Tricel Sewage Treatment Plant Problem & Solution

Illegal discharge
Tricel Sewage Treatment Plant
Chelmsford, Essex, CM1
13 December, 2011
Dry, Clay Soil
6 Person

At this property in Essex we installed and commissioned a sewage treatment plant to replace a failed septic tank system.

Mantair was contacted by the owner of a property located in the hamlet of Cooksmill Green, near Chelmsford in Essex.  The homeowner requested the services of Mantair to assist in the modernisation of a septic tank system.

On inspection of the foul drainage system it was evident that the existing septic tank discharged directly into a nearby roadside ditch.  On viewing the internal condition of the septic tank is was apparent that the structural integrity of the tank was impaired.

Using the Geological Survey Map of the Chelmsford area, Mantair engineers were able to determine that the underlying sub-strata was predominately clay.  With the ground conditions being impermeable a replacement septic tank soakaway system would not operate correctly as the discharged liquids would be unable to percolate through the sub-strata.


Mantair recommended that the septic tank be replaced with a packaged sewage treatment plant, which would provide suitable treatment so that the final effluent would be acceptable and in accordance with the Environment Agency’s requirements for discharge to the roadside ditch.

After discussing the clients concerns and requirements it was paramount that the new sewage treatment plant was both quiet and had minimal maintenance requirements.

Following the initial site survey and subsequent discussions with the client, Mantair recommended in accordance with the British Water Flows & Loads Code of Practice, the installation of a six person Tricel sewage treatment plant with Medo air blower.

As part of the project Mantair liaised with the Environment Agency and the local Building Control Department to obtain the relevant approvals for the installation and the discharge to the roadside ditch.

Prior to any ancillary works commencing Mantair engineers scanned the proposed location of the new sewage treatment plant and areas where any excavations were taking place to ensure that no underground services were present.


The scope of the installation works included:

  • Exposing the existing foul drainage pipe work and diverting to the location of the new Tricel sewage treatment plant;
  • Installation of the sewage treatment plant in a suitably sized excavation, including for a concrete base and back-fill;
  • Locating the Medo air blower within a Beehive blower housing – a purpose built housing designed to blend into the natural surroundings;
  • Provision of an RCD protected power supply to the Beehive housing;
  • Installation of the air main from the air blower to the Tricel sewage treatment plant;
  • Installation of a new 110mm diameter discharge drain to the roadside ditch;


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

All machinery was removed from site with the garden being left in a neat and tidy manner.

With our head offices based in Essex, we are ideally placed to provide Essex homeowners with a septic tank and sewage treatment plant installation service.  Mantair provides a comprehensive service, including free site inspections, guidance and advice on the most suitable system, complete installation, commissioning and full after sales care.

If you would like a Mantair engineer to visit you regarding an existing septic tank problem or sewage treatment plant installation, please fill out the form below or contact us on 01255 853890.