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)

PhD (Environmental Sciences) / Department of Hydrology and Water Resources / See the attached abstract below

This research investigates interacting biological, chemical, and physical factors affecting the efficiency of microbiological wastewater treatment at the W. J. Smith Wood- Preserving Company in Denison, Texas. The treatment process consisted of collecting exhaust boiler water containing unidentified boiler treatment compounds, steam condensate contaminated with preservatives and wood extracts, plant process waters, and rainfall runoff from plant grounds. With a 5-minute residence time, wastewater was passed over 2 oxidation towers in series, each containing approximately 47,000 square feet of surface area. Suspended solids were removed from the wastewater before discharge. Various amino acids such as serine, aspartate, cysteine, phenylalanine, alanine, proline, glycine, histidine, and tyrosine significantly stimulated phenol degradation in the laboratory. The plant wastewater contained approximately 0.1 mg/l of several of the stimulatory amino acids. It was assumed that these concentrations provided maximal stimulation in the field situation. The plant wastewater also contained sufficient nitrogen to permit the organisms to degrade up to 100 mg phenol/1 of water examined. Amino acids in the wastewater probably serve as a source of microbial nutrition. Toxicity of the wastewater to fish was not caused by the presence of phenol, phenol degradation products, or traces of pentachlorophenol. The wastewater was rendered non-toxic by diluting with between 4 to 9 volumes of stream water. Toxicity could also be removed by chemical coagulation followed by activated carbon adsorption. As a result of biological treatment, the plant now discharges the treated wastewater into the municipal sewage treatment facility.

<p>Drainage water recycling (DWR) is the practice of capturing, storing, and reusing subsurface drained agricultural water to support supplemental irrigation and has recently been proposed as a practice for improving the crop production and water quality performance in the tile-drained landscape of the U.S. Midwest. This study describes the development of a modeling framework to quantify the potential irrigation and water quality benefits of DWR systems in tile-drained landscapes and the application of the model using ten years of measured weather, tile drain flow and nutrient concentrations, water table, and soil data from two sites in the U.S. Midwest. From this modeling framework, the development and testing of an open-source online tool is also presented.</p><p></p><p>A spreadsheet model was developed to track water flows between a reservoir and drained and irrigated field area at each site. The amount of tile drain flow and associated nutrient loads that could be captured from the field and stored in the reservoir was estimated to calculate the potential water quality benefits of the system. Irrigation benefits were quantified based on the amount of applied irrigation annually. A reservoir size representing 6% to 8% of the field area with an average depth of 3.05 m was sufficient in meeting the annual irrigation requirements during the 10-year period at each site. At this reservoir size, average annual nitrate-N loads were reduced by 20% to 40% and soluble reactive phosphorus loads by 17% to 41%. Variability in precipitation within and across years, and differences in soil water characteristics, resulted in a wide range of potential benefits at the two sites.</p><p>An online tool was developed from the model, and a variance-based global sensitivity analysis was conducted to determine influential and low-sensitivity input parameters. The input parameter, depth of root zone, was the most influential input parameter suggesting that the estimation of total available water for the field water balance is a critical component of the model. Input settings describing the irrigation management and crop coefficients for the initial establishment and mid-season crop growth periods were also influential in impacting the field water balance. Reservoir seepage rate was influential in regard to the reservoir water balance, particularly at larger reservoir sizes. Sensitivity analysis results were used to develop a user-interface for the tool, Evaluating Drainage Water Recycling Decisions (EDWRD).</p><p>This study shows that DWR is capable of providing both irrigation and water quality benefits in the tile-drained landscape of the U.S. Midwest. The developed modeling framework supports future research on the development of strategies to implement and manage DWR systems, and the online tool serves as a resource for users to increase their awareness and understanding of the potential benefits of this novel practice.</p><p></p>

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)

