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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

Effect of a curtain drain on a mound septic system :: a comparative study.

Raabe, Joyce G. 01 January 1982 (has links) (PDF)
No description available.
2

Determination of fluorinated alkyl substances in aqueous systems

Schultz, Melissa M. 09 December 2004 (has links)
Fluorinated alkyl substances, which can be persistent, toxic, and bioaccumulative, have been quantitated in many densely populated and remote regions, including in air, surface waters, groundwater, and biota; however, little is known about their transport or behavior in the environment. Wastewater effluent is one of the principal routes for introducing environmental contaminants into aquatic environments. The partitioning behavior of fluorinated alkyl substances between aqueous and particulate phases is not well characterized; thus, sorption onto sludge can be a removal mechanism of fluorinated alkyl substances from the wastewater stream. This is another route into the environment if the biosolids are land-applied. In an attempt to analyze for the fluorinated alkyl substances in wastewater, known aqueous-film-forming-foam (AFFF)-laden groundwater sampled from 3 military bases was used to develop an assay using liquid chromatography (LC), electrospray ionization (ESI) tandem mass spectrometry (MS/MS). While working on the method development, fluorotelomer sulfonates were detected at Wurtsmith AFB, MI, and Tyndall AFB, FL, where total fluoroatkyl sulfonates ranged respectively from below quantitation (���0.60 ��g/L) to 182 ��g/L and from 1100 ��g/L to 14,600 ��g/L. The LC ESI-MS/MS method was modified to quantitate fluorinated alkyl sulfonates in wastewater by incorporating a htgh volume sample loop (500 ��L), which lowered detection and quantitation limits by at least a factor of 50. This method was applied to 24 h composites of influents and effluents collected from treatment plants distributed nationwide. Fluorinated alkyl substances were observed at all 10 plants sampled, and each wastewater treatment plant was found to have a unique distribution of fluorinated alkyl substances, despite similar treatment processes. In 9 out of the 10 plants sampled, at least one class of fluorinated alkyl substance exhibited significant increases in the effluent as compared to the influent levels. The high-volume-injection LC ESI-MS/MS method was also used to monitor the mass flows of perfluoroalkyl sulfonates and carboxylates through a municipal wastewater treatment plant for 10 d. The perfluoroalkyl carboxylates were overall removed by the wastewater treatment process (25-40% removal). Perfluoroalkyl sulfonates were found to increase significantly (~200%) in the final effluent, and the fluoroalkyl sulfonamide acetic acids were found to increase by approximately 500% throughout the sludge process. From this plant, significant quantities of fluorochemicals are discharged with treated wastewater and biosolids, indicating that wastewater treatment plants are point sources of fluorinated alkyl substances and must be considered when determining origins and behavior of fluorinated alkyl substances in the environment. / Graduation date: 2005
3

Physicochemical Transformations within Ephemeral Streambeds Related to Sewage Effluent Releases

Phillips, R. A., Wilson, L. G., Sebenik, P. G. 06 1900 (has links)
Project Completion Report, OWRT Project No. A-040-ARIZ / Agreement No. 14-31-0001-4003 / Project Dates: July, 1972 - June, 1974 / Acknowledgement - The work upon which this report is based was supported by funds provided by the United States Department of the Interior, Office of Water Research and Technology, as authorized under the Water Resources Research Act of 1964. / Hydraulic and physicochemical measurements were made on treated sewage effluent releases at established locations within the channel of an ephemeral stream, the Santa Cruz River of Southern Arizona. Water quality samples were taken in sequence so that incremental flows at different hydrograph stages could be traced as the effluent moved downstream. Hydrographs obtained from two H -L flumes were used to calibrate a modified kinematic wave model. Hydraulic parameters from the kinematic model and physicochemical measurements from water quality samples were combined together into a statistical-empirical kinetic model of nitrogen transformations which may occur in sewage effluent releases. There was fair agreement between the measured data and the nitrogen species values calculated with the model. Measured nitrogen species values indicated that the rate of nitrification in sewage effluent releases is related to flow distance and physical characteristics of the stream.
4

Plant and soil effects from the surface application of poultry litter to unmanaged pasture

