Greywater is the leftover water from baths, showers, hand basins and washing machines only, what implies that it is free of faeces and urine. Greywater can be recycled as processing water (whitewater) for toilet and/or urinal flushing or landscape irrigation. Energy recovery from greywater looks also very promising. The subject of this thesis is short research on the issue of the use of greywater in the first part, the following chapter provides examples of the use of greywater in practice. Practical part of thesis provides suggestion of use of greywater and their heat potential in swimming area Kraví hora with regard to completion of wellness centre. This part also includes economical analysis of suggested recycling.

The intent of this project is to provide tools for public administrators to implement and evaluate the cost of an alternative on-site residential water supply using rainwater harvesting and greywater reuse in their jurisdiction. These tools are then applied to the city of San Luis Obispo (SLO), California as a case study to demonstrate how rainwater harvesting and greywater reuse could be implemented to supply all residential potable and non-potable water needs, completely replacing the current centralized publicly-managed water system. Further, energy and direct fiscal costs of the alternative system are compared with the current system. A cost analysis is crucial given that sustainability is heavily linked to appropriately valuing a resource and increasing the visibility of same to the public. Pursuing sustainable water supply options is particularly important given critical water shortages and the need to decouple the energy/water equation in pursuit of reducing energy use and greenhouse gas (GHG) emissions. A decision tree and other tools were developed as part of this project for use by public administrators to determine the site-specific scope of an alternative residential water supply system. For example, a key question is the capacity of such a system to supply both potable and non-potable water needs. These tools were applied to single family (SF) residences in the case study city of SLO and resulted in an alternative residential system capable of completely substituting for public water supply. Implementation requires a major adjustment of indoor water demand from the SLO average of 55 gallons per capita per day (gpcd) to a ‘best practice’ water conservation mode of 27 gpcd, including a greywater reuse system for irrigation and toilet flushing. With demand held constant, the costs of the alternative on-site residential water supply system were then compared to the costs of the current centralized public water system for both the municipality and the consumer in SF residences in SLO. The public water supply costs were based on overall budgeted costs, including implementing a new project the city is partially financing for conveying Nacimiento Reservoir water to SLO. Consumer-billed costs include expected price increases proposed for the next year by the City largely due to the addition of the Nacimiento project. The volumetrically apportioned municipal water supply cost ($0.0049/gallon) is 37% lower than that billed to the consumer ($0.0078/gallon), but the wastewater processing cost for the City ($0.0125/gallon) is 39% greater than that billed to the consumer ($0.0076/gallon). Thus the combined water supply and wastewater processing costs for the City are only 4% greater than that billed to residential customers. It is notable that the City intends to significantly increase water prices billed to customers over the next several years which would shift the cost analysis in favor of the alternative system. The alternative system costs were based on operating costs (such as electricity) and the cost of the installed components of the system averaged yearly according to the life of the parts (10-50 years). The municipal cost for water supply ($0.0049/gallon) was 55% less than the cost for the alternative system ($0.0111/gallon), but the cost savings of wastewater processing using the alternative system ($0.0086/gallon) is 31% less than the municipal cost ($0.0125/gallon). The alternative systems savings are mostly a result of on-site greywater reuse for irrigation and indicate the scope of the immediate fiscal benefit to the municipality to substitute residential greywater systems for current public wastewater services. To calculate the overall cost difference in terms of both water supply and wastewater costs, the total costs used are as if all SF residences in SLO used the system. Overall, the municipal costs for combined water supply and wastewater processing ($4,137,598/yr) were 20% less than the alternative decentralized on-site system ($5,376,735/yr). The cost to the consumer for current water supply through the public water system ($0.0078/gallon) is 29% lower than the proposed alternative system ($0.0111/gallon). The wastewater processing cost to the consumer ($0.0076) is also 11% less than that of the alternative system ($0.0086/gallon). On this basis, the consumer cost using expected billing rates ($4,137,598) is 23% lower using the public water system than the cost of the alternative system ($5,376,735). Expected water and sewer rate increases may skew these results in favour of the alternative system where it is viable for the consumer to completely replace their water system and remove their household off the public water system to their financial benefit. The overall energy for water supply and wastewater processing used by the public water system was 34% lower (1,216,849 kWh/yr) than the