowledge to help them reduce the amount of water consumed. Companies that adopt a systematic approach to water reduction typically achieve a 30% decrease in the amount of water they use. By using less water, companies save money on both water supply and wastewater disposal. Taking action to save water may also allow companies to recover raw materials or product previously lost in effluent streams. This guide applies to both industrial and commercial and will help you work out where water is being used and where less water could be used. Savings can be made by companies of any size or type including companies that use comparatively little water per site or per person. Some have a finite water supply (e.g. from the mains water distribution system or groundwater and surface water sources), making it difficult to increase supply to meet any rise in demand. Increased availability may also be expensive. Managing water more efficiently can prevent any potential site expansion being limited by the availability of water or the need for an increased water supply. 1.1 The true cost of water The type of water used on site and the type of wastewater generated by site operations/activities will determine how much your company pays for water supply and wastewater disposal. Table 1 lists the different types of water and wastewater. Table 1: Types of water and wastewater in the UK Water sources Mains water (wholesome* and unwholesome) Water abstracted from groundwater (borehole) and surface water * Drinkable. Wastewater types Domestic wastewater (sewage) Trade effluent Surface drainage (roof and site runoff) Discharge to surface water and groundwater There are a number of charging schemes for water and wastewater (sewerage and trade effluent charges) in the UK. The amount paid depends on: the service provider; the size of the meter; the tariff structure agreed with your service provider; and the year unit costs are reviewed on an annual basis. Appendix A gives details of individual charging schemes and how to understand your bills. 1.2 Understanding where costs arise As well as easily identified costs such as charges for water use, sewerage, surface water and trade effluent, there are many hidden costs associated with water use and the disposal of wastewater. The true cost of water may be more than three times the total amount charged for supply and disposal. Figure 1 shows the elements making up the true cost of water.

5 WRAP Tracking Water Use to Cut Costs 3 Figure 1: The true cost of water Easily identified costs Water charges Sewerage charges Effluent charges Cost of energy to heat water Cost of chemicals for water treatment Cost of wasted energy (e.g. pumping) Hidden costs Cost of chemicals for effluent treatment Cost of raw materials/product in effluent Cost of labour Hidden costs can include: the energy costs associated with heating/ cooling water prior to use; lost product or raw materials in effluent, resulting in sale losses and increased effluent strength leading to higher trade effluent charges; water treatment prior to use (e.g. ion exchange or membrane technologies such as reverse osmosis), including the cost of chemicals for regeneration and replacement columns/packing materials, and the labour costs incurred in running and maintaining these systems; pumping costs including energy, labour and maintenance costs; and wastewater treatment prior to re-use or discharge, including the cost of acid/alkali for ph adjustment, flocculants, coagulants, pumping costs, labour and maintenance. Environmental review identifies true effluent costs An environmental review at a chemicals company revealed that total effluent costs were 23,000/year and not 4,000/year as previously thought. The review also showed that, as well as paying extra effluent charges, the company was losing saleable product in the effluent. Following improvements and procedural changes, the company reduced its effluent charges by 3,000/year and saved 8,500/year through product recovery from the effluent.

6 WRAP Tracking Water Use to Cut Costs Added value water Water treated before use has an added value because time and money have already been spent on it before it is used for its main purpose. Table 2 summarises typical costs of water. Table 2: Comparable costs of different water types Water type Typical cost UK mains supply /m 3 * Chlorinated water /m 3 Softened water /m 3 Demineralised/ deionised water Condensate gas heated ** Steam gas heated ** /m /m /tonne * UK mains supply based on standard 2011/12 tariffs. ** Energy costs at 3.6p/kWh for gas and boiler efficiency of 90%. 1.3 What is a water balance? A water balance is a numerical account used to show where water enters and leaves your business, and where it is used within the business. It typically contains about the amount of water used by each main process and, for some processes, can be very detailed. Presenting the water balance as a diagram makes it easy to understand and use as a management tool. A water balance is based on the simple concept: what goes in must come out... somewhere (see Figure 2). It is best to start by looking at your company as a whole and then adding details as you go along. It is also helpful to think of your site or company as a series of blocks, with each block representing an activity or location with water inputs and outputs. Figure 3 shows water inputs and outputs for a fairly simple site; Figure 4 is a block representation of this site. Appendix B gives examples of water use in a number of industrial and commercial sectors. Figure 2: Water mass balance Evaporation Water in Product Leaks to ground Effluent

