• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 52
  • 1
  • Tagged with
  • 57
  • 57
  • 47
  • 38
  • 18
  • 15
  • 11
  • 11
  • 11
  • 9
  • 9
  • 9
  • 8
  • 8
  • 8
  • 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

Removal of algae from facultative pond effluent

Miqdadi, Issam Mahmoud Ahmad January 1992 (has links)
Wastewater stabilization ponds have gained popularity as a means of secondary wastewater treatment because of their low cost and simplicity of operation and maintenance, in addition to several other advantages. However, the presence of algae in the effluent from facultative ponds may cause undesirable environmental impacts, such as DO depletion or eutrophication, in water bodies to which this effluent is discharged. Thus, regulations and/or the adverse environmental impacts of effluents containing algae sometimes necessitate reduction or removal of algae from pond effluents. Many methods have been used for the purpose of removal of algae from wastewater stabilization pond effluent. Upflow rock filtration and coagulationsedimentation have been investigated in this research. In the past, mechanisms of removal of algae in rock filters and factors that affect the removal process have not been well explained. Design of these filters has not been related mathematically to the operating variables. Three pilot rock filters were built for the purpose of this research. The first filter was filled with rock of 1 cm average diameter, the second and third filters were filled with 5 cm and 10 cm average diameter rock, respectively. Five different hydraulic loadings were applied to these filters, with variable influent characteristics and under different environmental conditions. The results of this research have shown that gravitational settling and hydrodynamic forces are the most important mechanisms affecting removal of algae in upflow rock filters. Also, a method of design of unisize-media upflow rock filters for removal of algae from facultative pond effluent has been established. The cost of coagulant has been the main disadvantage of the process of coagulation-sedimentation for algae removal from wastewater stabilization pond effluent. In this research, jar tests were carried out to determine the effect of settling time and/or addition of kaolinite or bentonite with the primary coagulant, alum, on the optimum dose of this primary coagulant required for removal of algae from facultative pond effluent. Both increase in settling time and coagulant aids, namely kaolinite and bentonite, have reduced optimum alum dose. Kaolinite and bentonite, applied as low-cost primary coagulants, were also effective in removing algae from facultative pond effluent. From the very limited experiments carried out at the end of this research, it was shown that crossflow microfiltration has some potential as a process for algae removal from facultative pond effluent. A mathematical model has been developed in this work to describe the eutrophic state of King Talal Reservoir in Jordan. The model predicts that even elimination of phosphorus from the effluent of Al-Samra Wastewater Stabilization Ponds will not bring the reservoir into an oligotrophic state.
2

Uso de flutuadores como ferramenta de avaliação da influência do vento na circulação de uma lagoa de estabilização facultativa primária

Casarotti, Edson Geraldo [UNESP] 05 April 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:29:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-04-05Bitstream added on 2014-06-13T20:59:25Z : No. of bitstreams: 1 casarotti_eg_me_ilha.pdf: 1046762 bytes, checksum: b3101241568cb1eabd1384cb9c88c4f7 (MD5) / Umas das formas de garantir a disposição final adequada das águas residuárias é submetê-las ao tratamento através das lagoas de estabilização. Um dos fatores consideráveis para estas unidades de tratamento são as características hidrodinâmicas presentes no processo. Um das lagoas de estabilização é a influência dos ventos na massa líquida. O presente projeto de pesquisa avaliou a influência do vento no comportamento da circulação da massa líquida da Lagoa Facultativa 2 da Estação de Tratamento de Esgotos (ETE) da cidade de Álvares Florence – SP, por meio de flutuadores de diferentes dimensões (15, 21 e 35 cm). Foram confeccionados 9 flutuadores, 3 grupos com 3 flutuadores (um de cada dimensão) e lançados nas 3 entradas existentes na lagoa. A pesquisa foi dividida em duas etapas: na primeira etapa foram averiguados o tempo de percurso dos flutuadores ao longo de uma célula da lagoa facultativa 2 e o efeito de borda. Na segunda etapa foi verificada a influência dos ventos na movimentação da massa líquida e as condições de mistura proporcionadas por esta influência por meio dos flutuadores e análises de DQO. O método dos flutuadores para verificação da influência do vento e a circulação de uma lagoa facultativa mostrou-se como uma alternativa efetiva e simples quando comparado ao método com traçadores / One of the ways to ensure the proper disposal of wastewater is subject them to treatment by stabilization ponds. One of the significant factors for these treatment units are the hydrodynamic characteristics present in the process. Wind is external physical aspects that affect the hydrodynamic behavior of the stabilization ponds due to their influence on the circulation of the liquid mass. This research project evaluated the influence of wind on the behavior of the liquid mass flow of the facultative pond 2 of Sewage Treatment Plant in the city of Álvares Florence – SP, by means of floats of different sizes (15, 21 and 35 cm). Nine floats were made, three groups with three floats (one of each size) and released in three entries in the pond. The research was divided into two stages: the first step, were checked the travel time of the floats along of the facultative pond 2 and edge effect. In the second step was verified the influence of wind on movement of the liquid mass and mixing conditions provided by this influence by means of floats and COD analysis. The method for verification of the floats of the wind influence and the movement of a facultative pond proved to be a simple and effective alternative when compared with the tracer method
3