alternative system (1,855,894 kWh/yr). The alternative on-site system’s electrically-driven pump is mostly responsible for this energy use and could be virtually eliminated by using gravity feed, as is common in many parts of the world currently using rainwater harvesting technology. Solar energy is also an effective solution to eliminate fossil-fuel based electricity. From a fiscal perspective, the alternative system costs are inflated given that an expected drop in supply cost would likely ensue with the economies of scale gained if an entire city was purchasing equipment for the alternative systems. This could override the results of the study showing the alternative system’s 20-23% higher fiscal cost than current public water system. Considering the ‘no fossil-fuel’ energy alternatives and the expected significant drop in supply cost with large scale purchasing, the alternative system provides a promising alternative residential water supply for SLO.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: South African water service providers experience major problems with providing adequate water services to consumers. Water service providers in South African urban areas rely on traditional centralised infrastructure, such as bulk supply networks, to provide water services. Alternative supply and stormwater drainage methods should be encouraged to help mitigate these problems. The researcher thus aims to quantify the potential impact that three alternative methods may have on a given dwelling in terms of its dependence on traditional bulk water services. The three alternatives considered in this thesis are the construction of green roofs, rainwater harvesting and greywater re-use. An efficiency of dwelling water use index (EDWI) was developed during this research project. It was designed in such a way as to show what portion of municipal water services could be replaced within the given dwelling by using the proposed techniques. The final EDWI-rating is obtained by using the EDWI-software tool developed as a part of this research. The derived EDWI-rating ranges from 0 to 100, with a rating of 100 indicating a dwelling requiring only the removal of a portion of sewage by a municipality, but no external water supply. Such a dwelling would also not require any water from a municipal network to meet domestic demand and all stormwater from its roof would be utilised within the plot boundaries. Results presented in this thesis illustrate how different geographical regions require different system specifications to obtain optimal EDWI-ratings, thereby lowering their dependence on the respective municipal water services. Validation of the EDWI-system proved difficult as no similar index could be found during the literature review. It was therefore decided to benchmark the EDWI-system using three model dwellings with nine configurations producing a total of 27 analyses. The EDWI-system provides a conceptual foundation for sustainable water services to South African households in serviced urban areas. Future work could further improve the EDWI-system by testing its practical application so that it may be extended to act as a national barometer, used to compare decentralised water services in terms of sustainability. / AFRIKAANSE OPSOMMING:Suid-Afrikaanse waterdiensverskaffers ondervind groot probleme met die voorsiening van voldoende waterdienste aan verbruikers. Waterdiensverskaffers in Suid-Afrikaanse stedelike gebiede maak staat op tradisionele gesentraliseerde infrastruktuur, soos grootmaatvoorsienings netwerke, om waterdienste te verskaf. Alternatiewe voorsienings- en stormwater dreineringsmetodes moet aangemoedig word om hierdie probleme aan te spreek. Die studie poog dus om die potensiële impak wat drie alternatiewe moontlikhede kan hê op 'n gegewe woning in terme van sy afhanklikheid van die tradisionele waterdienste te kwantifiseer. Die drie alternatiewe moontlikhede wat in hierdie studie ingesluit word is die konstruksie van groendakke, reënwater oes en grys water hergebruik. 'n Huishoudelike water gebruik doeltreffendheids indeks (EDWI) is ontwikkel gedurende hierdie navorsingsprojek. Die indeks is ontwerp om aan te dui watter gedeelte van munisipale waterdienste deur die voorgestelde tegnieke vervang kan word. Die finale EDWI-gradering is verkry deur gebruik te maak van die EDWI-programmatuur wat ontwikkel is gedurende die navorsing. Die afgeleide EDWI- gradering wissel tussen 0 en 100, met 'n telling van 100 wat ‘n woning voorstel wat slegs die verwydering van 'n gedeelte van die riool deur die munisipaliteit vereis, maar wat geen eksterne watervoorsiening benodig nie. So 'n woning vereis dus geen water van ‗n munisipale netwerk nie, en alle stormwater van die dak word binne die erf gebruik. Resultate wat in hierdie studie voorgelê word illustreer hoe verskillende geografiese streke ander stelsel spesifikasies vereis om optimale EDWI-gradering te verkry. Die navorser kon geen indeks kry wat soortgelyk is aan die EDWI-stelsel om dit mee te vergelyk nie. Dit was gevolglik besluit om die indeks te standardiseer deur gebruik te maak van drie model huise met nege samestellings van alternatiewe, waardeur 27 ontledings ontwikkel was. Die EDWI-stelsel bied 'n konseptuele grondslag vir volhoubare waterdienste vir Suid-Afrikaanse huishoudings in gedienste stedelike gebiede. Toekomstige navorsing kan die EDWI-stelsel verder verbeter deur die praktiese toepassing te toets. Die stelsel kan uitgebrei word om ‗n nationale barometer vorm wat gebruik kan word om desentralisasie van waterdienste te meet in konteks van volhoubaarheid.

