Sustainex 2013 - Water Efficiency Richard Barnard (PDF)
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Transcript of Sustainex 2013 - Water Efficiency Richard Barnard (PDF)
WHY LOOK AT WATER?
• Water availability – it is a finite resource and we don’t want to run out.
• Costs – water costs money – often much more than we think.
• Legal and regulatory reasons – eg Pollution Prevention and Control (Industrial Emissions) Regulations (Northern Ireland) 2012, The Water Supply (Water Fittings) Regulations (Northern Ireland), etc.
• Corporate requirements (eg CSR Reporting); and
• Good business sense !
WATER AVAILABILITY
Rainfall in Northern Ireland is very varied.
Wettest:
Killeter Forest - 1950 mm
Driest:
Lough Neagh - 800 mm
Source: Met office
To compare:
Khartoum, Sudan - 155 mm
Tripoli, Libya - 271 mm
Athens, Greece - 371 mm
Paris, France - 607 mm
Rome, Italy - 802 mm
Sydney, Australia - 1222 mm
Source: worldweather.com
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3
Incoming water meter
48956.8
Water supply: - standing charge £ - volumetric charge £/m3
Wastewater disposal: - standing charge £ - sewerage volumetric charge £/m3
- trade effluent charges £/m3
water in
WHERE DO COSTS ARISE?
added value
wastewater out
1 2
3
Incoming water meter
48956.8
Water supply: - standing charge £ - volumetric charge £/m3
Wastewater disposal: - standing charge £ - sewerage volumetric charge £/m3
- trade effluent charges £/m3
water in
WHERE DO COSTS ARISE?
wastewater out
MAINS WATER CHARGES
2012/13 tariffs Northern Ireland Water
Supply Pipe Size Water Up to 20mm £70 Over 20mm up to 25mm £117 Over 25mm up to 40mm £213 Over 40mm up to 50mm £335 Over 50mm up to 75mm £660 Over 75mm up to 100mm £1,195 Over 100mm £1,697
Standing charges
MAINS WATER CHARGES
2012/13 tariffs Northern Ireland Water
Discount Water Standard volumetric charge per m3 107.8p
Large user volumetric charges: (100,000 – 250,000m3) 20% 86.2p (250,000 – 500,000m3) 25% 80.9p (Over 500,000m3) 30% 75.5p
Variable 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 strata Under the Water (Northern Ireland) Order 1999, the consent of the Department of Environment is required to discharge any trade or sewage effluent into waterways or underground strata.
1 2
3
Incoming water meter
48956.8
Water supply: - standing charge £ - volumetric charge £/m3
Wastewater disposal: - standing charge £ - sewerage volumetric charge £/m3
- trade effluent charges £/m3
water in
wastewater out
WHERE DO COSTS ARISE?
SEWERAGE CHARGES
2012/13 tariffs Northern Ireland Water
Supply Pipe Size Sewerage Up to 20mm £80 Over 20mm up to 25mm £134 Over 25mm up to 40mm £243 Over 40mm up to 50mm £383 Over 50mm up to 75mm £755 Over 75mm up to 100mm £1,366 Over 100mm £1,942
Standing charges
SEWERAGE CHARGES
Remember: non-return to sewer allowance. It will be 5% unless it has been agreed with NIW that a different allowance will be applied
2012/13 tariffs Northern Ireland Water
Sewerage Standard volumetric charge per m3 173.3p
Variable charges
Charge (p/m3) = R + V + B x Ot + S x St Os Ss
R = 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/m3
2012/13 tariffs Northern Ireland Water
1 2
3
Incoming water meter
48956.8
Water supply: - standing charge £ - volumetric charge £/m3
Wastewater disposal: - standing charge £ - sewerage volumetric charge £/m3
- trade effluent charges £/m3
water in
wastewater out
WHERE DO COSTS ARISE?
added value
Easily Identified Costs
Hidden Costs or Added Value
Cost of water treatment Loss of product/in sales value
Cost of raw materials in effluent Cost of effluent treatment
Cost of wasted energy, eg heating, pumping
Water Charges Sewerage Charges
Trade Effluent Charges
WHAT OTHER COSTS?
m3/min x head (m) kW = 6.1 x pump efficiency
With an overuse of water of, say,100 m3/h used on first floor of a building then unnecessary power consumed through pumping may be given from:
= 1.66 x 15 6.1 x 0.6
= 7 kW
At 7.0p/kWh and 16h/d operation, 5d/week, 48week/year = £1,881/y
ADDED VALUE COSTS?
HOT WATER – ENERGY
The energy needed to heat water is given by: Energy required (kWh) = V x (T2 – T1) 860 Where V = volume of water heated (in litres) T1 = temperature of water to be heated (if unknown, assume 12°C) T2 = temperature water is heated to (°C) 860 = conversion factor to convert kcal to kWh (860 kcal/kWh)
Hot water tank
Water heater
Added value
Water Maintenance
Energy
Energy Labour
Chemicals Maintenance
Energy Labour
Maintenance
Raw water tank Softener
Mains water
Hot (65oC) softened water to supply
107.8p/m3 100 m3 per day 500 W UV light
= 0.8p/m3
1 m3 15 » 65oC 2.9 p/kWh
= 187.3 p/m3
1 m3 Salt and
regen water = 46.4 p/m3
Value of hot water = 342.3 p/m3
ADDED VALUE COSTS?
