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Higiene e segurança nas estações de tratamento de esgotos / Hygiene and safety at sewage treatment plantsReginaldo Vello Loureiro 04 May 1982 (has links)
A poluição dos recursos hídricos vem agravando-se a cada ano, em quase todos os países, inclusive no Brasil. Providências vêm sendo tomadas, principalmente nas grandes cidades, no sentido de combatê-la. Dentre os meios utilizados para a proteção da qualidade da água, destacam-se as Estações de Tratamento de Esgotos - ETE.s. Nestas ETEs trabalham diversos profissionais, dentre os quais os operadores. Estes, exercem variadas atividades, geralmente em todas as suas unidades. Com o aumento progressivo do número de Estações de Tratamento de Esgotos, a quantidade de operadores, anteriormente pouco significativa, tende a se tornar cada vez maior no Brasil, e deverá atingir um número considerável, em futuro bem próximo. Estes trabalhadores, como os de qualquer outra atividade industrial, estão expostos a riscos os mais variados, os quais são agravados ainda mais, devido à presença dos esgotos no local de trabalho. Procurou-se, neste trabalho, levantar os riscos existentes nas unidades das ETEs pesquisadas, e fazer recomendações, no sentido de minimizá-los. Aplicou-se, para tal fim, um questionário em 11 Estações de Tratamento de Esgotos, levantando-se dados relacionados com as condições sanitárias do ambiente de trabalho; hábitos higiênicos dos operadores; medidas preventivas, de caráter individual e coletivo, para evitar a ocorrência de acidentes nas ETEs; atividades do Serviço Especializado em Segurança e em Medicina do Trabalho; e Segurança Patrimonial nas ETEs. Foi feita, ainda, uma avaliação dos veis de iluminamento, à noite; ruído; explosividade; e concentração do gás sulfídrico, em algumas unidades das ETEs incluídas na pesquisa. / The pollution of water resources has become worse every year in almost every country of the world, including Brasil. Among the measures taken to correct it, installation of Sewage Treatment Plants, specially in big cities, stand out. Many professionals work at these Sewage Treatment Plants, among these are operators performing a variety of activities. With the increasing number of Sewage Treatment Plants installed, the number of operators, of little significance at the beginning, tends to become greater and greater in Brazil and it is antecipated that in the near future it will become considerable. These workers, like those in any other industrial activity, are exposed to a great variety of risks, that in this case are increased even more by the existence of sewage at their place of work. This paper intends to survey the existing risks in the Sewage Treatment Plants units studied as well as to make recommendations that may minimize them. In this sense, a questionnaire was applied at eleven Sewage Treatment Plants, collecting data regarding sanitary conditions of the work environment, higienic habits of the workers, preventive measures - individual and collective - to avoid the occurrence of accidents, activities of the Specialized Safety Service and Labour Medicine and Patrimonial Safety. At the same time an evaluation was carried out to assess the levels of night illumination, noise, explosiveness and the concentration of hydrogen sulfide in some of the Sewage Treatment Plants units covered in this study
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Spatial distribution of phosphorus in the sediments of a constructed wetland receiving treated sewage effluentRowley, Maxine Joy, University of Western Sydney, Hawkesbury, Faculty of Science and Technology January 1998 (has links)
The Byron Bay Sewage Treatment work consists of a conventional treatment system discharging into an 8 ha wetland. The wetland was constructed around the dune and swale remnants of a coastal beach ridge formation. The wetland design incorporated stands of broad leaf paperback, Melaleuca quinquenervia , in two distinct Sections, separated by, and each preceded by, open water Sections fringed by predominantly emergent macrophytes. Spatial and temporal patterns in sediment phosphorus concentrations were examined using sediment cores. Core consisted of three main sediment types - surface organic accumulation, pre-existing organic layers and sand. Results suggest that the design and management of wetland systems should be aimed at maximising the deposition of sediment (and associated phosphorus) and minimising subsequent phosphorus release from the sediment. This might be achieved through the removal of accumulated organic sediments to retain the phosphorus adsorption capacity of the system, consideration of wind direction during periods of high (floating) plant growth (as detritus may accumulate along the up-wind edges of the wetland), incorporation of deep zones to minimise sediment phosphorus release and the inclusion of stands of M. quinquenervia. Results highlight pitfalls in the prevailing approach to wetland design, which ignore the complex functions which occur in natural wetland systems. A more holistic approach incorporating a high diversity of ecozones in wetland design is proposed, in effect mimicking natural systems. / Master of Science (Hons)
