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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.
1

Selective coagulant recovery using the Donnan Membrane Process /

Prakash, Prakhar, January 2004 (has links)
Thesis (Ph. D.)--Lehigh University, 2004. / Includes vita. Includes bibliographical references (leaves 163-171).
2

The effects of dissolved oxygen concentration and biological solids retention time on activated sludge treatment performance

Parker, Jack Joseph, January 2001 (has links) (PDF)
Thesis (M.S.)--University of Tennessee, Knoxville, 2001. / Title from title page screen. Document formatted into manuscript-like pagination: x, 128 leaves : ill. (some col.). Vita. Includes bibliographical references (leaves 114-122).
3

Water treatment residual and vegetative filter strip effects on phosphorus transport dynamics

Green, Colleen H. January 2004 (has links)
Thesis (Ph. D.)--Colorado State University, 2004. / Includes bibliographical references.
4

Cytotoxic activity of Kigelia pinnata against melanoma and other neoplastic cell lines

Jackson, Simon James January 1996 (has links)
No description available.
5

An experimental and numerical study of flow distribution chambers

Wong, Voon Hon January 1999 (has links)
Flow distribution chambers are devices commonly used by the water industry to distribute flows in water and sewage treatment plants. These have simple designs, and are required to operate over a range of volumetric flowrates. Many chambers surveyed (Herbath and Wong, 1997b) were found to perform poorly. They suffered from flow mal-distribution, where the flow was not distributed according to design. The most common cause of flow mal-distribution was hypothesised to be due to the presence of a pipe bend below the chamber (Herbath and Wong, 1997a, 1997b). Therefore, an experimental and numerical study of the flow within a distribution chamber was conducted in this thesis to prove this hypothesis. A novel large-scale model (1: 13) of a typical distribution chamber was constructed. This allowed the collection of high quality and novel velocity and turbulence measurements near the free surface using hot film anemometry. The free surface location was measured using a vernier point gauge while the flow distribution between the outlets was metered by orifice plates. Records of the flow patterns were also kept. The experimental results showed that flow mal-distribution did not occur as expected since the model distribution chamber was designed with a long length of straight inlet pipe, to eliminate the suspected cause of flow mal-distribution. Novel velocity and water surface data were also collected in the experiments, which contributed towards the small body of knowledge in this area of research into flow distribution. CFD models of the physical model were created and solved using a commercial CFD code, CFX 4.1, developed by CFX International of AEA Technology. Steady state and transient two- and three-dimensional calculations of the symmetrical chamber were carried out in the course of the study. A novel adaptation of the existing code was made in obtaining solutions to the numerical models. A new solution strategy was made and refined in this stage of the research using the two-dimensional representation of the distribution chamber, for reasons of reduced computational time. Differencing schemes, surface sharpening, mass residuals, mesh refinement and different turbulence models were investigated during model refinement. The accuracies of the calculated results were determined by comparison with experimental results. It was found that the 3D model, incorporating the RNG k-c model, without surface sharpening, and using the Van Leer differencing scheme, gave good quantitative agreement with the experimental velocities, free surface location and flow distribution. The 2D results gave qualitatively good predictions. Quantitatively, the results were over-predicted which was due, to dimensional effects. The volume of the 2D model was reduced from the 3D model, while the inlet velocity was made the same. This replicated the momentum effects near the free surface that were the governing causes of flow mal-distribution. Nevertheless, this approach was much more practical in terms of computational effort. More importantly, the correct trends for flow mal-distribution could be predicted accurately. Therefore, the next stage of the research used the 2D model developed and validated here. This part of the research involved the novel adaptation of the existing symmetrical 2D results for investigating the asymmetric effects of pipe bends. Three different approaches for modelling the asymmetric effects of a pipe bend were investigated. The first, and the most simplistic, was to incline the incoming flow at an angle to the vertical. The second was to calculate the velocities and turbulence at the outlet of a simple 2D pipe bend, separate from the chamber. These calculated variables were then input into the chamber, to build up a picture of the asymmetric flow, iteratively. The third, and the most accurate method, was to couple the bend to the chamber. It was found that only the third method was capable of accurately representing the conditions within the chamber. Two different pipe bend. lengths were examined using the third approach. The distances chosen were typical of the bend distances found in some treatment plants. The results . from both simulations produced large flow mal-distribution and asymmetric flows within the chamber. A value of 10% difference between the flows from the two outlets was taken to be the maximum limit for mal-distribution. However, values of 44.5 % and 22.8 % were obtained for the larger pipe distance and short pipe distance respectively. Novel remediation strategies using numerical techniques were used to determine the most effective means of improving the flow distribution. The first, used a vertical flow splitter, placed directly above the chamber inlet. Although it altered the path of the jet, it was felt that it would be ineffective for all situations. Although the magnitude of the asymmetry was improved with the use of the splitter, the improvement was insufficient to warrant its recommendation. The other device tested was a horizontal plate located at a certain distance from the chamber inlet. For the longer bend case, a separation distance equivalent to two inlet hydraulic diameters was sufficient to deflect the jet, and reduced the magnitude of the flow asymmetry to around 2%. When the same plate location was used for the shorter bend case, the efficiency of the plate was reduced. Although there was an improvement in the distribution, the magnitude of the asymmetry was greater than 10%. The plate was subsequently lowered by half a hydraulic diameter. This gave a large improvement to the effectiveness of the plate, and the resulting asymmetry was reduced to 7.31 %. The horizontal plate was considered more promising since its function was to deflect and reduce the peak velocities of the jet. With the reduction in velocities, the magnitudes of the nonlinear terms in the Navier-Stokes equations are reduced. The solution to the equations would be more likely to be symmetrical.
6