2012/13 tariffs Northern Ireland Water
TRUE VALUE OF WATER
Type Typical cost 1
Mains supply £1.078/m3 (std) Chlorinated water3 £1.098/m3
Softened water £1.548/m3
Demineralised/Deionised water £3.028/m3
Hot water (65°C) – gas heated2 £3.068/m3
Hot water (65°C) – electrically heated2 £5.868/m3 Steam – gas heated2 £24.888/tonne Ice (-7oC) £11.358/tonne
1 – approximate, based on 12/13 costs excluding capital costs and renewals and excluding disposal costs 2 – heating 12 to 65oC; energy costs at 2.9p/kWh for gas and 7.0p/kWh electricity and boiler 90% efficient 3 – Simple sodium hypochlorite addition
2012/13 tariffs Northern Ireland Water
SO, WHAT DOES IT COST?
EXERCISE: Judge the flow and what this running tap would cost:
3 mm stream = m3/year
Cold water cost = £ /year
Hot water cost (gas) = £ /year
Hot water cost (elec) = £ /year
394
1,107
1,816
2,817
SO WHAT DO WE DO?
We’ll go through 12 key actions frequently identified that can improve water efficiency…..
1 - WATER BALANCE
Get a good understanding of water use on your site by using a water balance. It’s based on a very simple concept: what goes in must come out (somewhere). Draw a simple block diagram…
Source: Envirowise GG152
ESTIMATE WATER USE
Use sub-meter data or estimate water use if no data is available:
• ‘Domestic’ component from the number of people on site per day Staff / delegates 25 – 45 litres/person/day no canteen 50 – 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 if water balance doesn’t balance!
• Remember leaks of raw material or product – it may cost more than it looks…
3 – OVERFLOWS AND LEAKS
4 – DISTRIBUTION PRESSURE
• How is your hot and cold water distributed around your site?
• Is it off mains supply pressure, gravity supply or is it pumped?
• What pressure is the hot and cold supply operating at?
• Is the pressure too high?
Water tank
Third floor
Ground floor
Hand washing: 500 uses, 20 sec/use, 260 day/year Overuse 780 m3/year - £2,968/year
10 litres/min
28 litres/min
• Fit a pressure reducing valve or • Reduce the booster pump
pressure control setting
PRESSURE CONTROL
Do you need 10 bar or will 2 bar (or less) do?
7 – PROCESS TANKS
• Does the tank overflow?
• Is the tank difficult to clean?
• Is there any unnecessary water use?
9 – CLEANING
Tunnel or tray washers:
• Make sure all nozzles are present
• Make sure discharge is visible
10 - CLEANING - CIP
Advantages:
• Water efficient
• Recover cleaning chemicals
• Repeatability of clean
• Automatic
Bottle washer
Washwater tank
Mains supply
Overflow to drain
Hot water from cooling
Hot water supply
High-level top up valve
11 - PROCESS CONTROL
Bottle washer
Mains supply
Little overflow to drain
Hot water from cooling
Hot water supply
Low-level top up valve
Water source controlled
Washwater tank
Savings: £15,000 p.a water/effluent/energy
Costs: £2,000 Savings: £5,000 p.a water/effluent/energy
11 - PROCESS CONTROL
OTHER WATER SOURCES
• Rainwater harvesting
WATER USE QUALITY REQUIRED TREATMENT OPTIONS Nurseries, sports grounds,
gardens Toilet flushing Cooling (boilers) General cleaning Filter backwashing
LOW: Water is not used for consumption, and there is a very low risk of contact. Water should look clean and be odour free
First flush diverted Coarse filter
Laundry Cleaning of equipment or
process cleaning
MEDIUM: Water is not used for consumption, and there is a low risk of contact. Water must be clean and odour free, but not necessarily sterile
All of the above, plus Fine filter (possibly
membrane filter)
Food processing Cleaning food processing
equipment Substitute potable supply
HIGH: Water may be used for consumption, water must be clean, odour free and sterile
All of the above, plus Pathogen removal and/or
inactivation (e.g. UV treatment)
Source: Envirowise EN896 ‘Reducing mains water use through rainwater harvesting’
OTHER WATER SOURCES
• Borehole supply
TYPICAL 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 groundwater availability (quantity and quality)
Borehole construction required
Laundry Cleaning of equipment or
process cleaning
All of the above, plus May need storage May need treatment
Food processing Cleaning food processing
equipment Substitute potable supply
All of the above, plus May fall under Private Water
Supplies Regulations (Northern Ireland) 2009
Increasing quality requirem
ent
OTHER WATER SOURCES
Borehole 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 BENEFITS
Impact 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, is launching “Water Champions”, an award for businesses that have taken steps to reduce their environmental impact and save money by reducing their water use. The awards are free to enter and open to all businesses across Northern Ireland.
OTHER BENEFITS
FURTHER ASSISTANCE
If you would like further assistance you may find: • Invest NI
Maximising efficiencies (inc water) see • http://www.investni.com/index/already/maximising.htm Cut 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