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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.
21

Assessment of raw and treated sewage using in vitro assays

Booysen, Robin Alvin January 2014 (has links)
>Magister Scientiae - MSc / Water scarcity is becoming an increasingly relevant problem for urban centres, especially in Southern Africa. However, water availability is not the only concern for consumers, because water quality is just as relevant. Many studies have revealed adverse health effects in organisms exposed to polluted waters, and the main source of that water pollution was traced back to sewage treatment works (STWs). Physiological systems that are affected include the endocrine system (as well as the reproductive system) and the immune system. Recently, the Stellenbosch STW started upgrading its facility, but this procedure would also affect the STW‘s operations. Stellenbosch STW uses an activated sludge treatment, but also employs trickling filters (biofilters). After screening and grit removal, wastewater enters trickling filters, and then undergoes activated sludge treatment (aerobic basin). After activated sludge treatment (and settling) some water is chlorinated before entering a maturation pond. The other water goes directly to a larger maturation pond (for a longer period), instead. The final effluent then gets discharged into the Veldwagters River. Since STW operations is an important factor in STW effluent quality, this study aimed to investigate the water quality (at Stellenbosch STW) during the upgrade. Specifically, the bacterial quality, the steroidal quality (testosterone, progesterone, estrone: E1, 17 β- estradiol: E2 and 17 α-ethinyl estradiol: EE2) and the potential immunotoxic quality of waters were assessed. Water samples were collected after the grit removal (influent), after the trickling filters (biofilter effluent), while it was leaving the aerobic basin activated sludge effluent) and as it was leaving the maturation ponds (final effluent). To determine bacterial quality a semi-quantitative ReadyCult® assay was performed on raw water samples (detects total coliforms and Escherichia coli). Bacterial levels were high for all influent samples, water from the biofilter, water from the aerobic digester (activated sludge) and the final effluent (most days). The first collection date, however, showed less than 1cfu/mL of both E. coli and total coliforms for the final effluent. Raw water also underwent solid phase extraction, before the steroid concentrations were determined by enzyme-linked immunosorbent assays (ELISAs). Steroid levels were very high in the influent. Each treatment progressively reduced the steroid concentration. However, progesterone concentration increased during the biofilter treatment. The increase in progesterone was probably due to bacterial de-conjugation of hydrophilic-progesterone-conjugates. Nonetheless effluent steroid levels were significantly lower than the influent. Steroid reduction through the Stellenbosch STW was 96%, 95%, 55%, 78% and 87% for testosterone, progesterone, estrone, estradiol and ethinyl estradiol respectively. Much variability in steroid concentrations was noted between sampling dates. The activated sludge treatment was the best at reducing steroid concentration. Nonetheless, the STW still discharged steroids into the environment. Finally, the humoral immune effects of Stellenbosch STW influent and effluent was determined by using hybridoma cells and assessing affects on antibody production. Antibody levels were then detected by ELISA. No adverse effects to antibody synthesis/secretion were noted as a result of exposure to either influent or effluent.
22

Structural and functional diversity of epilithic bacterial communities in streams : effects of pollution

Mahmoud, Huda Mahmoud Abdullah January 2002 (has links)
No description available.
23

The effect of high salinity on the performances of activated sludge process and plastic trickling filter /

Wong, Yiu-kam. January 1981 (has links)
Thesis (M. Phil.)--University of Hong Kong, 1982.
24

