Sustainex 2013 - Water Efficiency Richard Barnard (PDF)
Water EfficiencyRichard Barnard
WHY LOOK AT WATER?• Water availability – it is a finite resource and we don’t want torun out.• Costs – water costs money – often much more than we think.• Legal and regulatory reasons – eg Pollution Prevention andControl (Industrial Emissions) Regulations (Northern Ireland)2012, The Water Supply (Water Fittings) Regulations (NorthernIreland), etc.• Corporate requirements (eg CSR Reporting); and• Good business sense !
WATER AVAILABILITYRainfall in Northern Ireland is veryvaried.Wettest:Killeter Forest - 1950 mmDriest:Lough Neagh - 800 mmSource: Met officeTo compare:Khartoum, Sudan - 155 mmTripoli, Libya - 271 mmAthens, Greece - 371 mmParis, France - 607 mmRome, Italy - 802 mmSydney, Australia - 1222 mmSource: worldweather.com
MAINS WATER CHARGES2012/13 tariffsNorthern Ireland WaterSupply Pipe Size WaterUp to 20mm £70Over 20mm up to 25mm £117Over 25mm up to 40mm £213Over 40mm up to 50mm £335Over 50mm up to 75mm £660Over 75mm up to 100mm £1,195Over 100mm £1,697Standing charges
MAINS WATER CHARGES2012/13 tariffsNorthern Ireland WaterDiscount WaterStandard volumetric charge per m3 107.8pLarge user volumetric charges:(100,000 – 250,000m3) 20% 86.2p(250,000 – 500,000m3) 25% 80.9p(Over 500,000m3) 30% 75.5pVariable charges
WASTEWATER ?Usually either to:• Foul sewer (regulated by NIW)- Domestic wastewater (Sewerage charges)- Trade effluent (TE consent and Trade Effluent Charges)• Waterways or underground strataUnder the Water (Northern Ireland) Order 1999, the consent of theDepartment of Environment is required to discharge any trade orsewage effluent into waterways or underground strata.
SEWERAGE CHARGES2012/13 tariffsNorthern Ireland WaterSupply Pipe Size SewerageUp to 20mm £80Over 20mm up to 25mm £134Over 25mm up to 40mm £243Over 40mm up to 50mm £383Over 50mm up to 75mm £755Over 75mm up to 100mm £1,366Over 100mm £1,942Standing charges
SEWERAGE CHARGESRemember: non-return to sewer allowance. It will be 5% unless it has been agreedwith NIW that a different allowance will be applied2012/13 tariffsNorthern Ireland WaterSewerageStandard volumetric charge per m3 173.3pVariable charges
Charge (p/m3) = R + V + B x Ot + S x StOs SsR = reception and conveyance (20.78 p/m3)V = primary treatment (23.43 p/m3)B = biological oxidation settled sewage (15.52 p/m3)S = treatment & disposal of primary sludge (18.09 p/m3)Os = COD crude sewage settled 1 hr (332 mg/l)Ss = total suspended solids crude sewage (247 mg/l)Ot = COD of trade effluent (mg/l)St = Suspended solids of trade effluent (SS) (mg/l)TRADE EFFLUENT CHARGES= 77.82 p/m32012/13 tariffsNorthern Ireland Water
EasilyIdentifiedCostsHiddenCosts orAddedValueCost of water treatmentLoss of product/in sales valueCost of raw materials in effluentCost of effluent treatmentCost of wasted energy, eg heating, pumpingWater ChargesSewerage ChargesTrade Effluent ChargesWHAT OTHER COSTS?
m3/min x head (m)kW = 6.1 x pump efficiencyWith an overuse of water of, say,100 m3/h used on first floor of a buildingthen unnecessary power consumed through pumping may be given from:= 1.66 x 156.1 x 0.6= 7 kWAt 7.0p/kWh and 16h/d operation, 5d/week, 48week/year = £1,881/yADDED VALUE COSTS?