O reúso de água é um instrumento importante que contribui para a redução da pressão sobre os mananciais e para redução do consumo de água potável para fins que não requeiram água de padrão potável. Neste contexto, o presente estudo teve como objetivo principal analisar um sistema de coleta e tratamento de águas cinzas provenientes de pias de banheiro, chuveiros e máquina de lavar roupas tendo em vista o reúso não-potável em edificações. Os objetivos específicos foram: caracterizar qualitativamente e quantitativamente as frações de águas cinzas; operar e monitorar um sistema de tratamento de águas cinzas sintéticas em escala piloto e analisar o efluente após tratamento. A partir de uma edificação existente no campus da EACH/USP, adaptou-se a estrutura hidráulica de forma a permitir a segregação e coleta desta fração de águas residuárias para caracterização e tratamento. A instalação de hidrômetros nas tubulações de alimentação dos pontos de uso (máquina de lavar, chuveiros e lavatórios) possibilitou analisar a produção de águas cinzas individualizada. Para o tratamento em escala piloto, adotou-se um biorreator de leito móvel com biofilme (MBBR) seguido por decantador. A avaliação do sistema de tratamento foi realizada com base no monitoramento periódico dos parâmetros físico-químicos durante o período de operação do sistema. Com base nos resultados obtidos, dentre as três frações de águas cinzas, a do chuveiro foi a que apresentou maior concentração de E.coli, enquanto que a maior concentração de coliformes totais foi na água cinza de lavatórios. As eficiências de remoção de DBO e DQO foram de 59 por cento e 70 por cento respectivamente. Houve baixa remoção de fósforo e não houve remoção de Nitrogênio Total durante o tratamento. / Water reuse is an important tool that can contribute to the reduction of the pressures from human activities on water resources and to reduce the demand for potable water for purposes that do not require high quality water. Therefore, the main objective of this study was to evaluate a greywater collection and treatment system from lavatories, showers and washing machine aiming the non-potable reuse in buildings. The specific objectives were: to characterize in terms of quality and quantity the greywater from each source, to monitor a pilot system for synthetic greywater treatment and to analyze the quality of the effluent after treatment. In an existing building in the University of Sao Paulo campus, the wastewater collection drains were modified to allow the segregated wastewater collection and the greywater characterization and treatment. To evaluate the greywater generation three water flow meters were installed in water inlet of each greywater source (washing machine, showers and lavatories). The greywater treatment included a moving bed biofilm reactor (MBBR) and a settling tank at pilot scale. The evaluation of greywater treatment was conducted based on the periodic monitoring of several physicochemical water quality parameters during the operation of the experimental system. Based on the results, amongst the three greywater sources, the greywater from showers had the highest E. coli count while the lavatories greywater had the highest total coliforms count. The removal efficiencies of BOD and COD were 59 per cent e 70 per cent respectively. In addition there was low removal of phosphorus and there was not Total Nitrogen Removal during the treatment.

