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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.
211

Performance of a Surface-Flow Constructed Wetland Treating Landfill Surface-Water Runoff

Hick, Justin 11 June 2013 (has links)
Landfills are a major potential source of groundwater and surface-water contamination. The compounds that can leach from landfilled materials include dissolved organic matter, inorganic macrocomponents, heavy metals, and xebobiotic organic compounds. Landfill surface-water runoff poses a threat to the environment due to high mobility, but has not been rigorously characterized with regards to common pollutants found in landfills. It is well documented that constructed wetlands can serve as an effective treatment option for many pollutants found in landfills. The Napanee Landfill has constructed a wetland in order to treat surface-water runoff coming off the landfill. The objectives of this study were to: 1) characterize the water chemistry of surface-water runoff for an inactive landfill; 2) evaluate the treatment potential for the constructed wetland system at the Napanee Landfill; and, 3) recommend design, maintenance, and operative improvements to enhance effluent water quality. The analysis of the landfill surface-water runoff entering the Napanee Landfill constructed wetland included the pollutants nitrate, ammonia, sulphate, phosphorus, and chloride. The median inflow and outflow concentrations for all of the observed pollutants did not exceed Canadian federal or provincial water quality guidelines. There were sampling days where ammonia, phosphorus, and chloride exceeded guidelines at the inflow and days where ammonia and chloride exceeded guidelines at the outflow. The only pollutant that saw a statistically significant decrease in concentrations was sulphate, with a change of 38% from the inflow to the outflow. Other changes of note were nitrate and phosphorus concentrations increasing by 50% and 23% respectively from the inflow to the outflow. There are a variety of improvements that can be made to the Napanee Landfill constructed wetland that would increase the treatment efficiency of ammonia. Incorporating a vertical-flow wetland would increase available surface area for nitrifying bacteria growth and would provide more oxygen for nitrification processes; both would increase the potential for significant ammonia treatment. Overall, the concentrations of the pollutants found in the surface-water runoff coming off of the Napanee Landfill constructed wetland did not pose a significant threat to the environment at the time of sampling and treatment processes were only successful in reducing sulphate pollutant concentrations.
212

Modelling urban runoff : volume and pollutant concentration of the Barker Inlet Wetland Catchment /

French, Rachel. January 1999 (has links) (PDF)
Thesis (M.Eng.Sc)--University of Adelaide, Dept. of Civil and Environmental Engineering, 2000? / Bibliography :leaves 158-171. A monitoring program, funded by the South Australian government (through the former MFP Development Corporation), was established to monitor the quality and quantity of storm water entering and leaving the wetland. This study formed part of the funded program. Simple regression models were developed; and will assist in the monitoring of performance of the wetland to alleviate the pollutant load into the Barker Inlet.
213

An investigation into the treatment efficiency of a primary pond in the Barker Inlet Stormwater Wetland System, South Australia /

Murphy, Sarah Elizabeth. January 1999 (has links) (PDF)
Thesis (M.Eng.Sc.)--University of Adelaide, Dept. of Civil and Environmental Engineering, 2000? / Corrigenda pasted onto front end-paper. The CD contains Excel spreadsheets containing data collected. Bibliography: leaves 209-222.
214

Impact of pre-ozonation on distillery effluent degradation in a constructed wetland system /

Green, Jeffrey. January 2007 (has links)
Thesis (MSc)--University of Stellenbosch, 2007. / Bibliography. Also available via the Internet.
215

Infiltration and temperature characterization of a wastewater hyporheic discharge system /

Stewart, Ryan D. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 113-118). Also available on the World Wide Web.
216

Methane and carbon dioxide fluxes in created riparian wetlands in the midwestern USA effects of hydrologic pulses, emergent vegetation and hydric soils /

Altor, Anne E., January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 134-146).
217

Användning av anlagd våtmark för efterpolering av rökgaskondensat : en studie vid Brista kraftvärmeverk i Sigtuna

