Pharmaceuticals that are found in marine ecosystems are a threatening environmental concern, which is known to harm both animal and plant life. One of the reasons for this problem is that the waste water treatment techniques are not optimized to clear waste water from its pharmaceuticals contain. In this master thesis four Swedish treatment wetlands were studied, and their ability to reduce numerous pharmaceuticals in waste water. The four treatment wetlands that were studied were those in Oxelösund, Trosa, Nynäshamn and Eskilstuna. Two ecotoxicological tests and chemical analysis were used. The ecotoxicological tests were performed on the copepod Nitocra spinipes and macro algae Ceramium tenuicorne, but the results were ambiguous and could not be related to the chemical analysis. The result from the chemical analysis showed that 50-70 % of the substances were reduced to some degree, and of which 15 % were almost completely reduced. In Nynäshamn’s wetland and Oxelösund’s wetland the pharmaceutical treatment were more efficient than in Trosa’s wetland and Eskilstuna’s wetland. This was probably due to the, at the time, more efficient biological activity. The pharmaceuticals that dominated the incoming waters to all the wetlands were more or less the same. On the contrary, substances were reduced to different degrees in the four wetlands. However, the reduction patterns for both Nynäshamn and Oxelösund were similar, which suggest that the same processes dominated in both wetlands. As the study was performed in cold winter conditions with bad oxygen supply it is likely that greater reduction would be obtained in warmer conditions.

From the Proceedings of the 1975 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 11-12, 1975, Tempe, Arizona / Denitrification is the only reaction capable of removing the tremendous quantity of nitrogen applied when high-rate land filtration systems are used for renovating sewage water. This study determined that a shortage of organic carbon limits denitrification, and the effects of increased dissolved organic carbon concentrations on soil clogging and movement of fecal coliform bacteria are clearly shown. Finally, the removal of dissolved organic carbon at different carbon concentrations during high rate soil filtration (40-50 cm/day) also limits denitrification.

The use of geosynthetic clay liners (GCLs) as (i) covers for arsenic-rich gold mine tailings and landfills, (ii) subsurface barrier for migration of hydrocarbons in the Arctic, and (iii) basal liner for sewage treatment lagoons were examined. After 4 years in field and laboratory experiments, it was found that best cover configuration above gold mine tailings might include a layer of GCL product with polymer-enhanced bentonite and a geofilm-coated carrier geotextile serving above the tailings under ≥ 0.7 m overburden. However, acceptable performance could be achieved with using a standard GCL with untreated bentonite provided that there is a minimum of 0.7 m of cover soil above the GCL. When GCL samples were exhumed from experimental landfill test cover with complete replacement of sodium in the bentonite with divalent cations in the adjacent soil, it was observed that the (i) hydraulic head across the GCLs, (ii) size of the needle-punched bundles, and (iii) structure of the bentonite can all significantly affect the value of the inferred in-situ hydraulic conductivity measured at the laboratory. The higher the hydraulic head and the larger the size of the needle-punched bundles, the higher the likelihood of internal erosion/structural change of bentonite at bundles that will cause a preferential flow for liquids to occur. A key practical implication was that GCLs can perform effectively as a single hydraulic barrier in covers provided that the water head above the GCL kept low. The hydraulic performance of a GCL in the Arctic was most affected by the location within the soil profile relative to the typical groundwater level with the highest increase in the hydraulic conductivity (by 1-4 orders of magnitude) for GCL below the water table. However, because the head required for jet fuel to pass through the GCL was higher than that present under field conditions, there was no evidence of jet fuel leakage through the barrier system. The leakage through GCLs below concrete lined sewage treatment lagoons was within acceptable limits, in large part, due to the low interface transmissivity between GCLs and the overlying poured concrete. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2014-02-28 08:53:29.171

