Project Description

Septic tanks replaced with sewage treatment plant for domestic client in Monmouthshire


The client was based in Monmouthshire and had 2 existing sceptic tanks which were obsolete. The tanks were adjacent to a fast flowing river and served 2 domestic properties. We were asked to replace the existing sceptic tank installation with a sewage treatment tank that would be large enough to serve the 2 properties.


The site presented a challenge as the new tank was to be situated adjacent to the river bank flood prevention wall. On arrival we arranged for the existing tanks to be emptied so we could ascertain the inlet pipe depth.

Once we had checked for any underground services we commenced excavation works, around 1m in depth we hit the water table. This meant as we dug we had to continuously pump the water out of the hole. At around 1.2m we hit rock which we then had to bring in a large hydraulic breaker to break out the rock to the required depth.

Before works commenced the client was informed that this was a likely scenario due to the location. As a result, a provisional sum was included in the quotation for an allowance to cover the cost of the extra works.


Tankology installed a Kingspan sewage treatment plant connecting all the existing drainage runs to the new location. Notably, instead of using the existing tank outlet, we diamond core drilled through the adjacent wall to discharge into the river.

We were able to do this as we had arranged all the necessary permits and documentation prior to starting the works. The existing tanks were left in place whilst a the new waste treatment tank was installed.

The new tank was located in the drive area, so a 40-ton chamber was created to protect the new tank and enable the clients to park around or on the area with domestic vehicles.

Project details


Client type

Installation type
Sewage treatment plant

Tanks used
Kingspan turnkey waste treatment tank

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