Use Of Greywater Research Articles

Health risk assessment along the wastewater and faecal sludge management and reuse chain of Kampala, Uganda: a visualization.

Reuse of wastewater in agriculture is a common feature in the developing world. While this strategy might contribute to the livelihood of farming communities, there are health risks associated with the management and reuse of wastewater and faecal sludge. We visualise here an assessment of health risks along the major wastewater channel in Kampala, Uganda. The visualization brings to bear the context of wastewater reuse activities in the Nakivubo wetlands and emphasises interconnections to disease transmission pathways. The contextual features are complemented with findings from environmental sampling and a cross-sectional epidemiological survey in selected exposure groups. Our documentation can serve as a case study for a step-by-step implementation of risk assessment and management as described in the World Health Organization's 2006 guidelines for the safe use of wastewater, greywater and excreta in light of the forthcoming sanitation safety planning approach.

Biomass production through grey water fertigation in eucalyptus hybrid and its economic significance

Bioenergy demand is accelerating day by day due to increase in population pressure whereas on other end worldwide water scarcity for irrigation is also becoming a challenge. This problem may be resolved through the fertigation with grey water for biomass production through short rotation intensive cultural plantation systems (SRICPS). The grey water generated from households constitutes the major portion of domestic wastewater with higher nutritive value. Reuse and recycling of grey water save natural water resources require for irrigation and moreover greywater use would be an added advantage to increase in the biomass due to its nutritive quality. Therefore, in present study, an experimental trial has been done for comparison of SRICPS biomass production within treatment (fertigated with greywater) and control (irrigated with bore well water) plots for biomass growth rate, biomass deficit and estimation of actual and potential biomass productivity with fertigation and control irrigation in same environmental condition by planting Eucalyptus hybrid (clone K‐413). Eucalyptus hybrid (clone K‐413) above ground biomass (AGBM) production per tree was observed to be 34.19 kg tree−1 in treatment plots as compared to 25.69 kg tree−1 in control plots during initial 2‐year of field observation and it envisages higher economic returns by fertigation due to higher biomass production per unit area as compared to control irrigation. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 222–226, 2015

Greywater use in Israel and worldwide: Standards and prospects

Water shortage around the world enhanced the search for alternative sources. Greywater (GW) can serve as a solution for water demands especially in arid and semi-arid zones. However, issues considered which include acceptability of GW segregation as a separate water treated stream, allowing its use onsite. Consequently, it is the one of next forthcoming water resources that will be used, primarily in the growing mega-cities. It will be even more rentable when combined with the roof runoff water harvesting and condensing water from air-conditioning systems. Reuse of GW is as well beneficial in the mega-cities subject to the high expenses associated with wastewater and fresh water conveyance in the opposite direction. The main problem associated with GW reuse is the quality of the water and the targeted reuse options. At least two main options can be identified: the public sector that is ready to reuse the GW and the private sector which raises extra issues related to the reuse risks. These risk stems from the on yard use of GW, relatively close to the household location.The main focus of the Israeli guidelines for GW use is on the private and single house. The problem is less rigorous in public facilities, where the amounts are relatively large and the raw GW is relatively diluted. The two main principles adopted for reuse are: (i) greywater can be minimally treated since it differs from the black wastes, and; (ii) no contact exists with the resident around. The aggravated standards are an indication of the sensitivity issues related to the problem.

Disinfection of E. Coli Contaminated Urine Using Boron-Doped Diamond Electrodes

We report the development of an electrochemical disinfection system for human urine, which does not require the addition of any external water or chemical reagents. It is designed to minimize energy consumption so that it may be powered from point-of-use sources such as photovoltaic solar panels. The system will be part of a modular outdoor toilet for use in less developed countries. Initial tests were conducted with a physiological saline solution and an organic dye to determine minimum-energy operating conditions. Disinfection was then quantified using synthetic urine and E. coli as the indicator organism. The colony forming unit (CFU) count of E. Coli was reduced from >109 CFU/100 mL to <1000 CFU/100 mL, World Health Organization permissible limits after treatment [World Health Organization, Guidelines for the safe use of wastewater, excreta and greywater, (2006)]. The effects of suspended fecal matter on disinfection efficiency were also studied.

