This keynote presentation explores the concept of a zero waste approach to water supply. This is a precursor to the circular economy of water

McCarton, Liam

O\u27hOgain, Sean

English

Arrow@TUDublin

Technological University Dublin ARROW@TU Dublin Other Resources School of Engineering 2013-04-24 Rainwater Harvesting - A Zero Waste Approach to Water Liam McCarton Technological University Dublin, liam.mccarton@tudublin.ie Sean O'hOgain Technological University Dublin, Sean.Ohogain@tudublin.ie Follow this and additional works at: https://arrow.tudublin.ie/ittengoth  Part of the Civil and Environmental Engineering Commons Recommended Citation McCarton L, O’Hogain S (2013) Rainwater Harvesting – Technology, Water Quality and Applications, Better Building: Water Conservation Strategies, International Conference for a Sustainable Built Environment, 24th April 2013, Croke Park, Dublin. This Presentation is brought to you for free and open access by the School of Engineering at ARROW@TU Dublin. It has been accepted for inclusion in Other Resources by an authorized administrator of ARROW@TU Dublin. For more information, please contact arrow.admin@tudublin.ie, aisling.coyne@tudublin.ie. This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License Technological University Dublin ARROW@TU Dublin Books/Book Chapters 2013 Rainwater Harvesting - A Zero Waste Approach to Water Liam McCarton sean ohogain Dr Follow this and additional works at: https://arrow.tudublin.ie/totalarcscbk  Part of the Civil and Environmental Engineering Commons This Presentation is brought to you for free and open access by ARROW@TU Dublin. It has been accepted for inclusion in Books/Book Chapters by an authorized administrator of ARROW@TU Dublin. For more information, please contact arrow.admin@tudublin.ie, aisling.coyne@tudublin.ie. This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License 1Better Building: Water Conservation StrategiesInternational Conference for a Sustainable Built Environment24th April 2013, Croke Park, Dublin.“Rainwater Harvesting – A Zero Waste Approach to Water”Liam McCarton, Dr. Sean O’Hogain,DTC Research Group, School of Civil Engineering, Dublin Institute of Technology www.dit.ie/dtc2Development  Technology  in the CommunityTechnology Transfer at Community Level:To link international expertise with local communities– to empower them to adapt water and sanitation technologies to suitsocio-economic & environmental conditionsResearch Group for the Promotion of SustainableEnvironmental, Water & Sanitation Technologies3• Innovation in Rainwater Harvesting  Design • Pilot Rainwater Harvesting Study 2005 – 2009, DOEHLG • School Rainwater Harvesting Study 2009-2012, DOEHLG• Zero Discharge Wastewater Treatment Systems• Reed Bed WWT System, 1996-2002, - Fingal Co. Co.• Hybrid  Reed Willow Bed  WWT System, 2007-2012 - South Dublin Co. Co.• Appropriate Technology • Sierra Leone , 2009-2013 – EU Funded Program• Water, Wastewater, Solar, Wind, Pump technology, 2011, EMAS, Bolivia, • Low Cost Pump Design , 2012 CANZEE, UK • Training Courses• TECSPAR Technology Transfer Project, 2005-2008 EU Alfa Programme in association with Polytechnic University of Catalunia, Spain and the University of Padua, Italy and University of Medellin, Colombia, University of San Luis Potosi, Mexico and the University of Conception, Chile.  Projects          www.dit.ie/dtc4Rainwater Harvesting – System Components2. Catchment Surface3. Effective Runoff1. Rainfall4. Conveyance System3. LossesFilter LossesFiltered Rainwater5a. Downpipe Filter 5b. Underground Filter6. StorageFilter LossespOverflow 7.Water UseRainfall: Ireland’s climate is very suitable for rainwater harvesting. East 750 – 1,000 mm per year, 150 wet days (days 1mm or more of rain)West 1,000 – 1,400 mm per year, 225 wet days Mountains > 2,000mm per year Catchment Surface: surface from which rain is collected Losses: some of the rainfall is trapped by the roof material or is held in depressions on the roof.Effective Runoff: A roof with a run-off co-efficient of 0.8 will convey 80% of the rainfall incident on it to the collection system for harvesting, while 20% of the rainfall will