A comparative study of anaerobic treatment of citrus processing wastewater

Fashanu, Julius Olusegun January 1996 (has links)
No description available.
4

Uso de flutuadores como ferramenta de avaliação da influência do vento na circulação de uma lagoa de estabilização facultativa primária /

Casarotti, Edson Geraldo. January 2011 (has links)
Orientador: Tsunao Matsumoto. / Banca: Milton Dall'Aglio Sobrinho / Banca: Luís Fernando Rossi Léo / Resumo: Umas das formas de garantir a disposição final adequada das águas residuárias é submetê-las ao tratamento através das lagoas de estabilização. Um dos fatores consideráveis para estas unidades de tratamento são as características hidrodinâmicas presentes no processo. Um das lagoas de estabilização é a influência dos ventos na massa líquida. O presente projeto de pesquisa avaliou a influência do vento no comportamento da circulação da massa líquida da Lagoa Facultativa 2 da Estação de Tratamento de Esgotos (ETE) da cidade de Álvares Florence - SP, por meio de flutuadores de diferentes dimensões (15, 21 e 35 cm). Foram confeccionados 9 flutuadores, 3 grupos com 3 flutuadores (um de cada dimensão) e lançados nas 3 entradas existentes na lagoa. A pesquisa foi dividida em duas etapas: na primeira etapa foram averiguados o tempo de percurso dos flutuadores ao longo de uma célula da lagoa facultativa 2 e o efeito de borda. Na segunda etapa foi verificada a influência dos ventos na movimentação da massa líquida e as condições de mistura proporcionadas por esta influência por meio dos flutuadores e análises de DQO. O método dos flutuadores para verificação da influência do vento e a circulação de uma lagoa facultativa mostrou-se como uma alternativa efetiva e simples quando comparado ao método com traçadores / Abstract: One of the ways to ensure the proper disposal of wastewater is subject them to treatment by stabilization ponds. One of the significant factors for these treatment units are the hydrodynamic characteristics present in the process. Wind is external physical aspects that affect the hydrodynamic behavior of the stabilization ponds due to their influence on the circulation of the liquid mass. This research project evaluated the influence of wind on the behavior of the liquid mass flow of the facultative pond 2 of Sewage Treatment Plant in the city of Álvares Florence - SP, by means of floats of different sizes (15, 21 and 35 cm). Nine floats were made, three groups with three floats (one of each size) and released in three entries in the pond. The research was divided into two stages: the first step, were checked the travel time of the floats along of the facultative pond 2 and edge effect. In the second step was verified the influence of wind on movement of the liquid mass and mixing conditions provided by this influence by means of floats and COD analysis. The method for verification of the floats of the wind influence and the movement of a facultative pond proved to be a simple and effective alternative when compared with the tracer method / Mestre
5

Improving understanding of the chemical and biological nutrient removal mechanisms in existing wastewater lagoons

Vendramelli, Richard Adam 24 June 2016 (has links)
Many rural communities in Manitoba use wastewater lagoons to treat sewage, but the nutrient removal process is not fully understood. This thesis’ purpose is to improve understanding of chemical and biological nutrient removal mechanisms of wastewater lagoon treatment and compare two different stabilization ponds – one aerated and one facultative. Samples were collected from stabilization ponds and analysed for a pond average. The facultative lagoon achieved overall ammonia-N removals similar to those of the aerated lagoon, and lower orthophosphate removals. Nitrogen appears to be removed by ammonia volatilization; and assimilation into biomass. Phosphorus appears to be removed by assimilation into biomass; and precipitation at alkaline pH. There appears to be nitrogen limiting conditions in the secondary cells of both stabilization systems based on nitrogen-phosphorus ratios. There does not appear to be any significant advantage between aerated or facultative lagoons; they will meet their ammonia limits, but will require additional phosphorus treatment. / October 2016
6