Made available in DSpace on 2016-12-23T14:04:29Z (GMT). No. of bitstreams: 1 Lea Marina Silva.pdf: 9837499 bytes, checksum: d2a3d5ef17c6b5b733efab787b6d3ed7 (MD5) Previous issue date: 2013-02-22 / This work studies the demand for unsafe drinking water and the development of a system for reuse of greywater for social interest housing (SIH). The study presents a characterization of the profile of water consumption in a community of SIH the Jabaeté Residential in Vila Velha (ES). Investigates what water conservation actions best apply in everyday community in question, analyzing the reuse compared to the other interventions evaluated and finally, proposes some possible configurations of reuse systems in this community, through architectural design, as preliminary studies. These studies indicated an average consumption of water in SIH studied of 79 l.p-1d-1 and other indexes relating to the demand for potable water in every household activity (the most representative is the laundry, responsible for approximately 41% for total consumption). The methodology was based on questionnaires and monitoring of water consumption by reading water meters. By applying a method of decision support Analytic Hierarchy Process (AHP) it was determined the advantage of practices such as the use of dual discharge and segregating urine basin on the reuse of greywater. Furthermore projectual studies were performed of two types of configurations reuse systems: the decentralized and semi decentralized system, for which it was budgeted deployment costs. Observed economic advantage from adopting the semi decentralized, whose implementation can be up to 112% cheaper than the decentralized system / Este trabalho estuda a demanda de água não potável e o desenvolvimento de um sistema de reúso de águas cinza para Habitações de Interesse Social (HIS). Para tanto, realiza a caracterização do perfil de consumo de água em uma comunidade formada por HIS o Residencial Jabaeté, em Vila Velha (ES); investiga quais ações de conservação de água melhor se aplicam no cotidiano da comunidade em questão, analisando o reúso frente às demais ações avaliadas; e, por fim, propõe algumas configurações possíveis de sistemas de reúso nessa comunidade por meio de projeto arquitetônico, no nível de estudo preliminar. Tais estudos apontaram um consumo médio de água nas HIS estudadas de 79 l/hab. dia e demais índices relativos à demanda de água potável em cada atividade doméstica (a mais representativa é a lavagem de roupas, responsável por aproximadamente 41% do consumo total). A metodologia utilizada foi aplicação de questionários e monitoramento do consumo de água pela leitura de hidrômetros. Através da aplicação de um método de suporte à decisão o Analytic Hierarchy Process (AHP), determinou-se a vantagem de práticas como uso de descarga dual e bacia segregadora de urina sobre a prática do reúso de água cinza. Além disso, foram realizados estudos projetuais de dois tipos de configurações de sistemas de reúso: o sistema descentralizado e o sistema semi-descentralizado, para os quais foram orçados os custos de implantação. Observou-se a vantagem econômica da adoção do sistema semi-descentralizado, cuja implantação pode ser até 112% mais barata que o sistema descentralizado

O reúso de água é um instrumento importante que contribui para a redução da pressão sobre os mananciais e para redução do consumo de água potável para fins que não requeiram água de padrão potável. Neste contexto, o presente estudo teve como objetivo principal analisar um sistema de coleta e tratamento de águas cinzas provenientes de pias de banheiro, chuveiros e máquina de lavar roupas tendo em vista o reúso não-potável em edificações. Os objetivos específicos foram: caracterizar qualitativamente e quantitativamente as frações de águas cinzas; operar e monitorar um sistema de tratamento de águas cinzas sintéticas em escala piloto e analisar o efluente após tratamento. A partir de uma edificação existente no campus da EACH/USP, adaptou-se a estrutura hidráulica de forma a permitir a segregação e coleta desta fração de águas residuárias para caracterização e tratamento. A instalação de hidrômetros nas tubulações de alimentação dos pontos de uso (máquina de lavar, chuveiros e lavatórios) possibilitou analisar a produção de águas cinzas individualizada. Para o tratamento em escala piloto, adotou-se um biorreator de leito móvel com biofilme (MBBR) seguido por decantador. A avaliação do sistema de tratamento foi realizada com base no monitoramento periódico dos parâmetros físico-químicos durante o período de operação do sistema. Com base nos resultados obtidos, dentre as três frações de águas cinzas, a do chuveiro foi a que apresentou maior concentração de E.coli, enquanto que a maior concentração de coliformes totais foi na água cinza de lavatórios. As eficiências de remoção de DBO e DQO foram de 59 por cento e 70 por cento respectivamente. Houve baixa remoção de fósforo e não houve remoção de Nitrogênio Total durante o tratamento. / Water reuse is an important tool that can contribute to the reduction of the pressures from human activities on water resources and to reduce the demand for potable water for purposes that do not require high quality water. Therefore, the main objective of this study was to evaluate a greywater collection and treatment system from lavatories, showers and washing machine aiming the non-potable reuse in buildings. The specific objectives were: to characterize in terms of quality and quantity the greywater from each source, to monitor a pilot system for synthetic greywater treatment and to analyze the quality of the effluent after treatment. In an existing building in the University of Sao Paulo campus, the wastewater collection drains were modified to allow the segregated wastewater collection and the greywater characterization and treatment. To evaluate the greywater generation three water flow meters were installed in water inlet of each greywater source (washing machine, showers and lavatories). The greywater treatment included a moving bed biofilm reactor (MBBR) and a settling tank at pilot scale. The evaluation of greywater treatment was conducted based on the periodic monitoring of several physicochemical water quality parameters during the operation of the experimental system. Based on the results, amongst the three greywater sources, the greywater from showers had the highest E. coli count while the lavatories greywater had the highest total coliforms count. The removal efficiencies of BOD and COD were 59 per cent e 70 per cent respectively. In addition there was low removal of phosphorus and there was not Total Nitrogen Removal during the treatment.