be lost to the RWH systemConv yanc  System: Includes gutters and down pipes to convey the rain from the roof to the storage tank.Filter: Typical filter char te istics:• water and weather resistant• removable and readily accessible for maintenance purposes• has an efficiency of at least 90%passes a maximum p rticle sizf <1.25 mm.Storage: Rainwater is stored either in an underground above ground tank. Typical components include an overflow device, pump, and floating filter. Rainwater Use: Stored rainwater extracted at times of demand for non-potable uses (such as W.C flushing, xte nal taps)There are three basic types of rainwater harvesting sy tems. • fed b  gravity to the points of use.• rainwater i collected in storage tank(s) and pumped directly to the points of use.• pumped to an elevated cistern and fed by gravity to the points of use.5RWH Systems– Direct Gravity SystemGravity Fed RWH Systems: Rainwater is collected from the roof, filtered and then conveyed directly to the storage (header) tank. Water is delivered to appliances via gravity.Top up from the mains water tank is provided via a non return valve or type A air gap. Downpipe Filter 6RWH Systems– Indirect Pumped SystemIndirect Pumped Systems: Rainwater is collected from the roof, filtered and then conveyed directly to the rainwater storage tank. Water is pumped to a rainwater header tank and delivered to appliances via gravity.Top up from the mains water tank is provided via a non return valve or type A air gap. Downpipe Filter 7RWH Systems– Direct Pumped SystemDirect Pumped Systems: Rainwater is collected from the roof, filtered and then conveyed directly to the rainwater storage tank. Water is pumped to  appliances.Top up directly to rainwater storage tank from the mains water supply.  Downpipe Filter 8Frequently Asked Questions• What are the hazards associated with rainwater ?• How pure is rainwater ?• What is the risk of the mains supply  becoming contaminated by rainwater ?9RWH Water Quality: The path of contamination 10RWH Water Quality: RWH Treatment ProcessesRoof Catchment:Heat InactivationUV RadiationHot Water System:Thermal TreatmentStorage Tank:BiofilmSedimentationFilter:Suspended Solids RemovalPump:Heat TreatmentHigh Pressure11• Innovations in Rainwater Harvesting  Design • Domestic – Carlow• Agricultural – Meath• School - Mayo• Publications available from www.dit.ie/arrowProjects          www.dit.ie/dtc12RWH HouseDomestic Installation,  County Carlow.RWH System Components1. Roof Surface2. Rainwater Filter3. Rainwater Storage Tank4. Pump5. Supply Management System 6. Rainwater Header Tank7. Mains water Header Tank8. Overflow to surface water drainage system9. Mains water top-up1314Mains top upRainwater header tankMains header tankMeter & transmitter150.001.002.003.004.005.006.007.00Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec(m3)MonthsMonthly Supply-vs-Monthly DemandSupply DemandDomestic RWH: Water Quantity 160200400600800100012001400JanFebMarAprMayJunJulAugSepOctNovDec JanFebMarAprilMayJuneJulyMPN/100mlMonth SampledTotal Coliform Results012345678MPN/100mlMonth sampledE.coli Results0510152025cfu/100mlMonth SampledFaecal Coliform ResultsWater Quality EU Bathing Water Stds. 100%EU Drinking Water Stds.   37%Domestic RWH: Water Quality 17Agricultural Installation, County Meath18Farm schematicAgricultural Installation, County Meath19200100002000030000400005000060000cfu/mlMonth SampledColiform Results050010001500200025003000Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Mar May Juncfu/mlMonth SampledE.coli Results0100200300400500600700Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan MarMay Juncfu/100mlMonth SampledFaecal Coliform ResultsWater Quality First filtering system installed -Poor QualitySecond filtering system installed- Average Quality.Water QuantitySupplied 43% of Livestock water 21Case Study: School RWH221. ROOF CATCHMENT  2. RWH SYSTEM  OVERFLOW & FILTER  3. RWH HEADER TANK  4. RWH MAINS WATER TOP UP 5. RWH OVERFLOW 2324• Per capita consumption over the twenty one month period of the study was recorded as 2.81 m3/pupil/year • Non potable (WC) water use consisted of 1.49 m3/pupil/year. • RWH system - 52% of the total non potable (WC) water usage.