Studies in Europe, Japan, and North America have reported that wild fish exposed to treated sewage effluents can exhibit significant physiological and reproductive abnormalities consistent with exposure to hormonally active chemicals. The main objective of this research project was to examine the estrogenic and androgenic activity in treated sewage to determine the risk associated with treated sewage discharges in Australia and New Zealand. Several bioassays, including a sheep estrogen receptor and a rainbow trout androgen receptor binding assay, were set up and validated with model compounds. The assays were then used to measure the estrogenic and androgenic activity in sewage samples from 15 municipal sewage treatment plants (STP) utilizing a variety of treatment technologies. Raw sewage samples contained high levels of both estrogenic and androgenic activity, up to 185 ng/L estradiol equivalents (EEq) and up to 9330 ng/L testosterone equivalents (TEq), respectively. Secondary treatment processes such as activated sludge had the greatest impact on removal of biological activity from the wastewater. The estrogenic and androgenic activity in final treated effluents were <1 to 4.2 ng/L EEq and <6.5 to 736 ng/L TEq, respectively. Based on lowest observable effective concentrations reported in the literature, these levels are unlikely to induce biological effects in exposed fish in the short term. To examine potential long-term effects, resident mosquitofish chronically exposed to undiluted treated sewage were sampled. Several morphological biomarkers indicative of endocrine disruption were measured and compared with mosquitofish captured at a reference site. Mosquitofish captured in a constructed wetland for tertiary treatment of secondary treated sewage exhibited morphological differences such as elongated anal fins consistent with exposure to androgenic chemicals, although this effect was not measurable in fish collected at sites further downstream or at any of the other sites. Based on these results, it is unlikely that mosquitofish populations would be significantly affected by exposure to final treated sewage. A reverse transcription real-time polymerase chain reaction (RT-PCR) method to measure the production of a female-specific protein (vitellogenin) mRNA in adult male mosquitofish was developed, and this could be used as a rapid test to detect early changes in individuals exposed to estrogenic activity.

The aim of the diploma thesis was to monitor seasonal concentration changes of 7 antibiotics norfloxacin, levofloxacin, ciprofloxacin, azithromycin, erythromycin, trimethoprim and sulfamethoxazole in wastewater influent and (cleaned) water effluent in the Sewage Treatment Plant (STP) České Budějovice. Time-proportional 24 hours pooled samples of wastewater were collected every month from March 2011 to February 2012 in the influent and effluent pof the STP. The concentrations of target compounds were determined by using in line SPE/LC-MS/MS analysis. The highest average concentration in the influent was detected in case of norfloxacin (0.563 microgram/l) and ciprofloxacin (0.406 microgram/l). The highest average concentration in the effluent was detected in the case of trimethoprim (0.255 microgram/l) and erythromycin (0.117 microgram/l). Higher concentration of antibiotics was measured in the colder periods of the year. It was connected with increased use of antibiotics and with less cleaning efficiency of the STP in this season. The highest removal efficiency was determined for norfloxacin and ciprofloxacin, the lowest for erythromycin. The influence of the season on the removal efficiency of antibiotics was found esp. for azithromycin,trimethoprim and sulfamethoxazole.

Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Em várias regiões do mundo, assim como no Brasil, um alto percentual da população e até comunidades inteiras não têm acesso a um sistema de tratamento de esgoto centralizado, sendo comum o uso das fossas sépticas e/ou sumidouros e, em muitos casos, os esgotos são lançados in natura diretamente nos corpos hídricos. Com o objetivo de oferecer uma alternativa tecnológica de baixo custo de implantação e operação com vistas à minimização dos impactos ambientais e em atendimento a pequenas comunidades isoladas e de interesse social, o presente projeto desenvolveu com base em sistemas apresentados na literatura, um ecossistema engenheirado compacto para o tratamento de esgoto domiciliar de pequenos geradores. O sistema é composto por tratamento preliminar (caixa controladora de vazão e caixa de gordura), primário (fossa séptica), secundário (filtro aerado submerso e decantador secundário) e um conjunto de tanques vegetados por macrófitas aquáticas (Eichhornia crassipes, Schoenoplectus sp., Panicum cf. racemosum) intercalados por um tanque de algas para remoção da carga poluidora remanescente e nutrientes. O sistema foi instalado no CEADS/UERJ na Vila de Dois Rios, Ilha Grande, litoral Sul do Rio de Janeiro, operado e monitorado desde Abril de 2009, sendo que o presente estudo referese aos primeiros 200 dias de monitoramento. A remoção da carga poluidora foi monitorada na vazão de 200 L/h, posteriormente corrigida para 52 L/h, almejando alcançar os padrões de lançamento da Resolução CONAMA 357 e a NBR 13969 da ABNT, para os parâmetros de OD, pH, Temperatura, Nitrato, N amoniacal, DBO5, DQO, SSD, Cloreto e, Óleos e Graxas e outros parâmetros não incluídos na Resolução (Cond. Elétrica, COT, Alcalinidade, Dureza, Nitrito, Fósforo total e demais Sólidos (ST, SST, SSV, SSF e SDT ). Os resultados obtidos indicam que o sistema foi mais eficiente quando operado na vazão de 52 L/h, quando apresentou as seguintes taxas de remoção: 96 % (Nitrito); 71 % (Nitrato); 47 % (N amoniacal); 96,7 % (DQO); 95,7 % (DBO5); 10 % (Fósforo total). O sistema apresentou uma evolução ao longo do tempo de operação e após a redução na vazão, garantiu o enquadramento de 12 dos 14 parâmetros analisados (exceto N amoniacal e Fósforo total), nos padrões de lançamento contemplados pela Legislação Federal, CONAMA 357 e Legislação Estadual do RJ, SP, MG e GO. Para aumento da eficiência de tratamento, recomenda-se redimensionamento do filtro aerado submerso-decantador e tanques vegetados, com base nas recomendações do PROSAB 2. / In different regions of the world as well as in Brazil, a high percentage of the population and even entire communities do not have access to sewerage and/or centralized sewage treatment. The common scenario is the presence of septic tanks and sinks or, in many cases, sewage discharge directly into recipient water bodies. With the objective of making available a technological alternative with low cost of implementation and operation and to minimize environmental impacts, the present project developed based on systems reported in the literature, a compacted engineering ecosystem for treatment of domestic sewage from small generators. The system is formed by a preliminary (flow controller and grease tank), primary (septic tank) and a secondary treatment (submersed aerated filter and secondary decanter) and a group of tanks with aquatic macrophytes (Eichhornia crassipes, Schoenoplectus sp., Panicum cf. racemosum) interlaced by a tank with algae for removal of the remaining pollutants and nutrients. The system was installed at CEADS/UERJ, Vila de Dois Rios, Ilha Grande in the south coast of Rio de Janeiro and it has been operated and monitored since April 2009; this study reports the first 200 monitoring days. The removal efficiencies of the polluted load were monitored during the flow 200 L/h, later corrected to 52 L/h, with the aim of meeting the threshold limits established by the Resolution CONAMA 357 and NBR 13969 of ABNT, for the following parameters: DO, pH, Temperature, Nitrate, Ammoniacal Nitrogen, BOD5, COD, sedimentable solids chloride, Grease and Oil, and parameters not included in those Resolutions (EC, TOC, alkalinity, hardness, Nitrite, Total Phosphorus, and different categories of solids (TS, TSS, VSS, FSS and TDS). The results showed that the system was more efficient when operated with the lower flow (52L/h), when it achieved the following percentages of removal: 96% (Nitrite); 71% (Nitrate); 47% (Ammoniacal nitrogen); 96.7% (COD); 95.7% (BOD5); 10% (Total Phosphorus). The system presented an evolution throughout the operation period. After the flow reduction, 12 among 14 parameters analyzed, met the threshold limits established by the Federal Legislation, the Resolution CONAMA 357 and environmental legislations from the States of Rio de Janeiro, São Paulo, Minas Gerais and Goiás. To increase the treatment efficiency, it is recommended redesigning the submerged aerated filter and planted tanks, based on recommendations found in PROSAB 2.

