The report presents the results of a marine sanitation system demonstration performed both in the laboratory and on the Delaware River and Bay Authority's Cape May-Lewes Ferry. The sanitation system tested is a physical-chemical system capable of providing a high degree of secondary treatment using activated carbon. The system was designed as a 'flow-through system', that is, one which discharges a treated effluent overboard. After promulgation in June 1972 of the Environmental Protection Agency's 'No Discharge' standards, the program was revised to include the evaluatiion of the system in a recycle mode, using the treated effluent for sanitary flush water. Testing in the recycle mode was then conducted to determine the effects of such recycling on the treated wastewater, i.e., buildup and effect on treatment of constituents in the wastewater.