The Master’s Thesis deals with the application of membrane technologies in the production of drinking water from the effluent of a municipal wastewater treatment plant (WWTP). There were two types of pressure-driven membrane processes selected – ultrafiltration and reverse osmosis, to achieve water production of the required quality. For the needs of the diploma thesis, an already existing pilot-scale membrane unit of the ASIO TECH Company l.t.d. was used. There were 44 physical, chemical and microbiological parameters observed to assess the quality of the produced water and also the input water (effluent from the WWTP). None of the afore mentioned parameters exceeded the limit values, more specifically the highest limit values issued by the Decree 70/2018 Coll. However, the produced water cannot be considered as drinking water because of its low mineralisation. Before its potential application in practise, it is therefore necessary to choose an appropriate method of remineralisation as well as to follow all the other legislative requirements for the drinking water, which have already been out of the scope within the Master’s Thesis.

M. Tech. (Department of Civil Engineering and Building, Faculty of Engineering and Technology), Vaal University of Technology. / Potable water quality can deteriorate immensely from point of treatment to point of usage. This change in quality along a bulk distribution main may be attributed to numerous factors, such as the ingress of storm water. Furthermore, water utilities experience challenges in terms of the microbiological organisms that are not attributed to operational practices. For example, drinking water bulk distribution mains may be a shelter for these microorganisms that are sustained by organic and inorganic nutrients present within the pipe itself. These microorganisms may be active in the water being transported by the pipe, and can cause a significant drop in the water quality. In order to deal with the problem of deteriorating water quality, sufficient information within the bulk main is required, so that the consumer can be protected from ingesting contaminated water or water of poor quality. Hence, the overall objective of this study was to investigate and model water quality characteristics within the Modimolle reticulation network. Water samples were collected from various points throughout the entire system for quality analysis. Different sampling points were established along the main pipeline as well as within the Modimolle distribution system. Water quality software, EPANET, was then used to model the water quality deterioration for both the bulk line and the reticulation network of Modimolle extension 11. Residual chlorine was the main parameter which was monitored. This study presents results of a research on water quality variation within a long distribution mains conveying water up to 87 km. Results show that raw residual chlorine is constantly depleted along the pipeline, and is therefore unable to be maintained at the required level of 0.2 mg/l, as stipulated by the Department of Water Affairs. This means that if any harmful contaminants should enter the water, the residual chlorine in the water will not be able to protect the consumers from the contaminants.

