Activated Sludge and Ozonation Combined System of Sanitary Effluent Treatment to Bacterial and Protozoa Removal - A Case Study

In order to remediate district effluents, two types of treatments were combined that could be an efficient solution for the great problems involving sanitary effluent, water reuse, organic charge reduction and disinfection processes. Chemical and biological parameters of sanitary effluents before and after activated sludge treatment and subsequent oxidative ozone treatment were monitored. The activated sludge treatment significantly reduced the organic charge, observed by monitoring the chemical oxygen demand (COD) and the total organic carbon (TOC). After the treated effluent from the activated sludge underwent a subsequent treatment with ozone, further decreases in the COD and TOC values were observed. Ozone efficiently eliminated (100%) coliforms and Giardia spp. cysts, which normally are not eliminated by the activated sludge treatment.