RESUMO
Polishing ponds are units conceived for the post-treatment of the effluents from anaerobic reactors, are designed as maturation ponds, and aim at a further removal of organic matter and a high removal of pathogenic organisms. The paper investigates the performance of four very shallow (H = 0.40 m) polishing ponds in series, with very low detention times (1.4-2.5 days in each pond), treating anaerobic effluent from the city of Belo Horizonte, Brazil. The system was able to achieve excellent results in terms of BOD and E. coli removal, and good results in terms of ammonia removal, allowing compliance with European standards for urban wastewater and WHO guidelines for unrestricted irrigation. The paper presents the values of BOD and E. coli removal coefficients, which were much higher than those found in conventional pond systems. No statistically significant difference was found in the effluent E. coli concentrations from a pond with low depth and low detention time, and another pond in parallel, with double the depth and approximately double the detention time. The results endorse the applicability of the system composed by UASB reactors followed by very shallow ponds in series, with low detention times.
Assuntos
Reatores Biológicos , Escherichia coli/isolamento & purificação , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Purificação da Água/métodos , Anaerobiose , Biodegradação Ambiental , Brasil , Arquitetura de Instituições de Saúde , Nitrogênio/isolamento & purificação , Oxigênio/química , Oxigênio/metabolismo , Esgotos/química , Fatores de TempoRESUMO
Trabalho experimental realizado em ratos, utilizando o primeiro molar superior direito como dente teste e o primeiro molar superior esquerdo como dente controle, onde analisa-se a relaçäo entre a migraçäo epitelial e o processo de reabsorçäo radicular em dentes reimplantados. Verifica-se a capacidade do Colagel© de evitar a migraçäo epitelial