Elleby, Rasmus January 2015 (has links)
I Brista kraftvärmeverk i Sigtuna förbränns träflis och utsorterat avfall från hushåll och industri för att utvinna och exportera el och fjärrvärme. När rökgasen kyls ner, som en del av återvinningen av energi till fjärrvärmenätet, bildas rökgaskondensat. Direkt efter produktionen har kondensatet en temperatur av cirka 30 °C och innehåller höga halter av bland annat ammoniumkväve och vissa metaller. Efter rening av kondensatvattnet inuti verket efterpoleras det i en nyanlagd våtmark. Syftet med arbetet var främst att undersöka kvävereningen i våtmarken men även om riktvärden för utsläpp uppsatta av miljödomstolen efterlevs med avseende på total- och ammoniumkväve samt As och tungmetallerna Cd, Co, Cr, Cu, Hg, Ni, Pb, Tl och Zn. Arbetet syftade även på att bestämma våtmarkens area, volym och uppehållstid, undersöka eventuella skillnader i vattenföring mellan in- och utlopp samt undersöka vattentemperaturens effekt på kvävereningen. För att undersöka reningen togs veckovisa prover i våtmarkens in- och utlopp under nio veckor under hela oktober och november 2014. Proverna analyserades med jonkromatografi för bestämning av nitrat-, nitrit- och ammoniumhalt. Vidare användes data från Fortum, som driver verket, för att undersöka halter av kväve och olika metaller i våtmarken. Höjdmätningar med avvägningsinstrument användes för att bestämma våtmarkens volym och GPS för att bestämma våtmarkens längd och area. Vattentemperaturmätningar i våtmarkens utlopp genomfördes med hjälp av en logger under en tvåmånadersperiod. Vattenföring ut ur våtmarken räknades ut med hjälp av nivådata från en pumpbrunn vid utloppet. Resultaten visade att halterna av alla de studerade ämnena i både egna prover och från Fortum klarade riktvärdena för utsläpp till recipient. Halterna var även låga i rökgaskondensatet som lämnade Bristaverket vilket tyder på att reningen inuti verket fungerar bra. Våtmarkens area uppmättes till 2300 m2 och volymen till 940 m3. Den beräknade vattenföringen ut var i genomsnitt cirka 100 m3/dygn högre än inflödet. Fel i beräkningsmodellen kunde dock inte uteslutas som orsak till skillnaden. Vid låga lufttemperaturer verkade våtmarken klara av att kyla betydligt högre temperaturer hos rökgaskondensat än vad som vanligtvis skickas ut från verket. Därför rekommenderas att Fortum undersöker möjligheterna för minskad kylning av rökgaskondensatet för att möjliggöra en ökad reningsgrad av temperaturberoende processer i våtmarken, så som kväveavskiljning. / At the Brista combined heat and power plant in Sigtuna, wood chips and municipal and industrial waste are incinerated to generate and export electricity and distric heating. When the flue gas is cooled as a part of recycling its energy for distric heating, condensate is formed. Directly after production, the flue gas condensate has a temperature of approximately 30°C and contains relatively high levels of ammonia and certain heavy metals. After treatment inside the plant, the condensate is post-treated in a newly constructed wetland. The main aim of the study was to investigate the nitrogen removal in the wetland but also if current guideline values for effluents established by the environmental court are fulfilled in regard to levels of total and ammonia nitrogen as well as As and heavy metals Cd, Co, Cr, Cu, Hg , Ni, Pb, Tl  and Zn. The study also aimed to measure the wetland area, volume and retention time, investigate differences in water flow between the inlet and outlet as well as study the effect of water temperature on nitrogen removal. Water samples were taken weekly for nine weeks in October and November 2014 in the inlet and outlet of the wetland. The samples were analysed for nitrate, nitrite and ammonium ions using ion chromatography. Data from Fortum, the company that runs the heat and power plant, were also used to study levels of nitrogen and metals in the wetland. An optical leveling instrument was used to calculate the wetland volume and GPS was used to calculate its length and area. Measurements of water temperature in the outlet of the wetland were conducted using a logger during a two-month period. Water flow out of the wetland was calculated using water level data from a pump well connected to the outlet. The results showed that the levels of the studied compounds in samples collected in this study and by Fortum were all below guideline values. The levels were also low in the flue gas condensate leaving the combined heat and power plant, indicating that the treatment inside the plant is working well. The area of the wetland was measured to 2300 m2 and the volume 940 m3. The calculated water flow out of the wetland was at an average approximately 100 m3/day higher than the inflow, but an error in the calculation model is a possible cause of the difference. At low air temperatures, the wetland showed a capacity of cooling significantly higher temperatures of the flue gas condensate than what is usually released from the plant. Because of this, Fortum is recommended to investigate the possibility of reducing the cooling of the flue gas condensate and thus enabling a higher efficiency of temperature dependent treatment processes in the wetland such as nitrogen removal.
218

