<p>The purpose of this study was to investigate the various types of onsite greywater treatment facilities available at two housing communities (Hull Street and Moshoeshoe Eco Village) in Kimberley, South Africa. The objective was to undertake a close observation through personal experience of the installations, measure water consumption and greywater produced, do an inventory of household cleaning chemicals and conduct interviews of different stake-holders of the Housing Project to find out their views on greywater and Ecosan issues. The study was conducted between June and August 2006.</p><p>The average water consumption per household per day during the study period was 272 L and 170 L in Eco Village and Hull Street respectively. The average greywater produced per household per day was 190 L and 119 L in Eco Village and Hull Street respectively. In Hull Street, the average water consumed and greywater produced per person per day during this study was 51L and 36L respectively. Three main types of treatment systems were installed in the study area; sandfilters, infiltration pits and resorption trenches. The sandfilters were poorly designed and were not functioning properly. The infiltration pits though working they were experiencing problems of poor infiltration and required constant draining and maintenance in many homes, especially those that have high water consumption and produce much greywater. The resorption trenches that make use of aerobic mulch media followed by infiltration had been installed in one house unit and after about 7 months had not presented problems to the user. Close monitoring done on this facility for about 4 weeks showed proper functioning according to its design.</p><p>Quite a lot had been done over time to improve on the installations in Hull Street and Eco village. The toilet installations have been exchanged and a number of alternatives to improve on the treated greywater have been attempted. The users and the housing company’s personnel feel one of the major problems being encountered is in treating greywater. Appropriate ways to compost faecal matter are still being sought. Hence use of greywater, urine and composted faeces in urban agriculture by residents is yet to be visible and will need encouragement.</p><p>Generally, the residents at Hull Street and Eco Village like the community life, house structures and location. However, they wish that improvement be made in some areas to make life in these areas more comfortable. The residents of both Hull Street and Eco Village expect better greywater treatment facilities. The community in Hull Street requests shopping centres, sport facilities, fence around the area, and taxi services among others. It is important to note that many people did not ask for further improvements on the toilet systems which might indicate they are coping with the urine diversion alternative sanitation.</p><p>The user perception on whole was good, but the need for constant attention and maintenance seems to offer a hurdle to the infiltration and sand filter facilities to treat greywater.</p>

As water stresses increase across the U.S., interest in household water reuse is growing. Such reuse typically focuses on light greywater, that is all wastewater generated in the house excluding toilet waste and kitchen wastewater. As this practice becomes more widespread, higher level reuse is expected to require greater greywater treatment prior to reuse. Membrane bioreactors (MBRs) are an attractive technology for this application because they offer a robust combination of treatment processes and are already used in some households in countries such as Japan. This research sought to understand the role of phosphorus availability in determining the quality of effluent from MBR treatment of light greywater because phosphorus concentrations are expected to be low with phosphorus phased out of many consumer products. Less than 30 [mu]g/L of dissolved orthophosphate was present in synthetic greywater made from three common household products, and no measurable amount of dissolved orthophosphate was found in real greywater, but low concentrations of particulate phosphate were detected. These concentrations were well below levels believed necessary to achieve full BOD₅ removal in biological treatment. Nevertheless, MBR performance was not adversely affected until no supplemental phosphorus was provided. Measurement of extracellular enzyme activity showed an increase in the ratio of phosphatase activity to total glycosidase activity with declining phosphorus concentration, providing an early indication of nutrient stress before changes in effluent water quality were detected. Removal of three xenobiotic organic compounds (XOCs) in treatment of synthetic greywater was also evaluated under conditions of phosphorous limitation and balance. Abiotic removal mechanisms were not deemed to be important, but removal of methylparaben and sodium lauryl sulfate via biodegradation responded to nutrient limitation similarly to overall COD removal while removal of diethyl phthalate was affected to a greater extent. Measurement of plasmid DNA concentrations was evaluated as a potential indicator of the effect of nutrient limitation on plasmid-mediated biodegradation of XOCs. An overall reduction in the plasmid content was observed in all cases under conditions of phosphorus limitation; however, the extent of reduction was reactor dependent. / text