7 WRAP Tracking Water Use to Cut Costs 5 Figure 3: Water inputs and outputs for an example site Water supply Meter Liquid raw materials Evaporation and steam Factory laundry and washrooms Factory Factory shop and canteen Water in the product Domestic wastewater/ trade effluent Figure 4: Block representation of water inputs and outputs for an example site Mains water Meter Evaporation and steam Liquid raw materials Evaporation and steam Laundry and washrooms Toilets, handbasins and showers Washing machines Tumble dryers Factory Equipment washing Water added to product Boiler Steam generation Condensate recovery Water softening Condensate recovery Shop and canteen Toilets and sinks Dishwasher Food preparation Product Water in the product Leaks Boiler blowdown/ condensate Domestic wastewater/ trade effluent

8 WRAP Tracking Water Use to Cut Costs 6 ct 1.4 Why produce a water balance? A water balance helps you to: understand and manage water and effluent efficiently; identify the areas with the greatest opportunities for cost savings; and detect leaks. Evaporation and steam Liquid Small brewery saves money raw by materials stopping leaks Monitoring water use allowed a brewer to discover a significant water leak, which was due to three faulty control valves. Factory The valves were Laundry replaced and at a total cost of 400, leading washrooms to reduced water use of 10,800m 3 Water added to Toilets, handbasins /year. productthis represented and showersa saving of 13,000/year Boiler in water and Washing trade machines effluent charges. Tumble dryers Mains water The main benefits of using a water balance to identify and implement Water in opportunities to reduce water use are: the product Leaks reductions in: -- water supply costs; -- on-site water treatment costs; -- on-site effluent treatment costs, including chemicals and capital depreciation; -- effluent and sewage disposal costs; -- wasted raw materials or products; and -- management and handling costs (e.g. pumping, maintenance and heating); Meter Equipment washing improved compliance with current and future environmental regulations; better relationships with regulators, employees, the general public and the local community; improved environmental management; and greater employee awareness of environmental issues and the importance of waste minimisation to the company. Evaporation and steam Steam generation Condensate recovery Water softening Domestic wastewater/ trade effluent Remember You can t manage what you don t measure. Condensate recovery The waste hierarchy Shop and is a canteen framework prioritising the most Toilets environmentally and sinks Dishwasher desirable options for waste. The principles Food preparation of the waste hierarchy when applied to water (see Figure 5) consist of four levels of waste management. Apply this hierarchy to each process/area that uses water or generates wastewater at your site. Boiler blowdown/ condensate 1.5 How to use this guide This guide explains how to draw up a water balance for your site and then use it to save money by reducing water use. For small to medium-sized, this involves following the simple step-by-step described in Section 2. This is extended in Section 3 to cater for larger, more complex. Section 4 presents an action plan applicable to all. Figure 5: Waste hierarchy applied to water Yes 1. Can you eliminate water use at source? No 2. Can you reduce the amount of water used? No 3. Can you re-use water/wastewater? No y shop nteen 4. Can you recycle/recover water/wastewater? No Calculate the cost of disposal Implement water reduction

9 WRAP Tracking Water Use to Cut Costs 7 In this guide, the term domestic wastewater is used for domestic water and sewage discharged at the domestic sewerage rate. Trade effluent refers to effluents from industrial processes on which trade effluent charges are levied, based on the strength as well as the volume of effluent. The step-by-step approach to reducing water use described in this guide involves: 1. Obtaining commitment and resources. 2. A preliminary review. 3. Drawing up a water balance. 4. Adding detail to the water balance. 5. Using the water balance to save money. 6. Continuous improvement. You may want to use this guide to help drive forward a water saving campaign. Drawing up a water balance for your site forms part of the detail of a typical water saving campaign (see Figure 6). This process is broadly similar for industrial and commercial and usually entails four phases. Figure 6: The four phases of a typical water saving campaign PHASE 1 Initiation Obtain commitment from senior management. Involve staff and appoint the leader ( champion ) of the water saving team. Find out about water saving devices and their application. Talk to other interested people in your company. Develop a simple programme. Allocate sufficient resources. PHASE 2 Water use survey and development of a water balance Identify where, how and why water is used. Identify the water quality requirement at each point of use. Determine the water quality and availability at each point of discharge. Wholesale food distributor saves money at over 100 A wholesale food distributor fitted simple water saving devices at 109 of its UK outlets. For an average cost of around 675/site, water use and wastewater production were reduced by 65% overall. Each site saved on average around 980/year, giving a total reduction of 106,700/year. Nearly 1% of turnover saved by recycling process effluent A Humberside company, employing 180 people, investigated cost-saving opportunities while seeking improvements in environmental performance. Investment of 20,000 in new pipework and tanks allowed a liquid waste stream to be recycled. This has enabled the company to save 20,000/ year in effluent charges and 200,000/year in increased yield and reduced disposal costs. PHASE 3 Evaluation of water saving options Evaluate current and future water costs by area or item of equipment. Identify and evaluate cost-effective water saving devices and practices. Carry out trials of likely options. PHASE 4 Implementation Train staff (if necessary). Implement cost-effective water saving devices and practices. Monitor the implemented devices and practices. Communicate successes and savings to employees. Obtain feedback from staff.

