Evaluation of an ozonation system for reduced waste sludge generation

The ultimate disposal of biosolids has been and continues to be one of the most expensive problems faced by wastewater utilities. Previous work has sh own that the waste sludge generation in an activated sludge plant can be re duced by promoting cryptic growth conditions (i.e., biomass growth on intra cellular products). For this purpose, excess biosolids from a continuous fl ow activated sludge system were solubilized using ozone as the cell lysing agent, and then returned to the aeration tank. The results of these prelimi nary studies indicate that the proposed process configuration has the poten tial to reduce the waste sludge production by 40% to 60%. In the present re search, the details of the ozonation process is further investigated to det ermine the maximum solubilization efficiency. For this purpose, a number of variables such as the solids concentration in the excess sludge, ozonation time, and ozonation dosage rate are studied.