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Assessment of the biological quality of raw and treated effluents from three sewage treatment plants in the Western Cape, South AfricaHendricks, Rahzia January 2011 (has links)
<p>The aim of this study was to compare the water quality of raw wastewater and treated sewage effluents from three different sewage treatment plants in the Western Cape, South Africa. The treatment plants investigated are on the same river system. Sewage treatment plant 1 and 2 use older technologies, while sewage treatment plant 3 has been upgraded and new technologies (membrane bioreactor) were incorporated in the treatment processes. The first objective was to determine the occurrence of total coliforms, Escherichia coli (E. coli) and fluoroquinolone and sulfamethoxazole antibiotic residues in raw wastewater and treated sewage effluents. Bacteria in treated sewage effluents can result in diseases such as dysentery, gastroenteritis, and typhoid upon exposure. A chromogenic test was used to screen for coliforms and E. coli. Enzyme linked Immunosorbent Assays (ELISA) were used to quantitate antibiotic residues (fluoroquinolones and sulfamethoxazole) in raw wastewater and treated sewage effluents. This study showed that bacteria are present in raw wastewater and residual bacteria are released with treated sewage effluents from sewage treatment plants.</p>
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Determination of Antibiotics in the Swedish Environment with Emphasis on Sewage Treatment PlantsLindberg, Richard January 2006 (has links)
Metoder har utvecklats för att kunna bestämma tolv antibiotikasubstanser, vanliga inom human medicin, i miljöprover. Fokus lades på trimetoprim samt substanser från följande grupper: fluorokinoloner, sulfonamider, penicilliner, cefalosporiner, nitroimidazoler, tetracykliner samt makrolider. Vid extraktion användes fast-fas extraktion för vattenprover och ultraljuds-assisterad fast-fas/vätske extraktion för fasta prover. För separering och bestämning användes vätskekromatografi tandemmasspektrometri. Interna standarder nyttjades för att öka noggrannhet och precision. Extraktionsutbyte låg mellan 50% och 100% för vattenfaser och 14% och 100% för fasta faser. Koncentrationer och massflöden bestämdes för antibiotikasubstanser i inkommande och utgående vatten och slam, från fem avloppreningsverk i Sverige, samt i avloppsvatten från ett sjukhus. I sjukhusavloppsvattnet så påträffades ciprofloxacin (en fluorokinolon) och metronidazol (en nitroimidazol) i höga halter (µg/L nivå). Screening-studien vid de fem avloppsreningsverken visade att norfloxacin, ofloxacin, ciprofloxacin och doxycyklin ofta förekom i inkommande och utgående vatten och slam. Trimetoprim och sulfametoxazol påvisades inte i slam men förekom i snarlika koncentrationer i det utgående vattnet relativt det inkommande. I vattenfasen så förekom de sex antibiotikasubstanserna i ng/L nivån och i slam förekom norfloxacin, ofloxacin, ciprofloxacin, och doxycyklin i låga mg/kg nivån. En studie genomfördes där beteendet hos antibiotikasubstanser under avloppsrening studerades. De två fluorokinolonerna, norfloxacin och ciprofloxacin, adsorberade till slam och mindre än 5% av den totala mängd som kommer till avloppsreningsverket påvisades i det utgående vattnet. I slam var motsvarande andel 70%. Resultat från en process som värmebehandlar rötat avvattnat slam antyder att cirka 50% av de två fluorokinolonerna bryts ner. Trimetoprim adsorberade inte till slam och 100% av total mängd återfanns i det utgående vattnet. Teoretiska beräkningar av koncentrationer och massflöden visade god korrelation till kvantitativa resultat. Ökad noggrannhet i beräkningarna fås genom att beakta stabilitet och fasfördelning. Effekten av antibiotikasubstanser i miljön är idag okänd. Resultat från testprotokoll där deras toxicitet bedöms är i många fall irrelevanta. Tester där organismer är kroniskt exponerade av biologiskt aktiva substanser vid låga koncentrationer är få. Dessutom så fokuserar de ej på de stora potentiella effekterna såsom utveckling eller bevaring av resistenta stammar av bakterier i miljön. Ytterligare studier av förekomst, öde och effekt av antibiotikasubstanser i miljön är nödvändiga. / Methods were developed for determining levels in environmental samples of twelve antibiotics that are commonly used in human medicine: trimethoprim and substances from the following groups: fluoroquinolones, sulfonamides, penicillins, cephalosporines, nitroimidazoles, tetracyclines and macrolides. These substances were extracted from liquid and solid samples by solid phase extraction and ultrasonic-assisted liquid/solid extraction, respectively. Liquid chromatography tandem mass spectrometry was then used to separate and quantify them, and internal standards were added to improve the accuracy and precision of the determinations. Extraction yields from aqueous and solid phases were in the ranges 50 - 100% and 14 - 100%, respectively. Concentrations and mass flows of antibiotic substances were determined in a hospital effluent and in the raw sewage water, final effluent, and sludge from five sewage treatment plants (STPs) scattered across Sweden. High levels (in the µg/L range) of ciprofloxacin (a fluoroquinolone) and metronidazole (a nitroimidazole), were found in the hospital effluent. The screening study of the five sewage treatment plants revealed that