One of the factors emphasized by Leadership in Energy and Environmental Design (LEED), a national consensus-based standard under the United States Green Building Council (USGBC) for developing sustainable or high performance buildings, is water efficiency. A LEED registered project can attain up to five points under water efficiency upon successful integration of various techniques to conserve water. Many techniques are available to conserve water and grey water reuse is one option considered by many LEED registered projects. In spite of widespread popularity, some of the sustainable techniques including grey water reuse, which is recommended by the USGBC and various agencies engaged in green building constructions, are not viable in many parts of the United States due to their effects on construction cost and project schedules. Even though a project could get one or multiple points upon successful implementation of a grey water reuse system and conserving potable water, the following factors may have a positive or negative effect on the design team’s decision to implement a grey water reuse system: capital cost, maintenance cost, LEED credits, local plumbing codes, project schedule, local water conservation issues, complexity of the system, etc. Implementation of a grey water reuse system has a significant effect on the capital cost of a project. The increase in cost may be attributed to dual sanitary and grey water distribution piping which doubles construction piping costs. Disinfection treatment, filtration, overflow protection, grey water storage tanks, etc. also add to the cost of construction. Ninety percent of the projects claim that project schedule is not affected by the implementation of a grey water reuse system in a green building project. The factors which prevent the project team from implementing a grey water reuse system include capital cost, maintenance cost, local plumbing codes, local water conservation issues, complexity of the system, etc. LEED credits and the spirit of sustainability are the factors which have a positive effect on the design team’s decision to implement a grey water reuse system.

One of the factors emphasized by Leadership in Energy and Environmental Design (LEED), a national consensus-based standard under the United States Green Building Council (USGBC) for developing sustainable or high performance buildings, is water efficiency. A LEED registered project can attain up to five points under water efficiency upon successful integration of various techniques to conserve water. Many techniques are available to conserve water and grey water reuse is one option considered by many LEED registered projects. In spite of widespread popularity, some of the sustainable techniques including grey water reuse, which is recommended by the USGBC and various agencies engaged in green building constructions, are not viable in many parts of the United States due to their effects on construction cost and project schedules. Even though a project could get one or multiple points upon successful implementation of a grey water reuse system and conserving potable water, the following factors may have a positive or negative effect on the design team’s decision to implement a grey water reuse system: capital cost, maintenance cost, LEED credits, local plumbing codes, project schedule, local water conservation issues, complexity of the system, etc. Implementation of a grey water reuse system has a significant effect on the capital cost of a project. The increase in cost may be attributed to dual sanitary and grey water distribution piping which doubles construction piping costs. Disinfection treatment, filtration, overflow protection, grey water storage tanks, etc. also add to the cost of construction. Ninety percent of the projects claim that project schedule is not affected by the implementation of a grey water reuse system in a green building project. The factors which prevent the project team from implementing a grey water reuse system include capital cost, maintenance cost, local plumbing codes, local water conservation issues, complexity of the system, etc. LEED credits and the spirit of sustainability are the factors which have a positive effect on the design team’s decision to implement a grey water reuse system.

Maintaining a supply of potable water is a growing concern in the USA, particularly in many southern and western states. One method of sustaining water supply in these areas is the use of greywater for commercial and residential landscape irrigation. Greywater is derived from residential use such as showers, laundering and bathing, and accounts for approximately 65% of residential waste water. I investigated the effects of municipal tap water, harvested rain water, washing machine and bath water (greywater) on the carbon and nutrient dynamics of soil, foliage and leachate and on soil microbial diversity. I also examined the presence or absence of E. coli in source water and leachate. There was a significant difference in leachate chemistry among irrigation treatments. Average leachate pH and conductivity was significantly lower in treatments irrigated with harvested rain water. Fertilization did not affect any of the leachate chemistries with the exception of orthophosphate-P, but significantly reduced carbon in soil without grass (blank) and domestic tap water treatments. E. coli colonies were detected in source water (greywater), but not in leachate suggesting that there was no movement through the soil profile. The results of principal component analysis (PCA) on whole-soil fatty acid methyl ester (FAME) profiles indicated distinct differences in soil microbial community composition due to irrigation with greywater as compared to rainwater, suggesting that water source may affect soil microbial community composition.

