Sustainable algae biofuel production is rising in demand, and the need to establish an efficient and proper algae harvesting method is extremely essential. Membrane filtration technology seems to be the most promising as a solid-liquid separation process. However, fouling seems to be the major problem for membranes. There is limited research on how to solve the problem of fouling, and cake buildup inside the membranes. A novel membrane design is required to solve the problem of fouling and cake buildup inside the membranes. The objective of this research is to construct a novel two way membrane design for algae biomass harvesting and water recycling. The methods used include culturing algae species, filtering them through the membrane module, and sample analysis for determining the water quality. The results show that the present filtration model had no fouling, or cake buildup as opposed to the previous filtration model. The present model permeate has a very low optical density of 0.007 absorbance at 750 nanometers. This result shows that permeate is completely devoid of algae.

Water scarcity and water pollution are ongoing problems that require a rethinking of water use in the community. This calls for cooperation between the expert systems of water supply and sewerage as well as some level of public involvement. It is the interaction between the experts or providers, and the public as users or customers, that is the focus of this study on the experience of recycling water sourced from sewage effluent. This cross-national research explores the drivers behind water reuse; the way water reuse is presented to the public for consideration; the public response to water reuse; the influence of environmental and public health risk concerns; and the function of trust in the acceptance of potable water reuse and the sustainability of non potable reuse. The absence of social science published literature relating to the experience of recycled water guided a grounded theory approach to this research, using a triangulation of methods for data collection and case study analysis. The social-psychological studies of Bruvold (1972-1988), located in water industry literature, were consulted to organise an audit of secondary, survey data obtained through industry contacts and fieldwork. In this way, acceptance of potable and non potable water reuse in the USA, UK and Australia is mapped to provide background data for a set of minor case studies that explore the experience of potable reuse. Residential water reuse experience is investigated through embedded case study research. Primary data were collected at two residential sites in Adelaide and two in Florida. Recycled water is used for garden watering and toilet flushing at New Haven, and is planned for Mawson Lakes in Adelaide. Altamonte Springs and Brevard County in Florida recycle water for garden watering and outdoor uses only. Twenty residents were interviewed at each site involving semi-structured interviews: in-depth, face-to-face interviews in Adelaide and telephone interviews on site in Florida. Individual managers of the recycled water systems were also interviewed and, at New Haven, additional key stakeholders were consulted. Qualitative data analysis, employing a grounded theory approach, discovered the value of Sztompka�s (1999) framework for the �social becoming of trust�. This research illustrates that the positive historical culture of trust at the Florida sites, coupled with robust structural support for residential water reuse that encourages positive provider-customer interactions, develops trust in non potable reuse and uses involving a higher level of contact. In the Adelaide sites, weak structural support induces reliance on informal structure that increases the public health risk, jeopardising the sustainability of residential reuse. In relation to potable reuse experience that centres on the Californian experience, a social dilemma is created through a strategic, marketing approach to public consultation and the lack of public communication on current water sources. Sztompka�s (1999) framework for trust as an ongoing process is expanded to include principles of public participation that will further consolidate trust in water reuse to achieve sustainable outcomes.

Water recycling schemes are increasingly being implemented across Australia as an effective means of converting wastewater into a valuable resource. There is currently a lack of specific guidelines for the monitoring of groundwater resources associated with these schemes. This is despite it being widely acknowledged that a monitoring system is a fundamental component of a scheme, due to the risk of altering the hydrogeological processes and resource devaluation. The aim of this research was to address this information gap, by developing guidelines that provide a platform for the continuous improvement in groundwater monitoring systems for recycling schemes. To achieve the stated aim, an action research strategy formed the methodological approach for the implementation of the objectives. Existing guidelines for monitoring systems were reviewed, consolidated and refined, in consultation with industry expertise. The developed guidelines were then verified through the implementation of a case study at the Hawkesbury Water Recycling Scheme (HWRS), with the resulting information providing for a preliminary characterisation of the resources. Designed on current best practice, and to meet statutory requirements, the guidelines addressed the identified information gap. The research recommends the integration of groundwater monitoring systems into the environmental management system for recycling schemes, to provide for continuous refinement through the interpretation of the knowledge base developed in previous cycles. Adoption of this practice will initiate improved decision making and management processes, and provide for future resource protection and enhancement. / Master of Science (Hons)

