As human population increases, the need for water increases in domestic, agricultural, industrial and urban sectors. Wastewater reuse after treatment is gaining acceptance world wide, as availability of fresh water sources decreases. However, it is also important to point out social and cultural differences that still exist in different pars of the world including those where reuse of wastewater for food production or any domestic use is not yet acceptable. The major concerns with effluent reuse are primarily its impact on human health and environmental risk. As a result, effluent reuse should be undertaken with caution after careful consideration of the potential impacts and risks. This thesis examined the potential to use the hydroponics nutrient film technique to grow commercially important crops using secondary-treated domestic wastewater. The crops chosen were a fruit crop (Lycopersicon esculantum - tomato), a leafy crop (Beta vulgaris ssp. cicla - silver beet) and a flower crop (Dianthus caryophyllus - carnation). Secondary-treated domestic wastewater was chosen because of the reduced risk of pathogen and heavy metal contamination in the crops and due to the guideline requirements for use of treated effluent for food crops. The possibility of using the effluent after the hydroponics treatment for further irrigation was also studied. The ability of secondary-treated effluent to supply adequate nutrients to the crops was assessed relative to a commercially available hydroponics solution (Chapter 3). The amount of time the solution was left in the system (nutrient solution retention time) was dependant on the plant uptake of the solution. The results obtained showed that the nutrients in secondary treated effluent was adequate for the carnations, but not for the food crops. The food crops from both treatments were compared to the produce purchased from a supermarket. The food crops showed signs of nutrient deficiency, particularly nitrogen. Based on the findings of the first experiment, the nutrient solution retention time was amended to 14 days. The carnations were not tested with the shorter nutrient solution retention time (NSRT) because they performed well in the previous trial with the longer nutrient solution retention time. The edible food crops performed better and did not show signs of nutrient deficiency when the nutrient solution retention time was reduced to 14 days. Further statistical analysis was conducted with the data from Chapters 3 and 4. Nutrient and water balances were calculated and the possible reason that the plants grown in the 14-day nutrient solution retention time took up more water, was a result of increased nutrients and better growth. A simple model was constructed to calculate height of the plants using multiple regression. The model was validated against the data collected from this study. The experiment conducted in Chapter 6 determined the nutritional quality of the food crops. The harvests from the wastewater and commercially available hydroponics solution were compared to produce purchased from a supermarket and tested for total caroteniods, total soluble solids and ascorbic acid concentrations. The nutritional quality of the wastewater grown produce was comparable to those grown in the hydroponic solution and those purchased. The risk of pathogen contamination to food crops and the die-off of pathogens in the hydroponic channels were studied in Chapter 7. This was tested by spiking the commercial hydroponic medium with Escherichia coli and Salmonella typhimurium and monitoring bacterial pathogen die-off in the secondary treated domestic wastewater. The pathogen quality of the crop was tested in all treatments as well as on organically grown produce found at a local supermarket. The results of this experiment did not show any contamination on the surface of the food crops or within the food crops. This study demonstrated that growing tomatoes, silver beet and carnations using secondary-treated domestic wastewater was successful when the nutrient solution retention time was adjusted to the optimum level. In arid, developing and remote communities, this system is ideal as it conserves and reuses water for commercially important crops without compromising the health of the environment or of human beings. It can also be implemented in urban areas, as the system can be scaled according to the availability of space. In addition to this, the effluent after going through this system can be used for open irrigation as it meets the World Health Organisation guidelines. However, a number of additional concerns need further investigation. They include the transmission risk of other types of pathogen, which depends on the source of wastewater, and the effects of hormones and antibiotics on food crops and their effect on human health.