This study investigates the appropriateness of greywater reuse technologies in Canada. To design a technology to appropriately meet a user’s needs the approach must conform to existing technical, cultural, economic, environmental, and social conditions. The appropriateness of two greywater reuse systems (GWRS) were investigated according to three criteria; reliability/soundness/flexibility, affordability, and sustainability. The GWRS reduced water consumption from 9-20% of total household use, and often met required fecal coliforms concentrations at several sites. However, the study revealed that neither GWRS met all the appropriate technology criteria and significant barriers preventing greywater reuse were identified. Both GWRS produced effluent that largely did not meet current regulations, were prone to mechanical failure, and did not provide any financial benefits, resulting in a varied level of acceptance among users. In addition, the systems resulted in increased green house gas emissions. The study also concluded that the regulations governing greywater quality for toilet flushing and the technology’s robustness must be further refined. / Federation of Canadian Municipalities, City of Guelph, and the Ontario Centres of Excellence

This report investigates sustainable solutions for electricity and water savings in an urban neighbourhood consisting of a block of buildings in Sege Park, Malmö. The solutions were evaluated in terms of sharing, producing, recycling and saving. The proposed solution includes a solar panel system on the available rooftop area for electricity production. Recycling and water savings includes collecting rainwater and reusing greywater for daily water demand in terms of flushing toilets, laundry and irrigation. Energy savings are achieved by using heat exchangers for space and water heating. Results from simulations in MATLAB and Excel showed that the electricity production reached a coverage ratioof 20% of the yearly consumption with hourly matching. However, the block has an excess electricity production, a total of 17,400 kWh, that does not correlate with the demand. Water demand for flushing toilets, laundering and irrigation during an average day can be matched by the reuse of greywater alone. Collection of rainwater is not required, although possible. The amount of reusable water, 18,540 litres a day, can cover the greywater need for three blocks equivalent to the one investigated. The conclusion is that water demand can be covered by greywater but electricity demand is too high for self-sustainability, even with the best solar panels available today.

At the rate the population is growing it is important to find ways to be more efficient with the energy and water we use. The increase in population increases the need for electricity and water, but the way we are using our sources will not leave us with enough for future generations. The constant use of "dirty energy", energy that emits CO2 and other chemicals into the atmosphere, will continue to harm our environment. A new system is needed to help preserve water and produce green energy that will not harm the only earth we have.

Advanced oxidation processes (AOPs) have been used to treat drinking water and wastewater but their application to greywater is limited to photocatalysis. Therefore, three homogeneous AOPs were investigated in this project: Fenton, photo-Fenton, and UVC/H2O2 processes. Alum and ferrous sulphate coagulation were also compared and their supernatants were treated by UVC/H2O2. The process comparisons were based on the removal of chemical oxygen demand (COD), treatment type (physical separation versus chemical oxidation), sludge formation, complexity in operation, required pH, visual aesthetic of effluent and energy requirement. Treating greywaters collected from the researcher's home or laboratory, alum coagulation achieved 73% COD removal and was more effective than ferrous sulphate coagulation (49%) and the Fenton process (45%). The photo-Fenton process removed 83% COD, compared with 87% by overnight settlement and subsequent UVC/H2O2 treatment. Using ferrous sulphate and alum, sequential coagulation and UVC/H2O2 treatment removed 91% and 98% COD, respectively. Overnight settlement generated little sludge and the subsequent UVC/H2O2 treatment removed most organic contaminants by oxidation. All other processes produced a large quantity of chemical sludge from coagulation which requires appropriate disposal. Also, the residual iron in some treated water was not aesthetically desirable. The Fenton and photo-Fenton processes were complex and involved the optimisation of multiple parameters. Their requirement for different procedures according to the greywater type presents a major challenge to process design and operation. Due to the non-selectivity of the hydroxyl radicals (●OH), the UVC/H2O2 process was capable of treating all greywaters collected by the researcher, and its operation was moderate in complexity. The COD removal was modelled as a pseudo first-order reaction in terms of H2O2 dosage: The rate constant (k´) increased linearly up to 10 mM H2O2, above which the excess H2O2 scavenged the ●OH and reduced the rate. The overall kinetics of COD removal followed a second-order equation of r = 0.0637 [COD][H2O2]. In contrast to the literature, operation of UVC/H2O2 in acidic conditions was not required and the enhanced COD removal at the initial pH of 10 was attributed to the dissociation of H2O2 to O2H-. Maintaining the pH at 10 or higher resulted in poorer COD removal due to the increased decomposition rate of H2O2 to O2 and H2O. The performance of the UVC/H2O2 treatment was unaffected for initial pH 3 - 10 with the initial total carbonate concentration (cT) of 3 mM. For initial cT ≥ 10 mM, operating between pH 3 and 5 was essential. After 3 hours of the UVC/H2O2 treatment, the effluent met the requirement of Class B reclaimed water specified by the Environment Protection Authority of Victoria, and less than 1 org/100 mL of Escherichia coli survived. A subsequent treatment such as filtration may be required to meet more requirements for biochemical oxygen demand (BOD5), turbidity and total suspended solids. Since the biodegradability (as BOD5:COD) of the greywater was increased from 0.22 to 0.41 with 2 hours of UVC/H2O2 treatment, its integration with a subsequent biological treatment may be viable to reduce the costs and energy consumption associated with the UVC/H2O2 process.

