Drinking Water

6 March 2013

Andy CaseCEnv C.WEM BSc (Hons) MCIWEM

About me

Run Case Environmental, Teignmouth based environmental consultancy established in 2009 www.caseenvironmental.co.uk

Worked in the water and environmental industry for over 10 years, including South West Water and the National Trust

Work across Devon & Cornwall and further afield looking at mainly private water supplies and related issues.

Water – The Facts

70% of the surface of the Earth is water98 % sea water1.5 % ice0.4 % found in aquifers, rivers & lakes0.1 % atmosphere, plants & animals

Clean Water

800 million don’t have access to clean water3.5 million die of drinking water related illness each year700,000 of these are children – approximately 2000 per

dayIn developing countries half of all hospital beds are filled

with people suffering from poor quality water & sanitation.

Sources

RiversReservoirsGroundwater (springs, wells and boreholes)

What about sea water?

Sources - GroundwaterSpring

Borehole

Well

Source to tap?

££££

Reservoir Town

Meter

Typical Mains Water Treatment for Surface Sources

Inlet

Flash mixer Clarifier Sand filter Carbon filter

Chlorine contact tank

Coagulant added

pH corrected

Chlorine added

Phosphoric acid added

pH corrected

To final water tank and distribution

Source Water QualityHeavy rain - spate conditionsRun-off from fields – animal waste, fertilisers, pesticidesOperation of combined sewer overflowsDiffuse pollution – pesticide degradates, nitrateIndustrial pollutionFuel/chemical spillsAlgal bloomsSaline intrusion

Source Water QuantityNeeded most when less is availableAreas with the least rain have the biggest

demand for waterMost rain falls in winterMinimum abstraction levelsRecharge rates for aquifers

Water Supply in the South West

Big population variation, in summer some areas can doubleSeasonal rain fall expectationsTopography

33% of the countries coastline2.5% of the populationOver 30 water treatment works600 sewage treatment plants

Drinking Water & Climate ChangeMany issues already surrounding production and

distribution of drinking waterVery power & chemical intensive to operate & supply – if

oil/gas supplies stopped we’d have no waterImportance of sustainable water management;

- SUDs, allowing aquifers to recharge, limit run-off- Land management (chemicals, crops, livestock etc)- Water security.

Water UseWater use has increased from 90 litres per person to 180

litres per person in 50 years – why?

People want to be cleanerAppliances such as dish washers & washing machinesGardeningIncreased car ownership

Domestic Water Use

Water Saving MeasuresShowering – reduce time, fit aerator to showerheadUse washing machines/dishwashers only when fullInvest in efficient goodsBowl in sink (washing, food preparation)Modern toilet/water saving deviceCheck for leaks – not just taps but toilet overflowsGarden – grow plants that require little water, protect

from wind & sunOutside – avoid using the hosepipe

Alternative Water Sources – Rain?

Roof collectionAverage roof size of 80m2

Average rain fall in South West UK 800mm per m2

Annual amount 64 m3

Other points of collection?Patios/drivesOutbuildings

Rain WaterBenefitsNaturally cleanReduce run-off/flooding, contribute to sustainable urban drainagePotential saving £150/yearReduce demand on mains

ProblemsAcidic – pH correction or plastic plumbing neededMaintenanceCan collect debris/detritus from roof – first flush neededPosition of tank to be usefulStorage & potential bacterial concernsTechnically need to inform SWW so they can charge you sewerage

Alternative Water – Grey WaterEither partially treated water or previously used waterLimited uses due to qualityRequire modification of existing plumbingTreatment required, cost implication, servicingPotentially harmful to plants and environment depending

on previous useMicrobiological issues with use – legionella etc.

Way forward?

Encourage rainwater harvesting in new builds?Sustainable Urban Drainage?Variable rate billing?

Wash less?

Questions?