norfloxacin, ofloxacin, ciprofloxacin, and doxycycline were frequently present in the raw sewage water, final effluent and sludge. Trimethoprim and sulfamethoxazole were not detected in the sludge, but these substances were present in the final effluents at concentrations close to those of the raw sewage water. In the aqueous phase, these six antibiotics were present in the ng/L range and in the solid phase, norfloxacin, ofloxacin, ciprofloxacin, and doxycycline were present in the low mg/kg range. The behaviour of the antibiotic substances during sewage water treatment was also investigated in one of the STPs. The two fluoroquinolones, norfloxacin and ciprofloxacin, sorbed to sludge, and less than 5% of the total amounts that entered the STP were found in the final effluent. In sludge, the corresponding figure was 70%. Results from a process in which digested dewatered sludge was treated with heat (producing pellets) indicated that approximately 50% of the two fluoroquinolones had been degraded. Trimethoprim did not sorb to sludge and 100% of its total amount was found in the final effluent. Theoretical calculations of concentrations and mass flows correlated well with quantitative results for the antibiotics that were frequently detected, but not for the others. In order to increase the accuracy of the calculations, the stability and phase distribution of the antibiotics should be considered. The effects of antibiotics present in the environment are currently unknown. Results of test protocols to assess their toxicity are often irrelevant, and there have been few tests in which organisms have been chronically exposed to biologically active substances at low concentrations. In addition, these tests have not addressed the immense potential of antibiotics in the environment to induce the development of resistant strains of bacteria and to maintain populations of resistant strains. Further studies of the occurrence, fate, and, effects of antibiotic substances in the environment are required.
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Assessment of the biological quality of raw and treated effluents from three sewage treatment plants in the Western Cape, South AfricaHendricks, Rahzia January 2011 (has links)
<p>The aim of this study was to compare the water quality of raw wastewater and treated sewage effluents from three different sewage treatment plants in the Western Cape, South Africa. The treatment plants investigated are on the same river system. Sewage treatment plant 1 and 2 use older technologies, while sewage treatment plant 3 has been upgraded and new technologies (membrane bioreactor) were incorporated in the treatment processes. The first objective was to determine the occurrence of total coliforms, Escherichia coli (E. coli) and fluoroquinolone and sulfamethoxazole antibiotic residues in raw wastewater and treated sewage effluents. Bacteria in treated sewage effluents can result in diseases such as dysentery, gastroenteritis, and typhoid upon exposure. A chromogenic test was used to screen for coliforms and E. coli. Enzyme linked Immunosorbent Assays (ELISA) were used to quantitate antibiotic residues (fluoroquinolones and sulfamethoxazole) in raw wastewater and treated sewage effluents. This study showed that bacteria are present in raw wastewater and residual bacteria are released with treated sewage effluents from sewage treatment plants.</p>
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Integrated land capability for ecological sustainability of on-site sewage treatment systemsAl-Shiekh Khalil, Wael R. January 2005 (has links)
The research project was formulated to solve serious environmental and possible public health problems in rural and regional areas caused by the common failure of soil disposal systems used for application of effluent from on-site domestic sewage treatment systems. On-site sewage treatment systems adopt a treatment train approach with the associated soil disposal area playing a crucial role. The most common on-site sewage treatment system that is used is the conventional septic tank and subsurface effluent disposal system. The subsurface effluent disposal area is given high priority by regulatory authorities due to the significant environmental and public health impacts that can result from their failure. There is generally very poor householder maintenance of the treatment system and this is compounded by the failure of the effluent disposal area resulting in unacceptable surface and groundwater contamination. This underlies the vital importance of employing reliable science-based site suitability assessment techniques for effluent disposal. The research undertaken investigated the role of soil physico-chemical characteristics influencing the behaviour of effluent disposal areas. The study was conducted within the Logan City Council area, Queensland State, Australia. About 50% of the Logan region is unsewered and the common type of on-site sewage treatment used is a septic tank with subsurface effluent disposal area. The work undertaken consisted of extensive field investigations, soil sampling and testing, laboratory studies and extensive data analysis. In the field study, forty-eight sites were investigated for their effluent application suitability. The sites were evaluated based on the soil physico-chemical