Kraven på ägare till minireningsverk skiljer sig åt mellan olika kommuner

Stenbacka, Nina January 2015 (has links)
Discharge of inadequately treated waste water containing nutrients such as phosphorus and nitrogen as well as organic matter and bacteria is associated with a risk of eutrophication and contamination. The Swedish government has decided upon several Environmental Quality Objectives aiming to reduce the emissions of nutrients to water bodies. In Sweden, there are between 675 000 to 1 000 000 on-site sewage systems. Recent studies have shown that the function of small sewage treatment plants is in many cases insufficient. To prevent this regular service and supervision by a professional is needed. The focus of this study are small sewage treatment plants which use a technique where mechanical, chemical and/or biological reduction of pollutants is being used in the same facility to reduce nutrients in household wastewater. The aim of the study is to investigate how different municipalities ensure that small sewage treatment plants fulfill the requirements and reduce pollutants as efficient as the manufacturers claim. To do this, a survey was carried out, leading to a data-set that is covering more than 90 municipalities. The results show that many municipalities lack resources to ensure that small sewage treatment plants work properly. Operation and maintenance of the plants is an important issue, and should be given much more attention. Therefore the municipalities should request more documentation from the owners both before and after installation to make sure that the small sewage treatment plant can fulfill the required standard. About half of the municipalities demand that the owners acquire some kind of service agreement with the manufacturer.  If small sewage treatment plants should be a wastewater treatment solution that we can rely on in the future, there is a need of evaluating and analyzing these facilities more systematically.
25

The effect of high salinity on the performances of activated sludge process and plastic trickling filter

Wong, Yiu-kam. January 1981 (has links)
Thesis (M.Phil.)--University of Hong Kong, 1982. / Also available in print.
26

Tratamento físico-químico de efluentes de curtume por meio de filtros de membrana seletiva

Geromel, Camila Gabriela Alexandre [UNESP] 12 July 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:29:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-07-12Bitstream added on 2014-06-13T20:19:10Z : No. of bitstreams: 1 geromel_cga_me_ilha.pdf: 14105785 bytes, checksum: e0c2381cfa1566d3045b06433057e142 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Historicamente, as indústrias de curtimento de couro são consideradas extremamente poluidoras devido aos seus rejeitos com altas concentrações de matéria orgânica e metais pesados, características que influenciam em vários parâmetros de análise de efluentes, tais como DBO, DQO e sólidos totais. Vários trabalhos foram desenvolvidos, tendo como objeto de estudo o efluente da empresa Fuga Couros Jales Ltda, sediada no município de Jales/SP. O reator anaeróbio UASB em etapa única foi utilizado primeiramente, como dispositivo de tratamento, e posteriormente foi analisado este mesmo reator combinado a pré-tratamento físico químico e pós-tratamento biológico, no entanto nenhum deles apresentou satisfatória eficiência da remoção de DBO, assim como também não atenderam as exigências da legislação vigente, em praticamente quase todos os parâmetros analisados. O presente trabalho teve como objeto de estudo o efluente deste Curtume e seu objetivo principal foi reduzir a carga de compostos de enxofre por oxidação química e reduzir a carga orgânica e de sólidos nas etapas de coagulação-floculação-sedimentação com posterior separação por membrana microfiltrante, e a redução dos sólidos remanescentes no efluente, na etapa de ultrafiltração por membrana, a concentrações aceitáveis para o descarte de efluentes. Para tanto, foram analisados previamente em jar-test uma faixa de pH adequada de trabalho para adição de cloreto férrico e o policloreto de alumínio, assim como analisar seus comportamentos quanto à eficiência de remoção de sólidos e, com relação ao peróxido de hidrogênio, permanganato de potássio e sulfato manganoso quanto à sua eficiência na oxidação de sulfeto. Posteriormente, foram analisadas as interações entre cada um destes reagentes e, em posse dos resultados destas análises, optou-se por aplicar o sulfato... / Historically, the industries of leather tanning are considered highly polluting due to its tailings with high concentrations of organic matter and heavy metals, characteristics that influence on several effluent parameters, such as BOD, COD and total solids. Several studies have been developed, object of to study, the effluent from the company Fuga Couros Jales Ltda, whose locate in Jales/SP city, Brazil. The UASB reactor in single step was used on time first as a treatment device, and later the same reactor combined physical and chemical pre-treatment and post-biological treatment, however none showed removal efficiencies of DBO satisfactory, and also did not reached the goal of the current legislation practically in all analyzed parameters. This research had as object of its study the tannery effluent and its main goal was to reduce the sulfur compounds concentration by chemical oxidation, organic loading and solids reduction in the stages of coagulation-flocculation-sedimentation with subsequent microfiltration membrane separation, and, the reduction of solids still remaining in the wastewater, in ultrafiltration membrane step to acceptable concentrations for effluent disposal. Therefore, were analyzed previously in Jar-Test a pH range suitable for working with the ferric chloride and polyaluminium chloride, and, analyzing their behavior as regards the solids removal efficiency and, with respect to hydrogen peroxide, potassium permanganate and manganous sulfate as the efficiency in the sulfide oxidation. Subsequently, we analyzed the interactions between each of these reagents, and ownership of the results of these analyzes, we chose to apply the manganous sulfate and ferric chloride to the physical-chemical treatment. The proposed treatment presents a good sulfide and suspended solids removal (62% and 96%.), However... (Complete abstract click electronic access below)
27