10 WRAP Tracking Water Use to Cut Costs 8 for constructing/using a water balance For your water efficiency programme to be a success, you will need commitment from senior management. Use the simple six-step described below to construct a water balance for your site. Then use your water balance to identify opportunities to make significant cost savings by reducing water use and wastewater/ effluent generation. 2.1 Step 1 Obtaining top-level commitment and assessing the resources required Obtaining top-level commitment For your water efficiency programme to be a success, you will need commitment from senior management. This should be obtained at an early stage particularly if you do not have the necessary authority to commit resources to produce a detailed water balance or to investigate and implement water saving opportunities. It may be easier to obtain top-level commitment once you have started to develop your water balance and are in a position to: highlight current costs; identify the need for more ; suggest the scope for potential savings; and highlight some quick win opportunities. Your chances of success will be significantly improved if you can also suggest some no-cost and low-cost water saving measures, together with the anticipated costs and savings. Examples from other companies may be appropriate, but specific potential projects for your site will carry more weight. Examples might include fitting passive infrared (PIR) controls in the men s toilets or fitting water saving taps Assessing the staff and resources required The time and effort needed to produce a water balance depends on your site. On a simple site, it could take only a few hours. On a more complicated site, it could take significantly longer. Allocation of resources depends on the scale of the process or the area to be investigated (e.g. one person working part-time or a mixed team of engineering, production and environmental staff). Some companies have successfully employed students on work placements to gather data. Work experience student helps brewery save money A brewer employed a graduate trainee to map the water system, supervise the installation of new water meters for each main production/ office area, and monitor subsequent consumption. The waste reduction initiative led to water saving measures and cost savings of nearly 100,000/year. 2.2 Step 2 A preliminary review Your preliminary review should consist of: gathering existing data (e.g. annual water use and costs); a brief assessment of the major gaps in your ; and deciding how detailed a water balance is appropriate for your company. This will involve: -- estimating potential cost savings from water saving measures; and -- deciding your budget for obtaining missing and/or constructing a water balance. For each process or area, use the checklist given in Figure 7 to review water use and wastewater generation.

11 WRAP Tracking Water Use to Cut Costs 9 Walk around your site or building. Use a note-pad to make sketches and notes on activities and operations that use water. Tell other people what you are doing and ask them for their views on water use and current practices. Your tour of the site and the you obtain may highlight some fast start projects that will help you to secure top-level commitment. Figure 7: Example water review checklist Checklist Comment Process/area Is the process/activity really necessary? Water use Is it necessary to use water for the process/ activity or is there a cost-effective alternative? How can I reduce water use? Could I use lower quality water? Can I recover and re-use water anywhere? Is the use authorised and legal? Wastewater Is it necessary to produce this wastewater/ effluent? Is clean water going down the drain and, if so, why? Is the discharge authorised and legal? Can the wastewater/effluent be re-used in a process or used for lower grade duties (e.g. cleaning)? Would it be cost-effective to treat the wastewater/effluent on site for re-use?

12 WRAP Tracking Water Use to Cut Costs Gather existing data Table 3 provides a checklist of the type of you will need to produce a water balance. Start by collecting that already exists within the company. Check whether the appears accurate and consistent. For example, check the meter readings on your latest water bill and find out when your water meter(s) was last calibrated. To reduce the risk of errors in your calculations, use the same units for water use (e.g. litres or m 3 ) depending on the size of your flows. Water volume conversion 1m 3 = 1,000 litres = 220 gallons 1 gallon = m 3 or 4.5 litres Table 3: Useful existing data Type of data Water supply and treatment costs Water treatment Water and effluent quantities Water and effluent quality Effluent treatment costs Effluent discharge costs Effluent removed off site in tankers Site plans Details of process or unit operation Description Water supply bills Abstraction licence fee Pumping, chemicals, operating, maintenance and labour costs System type and capacity Meter readings in and out of site, on individual machines/process areas Data on rainfall or groundwater inputs Analysis of on-site water treatment and effluent samples (either in-house, by external laboratories or by water company) Equipment specifications from suppliers Pumping, chemicals, operating, maintenance and labour costs Trade effluent and sewerage bills Charges for discharge to controlled waters Waste disposal contractor s bills for tanker transport, treatment and disposal Quantities and quality of tankered liquids Water distribution and drainage plans, including water sources and location of meters Process flow and pipe/process technical drawings, including manufacturers specifications

