owens kleen tank is a self-contained, extended aeration, biological, wastewater treatment system that can be easily designed to fit almost any application. with success in recreational, marine, offshore and land-based markets, our marine sanitation devices treat both black (sewage) and gray water with certification from the united states coast guard (uscg type ii msd). easy maintenance, lasting reliability and optimum effluent compliance make the kleen tank the preferred choice