Use of powdered clay to upgrade activated sludge process

Abstract

Abstract Two experimental pilot plant units were run. The first unit was an upgraded activated sludge system with powdered clay addition (PC). The second one was a conventional activated sludge plant, run as a control unit (CU). The main objective of this study was to confirm the enhanced performances of upgraded PC unit, particularly as far as sludge settling characteristics and increased nitrification capacity are concerned. The experimental results showed that the application of this technique for overloaded plants upgrading resulted in a decrease of applied sludge loading, an increase of solids flow loading, a very low value of SVI and an enhanced nitrification capacity. Moreover, plant volume could be reduced by 30% compared to a conventional activated sludge process. The presence of powdered clay improves also physical characteristics of the excess sludge, namely its thickening capacity and dry solids content.