Aplicação do processo Oxic-Settling-Anoxic para a minimização da produção de lamas ativadas

Mestrado em Engenharia do Ambiente - Instituto Superior de AgronomiaThe high amount of sludge generated by biological processes in wastewater treatment plants (WWTP) is one of the biggest challenges in wastewater treatment. The need for development and optimization of alternative technologies to minimize sludge production brings high relevance to scientific research in the field. The aim of this study is to evaluate the introduction of an anoxic reactor in the sludge return line of an activated sludge wastewater treatment system, as a strategy for minimization of sludge production. The hydraulic retention time (HRT) chosen for the anoxic reactor was 24 hours. Two consecutive trials using different treatment processes were performed: activated sludge (reference trial) and Oxic-Settling-Anoxic (OSA) process (minimization trial). The results showed good system response to organic overloading, not compromising removal efficiencies. Microbiological analysis showed the presence of dense flakes and stability indicator organisms in the treatment system, such as Vorticellas sp., Epistylis sp., Rotifers, Arcellas sp. and Aspidisca sp. The comparison of the results between reference and minimization essays, showed a 78% sludge production reduction for OSA process