The Design and Testing of a Waterwaste Treatment Process suitable for Arctic Application

Bromley, David E.G. 10 1900 (has links)
The purpose of the project was to design and test the components of a potential package sewage treatment plant suitable for the Arctic environment. The designed treatment plant was simplistic in concept while utilizing the advantages of both biological and physical-chemical treatment. The system was tested over a ten-week period. The emphasis of the testing was on treatment of high-strength wastes. In addition the effects of temperatures and system start-up-shutdown conditions were assessed. The results indicated that the system operated well under most of the conditions tested. Both the physical-chemical and biological processes complemented each other with the former providing the necessary treatment at start-up and the latter providing low cost treatment once the system had been in. operation for a month. With the high degree of treatment performance achieved, it was felt the process was feasible for Arctic application. However, further testing was recommended to develop the complete package unit. / Thesis / Master of Engineering (ME)
28

An economic approach to water supply planning in southeastern Virginia

Anderson, William Bagwell 23 February 2010 (has links)
An examination was conducted of alternative responses to the water supply situation in four cities in southeastern Virginia. Cost/benefit analyses were performed for the provision of projected levels of use and for reductions in those levels of use achieved with the use of quotas, price increases, and water saving devices. An important element of these analyses was the consideration of the costs incurred as a result of waste water treatment with different levels of water use. The levels of the principal types of water use were estimated for each city. This provided a basis for the projection of water demand curves necessary for estimating the value of water. Optimal schedules for the development of additional water sources were derived through the examination of water demand, relative to the costs of operating and expanding water supply and waste water. treatment facilities. / Ph. D.
29

Disposição de lodo adensado de ETA em ETE com tratamento primário quimicamente assistido / Thickened water treatment sludge disposal in a wastewater treatment presenting a chemically enhanced primary treatment