Water recycling schemes are increasingly being implemented across Australia as an effective means of converting wastewater into a valuable resource. There is currently a lack of specific guidelines for the monitoring of groundwater resources associated with these schemes. This is despite it being widely acknowledged that a monitoring system is a fundamental component of a scheme, due to the risk of altering the hydrogeological processes and resource devaluation. The aim of this research was to address this information gap, by developing guidelines that provide a platform for the continuous improvement in groundwater monitoring systems for recycling schemes. To achieve the stated aim, an action research strategy formed the methodological approach for the implementation of the objectives. Existing guidelines for monitoring systems were reviewed, consolidated and refined, in consultation with industry expertise. The developed guidelines were then verified through the implementation of a case study at the Hawkesbury Water Recycling Scheme (HWRS), with the resulting information providing for a preliminary characterisation of the resources. Designed on current best practice, and to meet statutory requirements, the guidelines addressed the identified information gap. The research recommends the integration of groundwater monitoring systems into the environmental management system for recycling schemes, to provide for continuous refinement through the interpretation of the knowledge base developed in previous cycles. Adoption of this practice will initiate improved decision making and management processes, and provide for future resource protection and enhancement. / Master of Science (Hons)

abstract: Large-scale cultivation of photosynthetic microorganisms for the production of biodiesel and other valuable commodities must be made more efficient. Recycling the water and nutrients acquired from biomass harvesting promotes a more sustainable and economically viable enterprise. This study reports on growing the cyanobacterium Synechocystis sp. PCC 6803 using permeate obtained from concentrating the biomass by cross-flow membrane filtration. I used a kinetic model based on the available light intensity (LI) to predict biomass productivity and evaluate overall performance. During the initial phase of the study, I integrated a membrane filter with a bench-top photobioreactor (PBR) and created a continuously operating system. Recycling permeate reduced the amount of fresh medium delivered to the PBR by 45%. Biomass production rates as high as 400 mg-DW/L/d (9.2 g-DW/m2/d) were sustained under constant lighting over a 12-day period. In the next phase, I operated the system as a sequencing batch reactor (SBR), which improved control over nutrient delivery and increased the concentration factor of filtered biomass (from 1.8 to 6.8). I developed unique system parameters to compute the amount of recycled permeate in the reactor and the actual hydraulic retention time during SBR operation. The amount of medium delivered to the system was reduced by up to 80%, and growth rates were consistent at variable amounts of repeatedly recycled permeate. The light-based model accurately predicted growth when biofilm was not present. Coupled with mass ratios for PCC 6803, these predictions facilitated efficient delivery of nitrogen and phosphorus. Daily biomass production rates and specific growth rates equal to 360 mg-DW/L/d (8.3 g/m2/d) and 1.0 d-1, respectively, were consistently achieved at a relatively low incident LI (180 µE/m2/s). Higher productivities (up to 550 mg-DW/L/d) occurred under increased LI (725 µE/m2/s), although the onset of biofilm impeded modeled performance. Permeate did not cause any gradual growth inhibition. Repeated results showed cultures rapidly entered a stressed state, which was followed by widespread cell lysis. This phenomenon occurred independently of permeate recycling and was not caused by nutrient starvation. It may best be explained by negative allelopathic effects or viral infection as a result of mixed culture conditions. / Dissertation/Thesis / Masters Thesis Civil and Environmental Engineering 2015