<p>Utan vatten inget liv. Människor är beroende av rent vatten för sin överlevnad. I många länder orsakar idag bristen på rent vatten sjukdomar och för tidig död. Världens problem med sötvatten i form av brist och svåra föroreningar orsakade av människan kan te sig kolossala. Befolkningsökning och ändrade levnadssätt påverkar. Industrier och jordbruk har stor påverkan men också den enskilda människans vattenanvändning har betydelse.</p><p> </p><p>I Sverige tycks den allmänna inställningen vara att vi inte har ett problem med vårt användande av vatten. Men vid en närmare undersökning av vårt innanhav Östersjöns problem med exempelvis övergödning och syrebrist och utsläppen av näringsämnen ifrån våra enskilda avlopp kan man ställa sig frågande. Även svenskens nyttjande av grundvattenreserver kan te sig olämpligt utifrån ett ekologiskt hållbart perspektiv. Att sedan detta vatten renas till dricksvattenkvalitet för att sedermera användas till att vattna fuktälskande växter som är planterade i gassande sol i en sandig torr jord kan vara förbryllande. Medvetenhet utifrån det lilla perspektivet, till exempel den svenska hemträdgården, kan vara åskådligt. Samtidigt kan det kanske också bidra till en i framtiden miljövänligare politik där målet är att rent sötvattnen skall finnas tillgängligt för alla i ett långt perspektiv.</p><p> </p><p>I denna litteraturstudie, möjligheten till en rationell vattenanvändning i den privata hemträdgården ur ett ekologiskt hållbart perspektiv. Flertalet olika metoder att hushålla med vatten och att tillvarata, rena och använda sig av nederbörd och gråvatten belyses. Resultatet är indelat i två delar; hushållning och rening. I den första redogörs på vilka sätt en effektivisering av vattenanvändandet kan gå till. Lättast och effektivast görs detta genom att dra ner på förbrukningen. Detta går enkelt att göra med några få tekniker. Till exempel att bättra på jordstruktur med organisktmaterial, att placera växter på platser som liknar deras naturliga habitat, minska avdunstning och forma platsen så att nederbörd kan ledas dit den behövs. Att se över hur extrabevattning ska tillämpas på effektivast sätt samt vilken vattenkälla detta vatten kommer ifrån tillhör också detta hushållande stycke. I den andra delen redogörs för olika metoder som kan tillämpas i en trädgård för att rena grå- och dagvatten så att trädgårdens naturliga potential till att vara en del av jordens naturliga kretslopp främjas. Lättast görs detta genom en begränsning av föroreningar redan vid deras källa. Därefter kan infiltrationsytor, infiltrationsplanteringar, biodiken, gröna tak, dammar, konstruerade våtmarker, rotzoner, UV-ljus och aquakulturer vara mer eller mindre användbara metoder som kan tillämpas i hemträdgården.</p><p> </p><p>Vattenfrågan bör klarläggas redan vid planeringen av byggnader och trädgård. Varje tomt måste sättas in i sitt sammanhang då dessa unika med speciella förutsättningar och problem. Hemträdgården är en utmärkt plats för experiment och utvecklingsarbete av ett hållbart vattenanvändande.</p> / <p>Without water there would be no life on earth. People depend of clean water for their survival. Today in many countries the lack of clean water is causing disease and premature death. World problems with fresh water in the form of shortage and severe pollution caused by humans may seem colossal. Industries and agriculture have a major impact but also the individual’s water-use has consequences.</p><p> </p><p>In Sweden the public opinion seems to be that we do not have a problem with our use of water. But with a closer look on facts that is not the case. For example our inland sea, Östersjön, and our contribution to its problems with euthrophication, lack of oxygen with the spillage of nutrients from the sewers and agriculture. Also the Swedish use of ground water may seem inappropriate in an ecological sustainable perspective. What is even more puzzling is that this water gets cleaned to a drinking water quality and then gets used for watering plants in the garden or to wash the car. Consciousness from the small perspective (as the Swedish private garden) can contribute to a future environmentally friendly politic that will lead to a sustainable water-use in a long perspective.