Improvement of a conventional activated sludge process using a hybrid moving bed system

Abstract

The regulatory requirements of the European Directive 91/271/EEC about urban wastewater treatment make it necessary to improve the efficiency of many wastewater treatment plant (WWTP) built in Europe in recent decades. In this research, the benefits of the use of the innovative technology of moving bed in a conventional activated sludge were studied. The research compared the differences in organic matter removal between both systems in two equal pilot plants with settler as physical separation system: a conventional activated sludge system and a hybrid moving bed which part of the biomass attached in the carriers. The study showed that at low feed/mass loading, moving bed system is able to remove an additional 43.33% of BOD5 and an additional 30.08% of COD. So, an existing plant of low feed/mass loading activated sludge with an effluent of 30±5 mgO2/L of BOD5 could be restored with a hybrid moving bed getting an effluent of 17±2 mgO2/L of BOD5.