Fresh and Hardened Properties of Sustainable Concrete Using Recycled Household Greywater

This study investigates the production of sustainable concrete mixes using recycled household greywater. Batches consisting of different mixes of cement pastes, mortar specimens, and concrete specimens were produced and tested for both fresh and hardened properties. The main variable was the type of water used for mixing and curing. The study showed that the use of greywater had little or no effect on the setting times of cement pastes, while the average workability of fresh concrete was slightly increased. The study also showed that the compressive strength of sustainable concrete was within 90 % of the standard control mix. Generally speaking, the combined results of compressive strength, splitting strength and drying shrinkage of the batches cured using greywater and mixed with either potable or greywater were within acceptable limits, provided that greywater conforms to the limits imposed by the applicable Codes and Standards typically imposed on potable water used in concrete.

Critical Review: Regulatory Incentives and Impediments for Onsite Graywater Reuse in the United States

Graywater is a potential water source for reducing water demand. Accordingly, a review was undertaken of graywater reuse regulations and guidelines within the 50 United States. Major issues considered included acceptability for graywater segregation as a separate wastewater stream, allowable graywater storage, onsite treatment requirements, and permitted graywater use applications. Existing regulations and plumbing codes in the different states suggest that there are impediments to overcome but also potential incentives for graywater reuse. It is encouraging that regulations in 29 states promote safe graywater reuse, but there are also inconsistencies between plumbing codes and other regulations within and among the 50 states. Impediments to graywater reuse include disallowances of graywater segregation or collection, and restriction of graywater reuse to mostly subsurface irrigation with limited indoor use permission. Ease on restrictions and guidelines to promote development of low-cost and proven treatment technologies are needed to promote graywater reuse.

A monitoring of environmental effects from household greywater reuse for garden irrigation

The option of reusing greywater is proving to be increasingly attractive to address the water shortage issue in many arid and semiarid countries. Greywater represents a constant resource, since an approximately constant amount of greywater is generated from kitchen, laundries, bathroom in every household daily, independent of the weather. However, the use of greywater for irrigation in particular for household gardening may pose major hazards that have not been studied thoroughly. In this study, a 1-year monitoring was conducted in four selected households in Perth, Western Australia. The aim of the monitoring works is to investigate the variability in the greywater flow and quality, and to understand its impact in the surrounding environments. Case studies were selected based on different family structure including number, ages of the occupants, and greywater system they used. Samples of greywater effluent (showers, laundries, bathtub, and sinks), leachate, soil, and plants at each case study were collected between October 2008 and December 2009 which covered the high (spring/summer) and low (autumn/winter) production of greywater. Physical and chemical tests were based on the literature and expected components of laundry and bathroom greywater particularly on greywater components likely to have detrimental impacts on soils, plants, and other water bodies. Monitoring results showed the greywater quality values for BOD, TSS, and pH which sometimes fell outside the range as stipulated in the guidelines. The soil analyses results showed that salinity, SAR, and the organic content of the soil increased as a function of time and affected the plant growth. Nutrient leaching or losses from soil irrigated with greywater shows the movement of nutrients and the sole impact from greywater in uncontrolled plots in case studies is difficult to predicted due to the influence of land dynamics and activities. Investigative and research monitoring was used to understand greywater irrigation in households. Greywater quality is very site specific and difficult to predetermine or control except for the use of some recommended household products when using greywater. Investigative and research monitoring was indicated that greywater quality is very site specific and difficult to predetermine or control except for the use of some recommended household products when using greywater.