characteristics. The field investigation indicated that there were nine soil orders in the study area. These soil orders were Dermosols, Chromosols, Kandosols, Kurosols, Vertosols, Sodosols, Tenosols, Rudosols and Anthrosols. The soils in all the investigated sites were acidic soils in the pH range between 5 and 6.5. The complexity of the large data matrix obtained from the analysis was overcome by multivariate analytical methods to assist in evaluating the soils' ability to treat effluent and to understand the importance of various parameters. The analytical methods selected to serve this purpose were PROMETHEE and GAIA. The analysis indicated that the most suitable soils for effluent renovation are the Kandosols whilst the most unsatisfactory soil order was found to be Podosol. The GAIA analysis was in agreement with quantitative analysis conducted earlier. An extensive laboratory column study lasting almost one year was undertaken to validate the results of the data analysis from the field investigation. The main objectives of this experiment were to examine the soil behaviour under practical effluent application and to investigate the long-term acceptance rate for these soils. Twelve representative soils were selected for the column experiment from the previously investigated sites and undisturbed soil cores were collected for this purpose. The results from the column study matched closely with the evaluation conducted at the earlier stages of the research. Soil physico-chemical analysis before and after effluent application indicated that the soils' acidity was improved toward neutrality after effluent application. The results indicated that soils have a greater ability to handle phosphorus than nitrogen. The most favorable cation exchange capacity for soils to treat and transmit effluent was between 15 and 40 meq/100g. Based on the results of the column study, the long-term acceptance rate (LTAR) was determined for the investigated twelve soil types. Eleven out of twelve soils reported specific LTAR values between 0.18-0.22 cm/day. For the duration of the laboratory study, the Podosol order did not reach its LTAR value due to the extremely sandy nature of the soil. The time required to achieve LTAR varied between different soils from 40 to 330 days. The outcomes of this research was integrated into a soil suitability map for on-site sewage treatment systems for Logan City Council. This will assist the authorities in providing sustainable solutions for on-site systems failure.
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Fatores operacionais na manutenção da eficiência de um reator UASB compartimentado tratando esgoto sanitário / Operational factors in the efficiency maintenance of a compartmentalized UASB reactor treating sewagePrampero, Julio Cesar 02 March 2017 (has links)
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Previous issue date: 2017-03-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O uso de inovações estruturais em reatores UASB (Upflow Anaerobic Sludge Blanket) para sua utilização no tratamento de esgoto doméstico, como a compartimentação, é uma alternativa para aprimorar um sistema de tratamento simples e eficiente. Projetado com configuração estrutural inovadora o Reator UASB Compartimentado (RUC) utilizado foi operado em fluxo contínuo com esgoto sanitário do município de Ilha Solteira- SP. Objetivando a avaliação da eficiência do RUC quanto a seus fatores operacionais, a pesquisa foi dividida em quatro etapas. O RUC foi submetido e operado a uma carga orgânica de 1,21kgDQO/d e temperatura ambiente média de 22,47°C, alcançando médias de 74% de remoção de DQO e até 87%. Para remoção de nutrientes foram atingidas médias de 36% para Nitrogênio Total e 44% para Fósforo Total, com máximas de 63 e 64%, respectivamente. Demandou pouca operação de manutenção e baixa produção de lodo. Durante todo período de atividade deparou-se com diversos problemas operacionais, tais como: acúmulo de gordura, tanto na câmara de gases quanto aderida ao lodo, os quais levaram a obstrução do sistema de saída e equipamento de monitoramento dos gases, resultando na perda de eficiência e consequentemente, necessitando de descarga completa e reinoculação do RUC. / The use of structural innovations in UASB (Upflow Anaerobic Sludge Blanket) reactors for use in the sewage treatment, such as compartmentation, is an alternative to improve a simple and efficient treatment system. In an innovative structural configuration, the Compartmented UASB Reactor (CUR) used was run in continuous, using Ilha Solteira - SP municipal sewage. To evaluate the CUR efficiency as for operational factors, this research was divided in four steps. The CUR was submitted to an organic load of 1.21kgCOD/day, operated at average temperature of 22.47°C, showed average COD removal of 74%, reaching up to 87%. The nutrient removal average were 36% for Total Nitrogen and 44% for Total Phosphorus reached maximums of 63 and 64%, respectively. The reactor presented low maintenance and sludge production. During all time CUR come across operational troubles such as: fat accumulation in gas chamber and adhered to the sludge, which causing the obstruction of the exhaust system and monitoring device, resulted in efficiency loss and the needed to sludge discard and re-inoculation to restart.
