New Approach for Sewage Sludge Stabilization with Ozone

Due to a variety of physicochemical properties of the sewage sludge the selection of proper methods for its stabilization is difficult. In this work, the effect of ozone treatment on physico-chemical and microbiological parameters of sludge was investigated. Ozonation was carried out using a counter-current bed reactor, which ensures optimal mass transfer and the contact time of ozone with excessive sediment. The ozonation process was carried out for 15, 30, 45 and 60 min at an ozone concentration of 90−110 ppm. As a result of the ozone treatment it was possible to reduce the number of colony forming units. Also the potential for dewatering of the sludge improved while the total solids of the sludge did not change. The values of COD and BOD5 increased with time of the process.