Diffusers for Disposal of Sewage in Sea Water

For large sewerage systems the effectiveness of sewage disposal by dilution in the ocean depends on efficient dispersal of sewage into the receiving waters. By the use of large multiport diffusers on the ends of their outfalls, the Los Angeles County Sanitation Districts have, in recent years, greatly improved the characteristics of the ocean water near the disposal site despite steadily increasing discharges of primary effluent. This paper includes a history of the ocean outfall system operated at Whites Point, Calif., by the Los Angeles County Sanitation Districts; an outline of certain techniques developed to predict dilutions of sewage effleunt discharged in sea water; a description of the use of multiport diffusers for improving initial dilution; and a procedure for successful hydraulic design of large diffusers.