In this thesis, the application of molecular microbiology methods to understand wastewater treatment bio-reactions is described. Two different wastewater treatment systems were chosen for the experimental work. Firstly; the activated sludge processes at two different facilities in Sweden (Västerås and Eskilstuna) were investigated and compared in a context where low temperatures can affect the efficiency of the nitrogen removal performance in terms of nitrification. Initially, fluorescence in situ hybridization (FISH) was utilised in order to quantify some of the species involved in ammonia and nitrite oxidation at Västerås, providing information on how the different communities react to decreasing temperatures. Then, the polymerase chain reaction (PCR), cloning-sequencing method was employed in order to study the composition of the ammonia oxidizing bacteria (AOB) community at the same two wastewater treatment plants (WWTPs). Secondly; the potential use of constructed wetlands for the treatment of winery wastewater was studied. High ethanol concentration artificial wastewater with and without inorganic nutrients (nitrates and phosphates) was fed in a set of pilot-scale constructed wetlands. Pollutant removal performance and enzyme activity tests were carried out. Additionally, the bacterial community structure was investigated by means of denaturing gradient gel electrophoresis (DGGE). In the first set of studies it was shown that the AOB population which plays a major role in nitrifying reactors presented a seasonal shift and a higher diversity at Västerås during winter time, while the nitrification performance maintained stable levels and the ammonia removal efficiency increased. Thus, the higher ammonia removal efficiency at Västerås could be related to the diversity of the AOB population composition. Lastly, when constructed wetlands were in focus, the differential effects of ethanol and nutrients over the chemical oxygen demand (COD) removal performance were proven. In fact, the addition of nutrients on one of the experimental wetlands increased the COD (ethanol) removal and supported the maintenance of a bacterial population similar to the control wetland (no ethanol added). In conclusion, both studies proved a strong relationship between process performance (pollution removal) and the dynamics of the bacterial communities involved.

No description available.

Sludge digestion has gained importance in recent year because of increasing interest in energy recovery and public concern over the safety of land applied biosolids. Many new alternatives are being researched for reducing excess sludge production and for more energy production. With an increase in solids destruction, the nutrients that are contained in sludge especially nitrogen, are released to solution and can be recycled as part of filtrate or centrate stream. Nitrogen has gained importance because it has adverse effects on ecosystem's as well as human health. NH₄⁺, NO₂⁻, NO₃⁻-, and organic nitrogen are the different forms of nitrogen found in wastewater. While ammonia is toxic to aquatic life, any form of nitrogen can be utilized by cyanobacteria and result in eutrophication. NO₂/NO₃, if consumed by infants through water, can affect the oxygen uptake capability. Hence, removal of nitrogen from wastewater stream before discharging is important. The main purpose of this study was to evaluate the performance of the Cambi process, a thermophylic hydrolysis process used as a pre-treatment step prior to anaerobic digestion. Thermal hydrolysis, as a pre-treatment to anaerobic digestion increases the biological degradation of organic volatile solids and biogas production. The thermal hydrolysis process destroys pathogens and hydrolysis makes the sludge readily available for digestion, while at the same time facilitating a higher degree of separation of solid and liquid phases after digestion. Experiments were conducted in three phases for anaerobic digestion using the Cambi process as pre-treatment. The phases of study includes comparison of two temperatures for thermal hydrolysis (Cambi 150°C and Cambi 170°C), comparison of two solid retention times in anaerobic digestion (15 Day and 20 Day) and comparison of two mesophilic temperatures in anaerobic digestion (37°C and 42°C). Different experimental analyses were conducted for each phase, such as pH, bio-gas production, COD removal, VS destruction, nitrogen removal, odor and dewatering characteristics and the results are compared among all the phases. The second part of the study deals with aerobic digestion of anaerobically digested sludge for effective nitrogen removal and additional VS destruction, COD removal. An aerobic digester is operated downstream to anaerobic digester and is operated with aerobic/anoxic phase for nitrification and de-nitrification. The aerobic/anoxic phases are operated in time cycles which included 40minutes/20minutes, 20minutes/20minutes, full aeration, 10minutes/30minutes, and 12minutes/12minutes. Different time cycles are experimented and aerobic digester is optimized for effective nitrogen removal. 