Comparação e avaliação dos métodos colorimétricos utilizados para determinação de proteínas em lagoas de estabilização / Comparison and evaluation of colorimetric methods used to proteins determination in waste stabilization ponds

Miwa, Adriana Cristina Poli 21 February 2003 (has links)
As lagoas de estabilização representam um dos métodos mais simples utilizados para tratamento de esgoto sanitário. Grande parte da matéria orgânica presente no esgoto sanitário é constituída por proteínas, a qual torna-se fator limitante aos processos biológicos de tratamento de águas residuárias em que se encontram presentes. O objetivo deste trabalho foi avaliar e comparar métodos colorimétricos para determinação de proteínas, definindo qual é o mais apropriado para esse tipo de ambiente. Os métodos colorimétricos utilizados foram o de Lowry, de Bradford, do Biureto e do Ácido Bicinconínico. As proteínas padrões utilizadas foram soroalbumina, caseína e ovoalbumina. O método de Bradford apresentou várias desvantagens. Biureto I e III e proteína bruta medida a partir do Nitrogênio Total Kjeldah (NTK) apresentaram valores altos devido não medir somente proteínas. A quantidade de proteínas na amostra não foi suficiente para que ocorresse reação no método Biureto II. O método do Ácido Bicinconínico não reagiu com caseína e o custo do reagente é alto. Portanto, o método apropriado para esse tipo de amostra foi o Lowry que apresentou maior reprodutividade e sensitividade. Para comprovar esse resultado, uma análise de adição de padrão à amostra foi realizada para verificar se haviam substâncias interferentes, cujo resultado foi negativo / Stabilization ponds represent a simple method to treat sanitary sewage. A large part of the organic matter present in sanitary sewage consists of proteins, which become a limiting factor for the wastewater treatment in biological processes. The goal of this work was to evaluate and to compare colorimetric methods for protein determination, defining which is the more appropriate for this environment. The colorimetric methods used were the Folin-phenol, Bradford, Biuret and Bicinconinic Acid methods. The protein standards used were serum albumin bovin, casein and ovalbumin. The Bradford method introduced several disadvantages. Biuret I and III and brute protein introduced high values due don't measure only proteins. The proteins quantity in the sample wasn't enough so that it had occurred reaction in the Biuret II method. The method of Bicinconinic Acid didn't react with casein and the reagent cost is high. Therefore, the method appropriated for this sample was the Lowry that introduced larger reprodutivity and sensitivity. To prove this result, a standard addition analysis was performed to verify if there were interfering substances, whose result was negative
7

Removing Algae From Stabilization Pond Effluents By Using Trickling Filters

Kaya, Devrim 01 September 2005 (has links) (PDF)
The objective of this study is to remove turbidity originating from algae present in oxidation ponds effluents by an easy and inexpensive method. For this reason, a novel lab-scale Step Feed Dual Treatment (SFDT) process was constructed and the efficiency of trickling filter (TF) to remove algae and organic matter was investigated. SFDT process developed in this study is the unique, inexpensive and new system to scavenge algae from oxidation pond effluents. In this system, influent is first treated in a stabilization pond, and subsequently they directed to a TF, so as to provide a dual treatment. Moreover, some fraction of the raw influent was directly sent to TF to maintain a steady biofilm on the TF medium. Stabilization pond was not simulated in the experimental set-up as the main objective of the study is to observe TF ability to scavenge algae from pond effluent. To determine the magnitude of the effect of individual operational parameters (hydraulic loading rate, influent COD and chlorophyll-a concentration) and of their combinations on organics and particle removal efficacy an experimental design was followed. Experiments consistent with twolevel factorial design with three variables (23) were performed. Hydraulic loading rate (HLR) (0.5-2 m3/m2.day), influent COD (150-550 mg/l) and influent chlorophyll-a concentrations (Chl-a) (250-600 &micro / g/l) were selected as independent variables. The COD and algae removal (as Chl-a) were selected as dependent variables. Data obtained from the experiments showed that when HLR (m3/m2.day) was increased from 0.5 to 2, Chl-a, NTU, SS and COD removals were decreased, however, more than 85 % removal was attained in each case, except for COD. The lowest removal efficiencies were obtained for all the quality parameters when hydraulic loading was increased to 4 m3/m2.day. It was observed that in general removal percentages for turbidity, Chl-a, SS and COD increased considerably with the decreasing hydraulic loading rate. Highest removals were obtained at lowest HLR. The removal of algae in TF was presumably due to both flocculation (due to algal and bacterial EPS production) and degradation (through bacterial activity) of algae. In conclusion, trickling filter produced clear effluents, with less than 2 NTU, for most of the cases.
8