Household greywater use practices in Melbourne, Australia

Research on the potential of greywater reuse to reduce urban tap water demand has focused mainly on permanently installed greywater treatment or irrigation systems. These may be readily implemented in new housing developments, but experience in Australia shows their uptake by established households in urban areas is low. The majority of households employ simple and temporary methods for greywater collection and use, but their behaviour has not been well documented. We characterised the greywater use practices of over 1,000 Melbourne households during a 5-year period (2007 to 2011) which included 3 years of severe drought with stringent restrictions on outdoor tap water use. Greywater was most frequently collected from the laundry and bathroom, and generally used within 24 hours. Garden watering was the most common end use, and treatment of greywater to reduce microbial contamination was very rare. Volume estimates by householders suggest that on average around 10% of tap water used in the home was being collected for reuse. When drought conditions and water restrictions eased, over 40% of user households discontinued greywater use. Widespread adoption of permanent greywater collection, treatment and storage systems by households would be required to achieve a lasting effect on urban water consumption.

Offsetting water conservation costs to achieve net‐zero water use

Achieving net‐zero water use (in which annual potable water use is no greater than annual rainfall) and achieving reasonable payback periods for water conservation measures were investigated for a proposed mixed‐use housing development in Davis, Calif. Water efficiency scenarios were analyzed for indoor water use and landscape watering, along with the use of graywater and rainwater on landscaping. Potential cost savings were found in both water utility reductions associated with water conservation and energy efficiency associated with decreases in hot water use. The feasibility of selling carbon offset credits in California's new cap‐and‐trade program by reducing greenhouse gas emissions associated with the water–energy nexus was also investigated. Results indicated the feasibility of achieving net‐zero water use at the scale of a single‐family residence and the entire community through indoor and landscaping water conservation measures without the need for graywater or rainwater reuse.

Greywater and Rainwater Management in Buildings

The concept of reusing wastewater and rainwater in buildings has recently become more important. There are countries where the use of greywater in some buildings has already been made mandatory (e.g. in Japan for toilet flushing). Such measures are gradually being introduced in the EU, where water recycling projects exist for office buildings and hotels. The Czech Republic still lacks experience and a design background in this area. The article is based on TAČR project No. TA01020311, titled “The use of grey and rain water in buildings”, and summarizes basic information about the quality of greywater, and methods of treating it and recovering its heat.

深刻な水不足下における家庭レベルでの複合的対策：ネパール国カトマンズ市における事例

Water scarcity is a fundamental challenge in many countries. Governmental efforts to address it are often insufficient, making it necessary that adequate household-level coping measures are taken. Using the Kathmandu Valley as a case study, we investigated household coping measures and factors influencing the selection of these measures. Further, we quantitatively estimated the potential amount for gray water use and rainwater harvesting as coping measures in the Kathmandu Valley. Interviews were conducted with 217 households on their water sources/uses and socioeconomic characteristics; 32 households were selected for a survey on the details of water consumption for different purposes using the diary method. Households with shorter periods of piped water supply tended to have a larger number of water supply sources to cope with water shortages. Household income was found to be a major factor influencing the selection of coping measures. The average water consumption was 36.9 ± 11.1 L/cap/day. To cope with water scarcity, the low-income group reduced their water consumption for bathing and laundry while maintaining their consumption for more essential activities such as hygiene and cooking. The study suggested that a 10,000-L water-storage tank for rainwater harvesting would be sufficient to meet the minimum requirement (50 L/cap/day) over a year if gray water use could be practiced in addition to piped water supply.