12minutes aerobic and 12minutes anoxic phase gave better nitrogen removal compared to all the cycles. Over all the aerobic digester gave about 92% ammonia removal, 70% VS destruction and 70% COD removal. The oxygen uptake rates (OUR's) in the aerobic digester are measured corresponding to maximum nitrogen removal. The OUR's are found to be close to 60 mg/L during maximum nitrogen removal. The effluent from both anaerobic digester and aerobic digester was collected and analyzed for dewatering capability, cake solids concentration and odor potential. / Master of Science

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / RESUMO O presente trabalho propÃs investigar a tecnologia de eletrocoagulaÃÃo (EC) para o tratamento de efluente tÃxtil utilizando corrente contÃnua pulsada (CCP) e eletrodos de aÃo inoxidÃvel 304. O efluente utilizado foi coletado em uma indÃstria tÃxtil fabricante de redes localizada no municÃpio de Jaguaruana-CE. A Metodologia de SuperfÃcie de Resposta Box-Behnken foi utilizada para analisar e otimizar as condiÃÃes operacionais, visando a mÃxima remoÃÃo de cor, turbidez e demanda quÃmica de oxigÃnio (DQO) do efluente tÃxtil. Os experimentos foram realizados com um volume reacional de 2,6 L, em modo batelada. A cinÃtica de degradaÃÃo de DQO foi estudada atravÃs do ajuste de regressÃo nÃo linear, obedecendo ao modelo de cinÃtica de segunda ordem. Diante dos resultados obtidos a configuraÃÃo Ãtima considerada foi: velocidade de agitaÃÃo=200 rpm, frequÃncia dos pulsos elÃtricos=1000 Hz e espaÃamento entre os eletrodos=1 mm, em 50 minutos de EC. Nestas condiÃÃes foram obtidas remoÃÃes de cor, turbidez e DQO, respectivamente de 98,94%, 85,87% e 81,23%, adequando o valor de DQO ao padrÃo de lanÃamento exigido pela Portaria n 154/2002 da SuperintendÃncia Estadual do Meio Ambiente (SEMACE). Em adiÃÃo, verificou-se que o processo de EC tambÃm foi eficaz para a reduÃÃo de sÃlidos suspensos totais, nitrogÃnio total, sulfato e sulfeto, como tambÃm para a reduÃÃo da toxicidade aguda frente à Lactuca sativa, elevando os valores do Ãndice de Crescimento Relativo (ICR) e Ãndice de GerminaÃÃo (IG) inicialmente registrados para o efluente bruto. A concentraÃÃo de Ãons cloreto nÃo decresceu durante a EC, apresentando-se como um aspecto favorÃvel para a reutilizaÃÃo do efluente tratado no prÃprio processo produtivo tÃxtil, o qual demanda uma elevada concentraÃÃo de cloreto de sÃdio (NaCl). / The present work proposed to investigate the electrocoagulation technology (EC) for the treatment of textile effluent using pulsed direct current (CCP) and stainless steel electrodes 304. The effluent used was collected in a textile manufacturer networks in the municipality of Jaguaruana -CE. The Response Surface Methodology Box-Behnken was used to analyze and optimize the operating conditions, aimed at maximum removal of color, turbidity and chemical oxygen demand (COD) of the textile effluent. The experiments were performed with a reaction volume of 2.6 L in batch mode. The COD degradation kinetics was studied using non-linear regression fit, according to the second order kinetics model. Based on these results the optimal configuration was considered: agitation speed = 200 rpm, frequency of electrical pulses = 1000 Hz and spacing between electrodes = 1 mm, in 50 minutes of EC. Under these conditions color removals were obtained, turbidity and COD, respectively 98.94%, 85.87% and 81.23%, adjusting the COD value to discharge standard required by Ordinance No. 154/2002 of the State Superintendent of Half Environment (SEMACE). In addition, it was found that the CS process is also effective for reduction of total suspended solids, total nitrogen, sulfide and sulfate, as well as for the reduction of acute toxicity Lactuca sativa forward, raising the value of the Growth Index Relative (ICR) and germination index (GI) initially recorded for the raw wastewater. The concentration of chloride ions has not decreased during the EC, presenting itself as a favorable aspect for the reuse of treated effluent in own textile production process, which demands a high concentration of sodium chloride (NaCl).