Urbanization has led to rapid and uncontrolled growth of informal housing settlements in many developing countries. As most slum growth is unplanned, these areas tend to lack basic infrastructure including sanitation. The high user rates, lack of water and electricity infrastructure, space limitations, and scant financial resources make sanitation provision a major challenge in slums. As most decentralized sanitation technologies fail when applied in these environments, better technologies need to be developed that cater to the specific needs of slum dwellers. One promising technology, the membrane bioreactor (MBR) is routinely used in developed countries when a compact and resilient treatment system is required. However, the energy requirement of existing MBRs is high, as most are aerobic systems which require aeration. Anaerobic MBRs (AnMBR), which do not require aeration, have led to an improvement of the energy profile of MBRs. As research into the technology is still in its infancy, little is known regarding its applicability in high-density urban environments. This body of research is aimed at understanding the AnMBR’s treatment performance and overall reliability in challenging circumstances similar to those encountered in slums. The appropriateness of an AnMBR was investigated with pilot and full-scale systems treating real wastewater in field conditions. The first investigation, discussed in Chapter 3, was used to determine the resilience of AnMBR treatment when subjected to periods of disuse and high fluctuations in incoming feed strengths. Decentralized systems often see much higher variations in feed composition than centralized systems as they lack large collection systems which homogenize the influent wastewater. Depending on the application, periods of low and no flow are also possible. During this long-term study it was observed that the membrane served an important role in controlling the effluent quality, especially when environmental conditions and feed characteristics varied so significantly as to upset biological stability. The system achieved an average COD removal efficiency of 88.2% throughout the study. It was also observed during this study that the system had higher removal efficiencies when treating higher COD concentrations. Higher strength wastewaters can routinely be found in decentralized applications where dilution water is minimal. These locations include water-efficient buildings, direct coupling to public toilets, and fecal sludge treatment plants. It was also found that the AnMBR was capable of rapidly recovering from extended periods of disuse. This ensures that the AnMBR can be applied to areas, such as schools and hotels that experience large seasonal variations and periods of disuse. The second investigation, described in Chapter 4, examined how fluctuations in ambient temperatures affect fouling resistance. In small decentralized applications, operating the reactor at ambient temperatures is the most likely scenario, as controlling the reactor temperature would incur a high energy demand. Operating at ambient temperatures means that variations can be high, and that temperatures can drop below ideal ranges. Temperature is known to affect biological treatment and to a lesser extent membrane filtration, but the interactions between the two are not fully understood. To determine the effect of temperature on operation, a pilot scale AnMBR was used to treat wastewater with fluctuating ambient temperatures. Three trials were conducted during summer and winter conditions, as well an artificially heated period. It was found that membrane permeability can be greatly affected by operating temperature but its effect varied depending on the fouling state of the membrane. Virgin, or recently cleaned membranes were not affected by low temperatures, while the permeability of slightly fouled membranes was negatively correlated to changes in temperature. When slightly fouled, a membrane TMP could increase by 2.4 times with a 10oC drop in temperature. The magnitude of the TMP increase could not be explained by changes in water viscosity alone. The effect of temperature on TMP decreased when fouling became severe and normal operating pressures were high. These results suggest that seasonal adjustments to AnMBR operation would be necessary to prevent sharp and excessive increases in operational TMP during cold spells. Chapter 5 investigated the feasibility of recovering water, nutrients, and energy in an off-grid and decentralized AnMBR. This investigation performed an energy, nutrient, and mass balance for a theoretical AnMBR treating water from a public toilet in a high density setting. What was concluded from this study is that complete water recycling can be accomplished in such an environment. Onsite water recycling would allow the system to be applied in arid urban areas as well as places lacking regular water provision. The study also concluded that the energy content of wastewater in a high density area would be sufficient to power an AnMBR and electronic toilet. For areas where low wastewater strengths would be expected, food waste addition to the wastewater would improve the energy profile of the system. As many urban areas of developing countries struggle with solid waste management, there is the opportunity to link food waste management with wastewater treatment. This study also highlighted the potential problems that ammonia and salinity buildup could have on a system that achieves complete water recycling. Once the system specifically designed for urban areas was deemed theoretically feasible, a full-scale, solar-powered, prototypical system was constructed in Florida and tested in India (Chapter 6). This system, which was applied in Kerala, India, was investigated for its treatment and membrane performance as well as energy consumption. During the first four months of operation, the system was able to produce high quality product water that could be used for toilet flushing. This was achieved despite the low strength of the incoming feed water and higher than anticipated wastewater production rates. The wastewater strength was low due to the system’s application in a school setting and high levels of dilution water. The reliance on multiple anti-fouling mechanisms allowed the system to operate for 4 months without a significant change in TMP. The average energy consumption per unit of produced water depended on the amount of water treated per day. On average the energy consumption was 1.52 kWh/m3, but that value dropped to 0.83 kWh/m3 when volumes greater than 200 liters were treated per day. The lowest value measured during this trial was 0.16 kWh/m3 when 1,394 liters were produced. All of the energy used by the system was produced by onsite photovoltaics, with minimal carbon footprint. While the system was capable of meeting the water demand of the toilet system, further improvements in the energy demand of the system will be necessary to make the system more cost-effective, robust and reliable. These results suggest that AnMBRs can be applied in high density urban areas for the dual objectives of wastewater treatment and resource recovery. Their reliable treatment in the face of large fluctuations in feed concentration, volume, and temperature suggests they are appropriate for decentralized applications. Membrane filtration allows water to be reliably recycled onsite with minimal operator oversight. The low energy requirements of the system allow for onsite renewable energy sourced, such as photovoltaics to be used to power the system. AnMBRs are able to address many of the challenges that traditional sanitation technologies cannot, which makes them a promising technology to address the problems encountered in slum sanitation.

