Commercial Sludge and Slurry Pumps . KZN model sump pumps are a commercial, heavy duty, top discharge, dewatering sump pump, designed for pumping very dirty water and farm waste. Featuring heavy duty inlet agitators, the KZN range is suitable for pumping sludge and slurries. Models in the range: DT37KZN - 3.7kW with 3" outlet