O objetivo foi desenvolver e avaliar uma metodologia simplificada para detecção de vírus entéricos humanos em lodo de esgoto. O método foi baseado em eluição viral com solução protéica, seguida de ultracentrifugação. Alguns parâmetros foram avaliados (tempo e pH de eluição, condições de clarificação e purificação). A seguir, foi aplicado à pesquisa de adenovírus, vírus da hepatite A e norovírus em amostras colhidas ao longo de 12 meses em duas ETEs do estado de São Paulo. Amostras pareadas de esgoto foram também examinadas como referência da presença viral. A detecção viral por PCR, RT-PCR e PCR em tempo real, revelou a presença de adenovírus, incluindo os entéricos (espécie F) e vírus da hepatite A tanto nas esgoto como no lodo de ambas as ETEs. Norovírus não foram detectados. Vírus infecciosos não foram detectados no lodo submetido ao tratamento químico (ETE A). Parte dos vírus presentes na água de esgoto ficaram retidos no lodo e análises estatísticas revelaram que o tratamento químico adotado na ETE A é eficiente para a inativação viral. / The aim was to develop and evaluate a simplified methodology for detection of human enteric viruses in sewage sludge. The method was based on viral elution with protein solution, followed by ultracentrifugation. Several parameters were evaluated, including time and elution pH, clarifying and purifying conditions. The method was applied to the detection of adenoviruses, hepatitis A virus and noroviruses in sewage sludge samples collected for twelve months at two sewage treatment plants in Sao Paulo state. Raw sewage samples were also collected as a reference for viral presence. PCR, RT-PCR and Real-Time PCR revealed the presence of adenoviruses, including the enteric ones (species F) and hepatitis A virus found both in sewage and sludge. Noroviruses were not detected in any samples. Cell culture infectious viruses were not detected in the sludge subjected to chemical treatment (STP A), and statistical analyses revealed the efficiency of this treatment for virus inactivation.

Made available in DSpace on 2015-05-14T12:09:28Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3492986 bytes, checksum: cb918a3cba1ca29e84bfc06dbb5b6d70 (MD5) Previous issue date: 2014-03-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The efficiency of removal of the biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids (TSS) and volatile suspended solid (SSV) were studied in two anaerobic reactors which received semi-settled effluent (flow limited around 3.2 times the average flow) of a septic tank, one being adhered growth (R1, with bed of gravel Nº. 4) and the other dispersed growth (R3 without support material for microbial growth). This system was installed in the University Residence at UFPB in João Pessoa-PB. The treated sewage came from two bathrooms that catered to a theoretical population of 4 inhabitants. Eleven samples of the effluent from the septic tank and the effluent from the reactors 1 and 3 were performed in the period between 28/02/2013 and 10/12/2013. The temperature and pH of the reactors were presented in the range 24.5 to 28.1 ° C and 7.3 to 8.1, respectively. Those values are from the anaerobic treatment of household sewage. The BOD5 removal efficiencies (32.8 and 27.1% in R1 and R3, respectively), COD (43.4 and 33.0% in R1 and R3, respectively), SST (56.2 and 48.0% in R1 and R3, respectively) and VSS (54.7 and 46.2% in R1 and R3, respectively) were high. It demonstrates a good applicability of these low-cost housing units which are devoid of collective sewage system in the reduction of pollution load released in water bodies systems. An analysis of variance showed no significant difference of 5% between the average of the corresponding parameters of the two reactors, suggesting that reactor that receives discharges from the attenuation peaks, there is no need of support means, which may represent a reduction in costs involved. / Estudou-se a eficiência de remoção de demanda bioquímica de oxigênio (DBO5), demanda química de oxigênio (DQO), sólidos