Master of Science / Civil Engineering / David R. Steward / With an increasing population, municipalities in the United States are struggling to secure safe, reliable water sources for future water demands. Alternative water sources are being considered to improve the overall water management picture. Wastewater reuse, reusing wastewater effluent for beneficial purposes, is an alternative water source that is gaining popularity in the United States. In this study a theoretical framework was developed to enable a region to quickly assess the feasibility of reusing wastewater for irrigation needs. Three criteria were established for the framework; they are, regulations and guidelines for reuse, adequate flow ratio, and cost benefit analysis. As a region moves through the framework and criteria a list of feasible wastewater facilities and end users are established. A model was developed for the cost benefit analysis based on regional input. As regulatory frameworks and economic factors evolve over time the model can be updated to assess how these changes will affect water reuse in a region. The model will provide a useful tool for a region to integrate wastewater reuse into the water resource management process. The Lower Arkansas River Basin (LARK) was highlighted by the Kansas Water Office as a region that should investigate the role of reuse in water conservation. Results from this report indicate 963 million gallons per year (MG/yr) of wastewater effluent could feasibly be used to irrigate 9 hole and 18 hole golf courses in the region. The results determined that any 18 hole golf course within a 15.9 mile radius of a wastewater treatment facility in the LARK could payback the capital costs for wastewater reuse within 10 years. This information is a useful tool for the region to start the discussion for implementing wastewater reuse in the region. The results from this report indicate wastewater reuse for golf course irrigation is economically feasible in the LARK. Establishing a safe reliable water source for the future is paramount to the future of Kansas. Future research is needed to determine how the wastewater diversion affects the environmental balance of the permitted discharge location.

The risk of the Iraq’s marshlands disappearing is still high unless serious measures are adopted. Sewage discharge and irrigation-water pressure, compounded by the effects of climate changes and the extent of the planned dam construction in upstream countries, make this event more likely. Most of the marshlands’ inhabitants (Marsh Arabs) are suffering from lack of access to safe, clean water and lack of sanitation and are reluctant to look for better places to live and work. Constructed wetlands are among the best alternatives to solve their problems. The application of constructed wetlands to meet more stringent standards for wastewater reuse in agriculture contributes to mitigating the wastewater impact and irrigation pressure on the marshland ecosystem. It is here proposed that a 3.6 ha free-surface flow wetland  could manage the more stringent standard for reuse (15 mg/l) for BOD5 and TSS. A monitoring programme should nevertheless be associated with this kind of project to minimize health risks that may arise as a result of implementation. Despite the absence of studies that deal with wastewater reuse in irrigation projects at the national level (in Iraq), similar studies worldwide provide evidence of reuse possibilities. Furthermore, a performance requirements framework for wastewater reuse in irrigation projects such as the one suggested by Biswas, draws an approach to meet sustainable development indicators and would likely contribute to support and encourage the Marsh Arabs to settle back in their own areas.

Bromide and nitrogen are wastewater effluent constituents that have raised concern for their potential to affect disinfection byproduct (DBP) formation at drinking water treatment plants (DWTPs) downstream of wastewater discharges. Despite the toxicity of brominated and nitrogenous DBPs, wastewater treatment does not usually remove bromide and nitrogen prior to discharge. Bromide is a conservative chemical and thus is not removed from surface waters via natural transformations after being released, although it may be diluted. Nitrogen is biologically reactive; it can be transformed and removed by bacteria in the environment and in wastewater treatment plants (WWTPs). While this nitrogen cycling may reduce impacts on downstream DWTPs, it also produces nitrous oxide (N2O), a greenhouse gas, as a byproduct. Thus, interaction with the environment alters the potential impact of bromide and nitrogen on drinking water systems. The objective of this work was to examine the impacts of nitrogen and bromide present in wastewater effluent on DBP formation at downstream DWTPs, within the context of current and possible future DBP regulations. Three major conclusions were reached. First, within Southwestern Pennsylvania, an area where surface water bromide concentrations have increased due to fossil fuel extraction-based wastewater discharge, no statistically significant improvement in species-specific risk was observed over the past 20 years, despite decreasing TTHM levels. Second, nitrogen treatment decisions at WWTPs influence the formation of N-nitrosodimethylamine (NDMA), an unregulated but toxic DBP, at downstream DWTPs in areas of high de facto reuse (DFR). More plants using nitrifying wastewater treatment resulted in significantly lower NDMA detection rates and concentrations observed at chloraminating DWTPs located downstream. Third, the current approach to estimating national emissions of N2O related to wastewater treatment may underestimate emissions by an order of magnitude. Further, nitrogen removal at wastewater treatment plants reduces total N2O emissions attributable to wastewater treatment by reducing the N2O that would be generated in receiving surface waters. Thus, in both cases, impacts of WWTPs on downstream DWTP DBPs were observable. While natural cycling may remove nitrogen from surface water, in-plant removal of nitrogen prevents large amounts of N2O emissions.