The subject of water scarcity and the rate of water consumption has become popular topics over the last few decades. It is possible that society may consume or contaminate much of the remaining readily available water if there is not a paradigm shift. This deep rooted concern has prompted investigations to identify alternative water use and treatment methods. Within this report, information is presented from the use of innovative water harvesting and on-site sewage treatment and disposal systems (OSTDS) at Florida’s Showcase Green Envirohome (FSGE.net), while also addressing low impact development (LID) practices. FSGE is a residential home that demonstrates methods that use less water and reduce pollution. Population increases have more than just an effect on the volume of water demanded. Adverse impacts on surface and groundwater quality are partially attributed to current design and operation of OSTDS. Nutrient loading from wastewater treatment systems may be a concern where numerous OSTDS are located within nutrient sensitive environments. Groundwater nitrate concentrations have been shown to exceed drinking water standards by factors of three or greater surrounding soil adsorption systems (Postma et al., 1992, Katz, 2010). As a contribution to efforts to reduce water use and improve water quality, this study investigates the viability and effectiveness of a residential integrated stormwater, graywater, and wastewater treatment system (ISGWTS) installed and operating for over a year at FSGE. ii Within this report is a continuation of results published previously that consisted of preCertificate of Occupancy (pre-CO) data and an optimization model at the Florida’s Showcase Green Envirohome (FSGE) in Indialantic, Florida (Rivera, 2010). This current report contains 12 months of post-CO data, along with data from bench scale models of the on-site septic treatment and disposal system (OSTDS). There are two main objectives of the study. The first objective is to quantify the performance of the passive treatment Bold & GoldTM reactive filter bed (FDOH classified “innovative system”) for nutrient removal. The second objective was to monitor the water quality of the combined graywater/stormwater cistern for non-potable use and assess the components (green roof, gutters, graywater piping). The performance of the passive innovative system is compared to past studies. Also a bench scale model that is constructed at the University of Central Florida (UCF) Stormwater Management Academy Research and Testing Lab (SMART Lab) is operated to provide data for two different retention times. Complex physical, biological, and chemical theories are applied to the analysis of wastewater treatment performance. The data from the OSTDS and stormwater/graywater cistern are assessed using statistical methods. The results of the OSTDS are compared to FDOH regulatory requirements for “Secondary Treatment Standards”, and “Advanced Secondary Treatment Standards” with promising results. The bench scale results verify that both nitrogen and phosphorus removal are occurring within the filter media and most likely the removals are due to iii biological activity as well as physiochemical sorption. The flow into the OSTDS has been reduced with the use of separate gray water system to only 29 gallons per person per day (gpcd). After the FSGE certificate of occupancy and for one year using the Bold & Gold Biosorption Activated Media (BAM), the TSS, BOD5, and CBOD5 are below the required 10 mg/L for the FDOH classified Advanced Secondary Treatment Systems. The effluent for the conventional drain field TSS, BOD5, and CBOD5 are above 10 mg/L (29.6, 35.7, and 29.0 mg/L). The effluent total nitrogen and total phosphorus for the innovative system are 29.7 mg/L and 4.1 mg/L, which are not low enough for the 20 mg/L nitrogen requirements, but are below the 10 mg/L phosphorus requirements. The conventional drain field has an effluent total nitrogen concentration of 70.1 mg/L and an effluent total phosphorus concentration of 10.6 mg/L, which both fail to meet FDOH Advanced Secondary Treatment requirements. The high nitrogen in the effluent can be attributed to high influent concentrations (about 3 times the average at about 150 mg/L). Longer residence times are shown to produce a removal greater than 90%. Also, nitrate average levels were below the 10 mg/L standard. The combined stormwater/graywater cistern is analyzed against irrigation standards. The graywater is filtered and disinfected with ozone to provide safe water for reuse. Nutrient concentrations are measured to compare with regulatory standards. For irrigation standards, salinity in the form of sodium, calcium, and magnesium are measured. Although high sodium adsorption ratio (SAR) and electrical conductivity (EC) values were recorded, their adverse iv impact on the vegetation has not been observed. . The only observed effect within the home to date is scale formation in the toilet. The use of potable water in FSGE is reduced to 41 gpcd using the integrated stormwater and graywater system. A minor volume of backup artesian well water was added to the cistern during the one year home occupancy phase. Based on less use of potable water and at the current potable water cost rate, the integrated stormwater and graywater system at FSGE will save the typical homeowner about $215 per year. If irrigation were used more often from the cistern, the cost savings in reduced potable water used for irrigation would increase the savings. The treatment cost for B&G BAM over a 40 year period of time based on a flow of 29 gpcd (as measured at FSGE) and for 4 persons is $2.07 per thousand gallons treated. The yearly cost of treatment is about $87.65. There is a reduction in potable water use estimated at 64% of the sewage flow (or 18.5 gpcd) which equates to about 27 thousand gallons in one year. The current average cost of potable water is $4.40 per thousand gallons. Based on reduced potable water usage, the savings per year are about $118.84. Thus the yearly savings in potable water cost ($118.84) offsets the cost of OSTDS treatment at FSGE for nutrient control ($87.65) using the data collected at FSGE. This comparison does not include the inflation cost of water over time. There is also an environmental preservation intangible cost (not quantifiable from this study) from reduced surface runoff and reduced pollutant discharges.