Investigations into the Dynamic Behaviour of a Full Scale Municipal Activated Sludge Waste Water Treatment Plant

Holloran, Michael Francis 04 1900 (has links)
<p> Although both steady state and dynamic simulation studies of the activated sludge process are available, the data bases employed have traditionally been: derived from bench scale studies, derived from historical monitoring data, synthetic based on mathematical functions. Actual plant operating data, if available, would reflect full scale operation and would provide a much better data base to judge existing or future process models. This study was designed to provide a more comprehensive data base than presently existed on a full scale municipal activated sludge system. Both flow and component concentrations were continuously measured on two hour intervals for two periods of 10 days and 5 days duration. Streams sampled included the plant influent, the primary clarifier effluent, the aeration tank effluent, the secondary clarifier effluent, the activated sludge recycle and the waste sludge line. Based on total nitrogen and total phosphorus, the data were examined for mass flow closure around the aeration tank. A time dependent mixing model based on two unequal volume stirred tank reactors in series was found to adequately describe the observed variation in aeration tank input-output data. The measured aeration tank inflow and outflow was corrected to give a hydraulic balance using a statistical procedure which generates flow corrections based on expected measurement error. The resulting total nitrogen and total phosphorus material balances were found to improve based on a reduction of the residual sum of squares.</p> / Thesis / Master of Engineering (MEngr)
7

Disposição de resíduos gerados em estações de tratamento de água em estações de tratamento de esgoto / Disposal of water treatment plants sludge in wastewater treatment plants