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Alternativas sustentáveis de tratamento de esgotos sanitários urbanos, através de sistemas descentralizados, para municípios de pequeno porte / Sustainable alternatives for treatment of urban sewage for small municipalities through decentralized systemsSamuel, Paulo Robinson da Silva January 2012 (has links)
A precariedade do tratamento dos esgotos sanitários no país, principalmente em pequenos municípios, aliado à falta de recursos financeiros, necessitam apoio tecnológico e científico, sendo motivo de preocupação e atenção. O objetivo geral deste trabalho é propor alternativas de sistemas de tratamento de esgotos sanitários urbanos para a cidade de Feliz/RS, município brasileiro de pequeno porte, visando à melhoria da qualidade dos seus recursos hídricos. Para a realização deste trabalho foi necessário realizar o diagnóstico do sistema de tratamento de esgotos sanitários na área urbana do município; avaliar o impacto gerado pelos esgotos sanitários urbanos no manancial hídrico do município e propor sistemas de tratamento de esgotos sanitários mais sustentáveis e que atendam os padrões de emissões de efluentes líquidos, permitidos pela legislação, em águas superficiais. A estratégia de pesquisa adotada neste trabalho foi a pesquisa construtiva, cuja metodologia foi dividida em três etapas: I) delimitação da área geográfica e análise documental; II) levantamento quantitativo de domicílios, por bairro, e coleta de amostras de água, em três pontos do manancial que banha o município de Feliz; III) apresentação de propostas de sistemas de tratamento de esgotos sanitários. Nas etapas II e III houve a aplicação do modelo matemático, QUAL2K, no trecho do rio estudado, no município de Feliz, simulando as diversas condições da qualidade da água e comparando-as com os padrões de emissões de efluentes permitidos pela legislação, em águas superficiais. Os resultados mostraram que a região urbana do município de Feliz apresenta inexpressivos índices de tratamento de esgotos domésticos. Os esgotos lançados sem tratamento, provenientes das redes pluviais, são os principais poluentes do rio, na área urbana. Foram pesquisados sistemas descentralizados de tratamento de esgotos propostos, entre os quais: wetlands, UASB e filtro anaeróbio, e tanque séptico e infiltração. A simulação mostra que estes sistemas propostos poderão se tornar efetivos, no sentido de tratar os esgotos domésticos urbanos de forma mais sustentável e na redução dos níveis dos parâmetros analisados, embora não atinjam os limites estabelecidos pela legislação, para que o trecho estudado possa ser enquadrado como atendendo à legislação e aos anseios da população local. / The lack of adequate sewage treatment in the country, especially in small municipalities, together with the scarceness of financial resources, requires technological and scientific support, being a major concern and asks for the due attention. The general objective of this work is to propose alternative systems of urban sewage treatment for the municipality of Feliz, a small Brazilian municipality in the State of Rio Grande do Sul, , , aiming at improving the quality of its water resources. The elaboration of this work included a system diagnosis of sewage treatment in the urban area, the assessment of the impact of sewage generated by urban water sources and a proposal for the treatment of sewage systems in a more sustainable way, that meets the emissions standards for effluents , as allowed by legislation, in surface waters. The research strategy adopted in this work was the constructive research, whose methodology was applied in three steps: I) a geographical area delimitation and documental analysis II) a quantitative survey of households, by area, and collection of water samples at three points in the river that crosses the town of Feliz, III) a presentation of proposals for more sustainable sewage systems treatment. In stages II and III a mathematical model, QUAL2K, was applied in the studied stretch of the river, simulating the various conditions of water quality and comparing them with the effluent emissions standards allowed by law, in surface waters. The results showed that the urban area of Feliz presents a very low rate of domestic sewage treatment. The untreated sewage released into the local system of stormwater is the main pollutant of the river in the urban area. The following decentralized systems of sewage treatment were studied: wetlands, anaerobic filter and UASB and septic tank and seepage. The simulation showed that these proposed systems can be effective in order to treat more sustainably the domestic sewage and to reduce the levels of the analyzed parameters, although not reaching the limits established by the legislation for the studied stretch so to enabled it to be framed as being in compliance with the Brazilian legislation and with the wishes of the local community.