The diploma thesis deals with the application of membrane processes for the treatment of washing water from sand filters of pool technology to parameters suitable for its reuse, not only on a theoretical level, but also on a real example. The experimental part deals with the monitoring of relevant parameters given by Decree no. 568/2000 Sb. and other technologically significant water quality indicators. All monitored parameters in the reverse osmosis permeate reached satisfactory values and thus it was concluded that the effluent water is suitable for reuse. Instead of being discharged into the sewer, it is possible to recycle 70 to 80 % of the washed water per day thanks to the applied technology, which saves approximately 20 m3 of water per day.

The shopping trolley have been frequently used in our daily life. However, the hygiene condition of cart makes people worry a lot, especially the handle brothers. Nowadays, several methods have been proposed to clean the shopping carts but considered uneconomic and inflexible. In this study, we aim to design an integrated cart washing system based on a trailer applied to medium or small supermarket. This system should be more efficient, economic, easily to operate, safer and les water consummation. The integrated cart washing system has three basic functions of washing, disinfection and drying. The system is controlled by PLC program, all steps in the cleaning process are fully automatic insider the trailer and each component are adjustable according to various shopping carts. The system only requires one person to operate and it costs 30 seconds to wash a single cart, able to wash up to 120 cart/hour. Disinfection and drying steps provide high washing quality. Moreover, water-recycling design can save part of wasted water. The modelling and assembly was designed in Autodesk Inventor 2016, the hardware design circuit-writing diagram was performed in AutoCAD, the software design of Programmable logic controller (PLC) was made in STEP 7-Micro/Win. Theoretical calculation and simulation prove the safety and possibility of our system. We concluded that this system might have commercial interests in the market.