Scalize, Paulo Sergio 08 August 2003 (has links)
O presente trabalho foi realizado em duas fases. Na primeira, foram estimados os efeitos produzidos nos decantadores primários de uma ETE, após receber resíduo da ETA-SC, que utiliza sulfato de alumínio como coagulante. Foram realizados ensaios em colunas de sedimentação, onde os parâmetros SST, SSV, cor, turbidez, DQO, coliformes totais, Escherichia coli e parasitas, pesquisados no sobrenadante, diminuíram com o aumento da quantidade de resíduo adicionado. Com relação aos sedimentos obtidos nas colunas de sedimentação, foi encontrada maior quantidade de ST e menor resistência específica nos lodos provenientes das colunas que receberam os resíduos da ETA-SC. No teste de atividade metanogênica, a concentração molar de metano foi reduzida nos sistemas que receberam resíduo da ETA-SC, influenciando negativamente no desenvolvimento dos microrganismos metanogênicas. As espécies de microrganismos do gênero Methanothrix sp foram inibidas, sendo encontradas em maior número no frasco-reator controle e em menor quantidade a medida que se aumentou a quantidade do resíduo adicionado. Nesta etapa foi constatado que o resíduo da ETA-SC poderá apresentar interferências negativas sobre a digestão anaeróbia do lodo produzido em decantadores primários de uma ETE. Na segunda fase, na estação piloto, composta de lagoa de aeração seguida de lagoa de sedimentação, que recebeu resíduo da ETA-Fonte, que utiliza cloreto férrico como coagulante, foi verificado que tal resíduo melhorou a qualidade do efluente em termos de DQO, DBO, SST, turbidez, cor, amônio, nitrato, NTK e fosfato total. Os parâmetros ST, SDT, cloreto, nitrito, condutividade e pH não apresentaram diferenças significativas. Em relação ao exame microscópico não houve influências negativas no licor misto das lagoas de aeração. O lodo formado nas lagoas de sedimentação piloto apresentou-se em maior quantidade na lagoa que recebeu resíduo da ETA-Fonte. Neste lodo a resistência específica a filtração foi menor em comparação ao lodo da lagoa que não recebeu resíduo da ETA-Fonte. A desidratação deste lodo por centrifugação necessitou menor quantidade de polieletrólito. Baseado neste estudo não foi verificado interferências que possa impedir o lançamento do resíduo da ETA-Fonte na ETE-Araraquara. / This work was carried out in two phases. Effects of disposing the residues from a water treatment plant - ETASC, which uses alum as primary coagulant on the primary settling tanks was evaluated in the first one. Sedimentation tests using column indicated that parameters such as TSS, VSS, colour, turbidity, COD, total coliformes totais, Escherichia coli e parasites in the supernatant decreased with the increase of the amount of the water treatment wastes added to the column. With relation to the sediments produced in the column, it was found great amount of TS and lower specific solids resistance in those generated in the columns where the water treatment plant residues-WTPR were used. Molar concentration of methane was reduced in the tests performed with the sediments produced with water treatment plant residues and thus, altering negatively the development of methanogenic organisms. The growth of species of microorganism of genera Methanothrix sp was inhibited, which were found in great number in the control flask (with out WTPR) and in lower number as it was increased the amount of WTPR added to the column. It was observed that the WTPR generated in the city water treatment plant may interfere in the anaerobic digestion of sludge produced in primary settling tanks of a wastetreatment plant. A continuous pilot plant was operated in the second phase, which consisted of two aerated lagoon each one followed by a settling lagoon. Waste and WTPR from a watter treatment plant which ferric chloride were fed in one of the systems. It was observed that the use of WTPR improved the effluent quality of the settling lagoon evaluated in terms of COD, BOD, TSS, turbidity, color, ammonium, nitrate, TKN and total phosphate. Some parameters, such as TS, TDS, chloride, nitride, conductivity and pH did not present significant differences in both systems. Microscopic examinations indicated that no influence resulted in the aerated lagoon mixed liquor. A higher amount of sludge was formed in the lagoon system which received the WTPR. The specific resistance to filtration of this sludge was lower than that formed in the lagoon system with out WTPR addition. When dewatering both sludges, that one produced with the addition of WTPR required less amount of polymer. It was concluded that the WTPR produced in the water treatment plant of Araraquara may be disposed in the city wastewater treatment plant.
8

Avaliação da disposição de lodo gerado numa estação de tratamento de água em reator anaeróbio de fluxo ascendente e manto de lodo UASB. / Evaluation of throwing sludge generated on a treatment water station with an upflow anaerobic sludge blank reactor (UASB).

