Avaliação da eficiência de filtro biológico anaeróbio utilizado como tratamento secundário de estação de tratamento de esgoto

Abstract

This paper aims to evaluate the efficiency of an anaerobic biological filter as secondary treatment of the sewage treatment plant in the city of Campina das Missões – RS. In order to evaluate the filter efficiency, 8 samples of the effluent were collected between April and November, 2016. The sample collecting points for this analysis were at the entrance and at the exit of the anaerobic biological filter, and upstream, downstream and at the mixing zone of the receiving water body, tributary of the Tumurupará River. The following parameters were evaluated: temperature, color, turbidity, suspended and sedimentable solids, dissolved oxygen, chemical oxygen demand, biochemical oxygen demand, potential of hydrogen, absorbance, oils and greases, electrical conductivity, total and thermotolerant coliforms. Next, the results obtained on the different collecting points were compared to the Resolutions 357/2005 and 430/2011 of CONAMA, and to Resolution 128/06 of CONSEMA. The results showed an average removal efficiency of -52,28%, 20,36%, 32,96%, 20,69% and 96,47%, respectively, for sedimentable solids, chemical oxygen demand, biochemical oxygen demand, oils and greases and thermotolerant coliforms. In general, the evaluated system demonstrated low efficiency for the treatment of sewage, complying with the regulations in only 47% of the analyzed parameters. The results showed the necessity of improvements in the sewage treatment plant, as well as the adequation of the anaerobic treatment of the biological filter in order to comply with the current environmental legislation.