13 WRAP Tracking Water Use to Cut Costs 11 Locate your water meter Most commercial and industrial properties have a metered water supply. The water meter is usually located by the boundary of the property, often near a road. If the site has more than one incoming water mains, each supply should be fitted with a meter. Correct meter size results in cost savings Correcting the size of its water meter for current operations meant that a carpet manufacturer reduced its annual water supply costs by 89% ( 10,530). As a minimum, your mains supply meter(s) will allow you to monitor water consumption of the site on a routine basis (daily, weekly or monthly). How to read your water meter Metered companies are responsible for the water use recorded on their meter including wastage and leaks. Figure 8 shows a typical water meter. The white digits in the blue box display cubic metres (m 3 ) and those digits shown in red display 1/10th (100 litres) and 1/100th (10 litres) of a cubic metre. Thus, the reading on the example meter shown in Figure 8 is m 3. The figures shown in the dials provide a more detailed reading than 1/100th of a cubic metre. Other ways of measuring flow are described in Section Section contains about flow meters. Figure 8: Typical water meter SERIAL NUMBER CLASS: Qn m 3 /h Pn bar Cert N o. m What to do with your meter data Recording meter readings on a regular basis (daily, weekly or monthly) will allow you to identify trends in water consumption. Recording water consumption in a graphic format makes it much easier to analyse your pattern of water usage. To ensure you compare like with like, it is a good idea to normalise your data. For example, express water use in terms of production (m 3 water per tonne of product) or workforce (m 3 water per employee). This benchmark can be used to identify excess use or to demonstrate genuine reductions in water use. Figure 9 and Figure 10 present water consumption data for an example site. Although the data are recorded clearly in a suitable format in the table (Figure 9), the graph presented in Figure 10 shows the water consumption trends more clearly. The increase in water use from March to August becomes very apparent.

14 WRAP Tracking Water Use to Cut Costs 12 Figure 9: Example of metered water consumption at an example site Month Water use (m 3 ) January February March April May June July August September October November December Figure 10: Graph showing trends in water use at the example site Water use (m 3 ) Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Key? To be assessed Sub-meter Mains water

15 WRAP Tracking Water Use to Cut Costs 13 WRAP s monitoring tool is available at and can help you to easily record and track where water is being used in your company and analyse your findings. There are monitoring spreadsheets for recording water consumption data once a week, five days a week and seven days a week Are there major gaps in your knowledge? In your preliminary review, aim to account for at least 80% of the water you pay for including any major leaks. Examine your data and decide whether your overview of water use and costs is adequate or whether there are major gaps. If more is needed, it is likely to be in specific areas. Investigating your main uses of water (or higher value water see Section 1.2.1) is likely to provide most of your cost saving opportunities. Begin to develop a picture of your business along the lines of Figure 3 (see Section 1) as soon as possible. This will help you to identify gaps in available and to focus your efforts. You will develop the picture and add detail during Steps 3 and 4 (see Sections 2.3 and 2.4 respectively). You may prefer to leave the decision on what extra and measurements you need until you have produced your first water balance diagram (i.e. the equivalent of Figure 4 complete with numerical data). You will achieve this in Steps 3 and How detailed a water balance should you produce? A simple water balance covering the few largest water-using activities may be sufficient to control and reduce major uses of water and related resources. You need to decide how detailed a water balance is likely to be cost-effective for your company. How far to go is a matter of judgement, about which general advice is given below. You may also wish, at this stage, to define the scope of future work (e.g. whether to analyse the whole site or to consider one area in more detail). To decide how detailed your water balance should be, consider the potential benefits versus the cost. What is the likelihood of identifying costeffective opportunities to save water? How much money could you save? How much will it cost to investigate water use in more detail? For with significant water consumption, the potential savings will be more than sufficient to justify drawing up a detailed water balance. Water balance leads to halving of mains water consumption A soap manufacturer used a systematic approach to identify and quantify water use, and then implemented measures to reduce mains water consumption. A detailed water survey revealed how and where water was being used. A water balance was then prepared using data obtained from existing invoices and meters. A 50% reduction in mains water use and associated cost savings were achieved over a period of four years through a combination of good housekeeping measures and plant modifications. For that have relatively low water use, an alternative criterion for deciding whether to produce a detailed water balance is the size of annual water and effluent bills. For example, a multi-site organisation decided not to investigate water saving opportunities at where water and effluent bills were less than 300/year. However, the installation of simple, water saving devices, such as percussion (push) taps, toilet cistern volume adjusters and flushing controls, at over twothirds of its produced significant overall cost savings.