Alvarez Rosario, Carlos Gonzalo 13 March 2007 (has links)
As estações de tratamento de água de abastecimento (ETAs) têm a finalidade de fornecer água potável. Neste processo de tratamento de água são gerados resíduos, os quais historicamente têm sido lançados em cursos de água, aumentando o nível de degradação destes. O presente trabalho teve por objetivo avaliar o impacto do lançamento desses resíduos numa estação de tratamento de esgoto (ETE) com reator anaeróbio de fluxo ascendente e manto de lodo (UASB), buscando estudar uma alternativa para a disposição adequada desses resíduos. Para o estudo da influência do lançamento do lodo da ETA em um reator de fluxo ascendente e manto de lodo (UASB) foram utilizados dois reatores em escala piloto. O esgoto utilizado para alimentar o sistema de tratamento foi proveniente do Conjunto Residencial da Universidade de São Paulo, já o lodo utilizado foi obtido na ETA da cidade de Juquitiba. A presente pesquisa foi dividida em três fases: a primeira etapa (Fase 1) constituiu-se na partida dos reatores UASB 1 e UASB 2; na segunda etapa (Fase 2) estudou-se o desempenho dos sistemas sob regime estabilizado; e na terceira e última etapa (Fase 3) o reator UASB 2 recebeu adição de duas dosagens de lodo de ETA, sendo a primeira de 50 mg/L (Fase 3a) e a segunda de 75 mg/L (Fase 3b), em termos de sólidos em suspensão totais. As condições operacionais adotadas foram: vazão de 50 L/h e tempo de detenção hidráulico (TDH) de 8 horas. Os resultados apresentados no texto indicaram que, com o acréscimo de lodo da ETA, o reator UASB 2 não teve seu desempenho afetado negativamente, e a remoção de matéria orgânica em termos de DQO, DBO e fósforo foi muito próxima entre os reatores UASB 1 e UASB 2. Conclui-se que com a disposição de lodo em um reator UASB, não haverá interferência prejudicial no desempenho operacional do mesmo. / Water treatment stations have the purpose of providing potable water. In this process of water treatment, a variety of residuals are produced; these, historically have been discharged into water streams, increasing the water pollution. The objective of this work was to evaluate the impact of discharging residuals in a treatment station with an Upflow Anaerobic Sludge Blank Reactor (UASB), and try to find an alternative for the appropriate treatment of these. For the study of the influence of discharging WTA sludge into a UASB reactor, two reactors in pilot scale were used. The disposals used to feed the treatment system came from the apartment building where Sao Paulo University students live, while the sludge used was obtained in the water treatment station from Juquitiba city. This research has been divided into three stages: The first one (Stage 1) consisted of the setting of the reactors UASB1 and UASB2. In the second stage (Stage 2) it was studied the performance of the systems in the balance regime. In the third one (Stage 3), the reactor UASB2 received the supply of two portions of WTA sludge, the first one of 50 mg/L (Stage 3a) and the second one of 75 mg/L (Stage 3b). These amounts are determined in terms of the TSS. The operational conditions adopted were flow of 50 L/h and TDH of eight hours. The results obtained indicated that with the addition of WTA sludge the reactor UASB2 did not show inferior performance. At the same time the organic material removal, in terms of DQO, DBO and phosphorous content, was similar between the reactors UASB1 and UASB2, concluding that with the supply of WTP sludge in the reactor UASB, there won\'t he detrimental effects in the reactor performance.
9

Avaliação da disposição de lodo gerado numa estação de tratamento de água em reator anaeróbio de fluxo ascendente e manto de lodo UASB. / Evaluation of throwing sludge generated on a treatment water station with an upflow anaerobic sludge blank reactor (UASB).