</p><p> </p><p> </p><p>With this paper I would like to demonstrate, in a literature study, the possibility of a rational water-use in the private home garden from an ecological sustainable perspective.  Different methods of economising the water-use, gathering and cleaning stormwater and greywater will be illustrated. The result part will be divided into two parts; economization of water and cleaning of water.</p><p> </p><p>The first part describes the ways in which an efficiency of water-use can be preceded. The easiest way this is done is to cut down the consumption of water. This can easily be done with a few techniques. For example to improve the soil structure with organic material, placing of plants in places that resemble their natural habitat, reduction of evaporation and shaping pf the site so that precipitation can be managed where it is needed. Also to in which way irrigation is applied in the most efficient way and from which source this water is taken is presented in this part. The second part describes different methods of cleaning grey- and stormwater so the home garden’s natural potential to be a part of the earth’s natural rhythm is promoted.</p><p>Most easily this is done by stopping the pollution at the source. After that infiltration areas, bioswales, green roofs, ponds, constructed wetlands, reed beds, UV light and aquacultures can be more or less potential methods to be applied in the home garden.</p><p> </p><p>Water issues should be clarified already at the design process with homes and gardens. Each plot and garden is unique with its particular conditions and problems. Therefore needs every case to be seen in its particular context in order to obtain the optimal solution for that particular place.The home garden is a suitable place for experimental development of a sustainable water-use.</p>

Utan vatten inget liv. Människor är beroende av rent vatten för sin överlevnad. I många länder orsakar idag bristen på rent vatten sjukdomar och för tidig död. Världens problem med sötvatten i form av brist och svåra föroreningar orsakade av människan kan te sig kolossala. Befolkningsökning och ändrade levnadssätt påverkar. Industrier och jordbruk har stor påverkan men också den enskilda människans vattenanvändning har betydelse.   I Sverige tycks den allmänna inställningen vara att vi inte har ett problem med vårt användande av vatten. Men vid en närmare undersökning av vårt innanhav Östersjöns problem med exempelvis övergödning och syrebrist och utsläppen av näringsämnen ifrån våra enskilda avlopp kan man ställa sig frågande. Även svenskens nyttjande av grundvattenreserver kan te sig olämpligt utifrån ett ekologiskt hållbart perspektiv. Att sedan detta vatten renas till dricksvattenkvalitet för att sedermera användas till att vattna fuktälskande växter som är planterade i gassande sol i en sandig torr jord kan vara förbryllande. Medvetenhet utifrån det lilla perspektivet, till exempel den svenska hemträdgården, kan vara åskådligt. Samtidigt kan det kanske också bidra till en i framtiden miljövänligare politik där målet är att rent sötvattnen skall finnas tillgängligt för alla i ett långt perspektiv.   I denna litteraturstudie, möjligheten till en rationell vattenanvändning i den privata hemträdgården ur ett ekologiskt hållbart perspektiv. Flertalet olika metoder att hushålla med vatten och att tillvarata, rena och använda sig av nederbörd och gråvatten belyses. Resultatet är indelat i två delar; hushållning och rening. I den första redogörs på vilka sätt en effektivisering av vattenanvändandet kan gå till. Lättast och effektivast görs detta genom att dra ner på förbrukningen. Detta går enkelt att göra med några få tekniker. Till exempel att bättra på jordstruktur med organisktmaterial, att placera växter på platser som liknar