Tratamento de efluentes de piscicultura utilizando sistema tipo wetland povoado com espécies de macrófitas aquáticas de três tipos ecológicos diferentes /

Assunção, Argos Willian de Almeida. January 2011 (has links)
Orientador: Luiz Augusto do Amaral / Banca: Antônio Fernando Monteiro Camargo / Banca: Irineu Bianchini Júnior / Resumo: A aquicultura é uma atividade impactante para o meio ambiente, podendo causar eutrofização de corpos hídricos, introdução de espécies exóticas, transmissão de doenças e competição pelo uso da água. Os efluentes de criações de organismos aquáticos são ricos em matéria orgânica e nutrientes, nitrogênio e fósforo, decorrente de adubação, restos de ração e excreção. A partir de um viveiro de criação de pacu "Piaractus mesopotamicus" foi avaliado o impacto ambiental causado pela criação, a presença de organismos indicadores de contaminação fecal (Escherichia coli), e avaliada a eficiência de um sistema de tratamento tipo wetland construída utilizando três espécies de macrófitas aquáticas de tipos ecológicos diferentes: Eichhornia crassipes (flutuante), Ceratophyllum demersum(submersa) e Typha dominigensis (emersa). As variáveis analisadas foram temperatura, oxigênio dissolvido, condutividade elétrica, alcalinidade, dureza total, demanda química e bioquímica de oxigênio (DQO e DBO), nitrogênio (total, amoniacal, nitrito e nitrato), fósforo (total e ortofosfato) e o NMP de Escherichia coli, como ferramenta de análise foi aplicada uma análise multivariada de fatores. Os resultados demonstraram que a criação de pacu apresentou impacto ambiental significativo na qualidade da água do efluente do viveiro, gerando elevação da concentração de fósforo total, nitrogênio total e material particulado suspenso, aumento nos níveis de turbidez e demanda bioquímica e química de oxigênio. O sistema de tratamento foi eficiente no tratamento do efluente e todas as etapas do tratamento foram significativas para a remoção das variáveis relacionadas com o impacto ambiental. Todas as amostras apresentaram número mais provável de Escherichia coli dentro dos limites estabelecidos pela legislação brasileira / Abstract: Aquaculture is responsible for various types of environmental impacts, causing eutrophication of water bodies, introduction of exotic species, disease transmission and competition for water use. The effluents from aquatic organisms breeding are rich in organic matter and nutrients, nitrogen and phosphorus, due to fertilization, food leftovers and excretion. From a pacu "Piaractus mesopotamicus" breeding pond was evaluated the environmental impact in the water, the presence of fecal indicator organisms (Escherichia coli) and evaluated the effluent treatment by a constructed wetland using three species aquatic macrophytes of different ecological types: Eichhornia crassipes (floating), Ceratophyllum demersum (submerged) and Typha dominigensis (onshore). The analyzed variables were temperature, dissolved oxygen, conductivity, alkalinity, total hardness, chemical demand and biochemical oxygen demand (COD and BOD), nitrogen (total, ammonia, nitrite and nitrate) and phosphorus (total and orthophosphate), for data analysis was applied a multivariate factor analysis. The results demonstrated that the pacu breeding showed significant environmental impact on water quality of the effluent, causing elevation of total phosphorus, total nitrogen and suspended particulate material, an increase in turbidity and chemical and biochemical oxygen demand. The treatment system was effective in the treatment of effluent and all stages of treatment were significant for the removal of variables related to environmental impact. The most probable number of E. coli was in accordance with Brazilian law in all samples / Mestre
219