16 WRAP Tracking Water Use to Cut Costs Estimating potential savings Cost savings can arise from reductions in: water use (e.g. in domestic or process use); on-site water pumping and associated maintenance; water treatment (e.g. lower chemical costs and filter backwash); water heating or cooling requirements; effluent pumping; effluent treatment; and effluent discharge. As a general rule of thumb: if no water saving measures have so far been implemented, savings could be 30% or more of your water-related costs; if you have implemented some water saving projects but not applied a systematic approach, you may still make some significant savings, especially where higher value water consumption is reduced; and do not forget the possibility of reducing the amount of raw materials and product lost in effluent. This can be significant. Many people use at least twice as much water as is needed to perform a given task (e.g. washing down a piece of equipment with a continuously running hose). Typical reductions in water use for various projects are shown in Table Deciding your budget Once you have estimated the potential savings, use your company s method for new project appraisal to determine how much money might be available to obtain missing and/or construct a water balance. Identify the maximum project budget Identification of the maximum project budget can help to determine the areas on which to concentrate. This helps to assess and eliminate projects that are unlikely to be cost-effective. Maximum project budget ( ) = Calculated saving ( /year) Required payback period (years) Table 4: Typical achievable reductions in water use Water saving initiative Typical reduction* Commercial applications Toilets, men s toilets, showers and taps Industrial applications Closed loop recycle Closed loop recycle with treatment Automatic shut-off Countercurrent rinsing Spray/jet upgrades Re-use of wash water Scrapers Cleaning-in-place (CIP) Pressure reduction Cooling tower heat load reduction Per project 90% 60% 15% 40% 20% 50% 30% 40% Variable Variable Per site 40% (combined) * Assuming no water measures have previously been put in place.

17 WRAP Tracking Water Use to Cut Costs Step 3 Drawing up a water balance This step involves: producing a simple pictorial representation of the site; translating this picture into a block diagram; and adding volumes of major water and wastewater flows to your block diagram to produce an initial water balance Produce a pictorial representation of your site For any water balance, the first step is to produce a pictorial representation of your site. All premises whether a complex site or a single building can be described by a series of activities or operations. Figure 3 in Section 1 shows a typical example. Identify and mark on your picture: major uses of water; the location of on-site water meters (there is usually one on the mains supply entering a site); and the points at which domestic wastewater and/or trade effluent enter the site drainage system. For, use a site plan and process flow diagrams to help you produce a pictorial representation of the site. When drawing your picture, remember that: you are looking for major water-using activities as part of an operation, process or a piece of equipment where: -- water enters; -- a function occurs; and -- water or effluent leaves; and inputs and outputs may be in a different form (e.g. liquid raw materials, steam and product). To help you, examples of water-using activities in a hotel and on an industrial site are shown in Appendix C. Define major water-using operations by the type of activity carried out, such as cooking or drying (i.e. removing water from product). Alternatively, designate activity areas according to boundaries where flows can be measured easily. If a water-using operation becomes unmanageable, try splitting it into smaller units.

18 WRAP Tracking Water Use to Cut Costs Draw a block diagram Now translate your picture into a more manageable form by drawing a block diagram that indicates the relationships between operations. Figure 11 shows the block representation of Figure 3. The major waterusing activities at this site are the laundry/ washrooms, the factory and the shop/canteen. Each major activity on the site is represented by a box, which lists the significant water uses. Water feeding to the different activities is represented on the diagram by arrows connecting the relevant boxes. Standard practice is to show water inputs at the top and water outputs at the bottom of the diagram. All water, including the mains water supply, should also be shown Add data to the diagram to produce an initial water balance To produce the water balance, add the volumes of all major water and effluent flows to the block diagram. The units used should be consistent and are typically m 3 /day. Obtain numerical values for water/effluent flows from investigations and measurements (see Section 2.4). Aim to produce as complete an account as possible of where the water is going on the site. Use the gathered in your preliminary review to begin to construct a water balance for your site. If necessary, use a site plan and process flow diagrams to help you. Add the you can but, at this stage, you may not be able to account for a significant proportion of your water use. In Step 4, you will add detail to your water balance by carrying out more investigations and measuring flows. Figure 12 shows an initial water balance for the example company depicted in Figure 11. At this stage, only certain flows have been quantified (mains water input to the site, water input to the factory, liquid raw material input to the factory, water in the product, wastewater output from the factory and sewage/trade effluent leaving the site). The completed water balance for this site is shown in Figure 20 (see Section 2.4.7). Figure 11: Block representation of a simple example site Mains water Meter Evaporation and steam Liquid raw materials Evaporation and steam Laundry and washrooms Toilets, handbasins and showers Washing machines Tumble dryers Factory Equipment washing Water added to product Boiler Steam generation Condensate recovery Water softening Condensate recovery Shop and canteen Toilets and sinks Dishwasher Food preparation Product Water in the product Leaks Boiler blowdown/ condensate Domestic wastewater/ trade effluent