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Análise e seleção de alternativas sustentáveis de esgotamento sanitárioCornelli, Renata January 2014 (has links)
Esta tese teve como objetivo principal identificar e avaliar alternativas de projetos sustentáveis de tratamento de esgoto. Para tanto, seguiu-se as seguintes etapas: i) revisão sistemática para levantar a literatura sobre métodos de tratamento de esgoto entre os anos 2002 e 2012; ii) levantamento da legislação federal e do estado do Rio Grande do Sul quanto aos parâmetros a serem atendidos em projetos de esgotamento , e da opinião da equipe técnica (responsável pelo tratamento de esgoto em concessionárias municipais e estaduais) sobre os requisitos legais e as prioridades no planejamento de ações de melhoria no controle; iii) levantamento da percepção ambiental dos moradores do município de São Marcos/RS e das soluções para os problemas de esgotamento sanitário da cidade. Eles propuseram quatro soluções para os problemas; iv) proposta de uma ferramenta computacional para auxiliar na seleção de alternativas sustentáveis (social, ambiental e economicamente) de tratamento de esgoto. Esta ferramenta foi desenvolvida para facilitar a tomada de decisão quanto ao melhor projeto, tendo em vista que são inúmeros os parâmetros (de cunho técnico, de legislação, ambientais, sociais - inclusive as expectativas dos moradores- e econômicos) a serem considerados em um projeto sustentável; v) teste da ferramenta, considerando as quatro alternativas de sistemas propostas pelos moradores de São Marcos/RS. A ferramenta foi considerada útil pelos técnicos da prefeitura apesar de terem proposto a exclusão de vários critérios (sociais e ambientais) já que eles (os técnicos) consideram os fatores econômicos os mais importantes. Não há razão para reduzir os 45 critérios da ferramenta, pois espera-se que ela seja um instrumento não só de tomada de decisão, mas também de conscientização para que os projetos sejam mais sustentáveis. Ela pode e deve ser testada em outros municípios de pequeno, médio e grande porte a título de validação. / This thesis has as main objective the identification and evaluation of sewage treatment projects. It comprises the following: I) systematic literature review from 2002 to 2012, on articles discussing methods of sewage treatment; II) evaluation of the opinion of the technical staff (responsible for wastewater treatment in municipal and state utilities) about the parameters required by federal and state legislation and the priorities for an action and control plan; III) appraisal on the environmental perception of the residents of the municipality of Sao Marcos and their proposals for solving the dewatering problems; IV) proposal of a computational tool, auxiliary on the development of sustainable sewage treatment projects. A tool is necessary for handling the various variables (technical, economic, social and environmental) to be considered in order to achieve sustainability; V) testing of the tool, considering the four alternatives proposed by Sao Marcos residents. Technicians found the tool useful, although many criteria (social and environmental) were not necessary, since economics is the most important criteria. There is no reason to eliminate any of the 45 criteria, since the expectation is to use the tool as a means for introducing sustainability concepts in sewage treatment projects. The tool should be validated in other municipalities (small, medium and large).