Estudo dos mecanismos envolvidos na separaÃÃo e ruptura simultÃneas de biomassa algal pelo uso da tecnologia de eletroflotaÃÃo por corrente alternada / Study of the mechanisms involved in the separation and simultaneous rupture of algal biomass by use of alternating current electrocoagulation technology

Riamburgo Gomes de Carvalho Neto 08 November 2013 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Dentre as diversas etapas para a transformaÃÃo de microalgas em biodiesel, os processos de separaÃÃo e a ruptura celular dessa biomassa sÃo particularmente importantes, uma vez que as tecnologias disponÃveis para este fim apresentam elevados custos, comprometendo a viabilidade do aproveitamento energÃtico. Este trabalho teve como objetivo geral estudar os mecanismos envolvidos na separaÃÃo e ruptura simultÃneas de biomassa algal pelo uso da tecnologia de eletroflotaÃÃo por corrente alternada (EFCA), com objetivo principal de extrair o conteÃdo lipÃdico da biomassa algal, assim como verificar o potencial da tecnologia na remoÃÃo de nutrientes de efluentes de lagoas de estabilizaÃÃo. Foram realizados ensaios de coagulaÃÃo/floculaÃÃo em jar test com coagulantes sintÃticos (FeCl3 e Al2(SO4)3) e orgÃnicos (Tanfloc SG e SL) com o objetivo de avaliar a decantaÃÃo quimicamente assistida na separaÃÃo de biomassa algal. Foi desenvolvido um reator de EFCA para operar em batelada, utilizando-se eletrodos nÃo consumÃveis e baixa potÃncia elÃtrica. Foi avaliado o seu potencial de separaÃÃo com e sem o auxÃlio dos mesmos coagulantes utilizados nos testes de jarro e, em seguida, buscou-se variar as frequÃncias de operaÃÃo do conjunto de eletrodos com o objetivo de verificar a condiÃÃo Ãtima para separaÃÃo e rompimento celular das microalgas. Foi tambÃm avaliada a capacidade desta metodologia na remoÃÃo de nutrientes presentes nos efluentes e elucidar os mecanismos envolvidos. Foi possÃvel a remoÃÃo de biomassa algal tanto por meio da decantaÃÃo quimicamente assistida quanto pela EFCA, sendo que a segunda à mais atrativa nÃo somente pelas eficiÃncias de remoÃÃo de turbidez e clorofila-a encontradas, como tambÃm pela nÃo necessidade aparente de utilizaÃÃo de coagulantes, o que traz economia ao processo e facilita a reutilizaÃÃo da biomassa algal. A EFCA mostrou-se ainda capaz de promover com eficiÃncia o rompimento celular das microalgas e fazer com que os lipÃdeos liberados se aderissem à biomassa algal separada pelo processo. Foi possÃvel alcanÃar um rendimento lipÃdico de atà 14% em peso de massa seca, mesmo os estudos tendo sido realizados com uma matriz diversa de microalgas proveniente das lagoas de estabilizaÃÃo. O estudo dos mecanismos envolvidos revelou a boa capacidade do sistema em gerar gÃs hidrogÃnio, o qual alÃm de ajudar na separaÃÃo das microalgal pode tornar futuramente o processo energeticamente sustentÃvel. AlÃm disso, foi verificada a geraÃÃo de espÃcies oxidantes que ajudam tanto o processo de separaÃÃo quanto possivelmente de ruptura celular. O efeito de diferentes frequÃncias de vibraÃÃo nos rendimentos lipÃdicos encontrados nÃo foi aparente. Buscou-se ainda a elucidaÃÃo dos mecanismos de remoÃÃo de fÃsforo total, o que provavelmente se deu pela formaÃÃo de ferro durante o processo, cujos valores ficaram na ordem de 2,5 mg/L depois de 70 minutos de batelada. Jà para a remoÃÃo de amÃnia, possivelmente o mecanismo foi de oxidaÃÃo indireta da amÃnia atravÃs do excesso de Ãcido hipocloroso como a forma predominante de conversÃo da mesma em nitrogÃnio gasoso, o qual ajuda no processo de separaÃÃo. A utilizaÃÃo de microalgas diretamente de lagoas de estabilizaÃÃo mostrou-se uma potencial alternativa aos processos de obtenÃÃo de biomassa tradicionalmente utilizados (fotobiorreator e lagoas do tipo raceway), sendo que a tecnologia proposta se mostrou atrativa para todos processos que demandem separaÃÃo algal. / Among the various steps for microalgae transformation in biodiesel, the harvesting and cell disruption processes are particularly important, since technologies available for this purpose have usually high costs, undermining the energy recovery viability. This work studied the mechanisms involved in the simultaneous harvesting and cell disruption of microalgae using electroflotation by alternating current (EFCA), as well as to investigate the system capacity on nutrients removal from waste stabilization ponds effluents. Coagulation/flocculation tests were performed using synthetic (FeCl3 e Al2(SO4)3) and organic (Tanfloc SG e SL) coagulants to evaluate the chemically assisted sedimentation of the algal biomass. The EFCA reactor was designed to operate in batch, using non-consumable electrodes and low electrical power, and evaluated the harvesting potential in the presence and absence of coagulants. After this, experiments were performed varying the electrode frequency to verify the optima condition for simultaneous harvesting and cell disruption of microalgae. The system capacity in terms of nutrients removal was also investigated as well as the mechanisms involved. It was possible to remove algae biomass both using chemically assisted sedimentation and EFCA. However, the electrolytic technology is more attractive, not only for the turbidity and chlorophyll-a efficiencies founded, but also because there is no apparent need of coagulants, which makes the process cheaper and facilitates the microalgae biomass reuse. The EFCA was even able to promote the cell disruption of microalgae and the liberated lipids were able to attach to the algal biomass separated by the process. A lipid yield of 14 % in terms of dry matter was found, even when a complex matrix from waste stabilization ponds was used. The study of the mechanisms involved in EFCA revealed the good system ability to generate hydrogen gas, which contributes to microalgae harvesting and can make the process even more sustainable under an energetic perspective. Furthermore, the generation of oxidant species was found which helps the harvesting and cell disruption process. The effect of different vibration frequencies in the lipid yield was not apparent. We sought to elucidate the mechanisms involved on total phosphorus removal, and probably the removal was due to iron formation in the process, in which the concentrations were close to 2.5 mg/L after 70 minutes batch time. In terms of ammonia removal, possibly the mechanism was an indirect oxidation by excess of hypochlorous acid to form nitrogen gas, which helps the separation process. The use of microalgae from stabilization ponds showed a potential alternative for the processes traditionally used nowadays for microalgae production (photobioreactor and raceway ponds), and showed to be attractive to all processes that demand microalgae harvesting.
9