The reuse of domestic greywater for toilet flushing has the potential to reduce both water consumption and wastewater production, but there is a need for low-cost, low-maintenance greywater treatment systems that can meet reclaimed water quality standards. The purpose of this thesis is to develop a horizontal subsurface flow wetland design that can be sited in a greenhouse, to document the initial performance of the design treating real greywater, to determine the effect of plants, and to provide recommendations for design. Pilot wetlands (planted and unplanted replicates) were constructed in a passively heated greenhouse and fed real domestic greywater. Effluent quality was compared to national reclaimed water quality guidelines. After the first five months of the study, operational changes (reduced loading, aeration of influent, fill and drain) were tested to determine their effect on effluent quality. The results show that the original design basis, 7.5 gBOD m-2d-1, is not appropriate for greywater wetland design under the conditions of this study due to insufficient removal of BOD and turbidity (although suspended solids removal was acceptable). Anoxic conditions within the wetlands led to reduction of sulfate to hydrogen sulfide, which demands oxygen and leads to odour and turbidity problems. Plants did not affect treatment during the first five months. Aerating influent and operation in fill and drain mode may improve BOD removal at relatively high hydraulic loading rates, but effluent disinfection is required to completely remove E.coli. Design recommendations were developed, including tentative loading rates and plant species. / Ontario Centres of Excellence, NSERC

In recent years, the increasing awareness of scarcity of water resources, indications of likely climate variability, and the increasing pressure to use available fresh water resources more efficiently have together reinforced the need to look at infrastructure solutions with due regard to environmental considerations and social impacts, present and future. There is a vital need to apply an integrated approach to catchment management to implement sustainable solutions to resolve issues such as water supply and sewerage, drainage and river flooding. Many potentials solutions are available to control water demand and manage flood problems. Greywater recycling and rainwater harvesting are novel technologies. However, their catchment scale impacts on hydraulic and hydrological flows are poorly understood. The research aim is to identify the hydrologic and hydraulic impacts of scaling up such technologies at catchment scale. For this particular study, a computer simulation model will be used to evaluate how increasing urbanisation, climate change and the implementation of greywater recycling and rainwater harvesting may alter the water balance within a representative catchment. To achieve these aims data from the Carrickmines catchment in Ireland have been collected; a simulation model has been adapted to carry out the study, the model has been calibrated and validated, results have been analysed, and finally, a sensitivity analysis has been carried out. The results show that rainwater harvesting systems are comparatively more effective than greywater recycling techniques in reducing flood frequency and intensity. Under five year return period rainfall events, the implementation of rainwater harvesting at any scale and number of units is a useful technique to control river flow and floods. However, the study also shows that under extreme conditions the efficiency of rainwater harvesting systems decreases. The study concludes that implementing the two technologies within a single catchment is not a solution to several forms of hydrological problem. The study shows that implementing rainwater harvesting or re-use technologies are a very useful way to protect local freshwater reserves and therefore conserve our environment.

The Hull Street Integrated Housing Project, in Kimberley, is one of the projects supported by the Swedish International Development Cooperation Agency, Sida, in South Africa. The vision of the project is to provide low cost housing for the people of Kimberley. As a way of ensuring sustainability, the project adopts the Ecological sanitation (Ecosan) approach where urine and faeces are separated from the source. The concept of Ecosan is new to many people around the world. To make the concept workable and acceptable effective implementation strategies are required. At the Hull Street, after the first of the four phases 144 unit houses have been completed all fitted with the UDS. Urine from the UDS as well as the greywater from the kitchen and bathroom are connected to infiltrate into the ground. This arrangement is called the “quick-fix”. The faeces from the houses are sent to the compost yard for composting so that the residents could use the compost in their gardens. This study which involves interview with some selected workers and residents in Hull Street focuses on the modus operandi of the Ecosan unit of the Hull Street project with special emphasis on the methods of human excreta disposal and education strategies.

