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The use of treated effluent for agricultural irrigation in the Bottelary River area: Effluent quality, farmers perception and potential extentRui, Li January 2005 (has links)
Magister Scientiae - MSc / The Bottelary River area is located in a Mediterranean climate region, where the agricultural sector plays an important role. During the dry summer season, there is not enough precipitation to meet the agricultural irrigation requirements. Some farmers extract river water which is practically the final treated effluent from the Scottsdene Wastewater Treatment Works to irrigate crops. This research investigated the use of treated effluent for agricultural irrigation in this area, particularly focused on the effluent quality, farmers perception, and the potential extent. / South Africa
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Biosorption of precious metals from synthetic and refinery wastewaters by immobilized saccharomyces cerevisiaeMack, Cherie-Lynn January 2008 (has links)
The process of precious metal refining can be up to 99.99% efficient at best, and although it may seem small, the amount of valuable metal lost to waste streams is appreciable enough to warrant recovery. The method currently used to remove entrained metal ions from refinery wastewaters, chemical precipitation, is not an effective means for selective recovery of precious metals from a wastewater. Biosorption, the ability of certain types of biomass to bind and concentrate metals from even very dilute aqueous solutions, may be an effective point-source metal recovery strategy. The yeast, Saccharomyces cerevisiae, has been found capable of sorbing numerous precious and base metals, and is a cheap and abundant source of biomass. As such, it represents a possible precious metal sorbent for application to refining wastewaters. In this investigation, S. cerevisiae biomass was immobilized, using polyethyleneimine and glutaraldehyde, to produce a suitable sorbent, which was found to be capable of high platinum uptake (150 to 170 mg/g) at low pH (< 2). The sorption mechanism was elucidated and found to be a chemical reaction, which made effective desorption impossible. The sorption process was investigated in a packed bed column conformation, the results of which showed that the diameter and height of the column require further optimization in order to attain the metal uptake values achieved in the batch studies. When applied to a refinery wastewater, two key wastewater characteristics limited the success of the sorption process; the high inorganic ion content and the complex speciation of the platinum ions. The results proved the concept principle of platinum recovery by immobilized yeast biosorption and indicated that a more detailed understanding of the platinum speciation within the wastewater is required before the biosorption process can be applied. Overall, the sorption of platinum by the S. cerevisiae sorbent was demonstrated to be highly effective in principle, but the complexity of the wastewater requires that pretreatment steps be taken before the successful application of this process to an industrial wastewater.
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Novel Microbial Electrochemical Technologies and Microorganisms for Power Generation and DesalinationChehab, Noura A. 12 1900 (has links)
Global increases in water demand and decreases in both the quantity and quality of fresh
water resources have served as the major driving forces to develop sustainable use of
water resources. One viable alternative is to explore non-traditional (impaired quality)
water sources such as wastewater and seawater. The current paradigm for wastewater
treatment is based on technologies that are energy intensive and fail to recover the
potential resources (water and energy) in wastewater. Also, conventional desalination
technologies like reverse osmosis (RO) are energy intensive. Therefore, there is a need
for the development of sustainable wastewater treatment and desalination technologies
for practical applications. Processes based on microbial electrochemical technologies
(METs) such as microbial fuel cells (MFCs), microbial electrolysis cells (MECs) and
microbial desalination cells (MDCs) hold promise for the treatment of wastewater with
recovery of the inherent energy, and MDCs could be used for both desalination of
seawater and energy recovery. METs use anaerobic bacteria, referred to as
exoelectrogens, that are capable of transferring electrons exogenously to convert soluble
organic matter present in the wastewater directly into an electrical current to produce
electrical power (MFC and MDC) or biogas (MEC). In my dissertation, I investigated
the three types of METs mentioned above to: 1) have a better insight on the effect of
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oxygen intrusion on the microbial community structure and performance of air-cathode
MFCs; 2) improve the desalination efficiency of air-cathode MDCs using ion exchange
resins (IXRs); and 3) enrich for extremophilic exoelectrogens from the Red Sea brine
pool using MECs.
The findings from these studies can shape further research aimed at developing more
efficient air-cathode MFCs for practical applications, a more efficient integrated IXRMDC
configuration that can be used as a pre-treatment to RO, and exploring extreme
environments as a source of extremophilic exoelectrogens for niche-specific applications
of METs.
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Passive and active surfaces to reduce fouling of membranes and membane modulesJanuary 2019 (has links)
abstract: This dissertation investigates the mechanisms that lead to fouling, as well as how an understanding of how these mechanisms can be leveraged to mitigate fouling.
To limit fouling on feed spacers, various coatings were applied. The results showed silver-coated biocidal spacers outperformed other spacers by all measures. The control polypropylene spacers performed in-line with, or better than, the other coatings. Polypropylene’s relative anti-adhesiveness is due to its surface free energy (SFE; 30.0 +/- 2.8 mN/m), which, according to previously generated models, is near the ideal SFE for resisting adhesion of bacteria and organics (~25 mN/m).
