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summer2010horizonPAGE0summer2010horizonPAGE15In2005anexternalconsultingfirmBlackVeatchwascommissionedtocarryoutasurveyontheviabilityandsustainabilityofproducingpotablewaterfromharvestingexistingrainwaterexternalgroundtanksorusingdesalinationsystemsandotherextractingmethods.Thereportshowedthatthereisapotentialcostbenefittotheservicewitharelativelysmallcapitalinvestmentinproducingpotablewaterfromstationswithexistingharvestedwater.ThebenefitsareEliminatingtheuseofhelicopterflyingwatertostationsReducingtheresourcesinpreparationtimeanddeliverybythetenderandhelicoptergroundcrewReducingourcarbonfootprintIn2008aprojectwasinitiatedtoprovidepotablequalitywaterfromexistingharvestedrainwatertankstosustainplannedhusbandryandmaintenanceworktostations.FirstPhaseThefirstphaseoftheprojectwastocarryouttrialsonselectedstationsusingaspeciallyproducedmobilepurificationsystemtoproducepotablequalitywater.Samplesweretakenbeforeandafterthefiltrationprocesstobelaboratoryanalysedtoassesstheeffec-tivenessofthepurificationandthewaterquality.TheportablepurificationUnitTheportablepurificationsystemdesignusesproventechnologyfromthewaterindustrywhichwillconsumeminimalpowerandiseasilytransportedfromstationtostation.TheunitconsistsofasetofthreefiltersthattheuntreatedwaterpassesthroughAnactivecarbonfilter80micronwhichremovesorganiccompoundsandodour.Aparticlefilter5micronwhichremovesparticlesandcompounds.Asterilisingfilter0.4micronwhichremovesbacteria.ThefinalprocesspassesthroughaUVfilterwhichkillsbacteriaandviruses.WaterTreatmentResultsToensuretheresultswereunbiasedthewatertestswerecarriedoutbyanindependentconsultant.ThelaboratorytestresultsontheuntreatedwatershowedhighconcentrationslevelsofColiformBacteriaFaecalColiformsandTotalColiformsetcintheun-treatedwater.ThetreatedwatershowednotracesoftheabovewithagoodPlateCountat22C37C.ThisconfirmedthatthetechniquesusedtoproducepotablewaterqualityconformedtotheWaterSupplyRegulationsapplicabletobothEnglandandWales.SustainabilityofrainwaterresourcesFromtheBlackVeatchreporttheminimumroofcatchmentareaoftheselectedstationsis150m2.Thiswouldgiveaminimumof30m2ofwaterperannum.Thepotablewaterrequiredforvisitsmadeforhusbandryandmaintenanceworkis16m2.Thisfallsinsidetheminimumyieldandisthereforesustainable.ThewaterconsumptionfiguresarebasedonthedailyratesintheBlackVeatchreport.SecondPhaseThesecondphaseoftheprojectwastoselectastationandimplementafullscalepurificationsystemwherethetreatedwaterishousedinasterilestoragetankbeforedistribution.Thesystemwillbemonitoredforaperiodoftwelvemonthstoevaluatetheperformancewaterqualityuserinterfaceandcostbenefit.SouthBishopLighthouseSouthBishopwasidentifiedasoneofthestationswherethesystemcouldbeinstalledwithminimalimpact.Thesystemisdesignedtocontrolandmonitortwostagesthetreatmentcycleandthedistributionofthepotablewater.WaterTreatmentCycleThetreatmentcycleiscontrolledbythewatercontentsinthestoragetank.Whenthewaterlevelfallstoapredeterminedvaluethegroundtankpumpisactivated.TheuntreatedwaterispumpedfromtheexternalgroundtanksthroughthefiltrationunitandthenpassesthroughtheUVdisinfectorbeforeenteringthestoragetank.Whenthetreatedwaterreachesapredeterminedlevelinthestoragetankthetreatmentcycleisdeactivated.StorageTankThestoragetankcomprisesofbladderbagswithacapacityofapproximately2000litreshousedinsideasupportingtank.ThebladderbagscontainsuperceramicballswithsilverplatestoconstantlyprotectthetreatedwaterfrominfestationofpathogenicbacteriasuchasLegionellaeE.ColiandPseudomonas.Thestoredwaterhasanoptimumprotectionofapproximately5years.DistributionofthepotablewaterThewaterisdeliveredtotheaccommodationviaaselfregulatingboosterpumpsetwhichdeliversamaintainedpressureofapproximately1.5bar.Thiseliminatestheuseofheadertanksinwhichcontaminationwouldbelikelytooccur.PowerRequirementsThepowerrequiredforthewatertreatmentsystemhasapeakloadofapproximately4kWdownto1.5kWatnominalload.Thesparecapacityfromthegeneratororsolarsystemwillvaryfromstationtostation.SouthBishopisidentifiedashaving1.5kWofsparecapacityonthestationgeneratorandapproximately100AhrsfromtheHeatingBattery.Toprovidethepeakpowerrequiredaninverterchargerregimewillbeimplemented.TheHeatingBatterywillsupplytheadditionalpoweratpeakloads.TestingandMonitoringTheinstallationwascompletedandoperationalinDecember2009whenthemonitoringofthesystemcommenced.Whenpersonnelvisitthestationtheywillinsertanewsetoffiltersandremovethemfordisposalbeforedeparture.Thiswillensuretheintegrityofthesystemtoeliminatecontamination.Watersampleswillbetakenbeforedeparturetobeanalysedbyalaboratoryforwaterquality.ThisservestwopurposesitensuresthewaterqualityconformstotheWaterSupplyRegulationsforthenextvisitingpersonnelandgivesanhistoricalbackgroundofresults.AfterthemonitoringperiodanassessmentwilltakeplacebeforeimplementationofthesystematotherstationsshoulditproveeffectiveitisplannedtousethesystemaspartoftheCasquetsmodernisation.AtestrighasbeencreatedatHarwichforfurtherdevelopment.PortablepurificationunitbuiltbyG.B.Environmental.PotablewaterstoragetanksinstalledatSouthBishop.