Adenosine Triphosphate as a Control Parameter for Activated Sludge Processes

Adenosine triphosphate (ATP) was used as a measure of the viable biomass concentration in analyzing the biokinetic and settling properties of a laboratory activated sludge system treating a synthetic wastewater. Using a biokinetic model that incorporated the system's viability, it was found that the fraction of the living biomass decreased as the sludge age increased. The viability of the return sludge was low and that of the effluent biomass was high, whereas the viability of the mixed liquor was between the effluent and return sludge levels. The net growth rate of the viable biomass was found to be directly related to the substrate removal rate of the living organisms. The settling characteristics of the sludge, as a measure of sludge volume index and dispersed solids percentage, were functions of the ratio of ATP to suspended solids and the mean cell residence time.