19 0 WRAP Jan Feb Mar Apr May Jun Jul Aug Sep Oct Tracking NovWater DecUse to Cut Costs 17 Figure 12: Initial water balance for a simple example site Key? To be assessed Sub-meter Inputs Outputs Recirculation Meter Mains water m 3 /day Evaporation and steam 1m 3 /day Liquid raw materials? Evaporation and steam 75m 3 /day??? Laundry and washrooms Toilets, handbasins and showers Washing machines Tumble dryers Factory Equipment washing Water added to product Boiler Steam generation Condensate recovery Water softening Condensate recovery Shop and canteen Toilets and sinks Dishwasher Food preparation? Water in the product 5m 3 /day Leaks? 65m 3 /day Boiler blowdown/ condensate? Total 79m 3 /day Domestic wastewater/ trade effluent 84m 3 /day For an example of a non-industrial site, see the detailed water balance exercise for a medium-sized hotel in Appendix D. 2.4 Step 4 Adding detail to the water balance Now add detail to your initial water balance by: working out which activities/processes are likely to use the most water under both normal and abnormal operating conditions; measuring flows to add to your water balance; and continuing to account for more and more of your total water input until you decide that it is no longer cost-effective to make new measurements. Your preliminary review (see Section 2.2) may have enabled you to account for 80% or less of the site s water use when you drew up your initial water balance. Depending on the amount of water you use, it may be cost-effective to make measurements to identify 95% or more of your water use. This issue should have already been considered as part of your preliminary review. This step has various stages and involves: identifying water supplies; investigating water use; identifying sources of effluent; considering other water losses; quantifying water use and effluent flows through direct measurement, monitoring and, where necessary, estimating nonprocess uses; recording your as a water use chart and on a spreadsheet; adding the data obtained to your block diagram to complete your water balance; and accounting for any discrepancies.

20 WRAP Tracking Water Use to Cut Costs Identify water supplies The main water sources from which organisations can obtain their water are shown in Table 5. In most modern buildings, water from the mains and any abstracted water are kept separate from rainwater. When looking at water sources, make sure there is no crossover between these water systems. Some companies collect and treat rainwater for use within their processes. Table 5: Main sources of water Type Mains Surface water abstraction Groundwater abstraction Rainwater collection Supply route Metered flow via a water company supply pipe Extracted from a river, stream, lake, reservoir or canal Pumped from borehole(s) From a storage tank To help identify where water is used and which activities/processes use the most water, start by finding out about where your water comes from and how it is treated and distributed on site. How is water supplied to the site (e.g. mains, river, reservoir and/or borehole)? Is water stored on site (e.g. in tanks or lagoons)? What is the storage capacity? Is water treated on site? If so, how? How is water transferred (e.g. by pump, gravity or manually)? Figure 13 shows an example assessment of site water sources. The next stage is to measure flows (see Section 2.4.5). Look at your water and effluent bills to get an idea of the quantities of water used and the amount of effluent discharged from the site/area. Focus on the larger flows first Investigate water use Depending how complex your site is, use one or more of the following approaches to identify and investigate major uses of water. Walk around the site/process looking at everything to find water-using points and equipment. Identify the location of water meters and discuss with staff where water is used in their area. Where visible, trace water supply pipes from sources to water use points. Obtain drawings of the water supply system, where necessary. At the same time, make a note of effluent sources and trace pipework back to water supplies. This will save you time and effort later. The identification of effluent sources is described in more detail in Section Figure 13: Example water sources assessment Source Processes/ areas served Treatment Storage (type and capacity) Transfer method Use and frequency Quantity (m 3 /day) Mains Product None None Pumped Production hours To be investigated Borehole Product Softening Tank (5m 3 ) Pumped Downtime of mains pumps (5 days/year) To be investigated River Gardens None None Pumped and gravity Summer To be investigated

21 WRAP Tracking Water Use to Cut Costs 19 When collecting data, also gather supporting such as: number of employees on site or per shift; type of product being produced; number of lines operating; and s (e.g. number of rinses or cycles on washing operations). You may wish to develop a diagram to help you keep track of your findings. Such a diagram can be particularly useful if no plan of the water supply distribution system is available. Identify the points where water enters the site or is abstracted on site. Trace the water supply pipes from these points to any plant/equipment that uses water. Draw a flow diagram of pipework connections. Water use survey helps wallpaper manufacturer achieve significant savings By mapping its site water services and developing a water balance, a wallpaper manufacturer reduced water consumption at one of its by nearly 40%. These actions, together with recommendations from process improvement teams investigating site water use, highlighted how water was being used and where it was being wasted. Estimated annual savings of 143,000 were achieved at virtually no cost Identify sources of effluent The next stage is to find out where effluent is generated and being disposed of. Obtain drawings of the effluent drainage, surface water drainage and foul sewer systems. If these are not available, it may help to develop diagrams for your site. Appendix E provides guidance on how to produce and use site drainage plans to identify sources of effluent. Walk around your site/process finding out where water goes and looking for sources of effluent. Make a note of your observations. Talk to other people about where effluent is produced. Locate any effluent meters or sampling points. As well as discharges to sewer or watercourses, find out about liquid wastes and slurries removed off site in tankers. Use the list of typical effluent sources in Table 6 to help you identify all your sources of effluent and water losses.

