The Cape Cod Wastewater Renovation and Retrieval System is evaluating alternative means of wastewater treatment and developing design criteria for the recharge of water of potable quality to the groundwater reservoir of the coastal outwash plains of Cape Cod and the Islands. The three-year plan involves investigation of the in situ performance of the existing sand filter bed at Otis Air Force Base, a rapid infiltration system designed to enhance biological denitrification, and a spray irrigation-cropping program. The quantity and quality of the treated water, the receiving water, and the character of the soil is being carefully examined to project eventual water condition after many years of operation.