suspensos totais (SST) e sólidos suspensos voláteis (SSV) em dois reatores anaeróbios que recebiam efluentes semi-regularizados (vazão limitada a algo em torno de 3,2 vezes a vazão média) de um tanque séptico, sendo um deles de crescimento aderido (R1, com leito de brita n°4) e o outro de crescimento disperso (R3, sem material suporte para crescimento microbiano). Este sistema foi instalado na Residência Universitária da UFPB, em João Pessoa-PB. O esgoto a ser tratado era proveniente de dois banheiros que atendiam a uma população teórica de 4 habitantes. Foram realizadas 11 coletas do efluente do tanque séptico e dos efluentes dos reatores 1 e 3, no período compreendido entre 28/02/2013 e 10/12/2013. A temperatura e o pH nos reatores se apresentaram na faixa 24,5 - 28,1 °C e 7,3 - 8,1, respectivamente, valores estes, propícios ao tratamento anaeróbio de esgotos domiciliares. As eficiências de remoção de DBO5 (32,8 e 27,1%, em R1 e R3, respectivamente), DQO (43,4 e 33,0%, em R1 e R3, respectivamente), SST (56,2 e 48,0%, em R1 e R3, respectivamente) e SSV (54,7 e 46,2%, em R1 e R3, respectivamente) foram elevadas. Isto demonstra a aplicabilidade desses sistemas de baixo custo a unidades habitacionais desprovidas de sistema coletivo de esgotamento sanitário, na redução da carga poluidora lançada em corpos aquáticos. Um teste de análise de variância demonstrou não haver diferenças significativas ao nível de 5% entre as médias dos parâmetros correspondentes nos dois reatores, sugerindo que, para reatores que recebam vazões com atenuação dos picos, não há necessidade do meio suporte, podendo representar diminuição nos custos envolvidos.

Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Em várias regiões do mundo, assim como no Brasil, um alto percentual da população e até comunidades inteiras não têm acesso a um sistema de tratamento de esgoto centralizado, sendo comum o uso das fossas sépticas e/ou sumidouros e, em muitos casos, os esgotos são lançados in natura diretamente nos corpos hídricos. Com o objetivo de oferecer uma alternativa tecnológica de baixo custo de implantação e operação com vistas à minimização dos impactos ambientais e em atendimento a pequenas comunidades isoladas e de interesse social, o presente projeto desenvolveu com base em sistemas apresentados na literatura, um ecossistema engenheirado compacto para o tratamento de esgoto domiciliar de pequenos geradores. O sistema é composto por tratamento preliminar (caixa controladora de vazão e caixa de gordura), primário (fossa séptica), secundário (filtro aerado submerso e decantador secundário) e um conjunto de tanques vegetados por macrófitas aquáticas (Eichhornia crassipes, Schoenoplectus sp., Panicum cf. racemosum) intercalados por um tanque de algas para remoção da carga poluidora remanescente e nutrientes. O sistema foi instalado no CEADS/UERJ na Vila de Dois Rios, Ilha Grande, litoral Sul do Rio de Janeiro, operado e monitorado desde Abril de 2009, sendo que o presente estudo referese aos primeiros 200 dias de monitoramento. A remoção da carga poluidora foi monitorada na vazão de 200 L/h, posteriormente corrigida para 52 L/h, almejando alcançar os padrões de lançamento da Resolução CONAMA 357 e a NBR 13969 da ABNT, para os parâmetros de OD, pH, Temperatura, Nitrato, N amoniacal, DBO5, DQO, SSD, Cloreto e, Óleos e Graxas e outros parâmetros não incluídos na Resolução (Cond. Elétrica, COT, Alcalinidade, Dureza, Nitrito, Fósforo total e demais Sólidos (ST, SST, SSV, SSF e SDT ). Os resultados obtidos indicam que o sistema foi mais eficiente quando operado na vazão de 52 L/h, quando apresentou as seguintes taxas de remoção: 96 % (Nitrito); 71 % (Nitrato); 47 % (N amoniacal); 96,7 % (DQO); 95,7 % (DBO5); 10 % (Fósforo total). O sistema apresentou uma evolução ao longo do tempo de operação e após a redução na vazão, garantiu o enquadramento de 12 dos 14 parâmetros analisados (exceto N amoniacal e Fósforo total), nos padrões de lançamento contemplados pela Legislação Federal, CONAMA 357 e Legislação Estadual do RJ, SP, MG e GO. Para