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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Perfluorinated compounds, bishenol a and acetaminophen in selected waste water treatment plants in and around Cape Town, South Africa

Adeleye, Adeola Patience January 2016 (has links)
Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2016. / The release of wastewater to the aquatic environment is most likely to introduce some trace levels of organic contaminants, some of which may be toxic, carcinogenic, or endocrine disruptors, as well as, persistent in the environment. Additionally, increasing contamination of surface waters by wastewater effluents has made water treatment processes more challenging and expensive. The presence of these pollutants in the receiving water body may have negative effects on aquatic species and often pose potential human health risks through the reuse of treated wastewater for drinking purposes and other household use. In countries like South Africa, Namibia, USA, Singapore and Australia, water agencies are intensifying wastewater reclamation/wastewater reuse as part of their water resource agenda: in order to meet the demands of the growing populations. Nowadays, water reuse is generally considered as a viable method of water supply management. This study focused on the identification of the occurrence, quantification of emerging contaminants and evaluation of removal efficiency in wastewater treatment processes of three classes of emerging contaminants (ECs) in wastewater: 1) six types of perfluorinated compounds (PFCs), namely; perfluorooctanoic acid (PFOA), Perfluorooctane sulphonate (PFOS), perfluoroheptanoic acid (PFHpA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUDA); 2) bisphenol A (BPA); and 3) Acetaminophen (ACP). These contaminants were identified and quantified in four wastewater treatment plants in the Western Cape. These treatment plants include three WWTPs in Cape Town, namely: Bellville WWTP, Scottsdene WWTP and Zandvliet WWTP and one WWTP in the central Karoo (Beaufort West wastewater reclamation plant).
112

Wastewater Treatment Plant Control

Knowles, David Milton 01 January 1972 (has links) (PDF)
This report is the result of investigation of the feasibility of increasing the use of autamatic controls at the Florida Technological University Wastewater Treatment Plant. This investigation was to include a literature search and visits to wastewater treatment plants. During the writers course of study, he was privileged to make a series of tests of a residual chlorine analyzer which was made in the school shop. Since this work was closely related to automatic controls the data are included in this report.
113

Effects of sewage treatment plant effluents on mollusks and fish of the Clinch River in Tazewell County, Virginia

Goudreau, Stephanie E. 22 June 2010 (has links)
The Clinch River is renown for its rich mollusk and fish assemblages, including many endemic species. New sewage treatment plants (STP's) have recently been constructed along the Clinch River in Virginia, raising concern because of the disappearance of mollusks below existing STP's. Field and laboratory studies were conducted to determine mollusk and fish distribution in proximity to two STP's in Tazewell County, and the tolerance of two mollusk species to mono chloramine and unionized ammonia, the major toxicants in domestic STP effiuent. River reaches up to 3.75 km downstream of the STP outfalls at Tazewell and Richlands were depauperate of mussels. Tolerance to effluent seemed to vary among snails, sphaeriid clams, and the Asiatic clam <i>Corbicula flumineaK</i>. After an initial toxic zone below the Tazewell outfall, abundance of fish appeared to increase by 0.45 km below the outfall. The effluent at Richlands eliminated intolerant species, and more tolerant species were present as far as 0.45 km below the outfall. Laboratory bioassays with glochidia of <i>Villosa nebulosa</i> resulted in 24-h EC₅₀ and LC₅₀ values of 0.042 and 0.084 mg/L monochloramine, respectively, and 24-h EC₅₀ and LC₅₀values of 0.237 and 0.284 mg/L unionized ammonia, respectively. Glochidia rank among the most sensitive invertebrates in their tolerance to these toxicants. The snail <i>Pleurocera unciale unciale</i> was moderately sensitive, with 96-h LC₅₀ values of 0.252 mg/L mono chloramine and 0.742 mg/L unionized ammonia. Comparison of monochloramine and unionized ammonia concentrations monitored at 0.10 km below the outfalls indicated that mono chloramine was the major toxicant likely affecting fauna. / Master of Science
114

