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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

Wastewater treatment and resource recovery for poverty alleviation : a combined duckweed and water hyacinth pond system

Hounkpe Wendeou, Sèna Peace January 2016 (has links)
Floating macrophyte pond systems, with the ability to produce nutrient enriched plants simultaneously with wastewater treatment, are a sustainable solution to contribute to environmental protection and safe nutrient recovery from domestic wastewater. However, to meet the requirements for reuse with high strength wastewater containing high levels of metal pollution generated in developing countries, an adequate combination of water hyacinth and duckweed ponds is proposed in order to take advantage of the best characteristics of each of these macrophyte ponds. This research focused on the advancing of the understanding of the effectiveness of treatment and resource recovery under the effect of changing operational parameters such as pH, light intensity, influent metal content and fluctuating pollutants loading rate on pond performance and recycling ability in order to fill the noticed gap of knowledge. Experiments conducted in water hyacinth ponds (WHP), under batch and tropical natural weather conditions, revealed that pH between 6.4 and 7.1, full sunlight and seven days hydraulic retention time were optimum for plant biomass production and pollutant removal in WHP. WHP was able to regulate pH when the initial pH values moved outside this interval with a drop in biomass production as a side effect. These ponds showed a first order kinetic for the removal of iron, zinc and copper from aqueous solution and their accumulation in plants biomass with a preferential sequence Fe > Zn > Cu. However the presence of metals in water hyacinth biomass led to the reduction in ponds performances and a risk of re-pollution of the effluent through the release of metals into water. A comparative study carried out over sixty-two weeks in a pilot scale combined water hyacinth and duckweed ponds (DWP) channel and waste stabilization ponds channel working under fluctuating loading rates showed different environmental conditions occurred these ponds. The fluctuating loading rate was also found to have a reduced effect on the combined WHP/DWP channel performance and effluent quality stability with the effluents meeting the entire reuse requirement at high hydraulic flow rate (retention time greater than 20 days). Fish was able to grow in the WHP/DWP channel. Results suggested some guidelines on WHP/DWP system design, operation and maintenance. The overall outcome of this research is a significant contribution to the development of integrated combined WHP/DWP technology for treatment of wastewater and resource recovery on site.
2

Cultivo de Landoltia punctata na remoção de desreguladores endócrinos e no polimento de esgoto sanitário em lagoa com recirculação /

Zanetoni Filho, José Antônio. January 2019 (has links)
Orientador: Liliane Lazzari Albertin / Resumo: A situação de escassez de recursos financeiros destinados ao tratamento e coleta de esgotos municipais, no Brasil, torna essencial a busca por tecnologias de tratamento que priorizem baixos custos de instalação e operação. Além da negligência que existe no tratamento de esgotos, os métodos utilizados, muitas vezes, não são capazes de remover os micropoluentes que estão presentes nos esgotos domésticos. Os micropoluentes podem ser desde fármacos, que são expelidos na urina ou descartados de maneira inadequada, a hormônios naturais ou sintéticos. Esse trabalho consistiu em realizar um processo de polimento do esgoto sanitário da cidade de Ilha Solteira – SP. O sistema de polimento é constituído por dois tanques, onde foi cultivada a macrófita Landoltia punctata. Foi também avaliado e feito a recirculação do efluente, no tratamento de esgoto. Neste sistema de polimento, foram avaliadas as eficiências de tratamento para os parâmetros de DBO, DQO, NT, NO3-, PT e ST. As maiores eficiências de remoção para DBO, DQO, NT, NO3-, PT e ST foram de 66,35%, 59,08%, 26,76%, 28,38%, 6,85% e 40,08%. Outro aspecto avaliado foi a taxa de crescimento da macrófita cultivada em esgoto sanitário. As maiores taxas de crescimento relativo foram de 3,84 e 3,17 g.m-2.d-1 MS. Considerando a presença de desreguladores endócrinos (DEs) no efluente da Estação de Tratamento de Esgoto (ETE) de Ilha Solteira, foi analisado a absorção dos estrógenos 17α-etinilestradiol (EE2) e o estriol (E3) pela macrófita, av... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The scarcity of financial resources for the treatment and collection of municipal wastewater in Brazil makes search for treatment technologies essential with low installation and operation costs. In addition, the methods used are often not able to remove the micropollutants that are present in domestic sewage. Micropollutants can range from drugs that are expelled in the urine or inappropriately discarded to natural or synthetic hormones. This work consisted of a process to polishing the sanitary sewage of the city of Ilha Solteira - SP. The treatment system consists of two tanks, where the macrophyte Landoltia punctata was grown. In one of the tanks, a recirculation system was performed. In this polishing system, the treatment efficiencies for the BOD, COD, TN, NO3-, TP and ST parameters were evaluated. The highest removal efficiencies for BOD, COD, TN, NO3-, TP and ST were 66,35%, 59,08%, 26,76%, 28,38%, 6,85% and 40,08%. Another aspect evaluated was the growth rate of the macrophyte. The highest relative growth rates were 3.84 and 3.17 g.m-2.d-1 MS. Considering the presence of endocrine disrupters (DEs) in the effluent from the Sewage Treatment Plant (ETE) in Ilha Solteira - SP, 17α-ethinyl estradiol (EE2) and estriol (E3) were analyzed on the plant to evaluate possible risks on the reuse of the biomass. The maximum achieved efficiencies for removal of E3 and EE2 were 83.63% and 83.50%, respectively. The recirculation tank was more effective at removing E3, while the non-r... (Complete abstract click electronic access below) / Mestre

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