22 WRAP Tracking Water Use to Cut Costs 20 Table 6: Typical effluent sources and water losses Effluent sources/water losses Examples General Water treatment units Water storage, including boiler system Storms/surface water run-off Groundwater Fire-fighting water systems Car park Fuelling depot Refrigeration units Laboratories Drying processes Hot processes Oil interceptors Storage tanks Site cleaning Filter backwash, wet sludges, chemical spillages, ion exchange regeneration, reverse osmosis effluents Leaks and overflows Additions to effluent drains Infiltration to effluent drains Leaks, unnecessary use, wrong connections, safety/pump testing Vehicle washing wastewater Spilt fuel and oils to drain Condensate Condensate, cooling water, liquid effluents, mains water vacuum pumps Evaporation Steam, condensate Water/effluent removal Bund water/effluent drainage, tank overflows, delivery pump/shaft seal leaks Hoses Commercial Laundry Kitchens Toilets/bathrooms/washrooms Swimming pool and leisure facilities Boiler/heating systems/air-conditioning Gardens and water features Vehicle washing Effluent, steam, evaporation from dryers Effluent, steam, liquid wastes Effluent, steam Wash block effluent, swimming pool water Blowdown, condensate, steam Excess water run-off, overflows Effluent, detergents Industrial Cooling tower Steam system Condensate recovery Condensate Process/production Scrubbers/strippers Safety showers Effluent treatment plant Blowdown, evaporation, spray/mist Steam leaks and relief valve discharges, steam trap condensate, steam and evaporation, boiler scale and sludge, blowdown Vent losses to atmosphere, leaks and overflows Loss to product, loss to drain (excluding recovery) Effluent, evaporation, water in product Overflows, mist/vapour Leaks, unnecessary use Treated effluent, sludge, aerosols, liquid wastes (e.g. reverse osmosis concentrate)

23 WRAP Tracking Water Use to Cut Costs 21 Domestic wastewater usually goes down a foul sewer for treatment by your local water company or sewerage provider. Uncollected and uncontaminated rainwater should preferably be discharged to a soakaway or to a surface water drain. To avoid unnecessary treatment charges: check that rainwater is not entering the foul sewer; keep domestic sewage and surface water drainage separate from trade effluent; and label or colour code all drains. Make sure that staff are aware of the difference Consider other water losses To complete your water balance, you need to consider other ways in which water is lost from your site/process, for example: water may leave the site in product (e.g. in soft drinks manufacture); and as steam (e.g. some food processing uses large quantities of steam). Without about these other losses, it will be difficult to complete a representative water balance for your site. Remember to check for water losses in: products and by-products; emissions to atmosphere (e.g. evaporation, steam, mist, spray and losses from pressure relief valves); spillages, leaks and overflows; slurry and sludge wastes; hoses and taps left on; cooling water (including once-through); and leaks from underground tanks or pipes Quantify water use and effluent flows Once you have identified all major water uses and effluent sources, the next stage is to place them in order from largest to smallest. Do this through a combination of common sense, your own knowledge and discussions with other people. Starting with the largest anticipated water use/flow, find out how much water is used each time and how often it is used. Simple but effective methods include recording meter readings or timing water flow into a container of known volume (see Figure 14). Starting with the largest effluent source, find out how much effluent is generated each time and how often it is generated. The effluent flow may be the same as the flow of water used.

24 WRAP Tracking Water Use to Cut Costs 22 Figure 14: Two simple ways of measuring flow, (a) record meter readings (b) using a bucket and stopwatch approach (a) (b) Water flow can be measured either in pipelines or in channels. There are numerous options for flow measurement, each with its Key Sub-meter Inputs Outputs Recirculation Values from earlier assessment shown in Figure 12 Newly assessed values own advantages and disadvantages. More details are given in Section You can quantify flows in a number of ways. In order of preference, these are: Laundry and washrooms Toilets, handbasins and showers Washing machines Tumble dryers Meter measure directly: -- flow meter measurements; and m 3 /day bucket and stopwatch approach; 1m 3 /day Evaporation calculate and steam from other measurements where applicable; 5m 3 /day calculate from manufacturers published ; calculate from typical use ; and estimate from knowledge of the process. Liquid raw materials Bucket and stopwatch approach The direct measurement technique described below involves performing a spot check on the flow from a piece of equipment or process using a bucket or another container and a stopwatch (or a wristwatch with a second hand). The flow rate can be calculated from the volume of water/effluent collected over a known 85mtime. 3 /day You may need to undo a pipe connection temporarily to allow water/ effluent to flow into your container. This technique, 1mwhich 3 /day will not be applicable to all flows, is described below. Mains water Evaporation and steam 75m 3 /day Factory Equipment washing Water added to product Boiler Steam generation Condensate recovery Water softening Condensate recovery 4m 3 /day Assess health and safety requirements (e.g. use gloves and safety glasses). Assemble equipment (e.g. bucket, timer, note-pad, pen and rope Shop for and lowering canteen bucket Toilets and sinks into drain). Dishwasher Find a measuring point Food where preparation it is possible to catch all the flow in the bucket. 5m 3 /day Water in the product 5m 3 /day Leaks 5m 3 /day 65m 3 /day Boiler blowdown/ condensate 70 m 3 /day 4m 3 /day six-step Total 3 79 m 3 /day Domestic wastewater/ trade effluent

