Do you know the difference between a septic tank, a cesspool/cesspit and a sewage treatment plant?

Do you know the difference between a septic tank, a cesspool/cesspit and a sewage treatment plant?

When receiving sewage tankering requests from domestic and commercial clients, in many cases,the client cannot confirm what type of system they have on their sites. So to help understand what type of tank you may have and what their normal tankering and servicing requirements are for each system, we hope the following guidelines will be useful.

Septic Tank:

A septic tank is generally a two or three chambered tank with an inlet and outlet. It is designed to allow solids and liquids to separate in the chambers before the settled liquors gravitate through the outlet to a soakaway chamber or herringbone land drainage system. The liquors are still classed as raw effluent and cannot discharge to ground if positioned near a watercourse as this will cause pollution. The ground structure also needs to be suitable for a soakaway so percolation tests need to be carried out to confirm, acceptable porosity. If sized correctly for the application, most septic tanks only require an annual desludge. Here at BKP though, we always include a Free Health Check on each tankering visit and our operative will advise of any visible defects that need to be addressed now or in the future.


A cesspool or cesspit is effectively an underground holding chamber. Sewage will enter via the inlet and once the chamber is full, the tank will require a complete empty.The minimum size cesspool for a habitable dwelling is 18000 litres so for a family of four, on average this tank will require emptying every 20-25 days. To prevent overflowing of these holding tanks, many cesspools are now being fitted with high level alarms to advise clients when their tanks are at 75% capacity.This gives them plenty of time to arrange a tanker and to prevent any embarrassing situations! If you want a high level alarm for your cesspool, give BKP a call today.

Sewage Treatment Plant:

A sewage treatment plant is designed to treat the settled liquors to a higher quality to enable the final effluent to discharge to a watercourse, subject to the Environment Agency's approval. With so many different types of sewage treatment plants on the market, these can be easily identified by their mechanical or electrical parts. The more common makes are Klargester, WPL,Conder, Entec or Titan. With each STP installation, an Operating and Maintenance manual is provided stating what the servicing and tankering requirements are for their specific application but as a guide, a six monthly or annual visit should suffice.

BKP provide a unique combined service by coordinating both tanker and engineer to attend site at the same time; minimising the intrusion on site and enabling every eventuality to be covered whilst on site. Furthermore, any repairs, retrofits, emergency responses or new installations can also be handled by BKP Waste & Recycling. To find out more about our combined servicing and tankering package, contact our sales team today.

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