deras naturliga habitat, minska avdunstning och forma platsen så att nederbörd kan ledas dit den behövs. Att se över hur extrabevattning ska tillämpas på effektivast sätt samt vilken vattenkälla detta vatten kommer ifrån tillhör också detta hushållande stycke. I den andra delen redogörs för olika metoder som kan tillämpas i en trädgård för att rena grå- och dagvatten så att trädgårdens naturliga potential till att vara en del av jordens naturliga kretslopp främjas. Lättast görs detta genom en begränsning av föroreningar redan vid deras källa. Därefter kan infiltrationsytor, infiltrationsplanteringar, biodiken, gröna tak, dammar, konstruerade våtmarker, rotzoner, UV-ljus och aquakulturer vara mer eller mindre användbara metoder som kan tillämpas i hemträdgården.   Vattenfrågan bör klarläggas redan vid planeringen av byggnader och trädgård. Varje tomt måste sättas in i sitt sammanhang då dessa unika med speciella förutsättningar och problem. Hemträdgården är en utmärkt plats för experiment och utvecklingsarbete av ett hållbart vattenanvändande. / Without water there would be no life on earth. People depend of clean water for their survival. Today in many countries the lack of clean water is causing disease and premature death. World problems with fresh water in the form of shortage and severe pollution caused by humans may seem colossal. Industries and agriculture have a major impact but also the individual’s water-use has consequences.   In Sweden the public opinion seems to be that we do not have a problem with our use of water. But with a closer look on facts that is not the case. For example our inland sea, Östersjön, and our contribution to its problems with euthrophication, lack of oxygen with the spillage of nutrients from the sewers and agriculture. Also the Swedish use of ground water may seem inappropriate in an ecological sustainable perspective. What is even more puzzling is that this water gets cleaned to a drinking water quality and then gets used for watering plants in the garden or to wash the car. Consciousness from the small perspective (as the Swedish private garden) can contribute to a future environmentally friendly politic that will lead to a sustainable water-use in a long perspective.     With this paper I would like to demonstrate, in a literature study, the possibility of a rational water-use in the private home garden from an ecological sustainable perspective.  Different methods of economising the water-use, gathering and cleaning stormwater and greywater will be illustrated. The result part will be divided into two parts; economization of water and cleaning of water.   The first part describes the ways in which an efficiency of water-use can be preceded. The easiest way this is done is to cut down the consumption of water. This can easily be done with a few techniques. For example to improve the soil structure with organic material, placing of plants in places that resemble their natural habitat, reduction of evaporation and shaping pf the site so that precipitation can be managed where it is needed. Also to in which way irrigation is applied in the most efficient way and from which source this water is taken is presented in this part. The second part describes different methods of cleaning grey- and stormwater so the home garden’s natural potential to be a part of the earth’s natural rhythm is promoted. Most easily this is done by stopping the pollution at the source. After that infiltration areas, bioswales, green roofs, ponds, constructed wetlands, reed beds, UV light and aquacultures can be more or less potential methods to be applied in the home garden.   Water issues should be clarified already at the design process with homes and gardens. Each plot and garden is unique with its particular conditions and problems. Therefore needs every case to be seen in its particular context in order to obtain the optimal solution for that particular place.The home garden is a suitable place for experimental development of a sustainable water-use.