Comparação e avaliação dos métodos colorimétricos utilizados para determinação de proteínas em lagoas de estabilização / Comparison and evaluation of colorimetric methods used to proteins determination in waste stabilization ponds

Adriana Cristina Poli Miwa 21 February 2003 (has links)
As lagoas de estabilização representam um dos métodos mais simples utilizados para tratamento de esgoto sanitário. Grande parte da matéria orgânica presente no esgoto sanitário é constituída por proteínas, a qual torna-se fator limitante aos processos biológicos de tratamento de águas residuárias em que se encontram presentes. O objetivo deste trabalho foi avaliar e comparar métodos colorimétricos para determinação de proteínas, definindo qual é o mais apropriado para esse tipo de ambiente. Os métodos colorimétricos utilizados foram o de Lowry, de Bradford, do Biureto e do Ácido Bicinconínico. As proteínas padrões utilizadas foram soroalbumina, caseína e ovoalbumina. O método de Bradford apresentou várias desvantagens. Biureto I e III e proteína bruta medida a partir do Nitrogênio Total Kjeldah (NTK) apresentaram valores altos devido não medir somente proteínas. A quantidade de proteínas na amostra não foi suficiente para que ocorresse reação no método Biureto II. O método do Ácido Bicinconínico não reagiu com caseína e o custo do reagente é alto. Portanto, o método apropriado para esse tipo de amostra foi o Lowry que apresentou maior reprodutividade e sensitividade. Para comprovar esse resultado, uma análise de adição de padrão à amostra foi realizada para verificar se haviam substâncias interferentes, cujo resultado foi negativo / Stabilization ponds represent a simple method to treat sanitary sewage. A large part of the organic matter present in sanitary sewage consists of proteins, which become a limiting factor for the wastewater treatment in biological processes. The goal of this work was to evaluate and to compare colorimetric methods for protein determination, defining which is the more appropriate for this environment. The colorimetric methods used were the Folin-phenol, Bradford, Biuret and Bicinconinic Acid methods. The protein standards used were serum albumin bovin, casein and ovalbumin. The Bradford method introduced several disadvantages. Biuret I and III and brute protein introduced high values due don't measure only proteins. The proteins quantity in the sample wasn't enough so that it had occurred reaction in the Biuret II method. The method of Bicinconinic Acid didn't react with casein and the reagent cost is high. Therefore, the method appropriated for this sample was the Lowry that introduced larger reprodutivity and sensitivity. To prove this result, a standard addition analysis was performed to verify if there were interfering substances, whose result was negative
10

