The Difference between a Septic Tank and a Sewage Treatment Plant

A septic tank produces a very polluting effluent which must be discharged only to a soakaway for further treatment of the septic pollutants by the natural aerobic soil bacteria.

A sewage treatment plant produces a clean, non-polluting effluent which can be discharged directly to a stream ditch or other watercourse, or to a soakaway for dispersal into the soil.

Septic tanks do not require electricity for the process, but most sewage treatment plants do. The amount of electricity required by sewage treatment plants varies from plant to plant, so it is wise to ask before you buy.

Septic tank systems do not require actual servicing, but sewage treatment plants do. Septic Tanks require emptying at least once a year, whereas sewage treatment plants have emptying intervals between 3 to 60 months.