The purpose of this study was to investigate the various types of onsite greywater treatment facilities available at two housing communities (Hull Street and Moshoeshoe Eco Village) in Kimberley, South Africa. The objective was to undertake a close observation through personal experience of the installations, measure water consumption and greywater produced, do an inventory of household cleaning chemicals and conduct interviews of different stake-holders of the Housing Project to find out their views on greywater and Ecosan issues. The study was conducted between June and August 2006. The average water consumption per household per day during the study period was 272 L and 170 L in Eco Village and Hull Street respectively. The average greywater produced per household per day was 190 L and 119 L in Eco Village and Hull Street respectively. In Hull Street, the average water consumed and greywater produced per person per day during this study was 51L and 36L respectively. Three main types of treatment systems were installed in the study area; sandfilters, infiltration pits and resorption trenches. The sandfilters were poorly designed and were not functioning properly. The infiltration pits though working they were experiencing problems of poor infiltration and required constant draining and maintenance in many homes, especially those that have high water consumption and produce much greywater. The resorption trenches that make use of aerobic mulch media followed by infiltration had been installed in one house unit and after about 7 months had not presented problems to the user. Close monitoring done on this facility for about 4 weeks showed proper functioning according to its design. Quite a lot had been done over time to improve on the installations in Hull Street and Eco village. The toilet installations have been exchanged and a number of alternatives to improve on the treated greywater have been attempted. The users and the housing company’s personnel feel one of the major problems being encountered is in treating greywater. Appropriate ways to compost faecal matter are still being sought. Hence use of greywater, urine and composted faeces in urban agriculture by residents is yet to be visible and will need encouragement. Generally, the residents at Hull Street and Eco Village like the community life, house structures and location. However, they wish that improvement be made in some areas to make life in these areas more comfortable. The residents of both Hull Street and Eco Village expect better greywater treatment facilities. The community in Hull Street requests shopping centres, sport facilities, fence around the area, and taxi services among others. It is important to note that many people did not ask for further improvements on the toilet systems which might indicate they are coping with the urine diversion alternative sanitation. The user perception on whole was good, but the need for constant attention and maintenance seems to offer a hurdle to the infiltration and sand filter facilities to treat greywater.

[ES] Un porcentaje significativo de la energía se destina a la producción de Agua Caliente Sanitaria (ACS) en el sector comercial y residencial. Además, la mayor parte de la energía que contiene el agua se desperdicia en el ambiente tras su uso. Las bombas de calor han sido identificadas por su capacidad de producir ACS con una alta eficiencia y son una gran alternativa hacia la descarbonización de las ciudades. Además, son capaces de utilizar como fuente de calor, el calor contenido en el agua que actualmente se desperdicia. Sin embargo, la aplicación del uso de bombas de calor para ACS recuperando el calor de las aguas residuales presenta unas características diferentes a las usuales en bombas de calor. Por tanto, es necesario un análisis del problema más profundo y se require mayor investigación al respecto con el fin de lograr un desarrollo eficiente de la misma: 1. Un diseño de bomba de calor capaz de operar con alta eficiencia ante los grandes saltos de temperatura que tienen lugar en esta aplicación (ACS). 2. Un diseño de bomba de calor capaz de operar con alta eficiencia ante saltos de temperatura del fluido secundario variables (recuperación de calor). 3. La integración de esta bomba de calor en un sistema de ACS completo (estrategias de recuperación de calor, componentes, tamaño y estrategia de control). Normalmente, los ciclos transcríticos han sido considerados como una de las mejores soluciones para la producción de ACS (donde se tienen grandes saltos de temperatura en el agua, 10-60°C). Sin embargo, este tipo de ciclo presenta dos desventajas principales, la necesidad de altas presiones en la instalación y la dependencia de la eficiencia con el salto de temperatura del agua en el condensador. Sin embargo, los ciclos subcríticos han demostrado un gran potencial para saltos de temperatura del agua variables si se aplica un control del subenfriamiento adecuado. El objetivo de esta tesis es investigar la bomba de calor agua-agua más eficiente trabajando con un ciclo de refrigerante subcrítico para la producción de ACS utilizando como fuente de calor el calor disponible en las aguas residuales (a baja-media temperatura) para determinar el sistema más eficiente para este tipo de aplicación. El