The term cess-pit is often generally used to describe some form of tank unit normally in a garden area serving one or more properties. Most Cess Pits are actually septic tank systems, these are the most common form of waste water disposal but the tank could also be a sealed tank known as a cess pool.
More modern units are now found to be sewage treatment systems that use a natural biological action to break down the sewage waste into a cleaner form of effluent.
A "Septic Tank" is a form of holding chamber utilising a form of internal construction to slow down the flow through the tank unit. The outlet from the septic tank leads to a soakaway system below the ground surface.
A "Cesspool" is a large holding tank that is completely sealed having only an inlet and a vented air outlet. A cesspool is designed to hold all sewage and waste effluent and does not carry out any treatment or any discharge from the tank.
A "sewage treatment plant" is a system that uses natural biological aerobic action to treat sewage to a very clean level. Sewage treatment plants are now produced by a large number of different manufacturers. All of the systems are based on producing a final effluent quality significantly cleaner that that produced from a septic tank.