HOT WATER – ENERGYThe energy needed to heat water is given by:Energy required (kWh) = V x (T2 – T1)860Where V = volume of water heated (in litres)T1 = temperature of water to beheated (if unknown, assume 12°C)T2 = temperature water is heated to (°C)860 = conversion factor to convert kcalto kWh (860 kcal/kWh)
HotwatertankWater heaterAdded valueWaterMaintenanceEnergyEnergyLabourChemicalsMaintenanceEnergyLabourMaintenanceRaw watertank SoftenerMainswaterHot (65oC)softenedwater tosupply107.8p/m3100 m3 per day500 W UV light= 0.8p/m31 m315 » 65oC2.9 p/kWh= 187.3 p/m31 m3Salt andregen water= 46.4 p/m3Value of hot water= 342.3 p/m3ADDED VALUE COSTS?2012/13 tariffsNorthern Ireland Water
TRUE VALUE OF WATERType Typical cost 1Mains supply £1.078/m3 (std)Chlorinated water3 £1.098/m3Softened water £1.548/m3Demineralised/Deionised water £3.028/m3Hot water (65°C) – gas heated2 £3.068/m3Hot water (65°C) – electrically heated2 £5.868/m3Steam – gas heated2 £24.888/tonneIce (-7oC) £11.358/tonne1 – approximate, based on 12/13 costs excluding capital costs and renewals and excluding disposal costs2 – heating 12 to 65oC; energy costs at 2.9p/kWh for gas and 7.0p/kWh electricity and boiler 90% efficient3 – Simple sodium hypochlorite addition2012/13 tariffsNorthern Ireland Water
SO, WHAT DOES IT COST?EXERCISE:Judge the flow and what this running tapwould cost:3 mm stream = m3/yearCold water cost = £ /yearHot water cost (gas) = £ /yearHot water cost (elec) = £ /year3941,1071,8162,817
SO WHAT DO WE DO?We’ll go through 12 key actions frequently identified that can improvewater efficiency…..
1 - WATER BALANCEGet a good understanding of water use on your site by using a waterbalance. It’s based on a very simple concept: what goes in must comeout (somewhere). Draw a simple block diagram…Source: Envirowise GG152
ESTIMATE WATER USEUse sub-meter data or estimate water use if no data is available:• ‘Domestic’ component from the number of people on site per dayStaff / delegates 25 – 45 litres/person/day no canteen50 – 90 litres/person/day canteen• For plant and process use volumes, rated capacities of equipment/how long they operate for, etc• If all fails - bucket and stopwatch!
• Locate and check all overflows• Check for leaks – particularly ifwater balance doesn’t balance!• Remember leaks of raw material orproduct – it may cost more than itlooks…3 – OVERFLOWS AND LEAKS
4 – DISTRIBUTION PRESSURE• How is your hot and coldwater distributed aroundyour site?• Is it off mains supplypressure, gravity supply oris it pumped?• What pressure is the hotand cold supply operatingat?• Is the pressure too high?Water tankThird floorGround floorHand washing: 500 uses, 20 sec/use, 260 day/yearOveruse 780 m3/year - £2,968/year10 litres/min28 litres/min
• Fit a pressure reducing valve or• Reduce the booster pumppressure control settingPRESSURE CONTROLDo you need 10 bar or will 2 bar (or less) do?
PRESSURE – THE SAVINGSSource: Envirowise GG522
5 - LAGGING• Lagging – hot or cold it cansave water (and energy!)
6 – TURN IT OFF !• Once through pump sealwater?• Does flow stop if the unit is notworking?
7 – PROCESS TANKS• Does the tank overflow?• Is the tank difficult to clean?• Is there any unnecessary wateruse?
8 – HOSES• Diameter of hose – 25mm or 15mm?• Trigger operated?
