A toilet system comprising a bowl, a valve for supplying flush water to the bowl, an attrition chamber to which the effluent in the bowl is transferred by a motor-driven discharge pump connected to the attrition chamber for inducting the effluent from the bowl into the attrition chamber and discharging the treated effluent from the attrition chamber, a power-driven hydraulic attrition impeller within the attrition chamber for effecting hydraulic attrition of the solid matter in the effluent while in the attrition chamber, and a control circuit for effecting sequential operation such that discharge and attrition are commenced substantially simultaneously, followed by introduction of flush water, termination of the discharge, termination of the flush water and, finally, termination of the attrition.