Odstraňování olova z odpadní vody za využití umělého mokřadu / Removal of lead from wastewater using a constructed wetland

JAHODOVÁ, Jana January 2017 (has links)
Removal of lead from municipal wastewater using a constructed wetland with a horizontal subsurface flow was studied. Wastewater, wetland plant and sediment samples were analyzed using an AAS Thermo Scientific iCE 3500. Average concentrations of lead in inflow and outflow water in 2015 were 1.47 and 0.74 ?g/l, respectively. Average concentrations of lead in inflow and outflow water in 2016 were 0.75 and 0.38 ?g/l. The average efficiency of lead removal was 49.2 %. Lead concentrations in vegetation (Phragmites australis) varied in the range of 0.081-0.087 mg/kg and 0.48-0.17 mg/kg for the above and belowground biomass, respectively. Lead concentration in sediments were 9.79 and 4.86 mg/kg at distances of 1 and 10 m from inflow zone. Lead and other heavy metals were predominantly removed from wastewater at the initial part of the wetland bed.
220

Construção e operação de wetland como polimento de lixiviado de aterro de resíduos sólidos urbanos. / Wetland construction and operation as leachate polishing Municipal Solid Waste Landfill.

Fernando Braile Junior 13 April 2015 (has links)
O presente trabalho tem o objetivo de avaliar a metodologia de construção, de plantio, de manutenção, de operação e a eficiência de um sistema de tratamento por wetland construído como etapa de polimento da Estação de Tratamento de Lixiviado (ETC) de Aterro já encerrado de Resíduos Sólidos Urbanos na Região Metropolitana do Rio de Janeiro. Parte do efluente tratado por lodos ativados na ETC foi direcionado e tratado no wetland construído. Foi escolhido o projeto de Fluxo Horizontal Subsuperficial e a vegetação selecionada foi a taboa (Typha latifolia) que é nativa da área do aterro. Em média, foram feitas três amostragens mensais do afluente e do efluente do wetland, de maio a outubro de 2013. A eficiência do sistema foi avaliada por meio de parâmetros físico-químicos e de parâmetros coletivos específicos. A eficiência de remoção de Demanda Química de Oxigênio (DQO) foi de 60%, nitrogênio amoniacal de 67%, nitrito de 72% e nitrato de 57%. Outro parâmetro avaliado foi a toxicidade aguda, foram utilizados os organismos teste Danio rerio (peixe), a Daphnia similis (microcrustáceo) e a Aliivibrio fischeri (bactéria luminescente). Durante o período foram coletados diariamente as vazões de entrada e saída, a condutividade elétrica e o índice pluviométrico. Os resultados mostraram que o uso de wetland como etapa de polimento pode ser uma alternativa para o tratamento de lixiviado. / This paper aims to evaluate the methodology of construction, planting, maintenance and efficiency of a constructed wetland treatment system as a constructed wetland polishing step of the leachate treatment (ETC) of the closed Landfill station. One amount of the effluent from the activated sludge plant was directed and treated in a constructed wetland. We used an Horizontal Subsurface Flow plant and the selected vegetation was the Cattail (Typha latifolia) which is native to the disposal area. Three samples of influent and effluent of the constructed wetland were made on average per month in the period from May up to October 2013. The system efficiency was evaluated by physical-chemical parameters and parameters of specific groups. The COD (chemical oxygen demand) removal efficiency was 60%, ammonia nitrogen was 67%, nitrite and nitrate was 72% and 57%, respectively. It was also evaluated acute toxicity, the test organisms used were: Danio rerio, a Daphnia similis e a Aliivibrio fischeri. It was collected flow rates of input and output, eletric conductivity and rainfall daily. The results showed that the use of wetland, as a polishing step, may be an alternative for treatment of leachate.

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