Esta tesis doctoral está dirigida a la investigación y desarrollo de Procesos de Oxidación Avanzada (POAs), los cuales basan su capacidad en la generación in-situ de radicales hidroxilo (OH·), especie capaz de oxidar muchos compuestos orgánicos. Esta propiedad es aprovechada para conseguir la completa mineralización de los contaminantes o su degradación en sustancias más fácilmente biodegradables.Se plantean dos grandes objetivos:1) Contribuir al conocimiento científico a través del análisis y modelado del proceso UV/H2O2 aplicado a la degradación y mineralización de fenol. Para ello, se ha realizado una planificación experimental dirigida a estudiar la influencia de las variables de operación sobre parámetros globales del proceso, como el contenido total de materia orgánica o la toxicidad.2) Desarrollar una alternativa eficaz para la eliminación de materia orgánica de corrientes residuales de escasa biodegradabilidad mediante la aplicación de POAs. Se ha seleccionado el tratamiento de lixiviados de vertedero de residuos sólidos urbanos (RSU) como caso de estudio y se ha realizado un análisis comparativo de los procesos Fenton y foto-Fenton. Los experimentos se han realizado tanto a escala de laboratorio como a escala de planta piloto. / The aim of this thesis is the research and development of Advanced Oxidation Processes (AOPs). AOPs are based on the in-situ generation of hydroxyl radicals (OH·). These radicals are able to oxidize many organic compounds with high oxidation rates but in a non-selective way. This is useful to achieve the complete mineralization of the pollutants or its degradation into more easily biodegradable compounds.Two main objectives have been pursued in this thesis:1) To contribute to the scientific knowledge of the UV/H2O2 process through its analysis and modelling. Phenol degradation has been selected as a case of study. An experimental planning was established to study the influence of process variables on parameters such as total organic matter concentration and ecotoxicity.2) Research on new alternative treatments for suitable organic matter removal from recalcitrant waste effluents by AOPs. As study case, the leachate remediation from a municipal solid wastes landfill was selected. Fenton and photo-Fenton processes were compared and the operational conditions to achieve the maximum organic matter reduction and colour removal have been determined. Both laboratory scale and pilot plant experiments were carried out.

Esta pesquisa enfoca a avaliação do desempenho de nova configuração de unidade para tratamento biológico de esgoto sanitário por processo combinado, visando à remoção de nutrientes, especialmente nitrogênio. O sistema construído em escala piloto tem volume útil igual a 71,48 litros. Nesta nova configuração de reatores para tratamento terciário de esgoto sanitário, utilizaram-se três reatores sobrepostos, sendo: um reator UASB - “Upflow Anaerobic Sludge Blanket"; um reator de leito móvel e filme fixo aeróbio (com aplicação de oxigênio puro); e, um reator de leito móvel e filme fixo com ambiente anóxico. O material suporte utilizado nos reatores de leito móvel e filme fixo constituiu alternativa inédita no tratamento de efluentes líquidos. Foram utilizadas cavilhas “ranhuradas" de madeira, de dimensões aproximadas de 8,0 mm de diâmetro por 8,0 mm de comprimento. O desempenho geral do sistema quanto à remoção de matéria carbonácea e compostos nitrogenados, e as associações microbianas formadas nos três reatores são objetos principais de estudo deste trabalho. Foram obtidos resultados de remoção de DQO e de nitrogênio bastante satisfatórios, sobretudo quando o tempo de detenção hidráulica total esteve próximo a 20 horas, incluindo o compartimento de decantação (94,6 % para DQO; e 96,7 % para N-NTK, com formação de nitrato em concentrações inferiores a 10,0 mgN-NO3-/l). O TDH estudado variou entre 5 e 24 horas para os sistema completo. O estudo dos consórcios de microrganismos forneceu excelentes resultados quanto à quantidade, diversidade, e atividade das populações desenvolvidas nos diferentes ambientes, confirmando o bom desempenho do sistema e o fornecimento de ambiente adequado para o desenvolvimento