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Many countries, including South Africa, are facing the reality of insufficient water supplies to meet their present and future water demands due to decreasing freshwater availability and increasing demand. Increased populations and climate changes further exacerbate the problem. South Africa is considered the thirtieth driest country in the world with limited supplies of water which are unevenly distributed. Thus there is a need for alternative water sources to augment the freshwater supply. Wastewater reuse has been identified worldwide as a viable option to augment water supplies. While technologies are available to ensure proper treatment of wastewater to even potable standards, many countries have experienced public resistance to wastewater reuse due to negative perceptions of consumers. For wastewater reuse initiatives to be successful public acceptance is imperative. The aim of this study was to assess perceptions of consumers in the Vaal Triangle on wastewater reuse. This is the first study conducted in the Vaal Triangle on wastewater reuse hence this information can be valuable in future when wastewater reuse projects are implemented A questionnaire to measure perceptions of consumers on wastewater reuse was developed based on previous studies and distributed to people residing in the Vaal Triangle area. A response rate of 74% (515 completed questionnaires) was obtained from 700 distributed questionnaires. The results showed that socio-demographic factors such as age, race, qualification and level of employment affect the perceptions of consumers on wastewater reuse. Additionally, knowledge of wastewater reuse and water scarcity had a positive effect on consumer‟s perceptions. Some of the major reasons why consumers are not receptive to wastewater reuse are health concerns, lack of trust in the implementing agencies, poor management of the plants and safety of chemicals used to treat the water. Lack of knowledge on wastewater reuse was raised as a major concern in the study. All these concerns need to be addressed to ensure success of wastewater reuse projects within the area. Limitations within the study were identified and recommendations for future research were made. / MBA, North-West University, Potchefstroom Campus, 2015

Many countries, including South Africa, are facing the reality of insufficient water supplies to meet their present and future water demands due to decreasing freshwater availability and increasing demand. Increased populations and climate changes further exacerbate the problem. South Africa is considered the thirtieth driest country in the world with limited supplies of water which are unevenly distributed. Thus there is a need for alternative water sources to augment the freshwater supply. Wastewater reuse has been identified worldwide as a viable option to augment water supplies. While technologies are available to ensure proper treatment of wastewater to even potable standards, many countries have experienced public resistance to wastewater reuse due to negative perceptions of consumers. For wastewater reuse initiatives to be successful public acceptance is imperative. The aim of this study was to assess perceptions of consumers in the Vaal Triangle on wastewater reuse. This is the first study conducted in the Vaal Triangle on wastewater reuse hence this information can be valuable in future when wastewater reuse projects are implemented A questionnaire to measure perceptions of consumers on wastewater reuse was developed based on previous studies and distributed to people residing in the Vaal Triangle area. A response rate of 74% (515 completed questionnaires) was obtained from 700 distributed questionnaires. The results showed that socio-demographic factors such as age, race, qualification and level of employment affect the perceptions of consumers on wastewater reuse. Additionally, knowledge of wastewater reuse and water scarcity had a positive effect on consumer‟s perceptions. Some of the major reasons why consumers are not receptive to wastewater reuse are health concerns, lack of trust in the implementing agencies, poor management of the plants and safety of chemicals used to treat the water. Lack of knowledge on wastewater reuse was raised as a major concern in the study. All these concerns need to be addressed to ensure success of wastewater reuse projects within the area. Limitations within the study were identified and recommendations for future research were made. / MBA, North-West University, Potchefstroom Campus, 2015