9 – CLEANINGTunnel or tray washers:• Make sure all nozzles arepresent• Make sure discharge isvisible
10 - CLEANING - CIPAdvantages:• Water efficient• Recover cleaningchemicals• Repeatability of clean• Automatic
BottlewasherWashwatertankMains supplyOverflowto drainHot water fromcoolingHot water supplyHigh-leveltop up valve11 - PROCESS CONTROL
BottlewasherMains supplyLittle overflowto drainHot water fromcoolingHot water supplyLow-leveltop up valveWater sourcecontrolledWashwatertankSavings: £15,000 p.awater/effluent/energyCosts: £2,000Savings: £5,000 p.awater/effluent/energy11 - PROCESS CONTROL
12 - RECOVER AND REUSECondensate recovery• Why not collect it?• Value around £4.37/m3
OTHER WATER SOURCES• Rainwater harvestingWATER USE QUALITY REQUIRED TREATMENT OPTIONS Nurseries, sports grounds,gardens Toilet flushing Cooling (boilers) General cleaning Filter backwashingLOW: Water is not used forconsumption, and there is a very lowrisk of contact. Water should lookclean and be odour free First flush diverted Coarse filter Laundry Cleaning of equipment orprocess cleaningMEDIUM: Water is not used forconsumption, and there is a low risk ofcontact. Water must be clean andodour free, but not necessarily sterile All of the above, plus Fine filter (possiblymembrane filter) Food processing Cleaning food processingequipment Substitute potable supplyHIGH: Water may be used forconsumption, water must be clean,odour free and sterile All of the above, plus Pathogen removal and/orinactivation (e.g. UVtreatment)Source: Envirowise EN896 ‘Reducing mains water use through rainwater harvesting’
OTHER WATER SOURCES• Borehole supplyTYPICAL WATER USE ADVANTAGES DISADVANTAGES Nurseries, sports grounds,gardens Toilet flushing Cooling (boilers) General cleaning Filter backwashing Low cost supply No reliance on third parties No licence (up to 20m3/d) Reliant on groundwateravailability (quantity andquality) Borehole constructionrequired Laundry Cleaning of equipment orprocess cleaning All of the above, plus May need storage May need treatment Food processing Cleaning food processingequipment Substitute potable supply All of the above, plus May fall under Private WaterSupplies Regulations(Northern Ireland) 2009Increasingqualityrequirement
OTHER WATER SOURCESBorehole supply also:• Need to notify NIEA Water Management Unit, Lisburn• Over 20m3/d will need a licence• Fees may apply (>20m3/d)The legislation can be viewed at:http://www.ni-environment.gov.uk/water/water_resources.htm
OTHER BENEFITSImpact on carbon emissions as:• greenhouse gas emissions emitted in supply of 1Ml water (1,000 m3)is 0.34 tonnes CO2 equivalent (= 0.34kg CO2/m3)• greenhouse gas emissions emitted in treating 1Ml sewage (1,000 m3)is 0.71 tonnes CO2 equivalent (= 0.71kg CO2/m3)Adapted from Water UK Sustainability Report 2010/11.
The Consumer Council, with the support of Invest NI and NI Water, islaunching “Water Champions”, an award for businesses that have takensteps to reduce their environmental impact and save money by reducing theirwater use. The awards are free to enter and open to all businesses acrossNorthern Ireland.OTHER BENEFITS
FURTHER ASSISTANCEIf you would like further assistance you may find:• Invest NIMaximising efficiencies (inc water) see• http://www.investni.com/index/already/maximising.htmCut water costs information resources (inc on-site reviews)• http://www.nibusinessinfo.co.uk/content/cut-water-costs• NI Water• http://www.niwater.com/waterefficiencybusiness.asp• WRAP• http://www.wrap.org.uk/• Enhanced Capital Allowance (ECA) scheme• http://www.nibusinessinfo.co.uk/content/first-year-allowances-water-efficient-technologies