aumento da eficiência de tratamento, recomenda-se redimensionamento do filtro aerado submerso-decantador e tanques vegetados, com base nas recomendações do PROSAB 2. / In different regions of the world as well as in Brazil, a high percentage of the population and even entire communities do not have access to sewerage and/or centralized sewage treatment. The common scenario is the presence of septic tanks and sinks or, in many cases, sewage discharge directly into recipient water bodies. With the objective of making available a technological alternative with low cost of implementation and operation and to minimize environmental impacts, the present project developed based on systems reported in the literature, a compacted engineering ecosystem for treatment of domestic sewage from small generators. The system is formed by a preliminary (flow controller and grease tank), primary (septic tank) and a secondary treatment (submersed aerated filter and secondary decanter) and a group of tanks with aquatic macrophytes (Eichhornia crassipes, Schoenoplectus sp., Panicum cf. racemosum) interlaced by a tank with algae for removal of the remaining pollutants and nutrients. The system was installed at CEADS/UERJ, Vila de Dois Rios, Ilha Grande in the south coast of Rio de Janeiro and it has been operated and monitored since April 2009; this study reports the first 200 monitoring days. The removal efficiencies of the polluted load were monitored during the flow 200 L/h, later corrected to 52 L/h, with the aim of meeting the threshold limits established by the Resolution CONAMA 357 and NBR 13969 of ABNT, for the following parameters: DO, pH, Temperature, Nitrate, Ammoniacal Nitrogen, BOD5, COD, sedimentable solids chloride, Grease and Oil, and parameters not included in those Resolutions (EC, TOC, alkalinity, hardness, Nitrite, Total Phosphorus, and different categories of solids (TS, TSS, VSS, FSS and TDS). The results showed that the system was more efficient when operated with the lower flow (52L/h), when it achieved the following percentages of removal: 96% (Nitrite); 71% (Nitrate); 47% (Ammoniacal nitrogen); 96.7% (COD); 95.7% (BOD5); 10% (Total Phosphorus). The system presented an evolution throughout the operation period. After the flow reduction, 12 among 14 parameters analyzed, met the threshold limits established by the Federal Legislation, the Resolution CONAMA 357 and environmental legislations from the States of Rio de Janeiro, São Paulo, Minas Gerais and Goiás. To increase the treatment efficiency, it is recommended redesigning the submerged aerated filter and planted tanks, based on recommendations found in PROSAB 2.

Made available in DSpace on 2014-12-17T15:03:34Z (GMT). No. of bitstreams: 1 MiltonBV.pdf: 1188933 bytes, checksum: 0027ba3da37c2c26ef04d16c288622a2 (MD5) Previous issue date: 2006-11-30 / Waste stabilization ponds are the main technology in use for domestic sewage treatment in Rio Grande do Norte State (RN), northeast Brazil. The are around 80 systems, constructed mainly by municipal city halls, being series comprised by a primary facultative pond followed by two maturation ponds the most used configuration. Due to problems related with the production and destination of sludge and generation of bad odors, the designers have avoided the use of anaerobic lagoons. The majority of systems are rarely monitored to verify their efficiencies and to get new project parameters for future designing. This work has as purpose to make a diagnosis of efficiency of three series of waste stabilization pond series (WSPS) of Jardim Lola 1, Jardim Lola 2 and Beira Rio, located in the North Zone of the city of the Natal/RN, treating domestic raw sewage, on the removal of organic matter and thermotolerant coliform, comparing the operational conditions of the systems this inside of the bands foreseen in the project, through parameters BOD5, QOD, thermotolerant coliforms, dissolved oxygen, pH, temperature, ammoniac nitrogen, total and suspended solids. The work was carried through in the WSPS, all constituted