The purpose of this professional project is to address the practical implications of decentralized greywater usage in the City of Arroyo Grande. This professional project consists of two products: a brief greywater guide for the City and a background report. The greywater guide is intended for city planners to use for general information about greywater systems. The guide addresses Arroyo Grande’s potable water shortage; what greywater is; advantages and concerns about greywater use; plants that are tolerant and intolerant of greywater irrigation; appropriate detergents to use with a greywater system; and a summary of California greywater law. The background report discusses the City of Arroyo Grande’s potable water conditions and how water supply will be affected by growth projections for 2030. It is estimated that by the year 2030, Arroyo Grande’s water demand will outgrow its water supply by 283 acre feet. Future water shortages are a concern at a local level and also on a global level. Three case studies examine how water scarcity has prompted the successful use of greywater. These studies examine the Hashemite Kingdom of Jordan; the Casa del Agua project in Arizona; and a local study in Santa Barbara, California. The report concludes with California greywater law, and how the recent change in August, 2009 has greatly increased the legal accessibility of greywater reuse as an obtainable method of water conservation. In combination with education and outreach among city officials and residents, greywater has potential to play a main role in water conservation in Arroyo Grande.

<p>Greywater is domestic household wastewater without inputfrom the toilet, i.e. wastewater from sinks, the shower,washing machine and dishwasher in a home. Source separation ofgreywater can be a strategy to enhance recirculation of plantnutrients and/or improve water use. The risk for transmissionof disease when reusing greywater is largely dependent on thecross-contamination by faeces. High levels of faecalindicators, mainly thermotolerant coliform bacteria, have beenreported in greywater, indicating substantial faecal pollution.However, growth of indicator bacteria within the system leadsto an overestimation of thefaecal input and thus the hygienerisk. The faecal input of the greywater in Vibyåsen,Sollentuna, North of Stockholm, was estimated to be 0.04 ±0.02 g faeces person-1 day-1 from the quantification of thefaecal sterol coprostanol, compared to 65 g, 5.2 g and 0.22 gp-1 d-1 using E. coli, enterococci and cholesterolrespectively.</p><p>Prevalence of pathogens in the population and the faecalload based on coprostanol concentrations were used to form thebasis of a screening-level quantitative microbial riskassessment (QMRA) that was undertaken for rotavirus, Salmonellatyphimurium, Campylobacter jejuni, Giardia intestinalis andCryptosporidium parvum, looking at the treatment required to bebelow an acceptable level of risk (10-3) for reuse or dischargeof the greywater. The different exposure scenarios simulated–groundwater recharge, direct contact, irrigation andrecreational water–showed that a reduction of 0.7–3.7 log was needed for rotavirus, with the measured level offaecal load in Vibyåsen. The other pathogen of concern wasCampylobacter, where a 2.2 log reduction was needed forgroundwater recharge. The infectious dose of Salmonella is highand the excretion numbers of Giardia cysts and Cryptosporidiumoocysts low, resulting in no treatment requirements for theseorganisms under these circumstances. Pathogen input fromcontaminated food via the kitchen sink had a minor effect onthe microbiological quality of the greywater. Studies on virusoccurrence in greywater as well as validation of the faecalload of greywater at another site would give valuable input forfuture QMRAs.</p><p>Greywater treatment efficiency studies, especially on virusremoval, are scarce and more investigations are warranted.Active sludge may not be a suitable technique for greywater dueto the low carbon content in this flow. Chemical precipitationhas the advantage of removing phosphorus as well as virusesefficiently and it is suggested as one possible method fortreating greywater. Otherwise the most common practice forgreywater treatment in Sweden is soil infiltration. However, itis suggested that the recommendations for wastewaterinfiltration also be observed for greywater, despite the lowfaecal load, due to the simulated results on virus reductionneeded.</p><p><b>Key words:</b>greywater, greywater reuse, greywatertreatment, microbial risk assessment, groundwater recharge,irrigation, recreational water, faecal contamination, indicatorbacteria, index organisms, faecal sterols, bacteriophages,enteric pathogens, rotavirus, Salmonella, Campylobacter,Giardia, Cryptosporidium, Legionella</p>

