A Continuous Aeration Plant (CAP), is desigfned to provide full tratment to crude sewage in a normal domestic enviroment. The CAP teats sewage to a higher standard than a septic tank, but does no offer the same degree of control available from a Sequential Batch Reactor (SBR) The standard of effluent discharged from a CAP is such that it does not need to be passed through a soakaway and can be discharged directly to a watercourse.