Water reuse has become a promising alternative to alleviate stress on conventional freshwater resources in the face of population growth, sea level rise, source water depletion, eutrophication of water bodies, and climate change. Potable water reuse intentionally looks to purify wastewater effluent to drinking water quality or better through the development and implementation of advanced treatment trains. While membrane-based treatment has become a widely-adopted treatment step to meet this purpose, there is growing interest in implementing treatment trains that harness microorganisms as a more sustainable and less energy-intensive means of removing contaminants of emerging concern (CECs), through biological degradation or transformation. In this dissertation, various aspects of the operation of a microbially-active carbon-based advanced treatment train producing water intended for potable reuse are examined, including fate of dissolved organic carbon, underlying microbial populations, and functional genes are explored. Further, dynamics associated with antibiotic resistance genes (ARGs), identified as a microbially-relevant CECs, are also assessed. Overall, this dissertation advances understanding associated with the interplay between and within treatment processes as they relate to removal of various organic carbon fractions, microbially community dynamics, functional genes, and ARGs. Further, when relevant, these insights are contextualized to operational conditions, process upsets, water quality parameters, and other intended water uses within the water industry with the goal of broadening the application of advanced molecular tools beyond the scope of academic research. Specifically, this dissertation illuminates relationships among organic carbon fractions and molecular markers within an advanced treatment train employing flocculation, coagulation, and sedimentation (FlocSed), ozonation, biologically active carbon (BAC) filtration, granular active carbon (GAC) contacting, and UV disinfection. Biodegradable dissolved organic carbon (BDOC) analysis was adapted specifically as an assay relevant to assessing dissolved organic carbon biodegradability by BAC/GAC-biofilms and applied to profile biodegradable/non-biodegradable organic carbon as wastewater effluent passed through each of these treatment stages. Of particular interest was the role of ozonation in producing bioavailable organic carbon that can be effectively removed by BAC filtration. In addition to understanding the removal of fractionalized organic carbon, next generation DNA sequencing technologies (NGS) were utilized to better understand the microbial dynamics characteristic of complex microbial communities during disinfection and biological treatment. Specifically, this analysis was focused on succession and colonization of taxa, genes related to a wide range of functional interests (e.g. metabolic processes, horizontal gene transfer, DNA repair, and nitrogen cycling), and microbial CECs. Finally, NGS technologies were employed to assess the differences between a wide range of water use categories, including conventional drinking water, potable reuse, and non-potable reuse effluent's microbiomes to identify core and discriminatory taxa associated with intended water usage. The outcomes of this dissertation provide valuable information for optimizing carbon-based treatment trains as an alternative to membrane-based treatment for sustainable water reuse and also advance the application of NGS as a diagnostic tool for assessing the efficacy of various water treatment technologies for achieving treatment goals. / Doctor of Philosophy / Several factors have led to increased stress on conventional drinking water sources and widespread global water scarcity. Projections indicate that continued population growth, increased water demand, and degradation of current freshwater resources will negatively contribute to water needs and underscore the need to secure new potable (i.e. fit for human consumption) sources. Water reuse is a promising alternative to offset the growing demands on traditional potable sources and ameliorate negative consequences associated with water scarcity. Discharge of treated wastewater to marine environments is especially a lost opportunity, as the water will no longer be of value to freshwater habitats or as a drinking water source. Water reuse challenges the conventional wastewater treatment paradigm by providing advanced treatment of wastewater effluent to produce a valuable resource that can be safely used directly for either non-potable (e.g., irrigation, firefighting) or potable (i.e., drinking water) applications. The means of achieving advanced treatment of wastewater effluents can take many forms, commonly relying on the utilization of membrane filtration. However, membrane filtration is an intensive process and suffers from high initial costs, high operational costs, membrane fouling with time, and the production of a salty and difficult to dispose of waste stream. These drawbacks have motivated the water reuse industry to explore more sustainable approaches to achieving high quality effluents. One such alternative relies on the utilization of microorganisms to provide biological degradation and transformation of contaminants through a process known as biologically active filtration (BAF). Comparatively to membrane systems, BAF is more cost effective and produces significantly fewer byproducts while still producing high quality treated water for reuse. However, the range in quality of the resulting treated water has not yet been fully established, in part due to the lack of understanding of the complex microbial communities responsible for biological treatment. As water and wastewater treatment technologies have evolved over the past century, many biological treatments have remained largely 'black box' due to the lack of effective tools to identify the tens of thousands of species of microbes that inhabit a typical system and to track their dynamics with time. Instead, analysis has largely focused on basic water quality indicators. This dissertation takes important steps in advancing the implementation of the study of DNA and biodegradable organic carbon (BDOC) analysis to improve understanding of the mechanisms that drive different water reuse treatment technologies and to identify potential vulnerabilities. Insights gained through application of these tools are contextualized to observed operational conditions, process upsets, and water quality measurements. This helped to advance the use of DNA-based tools to better inform water treatment engineering practice. Specifically, this dissertation dives into the relationships between organic carbon and DNA-based markers within an advanced treatment train employing flocculation, coagulation, and sedimentation (FlocSed), ozonation, biologically active carbon (BAC) filtration, granular active carbon (GAC) contacting, and UV disinfection. Development and application of the BDOC test revealed that the bulk of organic carbon entering the treatment train is dissolved. Further, BDOC analysis served to characterize the impact of specific treatment processes and changes in operational conditions on both biodegradable and non-biodegradable organic carbon fractions. Such information can help to inform continued process optimization. Utilization of DNA-based technologies shed light on the functional capacity of microbial communities present within each stage of treatment and the fate of antibiotic resistance genes (ARGs). ARGs are of concern because, when present in human pathogens, they can result in the failure of antibiotics to cure deadly infections. Other functional genes of interest were also examined using the DNA-based analysis, including genes driving metabolic processes and nitrogen cycling that are critical to water purification during BAF treatment. Also, the DNA-based analyses made it possible to better understand the effects of disinfectants on microbes. Interestingly, some ARG types increased in relative abundance (a measure analogous to percent composition) response to treatments, such as disinfection, and others decreased. Characterization of the microbial communities and their dynamic response to changing operation conditions were also observed. For example, it was possible to characterize how the profiles of microbes changed with time, an ecological process called succession, during BAC filtration and GAC contacting. Generally, this analysis, coupled with the functional analysis, shed light on the important, divergent roles of bacterial communities on organic degradation during both BAC and GAC treatment. Finally, a study was conducted that compared the microbiome (i.e. entire microbial community) between a wide range of conventional drinking water, potable reuse water, and non-potable reuse waters. Here it was found that significant differences existed between the microbial communities of water intended for potable or non-potable usage. This work also looked to expand the application of NGS technologies beyond strictly academic research by developing the application of more advanced DNA-based tools for treatment train assessment and monitoring.

