Activated sludge systems with biomass particle support structures.

A mathematical model was developed to simulate the operation of an activated sludge system with biomass support particles. Based on the results of this simulation study, it would appear that a system with biomass particle supports offers several advantages not offered by conventional systems. These include the ability to resist failure from large hydraulic surges; stable nitrification under transient inhibitory conditions resulting from temperature changes, hydraulic surges, and/or toxic chemicals; and the ability to establish stable operating conditions with respect to both carbon oxidation and nitrification at short hydraulic retention times and low sludge ages.