trabajo se divide en dos partes diferenciadas: ¿ Diseño de la bomba de calor El desarrollo de la bomba de calor es una continuación del trabajo realizado en la tesis de M. Pitarch [1]. En dicha tesis, se investigó el papel del subenfriamiento en una bomba de calor subcrítica para la apliación de ACS. Se desarrolló un prototipo de bomba de calor con el diseño de dos configuraciones distintas en función del modo en el que se realizaba el subenfriamiento. Los resultados permitieron concluir que este tipo de bombas de calor (subcríticas) eran capaces de operar con eficiencias similares a las de las bombas de calor basadas en ciclos transcríticos si se opera con un grado de subenfriamiento óptimo. Sin embargo, en ambas configuraciones se requiere un componente más que en las bombas de calor convencionales. En esta tesis, se ha realizado un estudio y análisis teórico de la bomba de calor. Se ha desarrollado e implementado una estrategia de control para el subenfriamiento y se ha construído el prototipo de bomba de calor propuesto en [1]. De todo este trabajo se ha obtenido el diseño de bomba de calor basada en ciclos subcríticos más interesante para este tipo de aplicaciones. ¿ Diseño e integración de la Bomba de Calor y el sistema de ACS La integración del prototipo seleccionado en un sistema para la producción de ACS con recuperación del calor de las aguas residuales ha sido analizada.El sistema más simple y eficiente necesario para este tipo de aplicaciones (producción de ACS con recuperación de calor de las aguas grises) se compone de un intercambiador de calor (recuperador), una bomba de calor con subenfriamiento optimizado y dos depósitos de almacenamiento. / [CAT] Un percentatge significatiu de l'energia es destina a la producció d'Aigua Calenta Sanitària (ACS) en el sector comercial i residencial. A més, la major part de l'energia que conté l'aigua es malgasta en l'ambient després del seu ús. Les bombes de calor han sigut identificades per la seua capacitat de produir ACS amb una alta eficiència i són una gran alternativa cap a la descarbonització de les ciutats. A més, són capaços d'utilitzar com a font de calor, el calor contingut en l'aigua que actualment es desaprofita. Contribuint així, a aconseguir un sector energètic més respectuós amb el Medi Ambient. No obstant això, l'aplicació de l'ús de bombes de calor per a ACS recuperant el calor de les aigües residuals presenta unes característiques diferents de les usuals en bombes de calor. Per tant, és necessari una anàlisi del problema més profund i es requereix una major investigació al respecte amb la finalitat d'aconseguir una alta eficiència: 1.Un disseny de bomba de calor capaç d'operar amb alta eficiència davant dels grans salts de temperatura presents en aquesta aplicació (ACS). 2.Un disseny de bomba de calor capaç d'operar amb alta eficiència davant de salts de temperatura del fluid secundari variables (recuperació de calor). 3.La integració d'aquesta bomba de calor en un sistema d'ACS complet (estratègies de recuperació de calor, components, grandària i estratègia de control). Normalment, els cicles transcrítics han sigut considerats com una de les millors solucions per a la producció d'ACS (on es tenen grans salts de temperatura en l'aigua, 10-60°C). No obstant això, aquest tipus de cicle presenta dos desavantatges principals, la necessitat d'altes pressions en la instal·lació i la dependència de l'eficiència amb el salt de temperatura de l'aigua en el condensador i evaporador. L'objectiu d'aquesta tesi és investigar la bomba de calor aigua-aigua més eficient treballant amb un cicle de refrigerant subcrític per a la producció d'ACS utilitzant com a font de calor el calor disponible en les aigües residuals (a baixa-mitja temperatura) per a determinar el sistema més eficient en aquest tipus d'aplicació. El treball es dividix en: ¿ Disseny de la bomba de calor El desenvolupament de la bomba de calor és una continuació del treball realitzat en la tesi de M. Pitarch [1]. En aquella tesi, es va investigar el paper del subrefredament en una bomba de calor subcrítica per a l'apliació d'ACS. Es va desenvolupar un prototip de bomba de calor amb el disseny de dues configuracions distintes en funció de la manera en què es realitzava el subrefredament. Els resultats van permetre concloure que aquests tipus de bombes de calor (subcrítiques) eren capaços d'operar amb eficiències semblants a les de les bombes de calor basades en cicles transcrítics si s'opera amb un grau de subrefredament òptim. No obstant això, en ambdues configuracions es requereix un component més que en les bombes de calor convencionals. En la present tesi, es va realitzar un estudi i anàlisi teòric de la bomba de calor. Es va desenvolupar i implementar una estratègia de control per al subrefredament i es va construir el prototip de bomba de calor proposat en [1]. De tot aquest treball s'ha obtingut el disseny de bomba de calor basada en cicles subcrítics més interessant per aquest tipus d'aplicacions. ¿Disseny i integració de la Bomba de Calor i el sistema d'ACS La integració del prototip seleccionat en un sistema per a la producció d'ACS amb recuperació de el calor de el calor de les aigües residuals ha sigut analitzada.El sistema més simple i eficient necessari per a aquest tipus d'aplicacions (producció d'ACS amb recuperació de calor provinent d'aigües grisas) està compost per un bescanviador de calor (recuperador), una bomba subrefredada i dos depòsits d'emmagatzemament. / [EN] A significant percentage of energy is destined to produce Domestic Hot Water (DHW) within the building sector. Furthermore, most of that energy contained in the water is wasted to the ambient after its use. Heat pumps have been clearly identified as an efficient technology for DHW production, and as a main vector towards future de-carbonization of cities. In addition, they could use the heat from the wastewater as a heat source. Thus, contributing in two ways towards a more environmentally friendly energetic sector. However, the use of heat pumps for DHW recovering heat from wastewater faces several challenges that require further analysis and development: 1. A heat pump design capable to operate with high performance when variable secondary temperature lifts at the heat sink take place. 2. A heat pump design capable to operate with high performance when variable secondary temperature lifts at the heat source take place. 3. The integration of the heat pump within a system (heat recovery strategies, components, sizing, operation strategy). Usually, transcritical cycles have been considered the most suitable cycle for DHW production (high temperature lifts of the heat sink, 10-60°C). However, this cycle involves several drawbacks as for instance the requirement of high pressures in the installation or a significant reduction of the performance with the increase of water inlet temperature at the condenser. Instead, subcritical cycles have demonstrated great potential for DHW applications if a proper control of subcooling is performed. The objective of this thesis is to investigate the most efficient water-to-water heat pump working with a subcritical cycle for DHW production using as a heat source wasted heat at medium-low temperature and to determine the most efficient system based on heat pumps for this application. The work is divided in two differentiated parts: ¿ Heat pump concept This development is a continuation from the PhD work of M. Pitarch [1]. In that PhD work, the role of the subcooling in the performance of a subcritical heat pump for DHW applications was investigated. Two different configurations of a heat pump prototype were designed based on the way subcooling was made. The results showed that a subcooling optimized subcritical heat pump was able to provide comparable performance than present HPs employing transcritical cycles. However, both configurations require one more component than usual heat pumps. Thus, a new prototype based only on the typical components (compressor, condenser, expansion valve and evaporator) was proposed as future work. In this thesis, a theoretic analysis of the heat pump was done. A subcooling control methodology was developed and tested. The proposed prototype in [1] has been built and characterized. From all the results, the most convenient heat pump design was obtained. ¿ Integral Heat pump-DHW system The integration of the most convenient heat pump prototype within a system for the DHW production based on heat recovery from wastewater has been analyzed. The research has included the development of a model of the entire system in Trnsys and the optimization of the main components of the system: their sizing and their operation with the objective of reaching the maximum global efficiency of the complete system. Due to the complexity of the problem, the analysis was performed in three main steps: first, a study of the direct heat exchange,second, an study focusing on the condenser side, that is, the consideration of an infinite heat source (large availability of sewage water for instance) and third, the focus was done on the evaporator side. That is, the optimization of the complete system in which a finite heat source is considered (grey waters collected from the building for instance). The simplest and most efficient system required in DHW production and heat recuperation from wastewater has been determined. / Esta tesis se enmarca dentro del proyecto “APROVECHAMIENTO DEL CALOR RESIDUAL A BAJA TEMPERATURA MEDIANTE BOMBAS DE CALOR PARA LA PRODUCCION DE AGUA CALIENTE” a través de una beca FPI del Ministerio de Economía y Competitividad. / Hervás Blasco, E. (2020). Aprovechamiento del calor residual a baja temperatura mediante bombas de calor para la producción de agua caliente [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/137776 / TESIS

Philosophiae Doctor - PhD / The majority of rural communities in sub-Saharan Africa are predominantly poor and depend largely on small-scale subsistence farming. To date, various farming mechanisms (e.g. organic farming, crop rotation, agroforestry and inter-cropping) have been introduced to improve food security and to avert hunger; however, water scarcity remains a challenge. The sub-Saharan African region is currently regarded as water stressed and this has had a significant impact on rural livelihoods. Despite being considered as a water-scarce region, the demand for water for agricultural purposes continues to increase exponentially, while, on the other hand, its supply keeps on diminishing, particularly for agricultural production.