das diferentes populações nos três reatores. A idealização desta configuração tem como finalidade realização de tratamento de esgoto sanitário até nível terciário em planta compacta, podendo ser utilizada por pequenas e grandes comunidades, devido à possibilidade de se construir diversos módulos do sistema proposto. / This research is focused on the performance evaluation of a new system configuration of combined biological reactors, treating domestic wastewater till tertiary level. The pilot scale proposed system had a total useful volume of 71,48 liters. This new configuration involves three types of superposed reactors: an Upflow Anaerobic Sludge Blanket reactor; an aerobic fixed film mobile bed reactor (fed with pure oxygen); and a fixed film mobile bed reactor at anoxic environment. The support material used inside the fixed film mobile bed reactors was wood made grooved dowels. The main purposes of this work are to evaluate the systems general performance regarding COD and nitrogen removal, and the microbial associations inside the reactors. It reached quite satisfactory results regarding COD and nitrogen removal when the total hydraulic retention time (HRT) was around 20 hours, including the clarification zone volume (94,6 % for the COD; and 96,7 % for the TKN-N, whit nitrate formation below 10,0 mgN-NO3-/l). HRTs from 5 to 20 hours were studied. The microbial associations were present in large number, with a great diversity and high specific activities at the different environments, confirming the good results obtained and the suitable environment provided for the growth of the different populations inside the three reactors. The idealization of this treatment system has the goal to treat domestic wastewater from small to large communities till tertiary level, in compact treatment plants, due to the possibility of constructing several modules of the system.

Esta pesquisa enfoca a avaliação do desempenho de nova configuração de unidade para tratamento biológico de esgoto sanitário por processo combinado, visando à remoção de nutrientes, especialmente nitrogênio. O sistema construído em escala piloto tem volume útil igual a 71,48 litros. Nesta nova configuração de reatores para tratamento terciário de esgoto sanitário, utilizaram-se três reatores sobrepostos, sendo: um reator UASB - “Upflow Anaerobic Sludge Blanket”; um reator de leito móvel e filme fixo aeróbio (com aplicação de oxigênio puro); e, um reator de leito móvel e filme fixo com ambiente anóxico. O material suporte utilizado nos reatores de leito móvel e filme fixo constituiu alternativa inédita no tratamento de efluentes líquidos. Foram utilizadas cavilhas “ranhuradas” de madeira, de dimensões aproximadas de 8,0 mm de diâmetro por 8,0 mm de comprimento. O desempenho geral do sistema quanto à remoção de matéria carbonácea e compostos nitrogenados, e as associações microbianas formadas nos três reatores são objetos principais de estudo deste trabalho. Foram obtidos resultados de remoção de DQO e de nitrogênio bastante satisfatórios, sobretudo quando o tempo de detenção hidráulica total esteve próximo a 20 horas, incluindo o compartimento de decantação (94,6 % para DQO; e 96,7 % para N-NTK, com formação de nitrato em concentrações inferiores a 10,0 mgN-NO3-/l). O TDH estudado variou entre 5 e 24 horas para os sistema completo. O estudo dos consórcios de microrganismos forneceu excelentes resultados quanto à quantidade, diversidade, e atividade das populações desenvolvidas nos diferentes ambientes, confirmando o bom desempenho do sistema e o fornecimento de ambiente adequado para o desenvolvimento das diferentes populações nos três reatores. A idealização desta configuração tem como finalidade realização de tratamento de esgoto sanitário até nível terciário em planta compacta, podendo ser utilizada por pequenas e grandes comunidades, devido à possibilidade de se construir diversos módulos do sistema proposto. / This research is focused on the performance evaluation of a new system configuration of combined biological reactors, treating domestic wastewater till tertiary level. The pilot scale proposed system had a total useful volume of 71,48 liters. This new configuration