• Mains water top up provided 48%.25Further Studies • Thermal inactivation data for therange of bacteria relevant to health inhot water systems is rare althoughextensive work has been carried out inAustralia in the last number of years.• DIT Study – thermal inactivation ratesat hot water temperatures of 55o and60o260501001502002503001 2 3 4 5MPN/100mlTime (mins)Thermal Inactivation Rates - Coliforms and E.coli at 60ºCColiforms MPN/100mlE.coli MPN/100ml05101520253035400 mins 5 mins 10 mins 15 mins 20 minscfu/100mlTime (Mins)Thermal Inactivation Rates - Faecal Coliforms at 60ºCFaecal Coliformscfu/100ml0204060801001201400 mins 5 mins 10 mins 15 mins 20 minscfu/mlTime (mins)Thermal Inactivation Rates - TVC 22ºC and 37ºC at 60ºCTVC @ 22ºC cfu/mlTVC @ 37ºC cfu/ml02468101214160 mins 5 mins 10 mins 15 mins 20 minscfu/100mlTime (mins)Thermal Inactivation Rates - Pseudomonas Spp at 60ºCPseudomonascfu/100mlThe aims of the thermal experiments were to determine the time required to reduce a bacterial population by 100% or 1 log reduction, for the potential waterborne pathogens mentioned, in a water medium at temperatures relevant for domestic hot water systems. 27EU - Major Policy InitiativesGermany• Rain taxes collected for the amount of run off into the local storm sewer that is generated from the impervious surface cover of the property. France• A tax rebate of 40 % up to a maximum of € 5000 is be provided to all RWH systems.Belgium• National Legislation - all new constructions need to have RWH systems installed for the purpose of flushing toilets and external water uses. 28European RWH Market Drivers and RestraintsDriversRain TaxesProactive GovernmentHigh Water TaxesRestraintsSlow Construction Market Capital CostGermanyDriversEco ChequesMandatory RWHRestraintsSlow Construction Market Belgium DriversRising Water TariffsTax RebatesRestraintsSlow Construction Market France Drivers?RestraintsPlanning Permission Lack of Government Policy No financial IncentivesLack of education Storage over designed leading to high capital costs Ireland 2930Singapore – “Innovations in strategic vision  leads to innovations in technology” “Water dominated every Government policy” Prime Minister Lee Hsien LoongRainwater Harvesting- collected from unprotected and protected catchments.Imported Water - MalayasiaNEWater- Reclaimed water for non potable industry  Desalination- Reclaimed seawater  (future)31“Singapore – harvest every drop of water”“Two thirds of Singapore is already a water catchment”Rainwater harvestedon-siteRainwater channelled to canals Discharged to Reservoirs32“Singapore – Unprotected Urban Water Catchments”33Marina BarrageWater SupplyDamming of the Marina Channel created a 10,000hectacre water catchment meeting 10% ofSingapore Potable Water Supply DemandFlood Control –High rainfall with low tide ≡  weir -High rainfall with high tide, ≡, rainwater pumped over barrier to sea-Lifestyle attraction – “we used to keep people away from our water…now we want to attract them to the water as a resource, amenity”-Active Beautiful, Clean (ABC)34Singapore – “wastewater is a resource”NEWaterHigh quality reclaimed wastewaterfor non potable industrial users • Electronics industry• Power generation • Air conditioners 35“A Zero Waste Approach to Water ” To develop an integrated water strategy for Ireland we need:• Innovative thinking • Sustainable and resilient technologies• Education curricula reform • Co-ordinated Government and Community Action • Appreciation of rainwater and wastewater as a valuable resource36Innovation - not just technology !• “The Singapore example indicates that it is unrealistic to expect the existence of an efficient water management institution in a country, in the midst of other similar mediocre management institutions…• Water management institutions in a country can only be as efficient as its management of other development sectors.”(Tortajada, C, 2006)

Rainwater Harvesting - A Zero Waste Approach to Water

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Rainwater Harvesting - A Zero Waste Approach to Water

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