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.

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.

<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>

Thesis (MSc. (Geography and Environmental Science)) -- University of Limpopo, 2015. / Fresh water is a finite and vulnerable resource, essential to sustain life, development and the environment. Growth in population and economic activities have contributed to water scarcity, which is a frequent challenge in rural and township communities in South Africa. This study aimed at investigating onsite greywater reuse as a water conservation method in Lepelle-Nkumpi local municipality, Limpopo province. The study described the socio-economic characteristics, assessed the accessibility and availability of water supply, and ascertained the coping mechanisms for water scarcity as well as the perceptions and reuse of greywater. Four percent respondents each were selected from two settlements, namely, Mashite village and Lebowakgomo township (Zone F). Mashite village had a population size of 5314 people (1231 households) and Lebowakgomo Zone F had 5903 people and (1924 households). A systematic random sampling method was used to select the required households from the two settlements. Both open and close ended questionnaires were used. A Geographical Positioning System was also used to collect the absolute location of available taps in the study area. Data collected were analysed using SPSS version-22 and Arc GIS 10.1. The study found out that the socio-economic characteristics of importance on onsite greywater reuse included highest qualification, household size and employment status, but they varied in these two areas. In Mashite village the majority of the respondents went to secondary school (59%) as compared to Lebowakgomo Zone F where the majority (72%) attained tertiary qualification. Household size mean in Mashite is 6.18 as compared to Lebowakgomo Zone F (2.77). Sixty four percent of respondents in Mashite village were unemployed, whereas in Lebowakgomo 69% were employed. Water usage in the two areas differed; in Mashite village where they use less water (250 to 840 litres) as compared to Lebowakgomo Zone F, where more water is used (5900 to 8001 litres). In Mashite village, 87% of the respondents could not access water due to inaccessibility of taps and unavailability of water as compared to Lebowakgomo zone F (100%). It was also found that the Mashite community sometimes go for a period of two to three months without tap water whereas in Lebowakgomo water was comparatively regular. As a result both communities resorted to rainwater harvesting and greywater reuse. Seventy six percent (76%) of respondents in Mashite village and 30% of the respondents in ii Lebowakgomo Zone F harvested rainwater as a coping mechanism of water scarcity. Perceptions of greywater reuse were higher (76%) in Lebowakgomo Zone F compared to Mashite village (49%). A higher percentage of Mashite village respondents (98%) reuse greywater compared to Lebowakgomo Zone F respondents (59%). Both areas use greywater as water conservation method. These results reinforce the potential of domestic greywater reuse as an alternative for freshwater requirement. Greywater reuse as a water conservation method especially in villages can be used to alleviate the extent of water scarcity. / National Research Foundation (NRF)

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

Thesis (M. Sc. (Geography)) -- University of Limpopo, 2021 / Great interests in the geographical dimensions of poverty, food security, natural resources such as land and water, and livelihoods have been motivated by global efforts of reducing poverty and food insecurity, as part of the millennium development agenda. The achievement of household food security is a major concern facing the world at large, including South Africa due to the lack of land and water resources availability and accessibility. The study aimed at evaluating the potential reuse of greywater to improve household food security in two villages of Fetakgomo Local Municipality. The objectives of the study were to establish background characteristics, determine household food accessibility and availability, assess the reuse of greywater in relation to home gardening activities, ascertain the perceptions on greywater reuse and lastly to determine the household food security status of the households. The study adapted a mixed research approach and a 4% sample size was used. Ninety five and seventy eight households were randomly selected for Ga-Seroka and Ga-Nkwana villages, respectively. Data was collected using a structured questionnaire and the results were analysed using Statistical Package for the Social Sciences (SPSS) version-23 software. General Household Survey (GHS) in combination with Household Food Insecurity Access Scale (HFIAS) were used to assess household food security status of the two villages. The key results revealed that background characteristics of importance on greywater reuse include household size, educational level and employment status even though they varied in these two areas. Accessibility and availability of food was found to be more of a challenge in Ga-Seroka village than in Ga-Nkwana village. Respondents from Ga-Seroka village reused their greywater more as they drained it directly into their gardens. According to the HFIAS classification measure, 85% and 73% of households were categorised as least food insecure, 15% and 26% as medium food insecure and 0% and 1% as severely food insecure in Ga-Nkwana and Ga-Seroka villages respectively. Ga-Seroka village respondents preferred to reuse their greywater more often as compared to respondents in Ga-Nkwana village and were not reluctant to use it in their gardens. In conclusion, reuse of greywater has a potential to improve household food security. There is a need for the government to subsidize the households with incentives such as quality seeds and fertilizers in order to enhance their productivity and thus improving their household food security. Keywords: Food security, availability, accessibility, land, water, Fetakgomo Local Municipality, greywater reuse. / National Research Foundation (NRF)