Clearwater Sewage Treatment Plant Problem & Solution

Compromised Septic Tank, Failed soakaway
Clearwater Sewage Treatment Plant
Hatfield, Hertfordshire, AL9
21 February, 2015
Dry, High Water table
6 Person

Septic tank problems were identified at this property in Hertfordshire after the homeowner was informed about the septic tank flooding during a routine emptying. Mantair were recommended to the homeowner by a family member to solve the septic tank problems.


After conducting a survey of the existing drainage arrangements it was found that the septic tank problems at this property in Hertfordshire were mainly due to the age of the septic tank and soakaway.  Mantair engineers recommended replacing the failed septic tank with a modern sewage treatment plant.

Based on the property having four bedrooms and in accordance with the British Water Flows and Loads Code of Practice, a six-person Clearwater sewage treatment plant was installed.

The Clearwater plant is a ‘single tank’ system using a Biological Filter Process.  Within the Clearwater system there are three treatment zones.  Within the primary zone coarse solids are filtered and retained for gradual breakdown, whilst the resulting liquid is continuously distributed over a plastic biological suspended filter by an integral airlift, powered by a remote air blower.  The biological filter is designed to promote the growth of aerobic micro-organisms which ‘treat’ the liquids.  Within the final settlement zone fine solids settle to the floor leaving the resulting liquids as the treated final effluent.

The level of treatment within the Clearwater system is far superior to that of a septic tank and complies with the requirements of the Environment Agency for discharge direct to a natural watercourse.


On completion of the ancillary works Mantair engineers commissioned the Clearwater sewage treatment plant, including setting of air valves, checking all pipe work joints and viewing the discharge into the final discharge chamber.

We removed all machinery from site and left the grounds in a neat and tidy manner.

If you require the installation of a sewage treatment plant or merely require advice over the telephone regarding septic tank problems in Hertfordshire, please contact us on 01255 853890, or fill out the contact us form.