Field Tests on Small Marine Outfall

Abstract

Field tests were performed on a small marine outfall discharging domestic wastes. Dye was injected into the effluent flow entering the pump house and samples were taken in the sump and offshore in the sewage boil. Dilutions were evaluated from the sample concentrations and compared with theoretical predictions. Data were first collected with the outfall discharging freely in the horizontal direction. Following these tests a mixing tube was attached to the outfall. This consisted of a horizontal cylinder designed to provide some predilution before the effluent jet entered the receiving water. Data were again collected after the mixing tube was installed and the dilutions measured were compared with theoretical predictions. These showed that the theory used for the mixing tube under‐predicted measured values by more than 25%.