Previous research has indicated that electrochemical surfaces can be used to remove biofilms. To better elucidate the conditions and kinetics of biofilm removal, optical coherence tomography microscopy was used to visualize the biofouling and subsequent cleaning of the surface. The 50.0 mA cm-2 and 87.5 mA cm-2 current densities proved most effective in removing the biofilm. The 50.0 mA cm-2 condition offers the best balance between performance and energy use for anodic operation.
To test the potential to incorporate electrochemical coatings into infrastructure, membranes were coated with carbon nanotubes (CNTs), rendering the membranes electrochemically active. These membranes were biofouled and subsequently cleaned via electrochemical reactions. P. aeruginosa was given 72h to develop a biofilm on the CNT-coated membranes in a synthetic medium simulating desalination brines. Cathodic reactions, which generate H2 gas, produce vigorous bubbling at a current density of 12.5 mA cm-2 and higher, leading to a rapid and complete displacement of the biofilm from the CNT-functionalized membrane surface. In comparison, anodic reactions were unable to disperse the biofilms from the surface at similar current densities.
The scaling behavior of a nanophotonics-enabled solar membrane distillation (NESMD) system was investigated. The results showed the NESMD system to be resistant to scaling. The system operated without any decline in flux up to concentrations 6x higher than the initial salt concentration (8,439 mg/L), whereas in traditional membrane distillation (MD), flux essentially stopped at a salt concentration factor of 2x. Microscope and analytical analyses showed more fouling on the membranes from the MD system. / Dissertation/Thesis / Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2019
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Pollution Prevention and Water Reuse at Utah Department of Transportation FacilitiesStoudt, Amanda 01 May 2020 (has links)
As stormwater flows over roads, sidewalks, and other impervious surfaces, it picks up pollutants that are deposited on these surfaces. One common pollutant transported by stormwater is road salt. While the application of road salt is crucial for wintertime public safety, road salt has a host of negative environmental impacts. Road salt has been linked to increasing levels of dissolved solids in groundwater, vegetation damage, and behavioral changes in aquatic organisms. Studies have shown that these impacts are concentrated around salt storage facilities. As a result, the United States Environmental Protection Agency issued many state departments of transportation municipal separate storm sewer system (MS4) permits. In Utah, road salt is stored at Utah Department of Transportation (UDOT) maintenance stations, which are regulated by a Phase I MS4 permit. To comply with their MS4 permit, UDOT constructed retention ponds to capture salt-laden stormwater and truck wash water. However, without information and established maintenance and management plans informing pond design, these retention ponds suffer from design issues such as overflow throughout the winter season. Through pollution prevention assessments, pond and tap water analysis, pond sediment analysis, and surface water quality modeling at 11 UDOT maintenance stations, this project provides UDOT with site design guidelines and best management practices to ultimately reduce the impact of UDOT road salt facilities on the environment.
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Ozonation and/or Coagulation - Ceramic Membrane Hybrid for Filtration of Impaired-Quality Source WatersHa, Changwon 09 1900 (has links)
When microfiltration (MF) and ultrafiltration (UF) membranes are applied for
drinking water treatment/wastewater reuse, membrane fouling is an evitable problem,
causing the loss of productivity over time. Polymeric membranes have been often
reported to experience rapid and/or problematical fouling, restraining sustainable
operation. Ceramic membranes can be effectively employed to treat impaired-quality
source waters due to their inherent robustness in terms of physical and chemical
stability. This research aimed to identify the effects of coagulation and/or ozonation
on ceramic membrane filtration for seawater and wastewater (WW) effluent. Two
different types of MF and UF ceramic membranes obtained by sintering (i.e., TAMI
made of TiO2+ZrO2) and anodic oxidation process (i.e., AAO made of Al2O3) were
employed for bench-scale tests.
Precoagulation was shown to play an important role in both enhancing membrane
filterability and natural organic matter (NOM) removal efficacy for treating a highorganic
surface water. The most critical factors were found to be pH and coagulant
dosage with the highest efficiency resulting under low pH and high coagulant dose.
Due to the ozone-resistance nature of the ceramic membranes, preozonation allowed
the ceramic membranes to be operated at higher flux, especially leading to significant
flux improvement when treating seawater in the presence of calcium and magnesium.
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Dissolved ozone in contact with the TAMI ceramic membrane surface accelerated the
formation of hydroxyl (˙OH) radicals in WW effluent treatment. Flux restoration of
both ceramic membranes, fouled with seawater and WW effluent, was efficiently
achieved by high backwash (BW) pressure and ozone in chemically enhanced
backwashing (CEB). Ceramic membranes exhibited a pH-dependent permeate flux
while filtering WW effluent, showing reduced fouling with increased pH. On the
other hand, for filtering seawater, differences in permeate flux between the two
membranes was observed under basic pH conditions, showing that the TAMI
membrane flux was stable regardless of changes in pH, while the AAO membrane
flux was significantly decreased as pH increased to 10.