Greywater is domestic household wastewater without inputfrom the toilet, i.e. wastewater from sinks, the shower,washing machine and dishwasher in a home. Source separation ofgreywater can be a strategy to enhance recirculation of plantnutrients and/or improve water use. The risk for transmissionof disease when reusing greywater is largely dependent on thecross-contamination by faeces. High levels of faecalindicators, mainly thermotolerant coliform bacteria, have beenreported in greywater, indicating substantial faecal pollution.However, growth of indicator bacteria within the system leadsto an overestimation of thefaecal input and thus the hygienerisk. The faecal input of the greywater in Vibyåsen,Sollentuna, North of Stockholm, was estimated to be 0.04 ±0.02 g faeces person-1 day-1 from the quantification of thefaecal sterol coprostanol, compared to 65 g, 5.2 g and 0.22 gp-1 d-1 using E. coli, enterococci and cholesterolrespectively. Prevalence of pathogens in the population and the faecalload based on coprostanol concentrations were used to form thebasis of a screening-level quantitative microbial riskassessment (QMRA) that was undertaken for rotavirus, Salmonellatyphimurium, Campylobacter jejuni, Giardia intestinalis andCryptosporidium parvum, looking at the treatment required to bebelow an acceptable level of risk (10-3) for reuse or dischargeof the greywater. The different exposure scenarios simulated–groundwater recharge, direct contact, irrigation andrecreational water–showed that a reduction of 0.7–3.7 log was needed for rotavirus, with the measured level offaecal load in Vibyåsen. The other pathogen of concern wasCampylobacter, where a 2.2 log reduction was needed forgroundwater recharge. The infectious dose of Salmonella is highand the excretion numbers of Giardia cysts and Cryptosporidiumoocysts low, resulting in no treatment requirements for theseorganisms under these circumstances. Pathogen input fromcontaminated food via the kitchen sink had a minor effect onthe microbiological quality of the greywater. Studies on virusoccurrence in greywater as well as validation of the faecalload of greywater at another site would give valuable input forfuture QMRAs. Greywater treatment efficiency studies, especially on virusremoval, are scarce and more investigations are warranted.Active sludge may not be a suitable technique for greywater dueto the low carbon content in this flow. Chemical precipitationhas the advantage of removing phosphorus as well as virusesefficiently and it is suggested as one possible method fortreating greywater. Otherwise the most common practice forgreywater treatment in Sweden is soil infiltration. However, itis suggested that the recommendations for wastewaterinfiltration also be observed for greywater, despite the lowfaecal load, due to the simulated results on virus reductionneeded. <b>Key words:</b>greywater, greywater reuse, greywatertreatment, microbial risk assessment, groundwater recharge,irrigation, recreational water, faecal contamination, indicatorbacteria, index organisms, faecal sterols, bacteriophages,enteric pathogens, rotavirus, Salmonella, Campylobacter,Giardia, Cryptosporidium, Legionella / NR 20140805