Carlos Gonzalo Alvarez Rosario 13 March 2007 (has links)
As estações de tratamento de água de abastecimento (ETAs) têm a finalidade de fornecer água potável. Neste processo de tratamento de água são gerados resíduos, os quais historicamente têm sido lançados em cursos de água, aumentando o nível de degradação destes. O presente trabalho teve por objetivo avaliar o impacto do lançamento desses resíduos numa estação de tratamento de esgoto (ETE) com reator anaeróbio de fluxo ascendente e manto de lodo (UASB), buscando estudar uma alternativa para a disposição adequada desses resíduos. Para o estudo da influência do lançamento do lodo da ETA em um reator de fluxo ascendente e manto de lodo (UASB) foram utilizados dois reatores em escala piloto. O esgoto utilizado para alimentar o sistema de tratamento foi proveniente do Conjunto Residencial da Universidade de São Paulo, já o lodo utilizado foi obtido na ETA da cidade de Juquitiba. A presente pesquisa foi dividida em três fases: a primeira etapa (Fase 1) constituiu-se na partida dos reatores UASB 1 e UASB 2; na segunda etapa (Fase 2) estudou-se o desempenho dos sistemas sob regime estabilizado; e na terceira e última etapa (Fase 3) o reator UASB 2 recebeu adição de duas dosagens de lodo de ETA, sendo a primeira de 50 mg/L (Fase 3a) e a segunda de 75 mg/L (Fase 3b), em termos de sólidos em suspensão totais. As condições operacionais adotadas foram: vazão de 50 L/h e tempo de detenção hidráulico (TDH) de 8 horas. Os resultados apresentados no texto indicaram que, com o acréscimo de lodo da ETA, o reator UASB 2 não teve seu desempenho afetado negativamente, e a remoção de matéria orgânica em termos de DQO, DBO e fósforo foi muito próxima entre os reatores UASB 1 e UASB 2. Conclui-se que com a disposição de lodo em um reator UASB, não haverá interferência prejudicial no desempenho operacional do mesmo. / Water treatment stations have the purpose of providing potable water. In this process of water treatment, a variety of residuals are produced; these, historically have been discharged into water streams, increasing the water pollution. The objective of this work was to evaluate the impact of discharging residuals in a treatment station with an Upflow Anaerobic Sludge Blank Reactor (UASB), and try to find an alternative for the appropriate treatment of these. For the study of the influence of discharging WTA sludge into a UASB reactor, two reactors in pilot scale were used. The disposals used to feed the treatment system came from the apartment building where Sao Paulo University students live, while the sludge used was obtained in the water treatment station from Juquitiba city. This research has been divided into three stages: The first one (Stage 1) consisted of the setting of the reactors UASB1 and UASB2. In the second stage (Stage 2) it was studied the performance of the systems in the balance regime. In the third one (Stage 3), the reactor UASB2 received the supply of two portions of WTA sludge, the first one of 50 mg/L (Stage 3a) and the second one of 75 mg/L (Stage 3b). These amounts are determined in terms of the TSS. The operational conditions adopted were flow of 50 L/h and TDH of eight hours. The results obtained indicated that with the addition of WTA sludge the reactor UASB2 did not show inferior performance. At the same time the organic material removal, in terms of DQO, DBO and phosphorous content, was similar between the reactors UASB1 and UASB2, concluding that with the supply of WTP sludge in the reactor UASB, there won\'t he detrimental effects in the reactor performance.
10

Disposição de resíduos gerados em estações de tratamento de água em estações de tratamento de esgoto / Disposal of water treatment plants sludge in wastewater treatment plants