Comparison of lime and sodium hydroxide for the control of gas production from sewage sludges

Thota, Ravi Meher 31 October 2009 (has links)
The effects of lime and sodium hydroxide on gas production from stored sewage sludge were examined. The impact of calcium on gas production was also investigated. The rate and volume of gas production and change in pH over time were monitored in all the reactors in an effort to study the relationship between chemical dose, pH, and gas production. The duration of inhibition of gas production increased with the lime dose. Gas production was initiated only after the pH in the reactors decreased to near 8.0. A decrease in pH was observed in all the lime dosed reactors with an initial pH less than 12.0. An initial pH greater than 12.0 was required to completely arrest organic acid and gas production. For the sludge used in this study, a quick lime dose of 0.36 Ib/lb of dry solids, which elevated the pH to higher than 12.0, was required for complete inhibition of gas production. Gas production and pH patterns observed in sodium hydroxide dosed reactors were similar to those in lime dosed reactors. A decrease in pH by nearly 2 pH units was observed in these reactors after calcium chloride addition. This was thought to be primarily due to the precipitation of calcium carbonate. Gas production after elutriation was observed in all the reactors with an initial pH less than 11.5. The volume of gas produced after elutriation decreased with increase in initial pH. An NaOH (19N) dose of 0.29 Ib/Ib of dry solids was required for permanent prevention of gas production. Calcium alone was not capable of arresting gas production but it reduced the total gas production in the reactors with a pH less than 7.5. At pH values greater than 7.5, calcium had little effect on gas production. / Master of Science
115

Achieving effective asset management for water and wastewater utilities: A comparison of policy options for a special district and a medium city

Dale, Cari K 01 January 2005 (has links)
This project developed a model for effective asset management drawn from successful programs in the United States, Australia, and New Zealand. Asset management practices were examined at the City of Ontario Utilities Department; a medium sized utility, and also at the Rainbow Municipal Water District, a small sized utility. Gaps between the ideal model and the existing practices were investigated.
116

Detection and quantification of nitrifying bacteria from South African biological nutrient removal plants

Ramdhani, Nishani 30 July 2013 (has links)
Submitted in fulfillment for the requirements for the Degree of Doctor of Technology: Biotechnology, Durban University of Technology, 2012. / Nitrification is a crucial step in biological nutrient removal (BNR) processes, mostly carried out by a group of nitrifying bacteria which includes ammonia-oxidising bacteria (AOB) and nitrite-oxidising bacteria (NOB). Nitrification failure has proven to be a common operational problem in full-scale wastewater treatment plants (WWTP) since nitrifying bacteria are very sensitive to sudden changes in environmental or plant operating conditions. The current investigation was carried out to advance our understanding of the distribution of nitrifying bacterial populations and their performance at three different BNR plants in KwaZulu-Natal, South Africa. The latest molecular techniques such as fluorescent in situ hybridisation (FISH)-confocal scanning laser microscopy (CSLM), polymerase chain reaction (PCR) and real-time quantitative PCR (Q-PCR) were applied to detect and quantify nitrifying bacteria. When using FISH to target the nitrifying population, it necessitated optimising pre-treatment protocols of the samples to improve accuracy during quantification. Sonication was found to be the superior method of dispersion based on the least disruption of nitrifier cell integrity, irrespective of the sludge type. The effect of plant configurations and wastewater characteristics on the distribution of the nitrifying bacterial population and subsequently on the nitrification performance was evaluated using FISH and PCR. FISH results revealed the dominance of Nitrosomonas (AOB), Nitrobacter (NOB) and Nitrospira (NOB) for all BNR plants. The 16S rRNA analysis of PCR products using genus-specific primers, revealed the presence of more than one species of the same group at these plants. Nitrosomonas spp. including Nitrosomonas halophila, Nitrosomonas eutropha, Nitrosomonas europaea, Nitrosomonas aestuarii and an unidentified Nitrosomonas spp. were found to dominate among the AOB and Nitrobacter vulgaris, Nitrobacter alkalicus, Nitrobacter hamburgensis and an unidentified Nitrobacter spp. were the dominant species for NOB. Among these species, Nitrosomonas aestuarii, Nitrosomonas europaea, Nitrobacter hamburgensis were detected only from the industrial wastewater samples. The efficiency of two commonly used techniques viz., FISH and Q-PCR for the detection of nitrifiers from WWTP were also studied and compared, specifically targeting Nitrobacter sp. Even though there were slight variations in the quantification results, changes in the Nitrobacter community at these plants were consistent for both FISH and Q-PCR results. Both techniques have their own limitations and advantages. This study has helped to add to the platform of understanding the distribution and activity of nitrifying bacteria by correlating population dynamics with the operational parameters at full-scale level. The observations made in this study will assist researchers and engineers to minimise future nitrification failure at full-scale BNR plants. This study also confirmed the highly complex activities of wastewater treatment processes, which is dependant on a number of factors. Specific AOB or NOB predominant in wastewater rather suggests that the wastewater type and characteristics may contribute to significantly different microbial environments. Among the AOB, Nitrosomonas dominated at all BNR plants throughout the study period and for NOB both Nitrobacter and Nitrospira were found in significant numbers but their dominance varied across the plants. These dissimilar, distinct distribution patterns could be attributed to their environment which in turn impacted on the nitrification performance of the system. It was also noted that the co-existence of more than one group of these communities at the same plant could help the plant escape complete functional failures such as nitrification, due to sudden changes in temperature and substrate concentrations, as this function can be performed by different groups. Although it would have been meritorious to conduct a nitrogen balance in this study, this was not possible since the research focused on full-scale systems. / National Research Foundation / D
117