involves three types of superposed reactors: an Upflow Anaerobic Sludge Blanket reactor; an aerobic fixed film mobile bed reactor (fed with pure oxygen); and a fixed film mobile bed reactor at anoxic environment. The support material used inside the fixed film mobile bed reactors was wood made grooved dowels. The main purposes of this work are to evaluate the systems general performance regarding COD and nitrogen removal, and the microbial associations inside the reactors. It reached quite satisfactory results regarding COD and nitrogen removal when the total hydraulic retention time (HRT) was around 20 hours, including the clarification zone volume (94,6 % for the COD; and 96,7 % for the TKN-N, whit nitrate formation below 10,0 mgN-NO3-/l). HRTs from 5 to 20 hours were studied. The microbial associations were present in large number, with a great diversity and high specific activities at the different environments, confirming the good results obtained and the suitable environment provided for the growth of the different populations inside the three reactors. The idealization of this treatment system has the goal to treat domestic wastewater from small to large communities till tertiary level, in compact treatment plants, due to the possibility of constructing several modules of the system.

Nowadays, natural polymeric materials extracted from plants are the new alternatives for synthetic chemicals in water and wastewater treatment. The aim of this study is to evaluate the ability of Cassia fistula seed gum (CFG) as a coagulant aid with PAC in the treatment of textile wastewater. Jartest experiments were carried out to identify the optimal parameters of coagulation-flocculation for removing color and COD in synthesis wastewater containing Methyl blue and RB21 dyes, including pH, settling time, PAC dose, the optimal CFG dosage in comparing with the cationic polymer. After that, actual textile wastewater was treated by using PAC, PAC plus cationic polymer, and PAC plus CFG for evaluating the role of CFG. CFG supplementation has assisted the process effects at nearly 98% color, 85% COD for RB21 and 90% color, 70% COD for MB at the best dose of CFG 0.15 mL and 0.1 mL, respectively. The optimized parameters for the coagulation of real textile wastewater using PAC were pH = 6 and dose = 0.6 mL can removal 66% of color. By adding CFG to PAC, the efficient of treatment was increased about 70% even at the lower dosage of PAC and CFG (0.5 mL for each reagent). The yield of combining PAC and polymer was a little bit lower than PAC and CFG, for instant 68% color was decreased at the same condition. These achievements demonstrated a workable substitute of natural products such as Cassis fistula seed gum for synthetic chemical products in coagulation-flocculation process. / Hiện nay các loại vật liệu sinh học chiết xuất từ thực vật đang được nghiên cứu ứng dụng trong xử lý nước và nước thải thay cho các chất hóa học. Mục tiêu của nghiên cứu này là đánh giá hiệu quả của việc sử dụng gum được chiết xuất từ hạt cây Muồng Hoàng Yến (MHY) làm chất trợ keo tụ trong xử lý nước thải dệt nhuộm. Thí nghiệm Jartest được tiến hành nhằm xác định các điều kiện tối ưu cho quá trình xử lý nước thải tổng hợp chứa thuốc nhuộm Methyle Blue (MB) và RB21 bao gồm pH, thời gian lắng, liều PAC, liều gum MHY và liều polymer. Sau đó tiến hành xử lý nước thải thật với các điều kiện thích hợp đã xác định nhằm đánh giá vai trò của gum MHY. Gum MHY làm tăng hiệu quả của quá trình xử lý, đạt gần 98% đối với độ màu, 85% COD đối với RB21, 90% độ màu và 70% COD đối với MB với liều lượng tương ứng là 0,15 mL và 0,1 mL. Các thông số tối ưu cho quá trình xử lý trên mẫu nước thải thật là pH = 6, liều PAC = 0.6 mL có thể làm giảm 66% độ màu. Bổ sung gum MHY làm chất trợ keo tụ giúp gia tăng hiệu quả xử lý màu lên 70% dù với liều lượng rất thấp là 0,5 mL. Hiệu suất xử lý khi sử dụng kết hợp PAC và polymer thấp hơn trong trường hợp sử dụng PAC và gum MHY, cụ thể khoảng 68% độ màu được xử lý ở cùng một điều kiện. Những kết quả này cho thấy tiềm năng của việc sử dụng các vật liệu gum tự nhiên nhằm thay thế cho các hợp chất hóa học trong các quá trình keo tụ tạo bông để xử lý nước thải.

