Avaliação de uma estação de tratamento de esgoto doméstico por escoamento superficial

• Autor(a) principal: Fonseca, Sandra Parreiras Pereira
• Data de Publicação: 2007
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/788
• topic: Esgotos; Escoamento superficial; Coliformes; Modelagem; Sewage; Overland flow; Coliforms; CNPQ::ENGENHARIAS::ENGENHARIA SANITARIA::TRATAMENTO DE AGUAS DE ABASTECIMENTO E RESIDUARIAS

The objective of the present work was to evaluate the performance of a sewage treatment unit (ETE), constituted of sand box, equalization tank, septic tank and overland flow system, under the edafoclimatic conditions of Viçosa, MG, implanted in a Dystrudepts, with a clayey-sandy texture. The plant area was land leveled in four plans, each one with three borders of 1 m width, 25 m length with 2% of slope, and cultivated with Tifton 85 grass bermudagrass (Cynodon spp.). The application rate of 0,48 m3.h-1.m-1 was applied for ten hours a day and six day a week, during six months of operation. The samples of sewage collected along the borders, at every 2 meters up to 18 meters, were submitted to physical, chemical and coliforms analyses and after six months physical and chemical analyses were carried out in the soil and vegetation samples. The sewage pH tended to increase along the border, and the CE, the DBO, DQO, N-total, P-total and K+ concentrations tended to decrease. The Na concentration tended to remain constant along the border. The amounts of dry matter (DM), crude protein (CP), N, P and K of the grass Tifton 85 green matter tended to decrease along the length of the border. In the 0-10 cm layer of the soil there was an increase in the pH, CEes, OM, N-total, P-available, and the concentrations of K and Na exchangeable, however, with the sewage application, the increase was less along of the border. In the 50-60 cm layer the OM and N-total in the soil remained constant. The pH, CEes, P-available, Na and K tended to decrease along the border in the 50-60 cm layer. The exchangeable Na and K increased in the soil profile. The total and fecal coliforms - E. coli population remain practically constant along the border. These microorganisms are not recommended for the monitoring of ETE by disposal on the soil. The EPA model proposed in 1984 represented well the removal of the DBO and DQO, however the coefficients K and K differed from those observed by other authors under different edafoclimatic conditions, kind of effluent treated and application rates.