Comparison of response rates and cost-effectiveness for a community-based survey: postal, internet and telephone modes with generic or personalised recruitment approaches

BackgroundEpidemiological research often requires collection of data from a representative sample of the community or recruitment of specific groups through broad community approaches. The population coverage of traditional survey methods such as mail-outs to residential addresses, and telephone contact via public directories or random-digit-dialing is declining and survey response rates are falling. There is a need to explore new sampling frames and consider multiple response modes including those offered by changes in telecommunications and internet technology.MethodsWe evaluated response rates and cost-effectiveness for three modes of survey administration (postal invitation/postal survey, postal invitation/internet survey and postal invitation/telephone survey) and two styles of contact approach (personalised and generic) in a community survey of greywater use. Potential respondents were contacted only once, with no follow up of non-responders.ResultsThe telephone survey produced the highest adjusted response rate (30.2%), followed by the personalised postal survey (10.5%), generic postal survey (7.5%) and then the internet survey (4.7% for the personalised approach and 2.2% for the generic approach). There were some differences in household characteristics and greywater use rates between respondents to different survey modes, and between respondents to personalised and generic approaches. These may be attributable to the differing levels of motivations needed for a response, and varying levels of interest in the survey topic among greywater users and non-users. The generic postal survey had the lowest costs per valid survey received (Australian $22.93), followed by the personalised postal survey ($24.75).ConclusionsOur findings suggest that postal surveys currently remain the most economic option for population-based studies, with similar costs for personalised and generic approaches. Internet surveys may be effective for specialised groups where email lists are available for initial contact, but barriers other than household internet access still exist for community-based surveys. Given the increasing recruitment challenges facing community-based studies, there is an imperative to gather contemporary comparative data on different survey modes and recruitment approaches in order to determine their strengths, limitations and costs. Researchers also need to document and report on the potential biases in the target and respondent populations and how this may affect the data collected.

Grey Water Reuse for Agricultural Purposes in the Jordan Valley: Household Survey Results in Deir Alla

Installation of decentralized grey water treatment systems in small rural communities contributes to a more sustainable water supply. In order to gauge community attitudes about collection and use of grey water, a door-to-door survey in the farming community of Deir Alla, Jordan was conducted by Royal Scientific Society interviewers. Outcomes of a detailed survey, designed specifically for this project, offer insights on people’s views on general water and wastewater issues, as well as their motivation, practices and concerns related to using grey water treatment for a portion of their household wastewater and reuse of the treated grey water for irrigation. A total of 47 respondents from different socio-economic background, aged over 18 years, from this community in the Jordan valley took part in the survey. The level of formal education of the respondents was low, and most of households’ incomes were below the poverty line in Jordan. Most of the respondents reported that the quality of water supplied by public network is acceptable, but the quantity is insufficient to meet their demand, with supplies being delivered to the household once a week. Respondents relied on the public water network as a first-most important resource (85.1%), and 57.4% of the respondent relied on private water tankers as a second-most important resource in addition to the public network. However, 6% of the respondents relied only on private water tankers with no access to the public network. Storage tanks are common practice in all the houses in order to store enough water for at least one week. The survey responses provide evidence that rural communities are willing to accept reuse of treated grey water for irrigation. Furthermore, some of people in the studied area are willing to learn more about grey water treatment and reuse in order to operate grey water systems for irrigation purposes. Water scarcity in this rural area of Jordan is the main determinant of willingness to reuse the grey water, rather than socio-economic variables.

Effects of soil water content and organic matter addition on the speciation and bioavailability of heavy metals

