Upgrading performance of an activated sludge process through addition of talqueous powder

Abstract

This study is intended to induce better performance of existing activated sludge wastewater plants without modifying the physical structure of the plant. The process consists in injecting a specific mineral powder into the aeration stage with two precise purposes: firstly to improve floc structure and thus facilitate solid/liquid separation in the clarifier, and secondly to reduce nitrogenous pollution. By means of two experimental models the indisputable and rapid effect of talc/chlorite blend on the solid/liquid separation was established (with a sludge volume index improvement by a factor of 2 to 3 within a few days) compared with a control unit. The increase in nitrification capacity of the system is also clearly shown with nitrification yields being increased by 30%. These results lead us to believe that it is possible to use this process of enhanced nitrification for running a plant reliably without dysfunctioning. Problems linked to hydraulic or biological excess loading can be solved this way. Moreover, the addition of talqueous powder improves sludge dewaterability.