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Desempenho de tanques vegetados em um ecossistema engenheirado para tratamento descentralizado de esgotos domiciliares na Ilha Grande, RJ / Performance of vegetated tanks in an engineered ecosystem for decentralized treatment of sewage in Grande Island, RJTatiane Reis de Freitas 23 March 2011 (has links)
A falta de infraestrutura adequada para a coleta e o tratamento de esgotos atinge várias comunidades costeiras e de sistemas insulares do Estado do Rio de Janeiro, que vivem em condições de insalubridade. O objetivo do presente estudo foi avaliar o desempenho de um ecossistema engenheirado para tratamento descentralizado de esgoto domiciliar implantado no Centro de Estudos Ambientais e Desenvolvimento Sustentável (CEADS) da UERJ, na Vila Dois Rios, Ilha Grande - RJ, com ênfase na contribuição de macrófitas e algas em tanques vegetados como tratamento terciário para a melhoria geral da qualidade do efluente e em especial, para remoção de nutrientes. O sistema é composto por caixa controladora de vazão, caixa de gordura, fossa séptica, filtro aerado submerso, decantador secundário e o conjunto de tanques vegetados contendo as macrófitas aquáticas Eichhornia crassipes, Schoenoplectus sp., Panicum cf. racemosum + Cyperus ligularis, além de um tanque de algas entre as 2 primeiras macrófitas. Os principais parâmetros monitorados em amostras quinzenais obtidas durante o período de 09/2009 a 07/2010 em 10 pontos de coleta equivalentes à saída do efluente de cada unidade de tratamento foram: OD, pH, Cond. Elétrica, Temperatura, DBO5, DQO, SST, SDT, Nitrogênio amoniacal, Nitrito, Nitrato e Fósforo total. A vazão média do sistema foi 52 L/h. A produção primária de biomassa das macrófitas e o metabolismo no tanque com algas também foram estimados. A eficiência média do ecossistema engenheirado foi de 93% de redução dos SST, 93% de DBO, 90% da DQO, 30% de N amoniacal e, 38% de Fósforo. O conjunto de tanques vegetados promoveu um aumento médio de oxigênio dissolvido (OD) em 182% comparados ao valor de saída do decantador. Pode-se concluir que esse sistema contribuiu para uma melhoria geral da qualidade do efluente final com relação a praticamente todos os parâmetros, ainda que em alguns casos, apenas de forma incremental. Houve maior produção média de biomassa (peso seco.dia-1) e retenção média de água na espécie E. crassipes (aguapé) em comparação com as espécies Schoenoplectus sp, P. cf. racemosum e C. ligularis. A baixa produção primária no tanque de algas em relação à respiração, pelo menos no período monitorado, indica condições desfavoráveis à remoção de nutrientes (N e P) nesse tanque através da incorporação na biomassa. Uma investigação mais detalhada acerca dos parâmetros de projeto que inclua um eventual redimensionamento do decantador e do tanque de algas é sugerida. / The lack of appropriate infrastructure for sewage collection and treatment affects several communities living under unhealthy conditions in coastal areas and in insular systems in Rio de Janeiro State. The objective of this study was to assess the performance of an engineering ecosystem for the descentralized treatment of domestic wastewater located at the Centre of Environmental Studies and Sustainable Development (CEADS), UERJ, Vila Dois Rios, Ilha Grande, Rio de Janeiro State. The emphasis was put on the contribution of macrophytes and algae in vegetated tanks as a terciary treatment for the general improvement of the quality of the effluent, particularly regarding nutrients removal. The system includes a flow controlling box, grease box, septic tank, submersed aerated filter, secondary decanter and a set of vegetated tanks planted with aquatic Eichhornia crassipes, Schoenoplectus sp., Panicum cf. racemosum plus Cyperus ligularis besides an algae tank between the first two macrophytes tanks. The main parameters monitored in samples taken every 15 days during the period from September 2009 to July 2010 in 10 sampling points equivalent to the outflow of each treatment unit were: OD, pH, electric conductivity, temperature, DBO5, DQO, SST, SDT, Ammonia Nitrogen, Nitrite, Nitrate and total Phosphorus. The average flow from the system was 52 litres per hour. The primary biomass production by macrophytes and the metabolism (primary production and respiration) from the algae tank were also estimated. The average efficiency of the engineering ecosystem was 93% for SST, 93% for DBO, 90% for DQO, 30% for Ammonia Nitrogen and, 38% for total Phosphorus. The set of vegetated tanks promoted an average increase for dissolved oxygen (DO) of 182%, compared to the average DO found in the decanter outflow. It was concluded that the system of vegetated tanks contributed with a general improvement of the quality of the final effluent in relation to practically all parameters, even if in some cases only as an incremental level. There was more production of biomass (dry weight.day-1) and water retation by E. crassipes (water hyacinth) in comparison to the species Schoenoplectus sp, P. cf. racemosum and C. ligularis. The low primary production (measured as O2 production) in the algae tank in relation to the respiration (measured as O2 consumption), at least during the monitoring period, indicated unfavourable conditions to the nutrients removal (N and P) in these tanks. A more detailed investigation about the project parameters which includes an eventual decanter and algae tank re-dimensioning is suggested.
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