The mobility and bioavailability of cadmium, copper, lead and zinc were evaluated in three soils amended with different organic materials for two moisture regimes. Agricultural and reclamation activities impose fresh inputs of organic matter on soil while intensive irrigation and rainstorm increase soil waterlogging incidence. Moreover, scarcity of irrigation water has prompted the use of greywater, which contain variable concentrations of organic compounds such as anionic surfactants.Soils added with hay, maize straw or peat at 1% w/w were irrigated, at field capacity (FC) or saturated (S), with an aqueous solution of the anionic surfactant Aerosol 22 (A22), corresponding to an addition of 200mgC/kgsoil/day. Soil solution was extracted after one month and analysed for total soluble metals, dissolved soil organic matter and UV absorbance at 254nm. Speciation analyses were performed with WHAM VI for Cd, Cu, Pb, and Zn. For selected scenarios, metal uptake by barley was determined.Metal mobility increased for all treatments and soils (Pb>Cu>Cd≥Zn) compared to control assays. The increase was significantly correlated (p<0.05) with soil organic matter solubilisation for Cd (R=0.68), Cu (R=0.73) and Zn (R=0.86). Otherwise, Pb release was related to aluminium solubilisation (R=0.75), which suggests that Pb was originally co-precipitated with Al–DOC complexes in the solid phase. The effect of A22 in metal bioavailability, determined as free ion activities (FIA), was mainly controlled by soil moisture regime. For soil 3, metal bioavailability was up to 20 times lower for soil amended with hay, peat or maize compared to soil treated only with A22. When soil was treated with A22 at FC barley yield significantly decreased (p<0.05) for the increase of Pb (R=0.71) and Zn (R=0.79) concentrations in shoot, while for saturated conditions such uptake was up to 3 times lower.Overall, metal bioavailability was controlled by solubilisation of soil organic matter and formation of metal-organo complexes.

Critical Review: Present Onsite Graywater Reuse Regulatory Incentives and Impediments in the United States

Critical Review: Present Onsite Graywater Reuse Regulatory Incentives and Impediments in the United StatesGraywater reuse has been identified as a potential water source for reducing water demand. Accordingly, a review of graywater reuse regulations/guidelines within the fifty United States was undertaken. Major issues considered included acceptability for segregation of graywater as a separate wastewater stream, allowable graywater storage, onsite treatment requirements, and permitted graywater use...Author(s)Zita L.T. YuAnditya RahardiantoJ.R. DeShazoMichael K. StenstromYoram CohenSourceProceedings of the Water Environment FederationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Sep, 2012ISSN1938-6478DOI10.2175/193864712811725483Volume / Issue2012 / 15Content sourceWEFTECCopyright2012Word count179

Development of guidance for sustainable irrigation use of greywater in gardens and small-scale agriculture in South Africa

Greywater is untreated household effluent from baths, showers, kitchen and hand-wash basins and laundry (i.e. all non-toilet uses). More than half of indoor household water is normally used for these purposes and can potentially be intercepted by the householder for additional beneficial uses. Greywater use is practised on an informal basis to supplement irrigation water, either in urban gardens in middle- to upper-income suburbs or in food gardens in lower-income informal, periurban and rural areas. It holds the potential to contribute significantly to food security in poor settlements by providing a source of both irrigation water and nutrients for crop plants. However, there are presently no formal guidelines for the use of greywater in South Africa. This paper presents the rationale and framework of a guidance document for the sustainable use of greywater to irrigate gardens and small-scale agriculture in South Africa, developed under the auspices of the Water Research Commission. The 3 driving principles in developing this guidance were: protection of human health; protection of plants irrigated; and protection of soil and the environment. Risk-management scenarios were developed on the basis of the extent of greywater characterisation. Water-quality constituents for inclusion were selected from among those indicated as presenting a problem in previous studies. Guidance was provided for managing greywater quality, either by mitigation of greywater quality (by practices such as irrigation method, amelioration of soil, leaching of soil and planting of tolerant plant types) or by small-scale biological treatment of greywater. Guidance was also given regarding the volumes of greywaterwhich can be applied, together with factors to adjust these volumes for site-specific conditions.Keywords: greywater, irrigation, food security, sustainable agriculture, health, soil, plant growth