25 WRAP Tracking Water Use to Cut Costs 23 Position the empty bucket and start the stopwatch (or note the exact time) immediately the bucket starts to catch the flow. Remove the bucket, stop the timer and note the time when the bucket is nearly full (but not overflowing). Measure the contents of the bucket in litres using either graduations on the bucket or a measuring cylinder. Calculate the flow rate in litres/second by dividing the volume of effluent collected in litres by the number of seconds over which collection took place. Alternatively, calculate the flow based on the weight of the effluent and assuming the effluent has the density of water (i.e. where 1kg of effluent occupies 1 litre). Measure the flow at representative times, including both continuous and intermittent discharges. As this is a one-off measurement, repeat the test to determine variations in flows or average flow rates. Using manufacturers data If direct measurement is not practicable, consider obtaining data from manufacturers brochures, such as water use for washing equipment. Take care to use data for the exact model and note any modifications. If possible, compare these data with actual water use. Savings are possible if the unit is operating at above its recommended consumption. Estimating water use based on knowledge of the process If necessary, you may have to estimate water use based on your knowledge of the process. For example, for a tank filled each time for a pre-rinse and a wash, measure the tank dimensions and calculate the volume of water used. Remember to allow for partial filling or overflows. Take measurements to cover all operations affecting water or effluent quantities. In particular, check intermittent activities (e.g. cleaning) where water use is often variable and wasteful. More about measuring water use and flow is given in Section Monitoring washing/cleaning operations Monitor washing and cleaning operations by estimating or recording hose or tap use (for example, frequency, duration and flow rate) and calculating water/effluent quantities. Figure 15 shows an example calculation of water use by a hose. The same calculation can be applied to effluent generation. Figure 15: Example calculation of water use by a hose Calculation Result Instantaneous flow/average flow rate A Measured 0.5 litres/second = 1,800 litres/hour Length of event B Measured 2 hours Amount/event C A B 3,600 litres Frequency of event D Measured Twice a day Daily total E C D 7,200 litres/day Daily flow F E/1, m 3 /day six-step

26 WRAP Tracking Water Use to Cut Costs 24 Estimating non-process uses If you have combined domestic and effluent sewers, you may need to estimate domestic sewage quantities. Typical values for domestic water consumption are shown in Table 7. Water use in toilets can be estimated from the frequency of use and cistern volume. WC cistern volumes can be calculated from measurements obtained by gently tying up the ballcock before flushing the toilet and filling the cistern from a graduated bucket. Use in washbasins can be estimated by temporarily disconnecting the U bend and running the waste into a large, graduated plastic bucket while using clean water to simulate normal use, such as washing hands Record your When tracking water use, it is important to keep accurate records of your findings for future use. You can do this either as a water use chart or on a worksheet. Water use chart Producing a simple block diagram will help you to determine flows for your water balance. Figures 16 and 17 show example charts for a commercial site and an industrial site respectively. Table 7: Typical rates of domestic water use Item Toilets Sinks Showers Baths Dishwasher Laundry (washing machine) Vehicle washing Garden hose Residential occupant Employee (full-time, no canteen) Employee (full-time, with canteen) Average water use 6 9 litres/flush 3 6 litres/event litres/event (higher use for power showers) litres/event litres/event litres/event Ranges from 100 litres/ vehicle using buckets up to 900 litres/vehicle using a hose 8 30 litres/minute (500 1,800 litres/hour) 150 litres/day/person 25 litres/day/person 40 litres/day/person Figure 16: Water use chart: commercial example Location: Unit operation: Hotel Laundry Date: 31/03/12 Time: hrs Investigator: M Brown Source: Mains water Metered/unmetered Use 1: Washing machine Volume: 2.4m 3 /day Use 2: Sink Volume: 0.24m 3 /day