The pervious pavement system has been identified as an effective source control device capable of removing urban stormwater pollution by trapping pollutants within the system and biodegradation. Recent studies have further demonstrated that the pervious pavement system could be used as a source of renewable energy capable of reducing household energy bill by about 80%. In view of ever increasing demand for water and the continued reduction in available fresh water resources in the world, stormwater has been recognized as a potential valuable source of water which could be harnessed. The overall aim of this multi disciplinary research was to evaluate the suitability of a modified pervious pavement system (PPS) for water harvesting and re-use, particularly focussing on potential third world applications and taking advantage of the latest developments in materials that are available for such applications. The aim was a holistic one in which water re-use was examined in terms of both the potential advantages from an irrigation point of view without ignoring the very important public health concerns that are often of concern when water is stored in circumstances which do not fit the normally used criteria for potable supplies. The results of this study confirmed the pollution control capability of the porous pavement system as earlier determined by previous studies. Also, a novel experimental rig was designed to reproducibly create very high and realistic rainfall events over model pavement structures. Furthermore, the performance of a new geotextile, Inbitex Composite® in the pervious pavement system was determined for the first time. Furthermore, this study also tested for the first time, the performance of a pervious pavement system modified by the incorporation of Inbitex Composite® geotextile with slits and made prescriptions as to how this new geotextile could be best installed in a modified pervious pavement system in order to achieve high infiltration without compromising pollution control. This study tested the practical use of the pervious pavement system for water harvesting and storage for reuse in irrigation. In order to achieve this, the author took what could be considered as a holistic approach to water quality issues and determined the chemical, electrochemical and microbiological quality of water stored in the system as well as investigated the public health concern of the potential of pathogenic organisms in waters stored in unconventional water storage system as the pervious pavement system. It also determined that the pervious pavement system have the capability to recycle water with physical, chemical and microbiological qualities that will meet international standards for irrigation and that the system does not offer a conducive environment for potential pathogenic organisms if contamination incident occurs from adjoining areas. This study also became the first to practically relate Sustainable Urban Drainage System (SUDS) to agricultural benefit by demonstrating how a SUDS device (pervious pavement system) could be used in addition to its urban drainage control role, as a source of supply of high quality irrigation water to cultivate crops fit for human and animal consumption despite high application of pollutants. This study determined contrary to the observation of earlier studies that the use of slow-release iv fertilizer could lead to eutrophication problems in cases where the water is channeled to natural water courses. Furthermore, active response of potential pathogenic bacteria to the presence of slow-release fertilizer was observed in this study. This raises a huge question on the need to add fertilizer to the pervious pavement system. Coupe, (2004) had demonstrated that oil degrading microbes would respond positively to food sources in the system and hence, there was no significant need for simulation by nutrient addition, the author concluded in the study presented here that fertilizer addition should only be conducted if the waters are to be used for irrigation where the nutrients would be beneficial to the plants and that even in this case, the microbiological water quality should be constantly monitored and the addition suspended if the risk of contamination from adjoining areas is high.

A research project report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering (Civil Engineering). Vanderbijlpark, 2016 / South Africa is a semi-arid country with an average rainfall of 450 mm per annum. According to the Department of Water Affairs, the total registered water usage in 2013 met the estimated 2025 high water requirement of 17.3 billion m3/annum. Therefore, the need had arisen to reduce water consumption and increase water supply to ensure the sustainability of our nation’s water resources. Many studies show that wastewater reuse or water reclamation is an under-utilized and very viable water conservation concept in South Africa. The reuse of wastewater for direct potable or direct non-potable reuse is a highly debated topic requiring frequent engagement and investigation. Although direct reuse for potable uses is often more contentious than direct reuse for non-potable uses, it is worth investigating for possible future implementation at certain water scares areas. Hence, this study investigated the possibility of the future implementation of direct wastewater reuse at Hartbeesfontein - a selected South African community, for potable or non-potable use. The study incorporated potential users’ perceptions, the cost implications of reuse and water saving potential by means of different water balance models. The survey conducted, measuring the intention of the residents from Hartbeesfontein to accept direct wastewater reuse for potable and non-potable use, revealed the community’s overwhelming acceptance (about 70%) of a reuse system should it be implemented in the future. The community’s preference for wastewater reuse for non-potable use (75%) was higher than for potable use (67%). Hypothetically, it would be possible to reuse 85% of the community’s daily demand for potable use, if all the wastewater collected at the wastewater treatment plant could be treated. It would then mean that the municipality will only need to provide 15% of the daily water demand. The option to reuse wastewater for non-potable use (i.e. to supply an industry) could save the community 22% its daily water demand. In this study, the cost of wastewater treatment for potable use was approximately 350% higher than the cost of potable water supplied by the Midvaal Water Company. The cost of treating wastewater for non-potable use however was approximately 46% less than the cost of potable water supplied by the Midvaal Water Company. By incorporating the outcomes of the water balance, perceptions of the community and analysis of the different wastewater reuse scenario costs, it was evident from the study that direct wastewater reuse for non-potable industrial application was the most viable water reuse option for Hartbeesfontein. / MT2017