Ecological and economic aspects of treating vegetable oil industrial effluent at Darvill Wastewater Works in Pietermaritzburg.

Moodley, Shomenthree. January 1997 (has links)
The dissertation analyses the economic and ecological aspects of Darvill Waste Water Works (WWW) through key indicators from Sustainable Development Records (SDR). The SDR study identifies disturbances caused by large concentrations of soap, oil and grease (SaG), therefore a framework of proposed solutions to dealing with these problems has also been investigated. The first component of the study highlights the importance of adequate indicators. Key indicators provide important information that is useful to management and policy makers. The SDR used to analyse the DarvillWWW in Pietermaritzburg provides relevant information for the management of Darvill WWW and Umgeni Water (UW), the City Council and the Department of Water Affairs and Forestry (DWAF). According to the SDR model the Works is identified as a service providing social institution. The operation of this institution affects the community of Pietermaritzburg as well as the surrounding natural environment. SDR uses the key indicators of effectiveness, Thrift and Margin to analyse the economic and ecological impacts of the service provided.The study incorporates relevant data for Darvill WWW during 1993- 1996. Effectiveness measures the degree of compliance with national water quality standards as set out by the DWAF. Compliance of the following variables, E.coli, Chlorine, Soluble Reactive Phosphate (SRP), Total Suspended Solids (TSS), Conductivity, Chemical Oxygen Demand (COD) and Ammonia were investigated. These variables produce varying trends. Increasing compliance is linked to improved plant efficiency while decreasing compliance is linked to the poor quality of industrial effluent. Industrial effluent containing large concentrations of SOG is a particular problem. Thrift measures the costs of operating the Works in terms of energy, chemicals, labour and capital. Overall financial, energy and labour thrift declined while chemical thrift increased. Increasing chemical thrift is due to the reduced consumption of chemicals as a result of a greater reliance on the process of biological phosphate removal. Decreasing thrift is related to increased costs of capital, energy and labour due to the deteriorating quality of vegetable oil effluent. Margin measures the deviation of non-complying samples from water quality standards. Analysis of the data produced varying trends. The following variables were analysed, E.coli, Chlorine, SRP, TSS, Conductivity, COD and Ammonia. Marginal difference is studied in an attempt to analyse those samples which do not comply with national standards. Deteriorating quality of industrial effiuent seems to be the reason for deviation from the standards. Chemical margin was also studied for the period between 1993-1996. Chemical margin is a comparison between the value of sludge produced and the cost of chemicals used to produce the sludge. The SDR study highlights deteriorating quality of industrial effluent as a cause for concern to Darvill WWW. Proposed management options are investigated to provide a workable solution. The second part of the study investigates alternate options for handling wet industrial effluent from the vegetable oil industries. These industries were identified as the source of large concentrations of SOG that were entering the Works which impacts negatively on the operational capacity, thereby increasing operating costs and decreasing the quality of the service provided. Vegetable oil industries were found guilty of discharging industrial effluent that did not meet the City standards into the sewers, they were also charged with illegal dumping into rivers. The study identified the interested and affected parties and alternate solutions were proposed to the problems. Interested and affected parties include UW, Pietermaritzburg City Council, DWAF. Some of the aspects that were investigated include the local industrial tariff, the drainage By-laws, national legislation, the "polluter pays" principle and the principle of pollution prevention. Economic incentives using economic instruments were reviewed. These include ecotaxes such as marketable/tradable permits and pollution charges. These instruments may allow for more equitable charges thereby promoting the "polluter pays" principle. The use of these instruments may be able to achieve a workable solution but further investigations are necessary. SDR analysis indicates that Darvill WWW seems to be effectively treating wastewater but operating costs are increasing in order to achieve compliance. These costs are being unfairly borne by the City ratepayers and UW and a more equitable situation is necessary. / Thesis (M.Env.Dev.)-University of Natal, Pietermaritzburg, 1997.
118