Lucero, Daniel William 11 June 2009 (has links)
The poultry industry, a vital economic force in Virginia, must dispose of vast amounts of waste, mainly litter (PL) , generated during production processes. This study was conducted to investigate the short-term effects of various rates of PL application, i.e., cumulative 2-year totals of 9.8, 19.5, 29.3, 39.0, and 48.8 mt ha⁻¹, to unimproved pasture. Dry matter yield, N recovery and use efficiency, P recovery and use efficiency, and changes in botanical composition were measured on a mixed species, tall fescue (<i>Festuca arundinacea</i>) and bluegrass (<i>Poa pratensis</i>) pasture. Additionally. the accumulation and movement of P was measured in a Starr clay loam (fme-Ioamy mixed thermic Fluventic Dystrochrepts) by the Mehlich 3 (M3) and Bray 1 (Bl) soil tests. Dry matter yields increased curvilinearly with rate of PL application. This yield increase was attributed to correction of N deficiency in pasture by the PL application. Lower levels of PL increased forage yields in 1992 compared with 1991, due to residual effect of unmineralized N from PL applied in 1991. The PL application rate of 11.4 mt ha⁻¹ in 1991, followed by 8.1 mt ha⁻¹ in 1992 was the most environmentally and economically recommendable rate when compared with inorganic N and P recommended fertilizer rates. Forage yields on this treatment were 21.5 mt ha⁻¹ versus 21. 7 mt ha⁻¹ for the inorganic N and P fertilizer treatment. All rates of applied PL increased the percentage of tall fescue (from approximately 50 percent to > 80 percent) and decreased the percentage of bluegrass in this mixed pasture. Phosphorus from both PL and inorganic sources accumulated in the zone of application. In 1992, the highest rates of PL application had increased M3-extractable P levels by 20 fold over the control (192 mg P kg versus 11 mg P kg⁻¹) and caused movement of P into the 10 to 15 cm soil depth. Levels of P extracted by the M3 and Bl soil tests were highly correlated for both years (r² = 0.96 in 1991 and r² = 0.99 in 1992) but the M3 extracted substantially more P from the surface 0 to 5 cm depth (21 percent in 1991 and 23 percent 1992) while the Bl soil test extracted more P from the 5 to 30 cm soil depth (50 to 66 percent more in 1991 and 20 to 57 percent in 1992). Differences in total acidity and F concentrations account for differences of P extracted by the two procedures. Poultry litter is a suitable source of fertilizer for pasture renovation and production in the Piedmont Region of Virginia. / Master of Science
5

EIA of sewerage projects: an overview of the Hong Kong situation

Kan, Hon-shing., 簡漢成. January 1995 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
6

Potential environmental hazards of wastewater from hospitals and theirmitigation

Chan, Sai Yen, Victor, 陳世欽. January 2005 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
7

The nitrogen isotope fingerprint of wastewater effluents in Hong Kong

Anand, Archana January 2014 (has links)
Nitrogen pollution in marine waters is directly tied to human development – including agricultural runoff, atmospheric deposition, and urban wastewater effluents. After more than a century of urbanization, Hong Kong faces a major challenge in mitigating marine pollution, particularly nitrogen. Indeed, nitrogen pollution may be one of the primary causes of benthic ecosystem decline as evidenced by a contraction in the historical distribution of corals and seagrasses. Such ecosystems provide vital ecosystem services, not limited to nursery grounds for economically important fisheries. While the Hong Kong Government (HK Environmental Protection Department) has established long-term monitoring of marine nitrogen concentrations, the data obtained on the size of the total nitrogen pool does not indicate the proportion of which is derived from human activities. Stable isotope analysis of nitrogen (δ15N) can provide more accurate information on the source of nitrogen not only in the receiving environment but also in the marine and benthic organisms present. This project critically examines Hong Kong’s nitrogen sources from sewage effluents using stable isotope analysis. Objectives were to investigate (1) the δ15N of sewage effluents sampled across Hong Kong, Kowloon, New Territories, Lantau and Outlying Islands (2) the differences in δ15N across sewage treatment type and (3) the differences in δ15N between the wet and dry seasons with the aim of developing a new approach for detecting and mapping sewage impacts in Hong Kong. Through a 6-month sampling effort across 18 sewage treatment facilities, this study shows that 70% of δ15N values obtained from the sewage effluents were characteristically enriched (δ15N values up to 205 ‰) when compared with naturally occurring nitrogen sources in the biosphere (I10‰ < δ15N < 10‰). Overall, δ15N was more variable in plants with preliminary treatment and chemically enhanced primary treatment (CEPT) than in plants with primary, secondary or tertiary treatment. The mean daily flow rate explained 75.7% of the observed variability in δ15N values of preliminary treatment plants and 85% of the variability in primary treatment plants. This was also the case in plants having CEPT with a negative correlation of 46% between mean daily flow rate and sewage effluent δ15N values. This suggests varying models for the quantity and retention time of wastewater versus δ15N signatures for different treatment types that require further study. Microbial activity by aerobic bacteria and protozoa, ammonia volatilization and the amount of nitrogen present in the effluents are possible causes for δ15N enrichment. Enterococcus counts of three sites sampled indicated that that the municipal sewer system and wastewater treatment plant in Stonecutters Island (56,100 CFU 100 mlI1) and preliminary treatment facilities (57,800 CFU 100 mlI1) in Hong Kong Island are insufficient in preventing bacterial contamination in comparison to US EPA standards for recreational use of coastal marine waters (35 CFU 100 mlI1). These findings indicate that enriched δ15N values directly translate to the presence of anthropogenic inputs and that monitoring δ15N of primary producers is a feasible and important tool for monitoring wastewater management in Hong Kong. / published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
8