Centralized infrastructure (CI) is difficult to sustain with limited water and fossil fuel resources because CI withdraws 100% of water demand from the environment as an open-loop system and electricity is consumed to transport and treat water and wastewater while demand is increasing. Hybrid infrastructure (HI) is proposed to combine CI with decentralized alternatives such as low impact development (LID) technologies (i.e., xeriscaping, rain gardens, and rainwater harvesting) or greywater reclamation systems with membrane bioreactors (MBRs). Water, wastewater, and stormwater systems in the City of Atlanta (COA) were regarded as CI. HI was compared to CI using life cycle environmental impacts measured by water reuse index (WRI) and life cycle assessment (LCA) scores. WRI is a ratio of water withdrawal to sustainable water resources of wastewater (i.e., return flow) and stormwater discharge, which presents water stress level (e.g., 0.2 ~ 0.4: medium-high level). LCA score is determined as % of annual world average environmental damage per capita. As stormwater runoff, water demand, greywater generation, rainwater harvesting, etc. vary depending on land use and population density, feasibility of decentralized alternatives was evaluated in eleven residential communities. Five single-family residential communities were designated as between R-1 of 16 people/10 acres and R-5 of 169 people/10 acres and six multi-family residential communities were designated as between RG-1 of 148 people/10 acres and RG-6 of 5,808 people/10 acres. HI with LID technologies reduced WRI of COA that relies on CI from 0.45 to 0.12. HI reduced the LCA scores of CI with combined sewer system (CSS) by between 1% for RG-6 and 68% for R-1 and the LCA scores of CI with separate sewer system (SSS) by between 0% for RG-6 and 18% for R-1. As population density increases for the multi-family residential communities, harvested rainwater decreases and a small amount of water demand is satisfied. Consequently, it has a negligible impact on the LCA scores in RG-6. HI with greywater reclamation system reduced WRI of COA from 0.45 to 0.35. HI resulted in the LCA scores greater as compared to CI in the five single-family communities and RG-1, RG-2, and RG-3 because of the electricity consumption of small-scale MBR. However, the electricity consumption per kgal decreases with increasing MBR treatment capacity and the LCA scores were reduced by 5% for RG-4, 15% for RG-5, and 21% for RG-6. The MBR treatment capacity of RG-4 is 15.6 kgal/day.

Les eaux grises (EG) peuvent être considérées comme une ressource alternative à l’eau potable et peuvent donc être réutilisées, par exemple, pour l'arrosage d'espaces verts pour lequel une qualité ''eau destinée à la consommation humaine'' ne semble pas nécessaire. Toutefois la présence de microorganismes pathogènes et de composés organiques peut entraîner des risques sanitaires et environnementaux. Il est donc nécessaire de traiter ces EG avant de les réutiliser et caractériser les risques liés à leur recyclage, jusqu'à présent peu connus. Pour répondre à ces objectifs, la démarche a consisté à caractériser les EG afin de choisir un traitement adapté. Le procédé biologique retenu est un réacteur à lit fluidisé aérobie. Son optimisation a été basée sur l’étude de son comportement hydrodynamique et sur la cinétique de biodégradation des EG. Ses performances épuratoires ont également été déterminées. La qualité des EG traitées produites atteint les objectifs attendus par la réglementation française pour l'irrigation d'espaces verts avec des eaux usées traitées. En effet, la DCO et les MES obtenues dans l'effluent traité sont respectivement de 26 mg O2.L-1 et 5,6 mg.L-1. Le réacteur a permis de traiter 144 L.j-1 d'EG durant 16 mois. Trois parcelles de pelouse ont été irriguées respectivement par des EG brutes, des EG traitées et par de l’eau potable. Contrairement à la parcelle irriguée par les EG brutes, l'analyse de risques n'a montré aucune différence significative entre celle irriguée par les EG traitées et celle irriguée par l'eau potable. Ces travaux démontrent que les EG traitées produites dans cette étude peuvent être employées pour l’irrigation d’espaces verts. / A level of water quality intended for human consumption does not seem necessary for domestic uses such as irrigation of green spaces. Alternative water supplies like the use of greywater (GW) can thus be considered. However, GW contains pathogenic microorganisms and organic compounds which can cause environmental and health risks. As the risks related to recycling are unknown, GW treatment is necessary before reusing. To describe the risks related to GW reuses, the scientific approach performed in this study was to characterize domestic GW in order to select an appropriate treatment. The biological process chosen is an aerobic fluidized bed reactor. As this process has never been developed for GW, an optimization step based on the study of its hydrodynamic behavior and the kinetics of biodegradation of GW was performed. The treatment performances were then determined. The treated GW produced in this study reached the threshold values expected by the French regulation for irrigation of green spaces with treated wastewater. Indeed, the COD and the TSS obtained in treated GW were respectively 26 mg O2.L-1 and 5.6 mg.L-1. The fluidized bed reactor has been used to treat 144 L.d-1 of GW for 16 months. Three lawn plots were irrigated respectively with raw GW, treated GW and tap water asa reference. Contrary to the lawn plot irrigated with raw GW, the risk analysis performed in this study has shown no significant difference between the law plot irrigated with treated GW and the one irrigated with tap water. This study shows that treated GW produced from the fluidized bed reactor developed in this experiment can be used for irrigation of green spaces.