Thesis (M.A. (Communication Studies)) -- University of Limpopo, 2020 / This study aimed to develop a communication strategy for water re-use in Basic Education, which included illustrative learning materials which were suitable for online learning. To attain the intended aim, the study focussed on the subsequent objectives: to review and analyse learners’ and educators’ perceptions and understanding (knowledge) of water re-use; to examine strategies that could be employed to gain learners’ and educators’ understanding and acceptance of water re-use; to develop information or learning materials that would educate and enhance their understanding and informed decision making related to water re-use; and to discuss approaches to communicate water re-use in Basic Education. A qualitative orientation utilising participatory action research was employed as a research design for this study. A sample size of 80 participants, from four primary and four secondary schools in Mankweng Township was selected. 40 learners and 40 educators were selected. Convenience sampling was used to select the participants for this study. Data was collected by means of interviews, focus group discussions, workshops, teaching and participant observation. Thereafter, thematic analysis and NVivo software were employed to analyse data. This study employed Geertz’s notion of culture, Vygotsky’s social constructivism and the behaviour ecological model as theoretical frameworks to guide the research. Geertz’s interpretation of cultures was employed to understand culture and its effects on human behaviour, Vygotsky’s social constructivism was employed to understand the process of effective learning in educational contexts and the behaviour ecological model was employed to understand individuals’ behaviours and the background of the given behaviour. Understanding an individual’s behaviour and experiences towards water re-use assisted in developing water re-use illustrative learning materials. It also assisted with a communication strategy, which integrated Steyn and Puth’s steps, in the formulation of a communication strategy, joint approach model and a step by step content of a communication strategy and action plan model. The study revealed that the majority of individuals have negative perceptions and attitudes towards water re-use, due to a lack of awareness, knowledge and education. The “yuck” factor and health apprehensions were revealed to be major causes of such perceptions and attitudes. Education, campaigns and programmes, traditional and v new media, community meetings, rules, policies and regulation were reported as strategies which might be employed to promote water re-use. The study revealed that individuals’ home language must be made use of in all the water re-use promotional strategies. Communication approaches which promoted a platform for community participation, were revealed as appropriate for development programmes. As a result, participatory and development approaches to communication were considered suitable for communicating water re-use in Basic Education. The study further indicated that posters and storyboards were effective illustrative learning materials which could be employed to educate learners and raise their cognition regarding water re-use as a water conservation method. This would increase acceptability, awareness and practice and reduce negative perceptions, attitudes and concerns. The study indicated that water re-use communication should consider an individuals’ environmental, religious and cultural backgrounds, which would affect water re-use projects. The study also indicated that there was a relationship between an individuals’ perceptions, attitudes, education and culture.

Off-grid houses in the United States are often connoted with mostly non-professional, home-made structures and isolated, hippie living in remote rural areas. These off-grid homeowners may also complete their consumer-independent commitment with a minimal-waste, land-dependent lifestyle that includes methodical harnessing and recycling of resources and materials, raising livestock, and productive gardening on the property. This research paper explores the background, methods and kinds of typical off-grid living structures, their ability to harness natural resources for function and performance, and the ability of its occupants to remain resilient in the face of depleting fuel resources, extreme weather patterns, and rising costs of living. The goal of this research is to propose modern and resilient off-grid housing design to exist as normalized, micro-communities within typical suburban communities in the United States. The housing prototype, sited in Dudley, Massachusetts, optimizes passive resources for heating and cooling thermal comfort, prefabricated materials for construction, and modern technology for inhabitation. Its hyper-local design incorporates building science that integrates researched techniques and philosophies from current movements of sustainable design in the United States and Canada, such as Passive House, Net Zero, LEED, and the Living Building Challenge.