A method of treating sewage

摘要

A first holding tank (1) includes a base (2) and a plurality of sidewalls (3) extending upwardly from the base to define an open top (4). An inlet pipe (5) provides raw sewage (6) into tank (1). Tank (1) is part of a sewage treatment plant comprised of a number of like sequentially interlinked tanks. Tank (1) has an average depth of about 11/2 metres and a surface area of about 60 hectares. After a predetermined volume of sewage and other fluids are contained within tank (1) the inflow is halted and a number of live fish, in the form of Europcan carp, are introduced into tank (1). The inclusion of the fish allows the conversion of the sewage into fish manure that progressively builds up on the bottom of the tank. Moreover, the movement of the fish in tank 1 assists the processing of the sewage by aeration.