Pereira, Vanessa Egidio 19 August 2018 (has links)
Orientador: Edson Aparecido Abdul Nour / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-19T04:53:17Z (GMT). No. of bitstreams: 1 Pereira_VanessaEgidio_M.pdf: 4329646 bytes, checksum: a31a8ea164fb943468ec91be8b81ab42 (MD5) Previous issue date: 2011 / Resumo: Os sistemas de tratamento, para a potabilização da água ou para a redução da quantidade de poluentes presentes no esgoto antes de seu lançamento em corpos hídricos, englobam processos físicos, químicos e biológicos, sendo a geração de resíduos inerente tanto à concepção das estações de tratamento de água (ETA), quanto das estações de tratamento de esgotos (ETE). Os resíduos sólidos gerados em estações de tratamento de água têm características inorgânicas, sendo eles os resíduos retirados da água bruta por meio de processos químicos e físicos e também os produtos utilizados no condicionamento da água e na coagulação para remoção dessas impurezas. Como alguns estudos apontaram para disposições semelhantes para os dois tipos de resíduos, apesar das características diferentes de cada um, a proposta deste trabalho foi a de avaliar a possibilidade de tratamento combinado desses resíduos, aproveitando as diversas vantagens de cada material e verificando os impactos que podem ser gerados no tratamento do efluente. Utilizando essa premissa, foi avaliado o potencial de utilização de um lodo adensado proveniente de uma ETA como auxiliar em uma ETE que apresenta uma etapa utilizando processo físico-químico de tratamento. O estudo e levantamentos apresentados nesse trabalho tiveram por propósito apontar para uma solução técnica viável para a disposição do lodo gerado na estação de tratamento de água (ETA), adensado na estação de tratamento de lodo (ETL), transportado e lançado na estação de tratamento de esgotos (ETE), no município de Itatiba. Com base no trabalho desenvolvido, foi possível confirmar que o adensamento de lodo em sacos de geotecido possibilita que a água deles drenada possa ser lançada em córregos, pois atende aos padrões de lançamento exigidos pelas leis vigentes; o lodo, adensado na ETL e lançado na ETE, não prejudicou a eficiência do tratamento dos esgotos quanto à remoção de carga orgânica e sólidos suspensos totais, principalmente porque o processo adotado também utiliza coagulantes. Contudo, o limitante para o aumento do lançamento é determinado pelas condições em que foram consideradas para o projeto da ETE, principalmente quanto a carga de sólidos e volume afluente / Abstract: Treatment systems, even for water potabilization or to reduce the amount of pollutants in wastewater, include physical, chemical and biological processes, and waste generation are inherent to water or sewage treatment plants. Solid waste generated in water treatment plants have inorganic characteristic, being removed from raw water by chemical and physical processes and also products used in the conditioning of water and coagulation. The wastes generated in sewage treatment plants are derived from biochemical reactions and from decomposition of organic matter present in wastewater. As some studies have pointed to similar disposal solutions for both types of waste, despite their different characteristics, the purpose of this study was to evaluate the possibility of combined treatment of such waste, using the many advantages of each material and checking the impacts that they could generate in the sewage treatment. Using this premise, the potential use of a thickened sludge from a water treatment plant as to assist in a wastewater treatment plant was evaluated. The study and surveys presented here had the purpose to point a viable technical solution for the disposal of sludge generated in a water treatment plant narrow in the sludge treatment plant, transported and released at sewage treatment plant in Itatiba, São Paulo, Brazil. Based on the work developed, it was confirmed that the thickening of sludge in geotec bags allows water drained from them to be released into rivers, because it meets the discharge Brazilian standards required; the thickened sludge did not impair the efficiency of sewage treatment on organic load removal or suspended solids removal, mainly because the process adopted also uses coagulants. However, limiting the increase in the release is determined by project conditions, especially as the influent volume and solids load / Mestrado / Saneamento e Ambiente / Mestre em Engenharia Civil
30

Diatom analyses of sediment from Himmerfjärden estuary, southern archipelago of Stockholm : has the water discharge from a constructed sewage treatment plant led to eutrophication?

Elander, Lina January 2015 (has links)
A sediment core from Himmerfjärden estuary, south of Stockholm, was examined to detect records of eutrophication on the site since the opening of the sewage treatment plant Himmerfjärdsverket in 1974. The core was analysed with respect to the diatom record and lithology. Four macrofossil that were found in the sediment were dated using 14C-dating.    This study aims to detect changes in the environment of Himmerfjärden by using the diatom stratigraphy record. The results have been interpreted and discussed regarding natural environmental and climate change and/or anthropogenic impact, and detected changes will be associated with the history of the sampling site. The results show that the lowermost zone started to deposit around 1300-1490 cal yr BP and the homogeneous sediment indicates that the area was not suffering from hypoxia at that time. There is a successive transition towards more distinct lamination further up in the core which show that the environment in Himmerfjärden have changed and become hypoxic. This may have to do with factors such as the opening of heavily trafficked Södertälje Canal, and also the increased nutrient input from Himmerfjärdsverket.    This study could be a part of the process of working towards a “good environmental status” in the Baltic Sea. However, continued and improved work is needed for further and more accurate interpretations.

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