Water Resource Efficiency Gerard Enright STEM Project
Why is Water Important? Water availability – it is a finite resource and we might not always have the supply we need. Water costs money – often much more than we think. Carbon footprint of water Corporate requirements (e.g. CSR reporting). Good business sense !
The Cost of Water What we know Water Charges Sewerage Charges Trade Effluent Charges What We Don’t Know Water Treatment Costs Cost of Raw Materials in the Effluent Cost of Wasted Energy (Heating, Pumping) Cost of Maintenance
Standing Charges 2014 / 15 Supply Pipe SizeWaterSewerage Up to 20mm£66£76 Over 20mm up to 25mm£110£126 Over 25mm up to 40mm£202£230 Over 40mm up to 50mm£316£362 Over 50mm up to 75mm£624£714 Over 75mm up to 100mm£1,130£1,291 Over 100mm£1,605£1,837
Volumetric Charges DiscountWaterSewerage Standard volumetric charge per m 3 102p£1.638 Large user volumetric charges: (100,000 – 250,000m 3 )20%81.6p (250,000 – 500,000m 3 )25%76.5p (Over 500,000m 3 )30%75.5p
Unmeasured Charges Unmeasured TariffWaterSewerage Standing Charge£25.85£36.15 Variable Charge per each £1,000 NAV £9.93£13.61 Charge Cap£405£430
Trade Effluent Charges Charge (p/m 3 ) = R + V + B x Ot + S x St Os Ss R = reception and conveyance (19.03 p/m 3 ) V = primary treatment (21.46 p/m 3 ) B = biological oxidation settled sewage (14.21 p/m 3 ) S = treatment & disposal of primary sludge (16.57 p/m 3 ) Os = COD crude sewage settled 1 hr (285 mg/l) Ss = total suspended solids crude sewage (225 mg/l) Ot = COD of trade effluent (mg/l) St = Suspended solids of trade effluent (SS) (mg/l)
The Hidden Cost of Water – Raw Materials Excessive product / raw materials in effluent streams cost you money. Increase water consumption to during wash-down. Do you have a wash-down procedure Dry cleaning of floors, equipment and drains prior to wash down/disinfection. Increased effluent strength = higher trade effluent costs.
The Hidden Cost of Water - Heating You Pay 3 times for Hot Water 120 Ltr Hot Water Cylinder will take 2.3 Hours to heat from 12 Degrees to 65 Degrees with a 3.2 kW Immersion Heater. The energy needed to heat water is given by: Energy required (kWh) = V x (T 2 – T 1 ) 860
An Action Plan to Improve Water Efficiency
1 Find Your Water Bill What is it telling you? Are you getting a domestic allowance Are you getting a rateable allowance Are you details correct (NAV, supply pipe size, septic tank,) Is the meter reading correct Is there non return to sewer. Would you benefit from a metered supply
Find Your Water Meter
Start to Take Water Readings Take regular readings Give someone responsibility Most meters measure in M 3 = 1000 litres Mind the Spiders…….
Find Out When You Use Water Water profile Night-time usage Weekend usage Holiday usage Usage during lunch breaks Are there spikes in usage High staff numbers
Find Out Where You Use Water Identify areas of high usage. Use sub meters. Manufacturers guidelines Bucket test (30 seconds)
The Bucket Test
Find The Leaks And Overflows Locate and check all overflows Check for leaks – particularly if water balance doesn’t balance! Remember a leak may cost more than it looks…
Check Water Pressures 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?
Increased Pressure = Increased Usage
Ensure Pipes are Lagged Keeps hot pipes hot and cold pipes from freezing in winter How long does the water take to heat up. What is the water usage after a freeze
Not all Taps are Equal Check Taps, Springs, Triggers and Washers Tap 1 – 8 Litres / Min Tap 2 – 12 Litres / Min Tap 3 – 7 Litres / Min The Bucket Test…..
Water Saving Devices Sensors on Urinals Coke Bottle / Hippo Bag Low Volume Shower head Tap aerator
What can I do about my Water Usage? Monitor, Monitor, and Monitor Again……… Weekends, Evening, Holidays. Make sure your bill is right. Standing Charges Rateable Allowances Non Return to Sewer Identify What is Costing You. Find an alternative that is cheaper to run Improve your controls Find that leak Give People Responsibility Communicate and Train