Consequently, it is expected that ozone and/or coagulation prior to ceramic membrane
filtration can play a significant role in treating impaired-quality source waters (e.g.,
seawater and WW effluent), leading to maintaining sustainable membrane flux in
seawater pretreatment before reverse osmosis (RO) or water reuse applications.
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Florida’s Recycled Water Footprint: A Geospatial Analysis of Distribution (2009 and 2015)Archer, Jana E., Luffman, Ingrid E., Nandi, Arpita N., Joyner, T. Andrew 01 January 2019 (has links)
Water shortages resulting from increased demand or reduced supply may be addressed, in part, by redirecting recycled water for irrigation, industrial reuse, groundwater recharge, and as effluent discharge returned to streams. Recycled water is an essential component of integrated water management and broader adoption of recycled water will increase water conservation in water-stressed coastal communities. This study examined spatial patterns of recycled water use in Florida in 2009 and 2015 to detect gaps in distribution, quantify temporal change, and identify potential areas for expansion. Databases of recycled water products and distribution centers for Florida in 2009 and 2015 were developed by combining the 2008 and 2012 Clean Water Needs Survey databases with Florida’s 2009 and 2015 Reuse Inventory databases, respectively. Florida increased recycled water production from 674.85 mgd in 2009 to 738.15 mgd in 2015, an increase of 63.30 mgd. The increase was primarily allocated to use in public access areas, groundwater recharge, and industrial reuse, all within the South Florida Water Management District (WMD). In particular, Miami was identified in 2009 as an area of opportunity for recycled water development, and by 2015 it had increased production and reduced the production gap. Overall, South Florida WMD had the largest increase in production of 44.38 mgd (69%), while Southwest Florida WMD decreased production of recycled water by 1.68 mgd, or 3%. Overall increase in use of recycled water may be related to higher demand due to increased population coupled with public programs and policy changes that promote recycled water use at both the municipal and individual level.
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Integrating Microbial Electrochemical Technology with Forward Osmosis and Membrane Bioreactors: Low-Energy Wastewater Treatment, Energy Recovery and Water ReuseWerner, Craig M. 06 1900 (has links)
Wastewater treatment is energy intensive, with modern wastewater treatment processes consuming 0.6 kWh/m3 of water treated, half of which is required for aeration. Considering that wastewater contains approximately 2 kWh/m3 of energy and represents a reliable alternative water resource, capturing part of this energy and reclaiming the water would offset or even eliminate energy requirements for wastewater treatment and provide a means to augment traditional water supplies. Microbial electrochemical technology is a novel technology platform that uses bacteria capable of producing an electric current outside of the cell to recover energy from wastewater. These bacteria do not require oxygen to respire but instead use an insoluble electrode as their terminal electron acceptor. Two types of microbial electrochemical technologies were investigated in this dissertation: 1) a microbial fuel cell that produces electricity; and 2) a microbial electrolysis cell that produces hydrogen with the addition of external power. On their own, microbial electrochemical technologies do not achieve sufficiently high treatment levels. Innovative approaches that integrate microbial electrochemical technologies with emerging and established membrane-based treatment processes may improve the overall extent of wastewater treatment and reclaim treated water. Forward osmosis is an emerging low-energy membrane-based technology for seawater desalination.
In forward osmosis water is transported across a semipermeable membrane driven by an osmotic gradient. The microbial osmotic fuel cell described in this dissertation integrates a microbial fuel cell with forward osmosis to achieve wastewater treatment, energy recovery and partial desalination. This system required no aeration and generated
more power than conventional microbial fuel cells using ion exchange membranes by minimizing electrochemical losses.
Membrane bioreactors incorporate semipermeable membranes within a biological wastewater treatment process. The anaerobic electrochemical membrane bioreactor described here integrates a microbial electrolysis cell with a membrane bioreactor using conductive hollow fiber membrane to produce hydrogen gas, treat wastewater and reclaim treated water. The energy recovered as hydrogen gas in this system was sufficient to offset all the electrical energy requirements for operation.
The findings from these studies significantly improve the prospects for simultaneous wastewater treatment, energy recovery and water reclamation in a single reactor but challenges such as membrane biofouling and conversion of hydrogen to methane by methanogenesis require further study.
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Towards developing a communication strategy for water re-use in South AfricaMamabolo, Mamogobo Rosinah January 2020 (has links)
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
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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.
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CONSTRUCTION AND VALIDATION OF A STERIC PORE-FLOW MODEL FOR PREDICTING REJECTION OF SMALL AND UNCHARGED COMPOUNDS BY POLlYMIDE REVERSE OSMOSIS MEMBRANES / RO膜処理における低分子量物質の除去率予測手法の開発Haruka, Takeuchi 23 July 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21308号 / 工博第4506号 / 新制||工||1701(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 田中 宏明, 教授 清水 芳久, 教授 伊藤 禎彦 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
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