Melanoidin, a high molecular-weight heterogeneous pollutant in the effluents of molasses-using industries, poses a significant threat to the environment due to its non-biodegradability, unpleasant odour, and harmful effect. Various advanced oxidation processes (AOPs) that produce reactive oxygen species (ROS) are used for the degradation of melanoidins. Heterogeneous photo-Fenton process has emerged as a promising alternative approach in wastewater treatment owing to its enhanced catalytic activity, lower hydrogen peroxide (H2O2) consumption, and reusability of the catalyst. In this work, we investigated the photo-Fenton oxidation of melanoidins using heterogeneous catalyst ZnO@SnOx@nZVI supported on a flexible substrate. The effects of reaction pH, amount of catalyst and H2O2 on color and chemical oxygen demand (COD) removal, as well as the removal kinetics, were studied. It is found that the developed heterogeneous catalyst can lead to 97.3% decolorization of melanoidin (7000 COD) after 4 hours irradiation of simulated sunlight at pH 6 with a much lower dosage of H2O2 than the stoichiometric ratio with respect to COD. The generation of ·OH free radicals and residual H2O2 were monitored to understand the mechanism of melanoidin degradation at near-neutral pH with insufficient H2O2. The findings of this work have significant implications in treatment of non-biodegradable organic pollutants, owing to the advantages in avoiding low pH treatment condition, reducing the cost of H2O2, and enhanced chemical stability of photo-Fenton catalyst. / Melanoidin, en heterogen förorening med hög molekylvikt i avloppsvatten från industrier som använder melass, utgör ett betydande hot mot miljön på grund av dess icke-biologiska nedbrytbarhet, obehagliga lukt och skadliga effekt. Olika avancerade oxidationsprocesser (AOP) som producerar reaktiva syreföreningar (ROS) används för nedbrytning av melanoidiner. Heterogen foto-Fenton-process har framstått som ett lovande alternativ för avloppsrening på grund av dess förbättrade katalytiska aktivitet, lägre väteperoxid (H2O2) förbrukning och återanvändbarhet av katalysatorn. I detta arbete undersökte vi foto-Fenton-oxidationen av melanoidiner med hjälp av heterogen katalysator ZnO@SnOx@nZVI som stöds på ett flexibelt substrat. Effekterna av reaktionens pH, mängden katalysator och H2O2 på färg och avlägsnande av kemisk syreförbrukning (COD), liksom avlägsnandets kinetik, studerades. Det visade sig att den utvecklade heterogena katalysatorn kan leda till 97,3% avfärgning av melanoidin (7000 COD) efter 4 timmars bestrålning av simulerat solljus vid pH 6 med en mycket lågre dosering av H2O2 än det stökiometriska förhållandet med avseende på COD. Generering av ·OH fria radikaler och kvarvarande H2O2 övervakades för att förstå mekanismen för nedbrytning av melanoidin vid nära neutralt pH med otillräcklig H2O2. Resultaten av detta arbete har betydande konsekvenser vid behandling av icke- biologiskt nedbrytbara organiska föroreningar, på grund av fördelarna med att undvika behandlingsförhållanden med lågt pH, minska kostnaden för H2O2 och förbättrad kemiska stabilitet hos foto-Fenton-katalysatorn.