Lau Wai Kee Albert. / "Architecture Department, Chinese University of Hong Kong, Master of Architecture Programme 2000-01, design report." / On double leaves. / Includes bibliographical references. / Chapter Chapter 1 --- Prologue --- p.1 / Definition of the unseen space --- p.2 / Unseen space in the city --- p.3 / Chapter Chapter 2 --- Justification of selected unseen space --- p.4 / Definition of nullah --- p.6 / Surface transformation of the nullah --- p.8 / People perception of the nullah --- p.10 / People perception of wastewater --- p.12 / Chapter Chapter 3 --- Justification of site selection --- p.15 / Site analysis --- p.18 / Transportation character --- p.22 / Chapter Chapter 4 --- Physical identity of nullah --- p.25 / Intrinsic meaning of nullah --- p.26 / Chapter Chapter 5 --- Philosophy of nullah --- p.30 / Concept --- p.34 / Project mission --- p.38 / Conceptual strategy --- p.39 / Chapter Chapter 7 --- Philosophical meaning of water --- p.46 / People perception to water --- p.50 / Basic concept in water space design --- p.52 / Chapter Chapter 8 --- Precedent study --- p.56 / Urban rivers --- p.57 / Local rivers --- p.66 / Chapter Chapter 9 --- Design ideas --- p.68 / Appendix / Water quality of Kai Tak nullah --- p.75 / Annual rainfall --- p.76 / "Interview with Dr. Chung, Dept. of Biology, CUHK" --- p.78 / Biblography --- p.80