RESUMO
The objective of this paper was to assess bacteriological quality of drinking water in a peri-urban area located in the Metropolitan Region of São Paulo, Brazil. A total of 89 water samples were collected from community plastic tanks and 177 water samples from wells were collected bimonthly, from September 2007 to November 2008, for evaluating bacteriological parameters including: Escherichia coli, Enterococcus and heterotrophic plate count (HPC). Clostridium perfringens was investigated in a subsample (40 samples from community plastic tank and 40 from wells). E. coli was present in 5 (5.6 percent) samples from community plastic tanks (2.0 - 5.1x10(4) MPN/100mL) and in 70 (39.5 percent) well samples (2.0 - 8.6x10(4) MPN/100mL). Thus, these samples were not in accordance with the Brazilian Regulation. Enterococcus was detected in 20 (22.5 percent) samples of the community plastic tanks (1 to 79 NC/100mL) and in 142 (80.2 percent) well samples (1 to >200 NC/100mL). C. perfringens was detected in 5 (12.5 percent) community plastic tanks samples and in 35 (87.5 percent) wells samples (2.2 to >16 MPN/100mL). HPC were above 500 CFU/mL in 5 (5.6 percent) waters from community plastic tanks. In wells samples, the HPC ranged from <1 to 1.6x10(4) CFU/mL. The residual chlorine did not attend the standard established in the drinking water legislation (0.2 mg/L), except in 20 (22.5 percent) samples. These results confirm the vulnerability of the water supply systems in this peri-urban area what is clearly a public health concern.
RESUMO
The objective of this paper was to assess bacteriological quality of drinking water in a peri-urban area located in the Metropolitan Region of São Paulo, Brazil. A total of 89 water samples were collected from community plastic tanks and 177 water samples from wells were collected bimonthly, from September 2007 to November 2008, for evaluating bacteriological parameters including: Escherichia coli, Enterococcus and heterotrophic plate count (HPC). Clostridium perfringens was investigated in a subsample (40 samples from community plastic tank and 40 from wells). E. coli was present in 5 (5.6%) samples from community plastic tanks (2.0 - 5.1x10(4) MPN/100mL) and in 70 (39.5%) well samples (2.0 - 8.6x10(4) MPN/100mL). Thus, these samples were not in accordance with the Brazilian Regulation. Enterococcus was detected in 20 (22.5%) samples of the community plastic tanks (1 to 79 NC/100mL) and in 142 (80.2%) well samples (1 to >200 NC/100mL). C. perfringens was detected in 5 (12.5%) community plastic tanks samples and in 35 (87.5%) wells samples (2.2 to >16 MPN/100mL). HPC were above 500 CFU/mL in 5 (5.6%) waters from community plastic tanks. In wells samples, the HPC ranged from <1 to 1.6x10(4) CFU/mL. The residual chlorine did not attend the standard established in the drinking water legislation (0.2 mg/L), except in 20 (22.5%) samples. These results confirm the vulnerability of the water supply systems in this peri-urban area what is clearly a public health concern.
RESUMO
O tratamento de esgotos de pequenas cidades por lagoas de estabilização é uma maneira simples, eficiente e de baixo custo. Os esgotos são uma fonte de contaminação das águas e solos e, conseqüentemente, contribuem para a transmissão de doenças, além de serem uma ameaça à preservação do meio ambiente. Surge a necessidade de investigar as condições dos efluentes lançados nos cursos de água. O presente trabalho tem como objetivo realizar uma investigação da qualidade das águas residuárias tratadas por lagoas de estabilização de uma estação de tratamento de esgoto localizadas no município de São Lourenço da Serra no Vale da Ribeira no Estado de São Paulo e verificar os riscos sanitários e a comunidade aquática no Rio São Lourenço da Serra. Foram realizadas amostragens para avaliar o conjunto de lagoas anaeróbia e facultativa da estação de tratamento de esgoto do Município de São Lourenço da Serra. Os parâmetros utilizados foram pH, temperatura do ar e da água, condições climáticas, demanda bioquímica de oxigênio e nitrogênio amoniacal, bactérias termotolerantes, pigmentos fotossintéticos e comunidade zooplanctônica. Verificou-se que os sistemas de lagoa anaeróbia e facultativa foram eficientes na produção de efluente e apresentou alguns valores de acordo com a Resolução Conama nº 357, que estabelecem os valores limites para lançamento em corpos d´água. O rio São Lourenço está localizado em uma área de proteção ambiental. Os dados são comparados aos limites estabelecidos na Classe 1 e 2 e demonstram processo de eutrofização, colocando em risco à biodiversidade aquática e a saúde da população.
The treatment of sewer pipes of small cities using waste stabilization ponds is a simple, efficient, and low cost option. Sewer pipes are a fountain of water and ground contamination and consequently they contribute to diseases transmission, besides being a threat to the preservation of the environment. It is thus necessary to investigate the conditions of effluents going to water courses. The present work aims to carryout an investigation on the quality of residual waters treated by stabilization ponds of a sewer pipe treatment facility located in São Lourenço da Serra, Vale do Ribeira, State São Paulo and examine the sanitary risks and the local aquatic community. Samples were taken for evaluating theseveral anaerobic and facultative ponds of sewer pipe of the treatment facility of São Lourenço da Serra. Parameters used were pH, air and water temperature, climatic conditions, biochemical demand of oxygen and ammoniac nitrogen, thermo-tolerant bacteria, photosynthetic pigments and zooplanktonic community. We observed that the anaerobic and optional pond systems were efficient in the production of effluent and presentedvalues in accordance with the Resolution Conama nº 357, which establish limits for waste disposal in water sources. São Lourenço River is located in an area of environmental protection, and data were compared to limits established in Class 1 and 2 and demonstrate a process of euthrophization, putting in risk aquatic biodiversity and the health of the population.
El tratamiento de conductos de alcantarilla de pequeñas ciudades usando charcas de estabilización de desecho es una opción simple, eficiente, y de bajo coste. Los conductos de alcantarilla son una fuente de contaminación del agua y de la tierra y por consiguiente contribuyen a la transmisión de enfermedades, además de ser una amenaza a la preservación del ambiente. Es así necesario investigar las condiciones de aguas residuales que van a cursos acuáticos. El trabajo actual pretende realizar una investigación acerca de la calidad de aguas residuales tratadas por charcas de estabilización de una instalación de tratamiento de conductos de alcantarilla localizada en São Lourenço da Serra, Vale do Ribeira, estado São Paulo e examina los riesgos sanitarios y la comunidad acuática local. Se tomaran muestras para evaluar varias charcas anaerobias y facultativasdel conducto de alcantarilla de la instalación de tratamiento de Sã o Lourenço da Serra. Los parámetros usados fueran pH, aire y temperaturaacuática, condiciones climáticas, demanda bioquímica de oxígeno y nitrógeno amoniaco, bacterias termo-tolerantes, pigmentos fotosintéticos ycomunidad zooplanctónica. Observamos que los sistemas de charca anaerobios y opcionales fueran eficientes en la producción de aguas residuales y presentaron valores de acuerdo con la Resolución Conama nº 357, que establecen límites para la eliminación de deshechos en fuentes acuáticas. El Río São Lourenço está localizado en un área de protección ambiental, y los datos fueran comparados con los límites establecidos para las Clases 1 y 2 y muestran un proceso de eutrofización que pone en riesgo la biodiversidad acuática y la salud de la población.