Desempenho de lagoas de maturação utilizando macrófitas aquáticas e chicaneamento / Performance of maturation ponds using aquatic plants and baffles

Polisel, Kleber Castilho 30 September 2005 (has links)
As lagoas de estabilização têm sido, por suas características operacionais e baixos custos de implantação, consideradas como a opção mais viável para tratamento de águas residuárias em pequenas e médias comunidades. O sistema composto por lagoa anaeróbia e facultativa em série é o mais empregado no Brasil. Com o avanço no monitoramento das lagoas de estabilização que se iniciou na década de 90, no caso do Estado de São Paulo pela SABESP, e que hoje se encontra bastante estruturado, periódico e confiável, nota-se que esses sistemas apesar de projetados seguindo as técnicas mais recentes, não possuem a eficiência esperada quando em operação. Tornam-se então prementes os estudos no sentido de melhorar o desempenho dos sistemas existentes e fornecer subsídios para novos projetos de lagoas de estabilização. Este trabalho estudou a utilização de chicaneamento nas lagoas de estabilização verificando a influência das chicanas no comportamento hidrodinâmico e desempenho desses sistemas além da utilização de macrófitas aquáticas no processo de tratamento de águas residuárias. Concluiu-se que mesmo com aumento de eficiência de remoção de DQO, 'DBO IND.5', nitrogênio Kjedahl e amoniacal, para ambos os casos: lagoa com aguapé e lagoa com lentilha d’água, os inúmeros problemas operacionais e aumento de custos que surgiram da aplicação das macrófitas aquáticas tornam desaconselhável o uso de aguapé e lentilha d’água em lagoas de tratamento de esgoto. Com relação ao chicaneamento o sistema que mais se aproximou dos valores teóricos, com relação ao tempo de detenção hidráulico e número de dispersão (d), foi a lagoa com chicaneamento longitudinal, melhorando o comportamento hidráulico do sistema, podendo ser considerado uma medida simples e de baixo custo para incrementar a eficiência de lagoas de estabilização / Due to the operational characteristics and low investment costs stabilization ponds have been considered as the most viable option for wastewater treatment in small and medium size communities. Anaerobic and facultative ponds in series are the most used in Brazil. With the progress of monitoring of the stabilization ponds, that was initiated in the decade of 1990 in the State of São Paulo by SABESP, it was observed that these systems do not possess the expected efficiency when in operation, although they were designed following the best available knowledge at that time. Thus, new studies were direct to improve the performance of the existing systems and to supply subsidies for new projects of stabilization ponds. This research examines, separately, the use of baffles and macrophytes in a pilot scale stabilization pond verifying the influence of these elements on the hydrodynamic behavior and performance of the wastewater treatment. It was concluded that although there is an increase in removal efficiency of DQO, 'DBO IND.5', nitrogen Kjedahl and ammoniacal, the several operational problems and increase of costs that had appeared with the application of water hyacinths and duckweed in the pond, it is not recommended to use these aquatic plants in sewer treatment. Concerning the use of baffles the system that came closer to the theoretical values, in relation to the hydraulic time of detention and number of dispersion (d), was the pond with longitudinal baffles. These baffles improved the hydraulic behavior of the system and are a simple measure and of low cost to develop the efficiency of stabilization ponds

Page generated in 0.1335 seconds