Impact of microbial and physico-chemical qualities of treated wastewater effluent on receiving water bodies in Durban.

Naidoo, Shalinee. 11 September 2014 (has links)
Increase in magnitude of the global freshwater crisis together with the constantly changing demographics, hydrological variability and rapid urbanization will allow for continuous over exploitation of existing water resources, in an attempt to satisfy the rising socioeconomic demands. Increasing pressure on existing wastewater treatment plants, together with inefficient hygiene practices have exacerbated the nutrient and microbiological loads constantly entering surrounding water systems. This, coupled with the use of outdated guidelines has resulted, not only in an increase in waterborne related diseases but also an increase in waterborne-disease-related deaths. The current study investigated the physicochemical and microbiological quality of treated effluent from two independent wastewater treatment plants as well as their impact on the receiving watershed within Durban, South Africa over a one year period. Microbiological and physicochemical profiles were determined using standard methods whilst conventional PCR was used for the seasonal detection of human enteric viruses. Monthly variations were observed for all parameters with eight and six out of 12 month samples exhibiting increases in turbidity at the discharge point for the NWWTP and NGTW respectively, relative to before chlorination. Similarly, increases in nitrate and phosphate levels at the discharge point were also noted with the highest being recorded during December (215.23%) and September (12.21%) respectively. Temperature profiles ranged between 12 – 26 °C and 12.7 – 26 °C for the NWWTP and receiving Umgeni River whilst for the NGTW and receiving Aller River, it ranged between 16.5 – 26 °C and 12 – 25.7 °C respectively. Seasonal averages revealed relatively high COD values downstream of the Umgeni River during winter (263.22 mg/l) and spring (177.93 mg/l). Eight out of twelve samples exhibited increases in turbidity at the discharge point for the NWWTP with the highest values obtained during April (76.43 NTU). Significant positive correlations (p ≤ 0.05) were observed upstream and downstream of the Umgeni River between temperature and BOD (r = 0.624); turbidity (r = 0.537); TDS (r = 0.437); TSS (r = 0.554) and DO (r = 0.516). Percentage reduction of bacterial indicators at the discharge point ranged between 0.52 – 100% and 41.56 – 100% across the sampling period for the NWWTP and NGTW, respectively. Treated effluent from both plants did not meet the required guidelines, with a 100% reduction in the faecal coliform load being detected only during October 2012 for both plants. In addition, higher levels of indicator bacteia were observed at the discharge point for the NWWTP during February 2013 with observed counts (in CFU/ml) as high as 12.27 x 103; 6.61 x 103; 2.99 x103; 1.6 x 103 and 1.17 x103 for total coliforms, E.coli, faecal coliforms, faecal streptococci and enterococci, respectively. Similarly, higher levels of both somatic and F-RNA bacteriophages were detected during April (106.67 PFU/ml), May (309.33 PFU/ml). June (346.67 PFU/ml) and August (126.67 PFU/ml) compared to samples collected before chlorination for the NWWTP. Enteroviruses were detected in 100% of unchlorinated final effluent samples, 87.5% of chlorinated final effluent and 93.75% of receiving river samples whilst human adenoviruses were detected in 50% of final effluent samples before chlorination, 62.5% in samples collected at the discharge point and 62.5% of river water samples. This study revealed that whilst the independent treatment plants monitored, exhibited effluent qualities that met acceptable standards for some parameters such as pH and temperature, the effluent quality fell short of other standard requirements. Ensuring efficient surveillance and management of existing treatment plants coupled with guideline revision and monitoring compliance is imperative in preventing further risk of pollution to both the environment and human health. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2013.
119