Increasing freshwater scarcity is making reclamation of wastewater effluent more economically attractive as a means of preserving freshwater resources. The use of an integrated membrane system (IMS), the combination of micro/ultra-filtration (MF/UF) followed by reverse osmosis (RO) membranes, represents a key process for municipal wastewater reuse. A major drawback of such systems is the fouling of both the MF/UF and RO membranes. The water to be treated by the IMS system varies from one wastewater treatment plant (WWTP) to another, and its fouling propensity changes correspondingly. It is thus preferable to conduct pilot trials before implementing a full-scale plant. This thesis aims to look at the sustainability of IMS technology dedicated to indirect potable reuse (IPR) in terms of fouling minimisation and cost via a 600 m3 .d- 1 pilot plant. Wastewater reuse plants, using IMS, as well as statistical methods for membrane optimisation were reviewed. Box-Behnken design was used to define optimum operating envelopes of the pilot plant for both the microfiltration and the reverse osmosis in terms of fouling minimisation. Same statistical method was used to enhance the efficiency of the MF cleaning-in place through bench-scale test. Data from the pilot plant MF process allow to determine relationship between reversible and irreversible fouling, and operating parameters and feed water quality. Life cycle cost analysis (LCCA) of the both trains (MF/RO/AOP and MF/AOP) of the pilot plant was performed and compared with the LCCA of two full-scale plant.

O recurso água é de primordial importância para a vida, para a sociedade e para os processos industriais. A redução da disponibilidade de água, devido ao aumento de sua demanda, à poluição das bacias hidrográficas e à escassez de fontes limpas, pressionam os órgãos reguladores a elaborar leis que restrinjam seu consumo, a criar normas que controlem o despejo de efluentes e aplicar tarifas que elevem o custo do uso da água. Portanto, técnicas de conservação e reúso são elementos importantes para as empresas reduzirem seus custos e contribuírem positivamente com o desenvolvimento sustentável. O objetivo deste trabalho é apresentar um estudo de caso real que visa à redução no consumo de água em uma unidade industrial do setor Químico. Serão aqui descritos os processos industriais envolvidos, as necessidades e especificações associadas, as metodologias utilizadas para construção do cenário atual de consumo e para o desenvolvimento das propostas de reúso. O trabalho mostra que existem oportunidades de modificações nos processos de digestão, de destilação, de recuperação de produtos e de drenagens que implicariam uma redução no consumo de água, em economia financeira com uma taxa de retorno atrativa e com retorno do investimento em um curto espaço de tempo. / Water is essential for life, for society and for industrial processes. Any decrease in availability, as a consequence of increased demand and/or pollution of its sources, puts pressure on the regulating agencies to create specific legislation in order to restrict water consumption, control effluent discharge and to apply tariffs that raise the cost of water use. Therefore, wastewater reuse techniques are very important for companies to reduce costs and contribute to sustainable development. The objective of this project is to discuss the reduction of water consumption in a chemical industrial unit. The procedure covers the study of the industrial process pertaining to water, its requirements and specifications, the strategies applied to address the water/wastewater allocation issue. Finally, the project presents opportunities for modifications to some specific operation units such as digestion, distillation, product recovery and draining processes, which lead to a decrease in fresh water consumption and wastewater generation. Besides the environmental benefits, the company achieves financial savings as well as good relations with local community.

The imbalance between global population growth and resource consumption is indicative of unsustainable practices and foreshadows a grim future of continued resource depletion, food and water scarcity, social inequality, and deteriorating public and environmental health. Meanwhile, the urban centers of the world continue to experience exponential growth resulting in overwhelmed food, water, and sanitation infrastructure. Decentralized and satellite wastewater treatment technologies capable of resource recovery, such as anaerobic membrane bioreactors (AnMBR), foster synergistic opportunities to help manage the food, energy, and water sectors of urban environments. Specifically, the nutrient concentration and high effluent quality of permeate produced by AnMBR systems present applicability in controlled environment agriculture (CEA). The efficacy of AnMBR permeate is evaluated in a hydroponics growth study of cucumber (Cucumis sativus) grown in an outdoor greenhouse and tomato (Lycopersicon lycopersicum) grown indoors. Nutrient analysis of permeate generated by a small, pilot scale AnMBR developed for the treatment of domestic wastewater at ambient temperature indicated sufficient concentrations of N and P elements, however high proportion of NH4+ in N species decreased growth performance. Opportunities for optimizing AnMBR permeate for hydroponics applications exist and thus imply synergistic integration of decentralized AnMBR technology with controlled environment agriculture (CEA) such as hydroponics. A model is proposed for the integration of decentralized AnMBR and CEA systems capable of producing usable plant products within the urban environment. The integration of these systems is proposed as a solution to the challenges of with food security, stressed water supplies, and environmental degradation associated with unchecked urban growth in the developing and developed world