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It just popped out of the ground!

WCI received a frantic called from a home owner locally after their existing Biodisc sewage treatment plant was found to have ‘popped’ out of the ground the day after it was emptied by a licenced desludging contractor. WCI was able to visit site that same day, inspect the existing tank, undertake porosity tests and provide a quotation for submission to the building insurance.

Whereas the existing installation was to a drainage field, porosity tests highlighted a lack of porosity in the clayey soils. There was a seasonally dry ditch on site which, after discussions with the local Environment Agency Officer, became the new discharge point. A bespoke EA permit was applied for with the understanding that the installation work could precede the permit submission.

The insurance company approved the quotation, WCI applied for a Building Notice and once all legalities were sorted, we started the installation work.  After three days our clients were left with a new, fully compliant system and could use all the facilities!!

Why did it fail?

Once the existing Biodisc was removed from the previous excavation it became obvious that it was only installed under a thin cap of concrete. It was also evident that the drainage field had been failing and effluent had found its way into the excavation around the tank which added to the tanks buoyancy when it was emptied. As the tank showed signs of damage it was agreed with the owner and insurance company not to take any risks and replace the Biodisc with a new sewage treatment plant.


The replacement plant was a Solido Smart 8 population gravity sewage treatment plant. The Solido Smart is a technologically-advanced system which offers reduced running costs, minimal excavation and a long lifespan. The Solido Smart incorporates the Sequence Batch Reactor (SBR) technology. Wastewater is treated in batches rather than being treated continuously, resulting in an efficient treatment plant with reduced energy consumption and a prolonged life for all component parts. Rated at 0.65kwh per day based on a family of four, meaning less than £10 per person per year in electricity consumption.

If you have any questions about the information presented in this case study, or you would like to talk to us about your off mains drainage options, please contact WCI on 01984 623404 or via the contact form below.

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If you have any questions or just need some clarification on the regulations and how they apply to your property, please call us on 01984 623404