Drain 1
Supervision of a de-sudge of a traditional GRP onion septic tank
Drain 2
A newly extended soakaway serving a septic tank
Drain 3
A raised bed to infiltrate pumped treated effluent from a Waste Water Treatment Plant

Waste Water Treatment Plants

Are usually constructed from GRP tanks which can be integral (one tank typically serving 1-5 houses) or modular serving much larger developments. The purpose of the plant is to settle out any inorganics and to treat the raw sewage using aerobic bacteria, which starts the nitrification process, reducing the ammonia level.

Nitrification requires aeration and, therefore, an electrical supply is required to provide the power for the aeration pumps/blowers. Once the effluent is treated by the bacteria the water can be discharged directly into a water course and, providing you meet the criteria set out in the Exemption Permits, then one of these should be applied for, otherwise an Environmental Permit will be required.


If there is no watercourse nearby then the plant will discharge into a soakaway and this will need to be sized according to the soil permeability tests. An Environmental Permit will still need to be applied for if the discharge is greater than 2m3/day.

If you are replacing an existing system, this will also need approval from your local Building Control office.

Costs to be aware of:


There are the capital costs of the treatment plant which includes the supply, delivery, installation and electrical commissioning of the treatment plant.

Annual Running Costs

  • Electric Supply
  • De-sludging Intervals and costs
  • Environment Agency  permitting costs

How we can help?

We can help you choose the most cost effective waste water treatment plant according to your specific requirements, we can liaise with the Environment Agency and your Local Building Control Office, apply for any necessary Planning Applications and help with the appointment of contractors and undertake your site work. Easy !   

Recent Case Study

Case Study 1
Case Study 2
Case Study 3