USING QUANTITATIVE MICROBIAL RISK ASSESSMENT (QMRA) FOR SAFE GREYWATER REUSE

Background and Aims: Use of greywater for irrigating home gardens may potentially decrease domestic water consumption by over 50%, while contributing to sustainable garden irrigation in arid regions and in times of drought. Despite these important advantages, greywater reuse may also hold potential risks for public and environmental health. Pathogens in the water may spread disease through direct contact, consumption of produce, or may be transferred by vectors such as mosquitoes. The aim of the current study was to assess risks associated with on-site greywater reuse. Methods: A quantitative microbial risk assessment (QMRA) framework (Haas et al, 1999) was used for the assessment of three pathogens; Rotavirus, Pseudomonas aeruginosa, and Staphylococcus aureus. Different theoretical and empirical exposure and risks scenarios were tested. Results: Given the correlation between Rotavirus and E. Coli (WHO, 2006), it was postulated that in a single household, a maximum level of 102 E. coli CFU/100 ml is safe based on the World Health Organization acceptable risk of 1.4*10-3 for Rotavirus infection. The risk from P. aeruginosa and S. aureus in the tested exposure scenarios was so low, that it seems unnecessary to include them in the regulations. To reduce exposure level and consequently the risk, barriers such as subsurface drip irrigation, prohibition of irrigation of vegetables that are consumed raw, and washing hands with soap, should be used. Conclusions: As long as basic regulatory rules are maintained, greywater reuse in a single household poses little risk to public health. A similar approach should be taken towards the establishment of quantitative risk assessment for environmental pollutants such as salinity, organic matter and metals.

Potential fresh water saving using greywater in toilet flushing in Syria

Greywater reuse is becoming an increasingly important factor for potable water saving in many countries. Syria is one of the most water scarce countries in the Middle East. However, greywater reuse is still not common in the country. Regulations and standards for greywater reuse are not available. Recently, however, several stakeholders have started to plan for greywater reuse. The main objective of this paper is to evaluate the potential for potable water saving by using greywater for toilet flushing in a typical Syrian city. The Sweida city in the southern part of Syria was chosen for this purpose. Interviews were made in order to reflect the social acceptance, water consumption, and the percentage of different indoor water uses. An artificial wetland (AW) and a commercial bio filter (CBF) were proposed to treat the greywater, and an economic analysis was performed for the treatment system. Results show that using treated greywater for toilet flushing would save about 35% of the drinking water. The economic analyses of the two proposed systems showed that, in the current water tariff, the payback period for AW and CBF in block systems is 7 and 52 years, respectively. However, this period will reduce to 3 and 21 years, respectively, if full water costs are paid by beneficiaries. Hence, introducing artificial wetlands in order to make greywater use efficient appears to be a viable alternative to save potable water.

Rethinking water management: From centralised to decentralised water supplyand sanitation models

Since the second half of the 19th Century, centralised water and sanitation systems have been expanding all over the world. However, the limitations of this model are becoming increasingly obvious and, in recent times, a renewed interest for decentralised approaches is emerging owing to the capacity of decentralised systems to enhance water security and minimise environmental degradation. The decentralised alternatives explored in this paper include the use of rainwater harvesting and greywater reuse at the household level. This paper analyses the main distinctive features of decentralised water supply and sanitation systems and the main requirements to achieve a successful transition to decentralised water management.

Increasing Resource Efficiency through Residential Greywater Use

To support population growth, a viable fresh water supply, supporting water and wastewater treatment infrastructure, and electric capacity is needed. Historically the answer to growing demand was to build more reservoirs, however; viable potential sites are not plentiful. In addition, infrastructure for water supply and treatment is difficult, expensive, and time-consuming to develop. Greywater use offers the opportunity to stretch our water supply and electrical capacity through dual water use and less treatment. Greywater may offer a viable solution to increasing water supplies in the near term as we plan and development new water resources. This research identifies the potential impacts of greywater toilets on a large scale in two communities that are considering building additional water storage capacity. The use of greywater toilet systems in new and existing homes in these communities could potentially support new residential growth for 3.4 years in these areas. This could reduce the pressure on the existing water system while the new water supply infrastructure and electrical capacity are developed. This time extension may also support water saving technology development, thus further reducing water demand. A case study identifies possible savings from greywater toilets in reducing the demand on existing water resources.