Aerobic Digestion of Waste Activated Sludge

Activated sludge that had been grown on a completely soluble wastewater in a pilot plant was subjected to aerobic digestion in batch, lab-scale reactors. During the course of digestion, destruction of nonvolatile solids occured so that is was preferable to express the kinetics of digestion upon the loss of total suspended solids rather than volatile suspended solids. The first-order rate constant for the destruction of degradable suspended solids was found to be unaffected by the solids retention time (SRT) at which the activated sludge had been grown, whereas the nondegradable fraction of the activated sludge was found to increase as the SRT increased.