Paulo Sergio Scalize 08 August 2003 (has links)
O presente trabalho foi realizado em duas fases. Na primeira, foram estimados os efeitos produzidos nos decantadores primários de uma ETE, após receber resíduo da ETA-SC, que utiliza sulfato de alumínio como coagulante. Foram realizados ensaios em colunas de sedimentação, onde os parâmetros SST, SSV, cor, turbidez, DQO, coliformes totais, Escherichia coli e parasitas, pesquisados no sobrenadante, diminuíram com o aumento da quantidade de resíduo adicionado. Com relação aos sedimentos obtidos nas colunas de sedimentação, foi encontrada maior quantidade de ST e menor resistência específica nos lodos provenientes das colunas que receberam os resíduos da ETA-SC. No teste de atividade metanogênica, a concentração molar de metano foi reduzida nos sistemas que receberam resíduo da ETA-SC, influenciando negativamente no desenvolvimento dos microrganismos metanogênicas. As espécies de microrganismos do gênero Methanothrix sp foram inibidas, sendo encontradas em maior número no frasco-reator controle e em menor quantidade a medida que se aumentou a quantidade do resíduo adicionado. Nesta etapa foi constatado que o resíduo da ETA-SC poderá apresentar interferências negativas sobre a digestão anaeróbia do lodo produzido em decantadores primários de uma ETE. Na segunda fase, na estação piloto, composta de lagoa de aeração seguida de lagoa de sedimentação, que recebeu resíduo da ETA-Fonte, que utiliza cloreto férrico como coagulante, foi verificado que tal resíduo melhorou a qualidade do efluente em termos de DQO, DBO, SST, turbidez, cor, amônio, nitrato, NTK e fosfato total. Os parâmetros ST, SDT, cloreto, nitrito, condutividade e pH não apresentaram diferenças significativas. Em relação ao exame microscópico não houve influências negativas no licor misto das lagoas de aeração. O lodo formado nas lagoas de sedimentação piloto apresentou-se em maior quantidade na lagoa que recebeu resíduo da ETA-Fonte. Neste lodo a resistência específica a filtração foi menor em comparação ao lodo da lagoa que não recebeu resíduo da ETA-Fonte. A desidratação deste lodo por centrifugação necessitou menor quantidade de polieletrólito. Baseado neste estudo não foi verificado interferências que possa impedir o lançamento do resíduo da ETA-Fonte na ETE-Araraquara. / This work was carried out in two phases. Effects of disposing the residues from a water treatment plant - ETASC, which uses alum as primary coagulant on the primary settling tanks was evaluated in the first one. Sedimentation tests using column indicated that parameters such as TSS, VSS, colour, turbidity, COD, total coliformes totais, Escherichia coli e parasites in the supernatant decreased with the increase of the amount of the water treatment wastes added to the column. With relation to the sediments produced in the column, it was found great amount of TS and lower specific solids resistance in those generated in the columns where the water treatment plant residues-WTPR were used. Molar concentration of methane was reduced in the tests performed with the sediments produced with water treatment plant residues and thus, altering negatively the development of methanogenic organisms. The growth of species of microorganism of genera Methanothrix sp was inhibited, which were found in great number in the control flask (with out WTPR) and in lower number as it was increased the amount of WTPR added to the column. It was observed that the WTPR generated in the city water treatment plant may interfere in the anaerobic digestion of sludge produced in primary settling tanks of a wastetreatment plant. A continuous pilot plant was operated in the second phase, which consisted of two aerated lagoon each one followed by a settling lagoon. Waste and WTPR from a watter treatment plant which ferric chloride were fed in one of the systems. It was observed that the use of WTPR improved the effluent quality of the settling lagoon evaluated in terms of COD, BOD, TSS, turbidity, color, ammonium, nitrate, TKN and total phosphate. Some parameters, such as TS, TDS, chloride, nitride, conductivity and pH did not present significant differences in both systems. Microscopic examinations indicated that no influence resulted in the aerated lagoon mixed liquor. A higher amount of sludge was formed in the lagoon system which received the WTPR. The specific resistance to filtration of this sludge was lower than that formed in the lagoon system with out WTPR addition. When dewatering both sludges, that one produced with the addition of WTPR required less amount of polymer. It was concluded that the WTPR produced in the water treatment plant of Araraquara may be disposed in the city wastewater treatment plant.

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