Nitrogen removal from secondary effluent applied to soil-turf filter

Anderson, Elizabeth Leigh January 1978 (has links)
No description available.
9

Water Quality Transformations and Groundwater Recharge of Sewage Effluent Releases in an Ephemeral Stream Channel

Ince, S., Phillips, R. A., Wilson, L. G., Sebenik, P. G. 09 1900 (has links)
Project Completion Report, OWRT Project No. A-051-ARIZ / Agreement No. 14-31-0001-5003 / Project Dates: July 1974 - June 1975 / Acknowledgement: The work upon which this report is based was supported by funds provided by the United States Department of the Interior, Office of Water Research and Technology, as authorized under the Water Resources Research Act of 1978. / Bio-physicochemical measurements were made on treated sewage effluent releases at established locations within the channel of an ephemeral stream, the Santa Cruz River of Southern Arizona. Water samples were taken in chronological sequence as the effluent moved downstream, to trace changes in quality parameters during low and high hydrograph stages. Results indicate that dissolved oxygen (DO) concentrations at low effluent flows were higher than DO concentrations at high effluent flows; while, conversely, biochemical oxygen demand (BOD) concentrations at low effluent flows were generally lower than BOD concentrations at high effluent flows. Biochemical oxygen demand concentrations are affected by waste loadings, flow conditions, phytoplankton growth and nitrification. Mean river deoxygenation rates (k ) in sewage flows after six river miles from the Tucson Sewage Treatment Plant were always negative or increasing, indicative of nitrification, algal growth, and concentration of organic constituents through seepage losses.
10

Sistema de tratamento híbrido utilizado na remoção do corante reativo 5g de um efluente têxtil sintético