Water reclamation in Thurston County a review of LOTT's planned class A water expansion /

Smith, Kathryn Ann. January 1900 (has links) (PDF)
Thesis (M.E.S.)--Evergreen State College, 2009. / Title from title screen (viewed 4/15/2010). Includes bibliographical references (leaves 63-67).
120

Optimization of the woven fibre-immersed membrane bioreactor (WF-IMBR)

Shitemi, Kenneth Khamati, Pillay January 2017 (has links)
Submitted in fulfilment of the requirements for the Degree of Master of Engineering, Durban University of Technology, 2017. / In this research, the woven fibre microfiltration (WFMF) fabric which is produced locally in South Africa is used as a membrane material. It is cheaper in price in comparison with the current commercial membrane materials that are in use. The WFMF is also more robust when compared with the commercial membrane materials thus is able to withstand harsh working conditions. From previous studies on the WFMF, it has been shown that it can be used as a membrane material without any compromise to permeate quality. This research seeks to optimize the working conditions of this membrane material (WFMF) with an aim of achieving lower running costs and better anti fouling strategies in comparison to the commercial MBRs. The objectives and aims of this research was to come up with a MBR system whose running cost is lower than that for the commercial systems, which can be adapted for use in any environment, especially in the hardship regions where its robustness would be an added advantage. The performance of the WFMF submerged MBR was also optimised including antifouling operating regimes. This study was done in a pilot plant that was set up at Veolia wastewater treatment plant, Durban Metro Southern Works. The feed water for the pilot plant was pumped from the return activated sludge mixing chamber by means of a submersible pump. The MLSS concentration of the feed water was about 12 g/l. The various investigations that were conducted in the course of this research included the effect of spacing between membrane modules, relaxation steps and frequencies, evaluation of aeration rates and evaluation of coarse vs. fine bubbles which were all aimed at optimizing the performance of the immersed WFMF MBR. The permeate was checked for turbidity and COD levels to ensure that they were within the accepted water standards. From the experiments it is shown that the critical flux increased with an increase in aeration rate which is in concurrence with the literature and a starting flux of 30 LMH was chosen for the running of the pilot plant for the various experimental runs to be carried out. For the pipe diffuser height effect experimental run, the best results were achieved at a height of 5 cm below the membrane modules and the use of a pipe diffuser gave better results than the use of a disc diffuser. For the membrane module spacing effect the best results were obtained at the smallest possible width i.e. 3.5 mm. The best relaxation step sequence was found to be 9 mins on and 1 min off. COD, turbidity and DO was continuously determined during the course of the experimentation. Further studies should be done on use of the disc diffuser with increased surface area of aeration holes and also hole sizes of smaller diameters to check on its effectiveness as a means of reducing fouling on the membrane surface. / M

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