by a primary facultative pond followed by two maturation ponds. Socioeconomic characteristics of population are predominantly low and all the plants are very near of the contributing basins. The series were monitored from of May the November of 2002, totalizing 20 collections of grab samples of raw sewage and ponds effluents between 8:00 and 9:50 h. The main aspect to be detached by the results was the great concentration of organic matter (BOD and COD) and microorganisms the raw sewage which were around two times more concentrated than those values foreseen one in project. Considering all series the highest removals of organic matter were observed in system Beira Rio (84 and 78% of BOD and COD, respectively), which presented high hydraulic detention time (TDH = 89 days). On the other hand, Jardim Lola 1 and Jardim Lola 2 presented a much lower values of HDT (36 days and 18 days respectively) and their removals of BOD and COD were the same (76% and 60%, respectively). The Beira Rio WSPS, was the most efficient verified in relation to solids and ammonia, proving the great influence of the operational variables such as HDT and applied surface organic loadings on the performance of pond series. Although the treatment plants have reached efficiencies of thermotolerant coliforms around 99,999%, the concentrations in the final effluent can be considered very high for launching in aquatic bodies, particularly those produced by Jardim Lola 1 and Jardim Lola 2 series / O sistema de lagoas estabiliza??o ? o tipo de tratamento de esgoto dom?stico mais utilizado no Estado do Rio Grande do Norte, contando com 80 sistemas, constru?dos principalmente pelas prefeituras municipais, sendo o sistema de lagoas em s?rie constitu?das de lagoa facultativa prim?ria seguida de lagoas de matura??o um dos mais utilizados. Devido aos problemas relacionados com a produ??o e destino de lodo e gera??o de maus odores, os projetistas t?m evitado o uso de lagoas anaer?bias. Vale salientar que tais sistemas de lagoas comumente n?o s?o monitorados de forma adequada para verificar suas efici?ncias e obter dados para futuros projetos. Este trabalho tem como finalidade fazer um diagn?stico da efici?ncia de tr?s s?ries de lagoas de estabiliza??o na grande Natal, Jardim Lola 1, Jardim Lola 2 e Beira Rio, na remo??o de mat?ria org?nica e coliformes termotolerantes e, verificar se as condi??es operacionais dos sistemas esta dentro das faixas previstas no projeto, atrav?s dos par?metros DBO5, DQO, coliformes termotolerantes, oxig?nio dissolvido, pH, temperatura, nitrog?nio amoniacal, s?lidos totais e suspensos. Os sistemas estudados s?o constitu?dos por uma lagoa facultativa prim?ria seguida de duas lagoas de matura??o, que atendem a uma popula??o predominante de baixa renda a qual est? bem pr?xima da esta??o de tratamento de esgoto. As tr?s ETE s foram monitoradas no per?odo de maio a novembro de 2002, totalizando 20 coletas de amostras pontuais de esgoto bruto e efluentes das lagoas entre 8:00 e 9:50 h. Os principais aspectos a serem destacados no monitoramento foram a grande concentra??o de mat?ria org?nica e microrganismos nos esgoto brutos afluentes em rela??o ao previsto em projeto. Considerando toda a s?rie as maiores remo??es de mat?ria org?nica ocorreram no sistema Beira Rio (84 e 78% de DBO e DQO, respectivamente), que apresentava um TDH de 89 dias enquanto que os sistemas de Jardim Lola 1 e 2 eram de 36 dias e 18 dias respectivamente, foram determinadas remo??es semelhantes de DBO (76%) e de DQO em torno de 60%. O sistema Beira Rio tamb?m foi o mais eficiente na remo??o de s?lidos e de nitrog?nio amoniacal, comprovando a grande influ?ncia das vari?veis operacionais tais como tempo de deten??o hidr?ulica e carga org?nica aplicada, no desempenho dos sistemas de tratamento. Embora as esta??es de tratamento tenham atingido efici?ncias de coliformes termotolerantes em torno de 99,999%, as concentra??es nos efluentes finais podem ser consideradas muito elevadas para lan?amento em corpos aqu?ticos, particularmente as de Jardim Lola 1 e 2