Santos, Bruna Souza dos 25 March 2015 (has links)
CNPQ; Fundação Araucária; FPTI / Nos últimos anos observou-se um crescimento das atividades industriais que provocou impactos significativos aos recursos naturais, e as preocupações com o ambiente em geral adquirem especial importância. Neste contexto, a indústria têxtil considerada uma importante atividade responsável por parte desse desenvolvimento, se caracteriza como geradora de efluente líquido amplamente poluidor devido ao grande volume de água necessária nesse processo produtivo. Levando em consideração os métodos convencionais e também as dificuldades no tratamento dos efluentes têxteis, o processo eletrolítico conhecido como eletrofloculação se constitui em uma possibilidade importante. Este processo envolve a desestabilização de poluentes emulsificados, ou em suspensão, em meio aquoso. Desta forma o objetivo deste trabalho foi implantar um sistema de tratamento híbrido utilizado na remoção do corante reativo azul 5G de um efluente têxtil sintético, através da eletrofloculação associada a adição de coagulante natural a base de Moringa oleífera Lam, a fim de potencializar o nível de tratamento que seria alcançado com as técnicas utilizadas isoladamente Inicialmente trabalhou-se exclusivamente com a eletrofloculação para a remoção do corante. As variáveis analisadas foram: ddp (diferença de potencial aplicado), tempo e pH. Considerando o intervalo de confiança de 95% somente o termo quadrático da ddp e o termo linear do pH se mostraram significativos. Os valores de remoção da cor para os ensaios variaram de 64,38 a 90,87% e para a validação uma remoção média de 89,01%, valores muito próximos do predito pelo modelo. Na sequência foi realizada a otimização das condições para obtenção do extrato aquoso de Moringa oleífera. Avaliou-se as seguintes condições: salinidade e tempo de extração. A concentração do coagulante obtido, em água turva sintética também foi um dos fatores estudados. As melhores condições para o extrato aquoso de Moringa oleífera foram: 20 segundos de agitação em ultrassom, e solução de 20% em cloreto de sódio. Para potencializar o nível de tratamento as duas técnicas (eletrofloculação e coagulante natural a base de Moringa oleífera), foram testadas inicialmente em batelada e na sequência em fluxo contínuo. Os ensaios em batelada foram divididos em duas partes, o primeiro DCCR avaliou a intensidade de corrente elétrica (I), o tempo da eletrofloculação e a concentração do coagulante (MO), o qual obteve uma remoção de cor de 77,27% a 91,33%. Porém, nenhum termo foi significativo, mas o tempo apresentou menor efeito. Sendo assim, um novo planejamento foi realizado, o segundo DCCR, fixando o tempo na condição mínima, além das faixas de I e MO que também foram reduzidas. Obteve-se então uma remoção da cor para os ensaios de 13,45 a 80,8%, e para a validação uma remoção média de 86,56%. Para o módulo contínuo, as variáveis estudadas foram a intensidade de corrente elétrica (I), concentração do coagulante (MO) e tempo de retenção hidráulica (TRH). Dentre elas somente o TRH não se mostrou significativo. A remoção da cor variou de 8,46% a 90,25%. Nestes ensaios também foram realizados as análises das concentrações de Ferro Residual, e os valores obtidos variaram de 3,70 mg.L-1 a 9,03 mg.L-1, ficaram abaixo do valor máximo permissível pela Legislação (15 mg.L-1). Para maximizar a remoção da cor e minimizar a concentração de ferro residual, a função desejabilidade do software STATISTICA™ foi utilizada e nessas condições somente a I e a MO foram significativas. A partir da validação foi possível observar a tendência de remoção prevista pelo modelo. Obteve-se uma remoção da cor para a validação de 71,38% e uma concentração média de ferro residual de 5,2237 mg. L-1, porém, com um erro distante do esperado (32,85%). / In recent years there has been a growth of industrial activities that caused significant impacts to natural resources, and concerns about the environment in general are of particular importance. In this context, the textile industry considered an important activity responsible for part of that development is characterized as liquid effluent generating widely polluter due to the large volume of water needed in this production process. Taking into account the conventional methods and also the difficulties in treating textile effluents, the electrolytic process known as eletrofloculation constitutes an important possibility. This process involves the destabilization of the emulsified pollutants, or suspension in aqueous medium. Thus the aim of this study was to implement a hybrid treatment system used in removing the blue reactive dye 5G of a synthetic textile effluent by eletrofloculation associated with adding natural coagulant the basis of Moringa Oleifera Lam, in order to enhance the level treatment would be achieved with the techniques used alone initially worked up exclusively with eletrofloculation to remove the dye. The variables analyzed were: ddp (potential difference applied), time and pH. Whereas the 95% confidence interval only the quadratic term of the linear term DDP and pH were significant. The removal of color values for the tests ranged from 64.38 to 90.87% and validating an average removal of 89.01%, very close values predicted by the model. Following was carried out to optimize the conditions for obtaining the aqueous extract of Moringa oleifera. Salinity and extraction time: The following conditions were evaluated. The concentration of the coagulant obtained in synthetic turbid water was also one of the factors studied. The best conditions for the aqueous extract of Moringa oleifera were 20 seconds of ultrasound in agitation, and solution of 20% sodium chloride. To enhance the level of treatment the two techniques (eletrofloculation and natural coagulant Moringa oleifera the base), were initially tested in batch and following streaming. The batch tests were divided into two parts, the first CCRD evaluated the intensity of electric current (I), the time eletrofloculation and concentration of the coagulant (MO), which obtained a color removal of 91 to 77.27% 33%. But no term was significant, but time showed less effect. Thus, a new planning was done, the second CCRD, setting the time at a minimum, in addition to the R and MO tracks that were also reduced. There was thus obtained a removal color for testing 13.45 to 80.8%, and validating an average removal of 86.56%. For the continuous form, the variables studied were the intensity of electric current (I), the coagulant concentration (MO) and hydraulic retention time (HRT). Among them only HRT was not significant. The color removal ranged from 8.46 % to 90.25%. In these assays were also performed the analysis of the residual iron concentrations, and the values obtained ranged from 3.70 mg L- 1 to 9.03 mg.L-1, were below the maximum value allowable by law (15 mg.L-1). To maximize the removal of color and minimize the residual concentration of iron, the desirability function STATISTICA ™ software was used and under these conditions only I and MO were significant. From the validation was observed removing trend predicted by the model. Obtained was a color removal for the validation of 71.38 % and an average concentration of 5.2237 mg.L-1 of residual iron, but with a far from the expected error (32.85%).

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