RA Dalton Ltd was appointed to replace a failing and non-compliant septic tank serving a five-bedroom domestic property. The project required the installation of a Klargester Twin Stage 3,500 litre Gamma Septic Tank and the construction of a new drainage field to ensure compliance with current environmental regulations.

Our initial site visit revealed several complexities. We inspected the existing drainage system and checked for rainwater connections, but found no chambers on the inlet drainage, limiting access for a full survey. At the tank, we discovered two inlets and a blocked outlet, which raised concerns about potential flow restrictions.

A dye test was performed on a pipe running from the barns to the tank and rainwater pipes around the property appeared disconnected, with open downpipe outlets discharging onto the ground. A deep soakaway adjacent to the soil pipe was identified, but it seemed to run beneath the property without any visible chamber.

Due to these limitations, a CCTV survey was not possible. Instead, we recommended a full survey of the inlet drainage and percolation testing before installation to ensure the new system would function effectively.

The site presented several challenges:

• Livestock presence in the field posed contamination risks and required additional safety measures.
• The lack of manhole access restricted visual inspection, making accurate planning more complex.
• The existing tank was deemed unsafe, increasing the need for careful decommissioning.

Despite these obstacles, we were able to proceed with confidence and design a compliant solution.

To deliver a fully compliant and efficient wastewater solution, RA Dalton Ltd implemented a structured plan. The first step was conducting percolation tests to determine the correct size of the new drainage field, ensuring optimal soakaway performance. Based on these results, we prepared a detailed Risk Assessment and Method Statement to guarantee safe and controlled execution.

Once the site was prepared, we supplied and installed a Klargester Twin Stage 3,500 litre Gamma Septic Tank within a full concrete surround, providing long-term durability and compliance with regulations. To facilitate future maintenance, we installed shallow inlet and outlet inspection chambers.

The new drainage system included approximately 10 metres of 110mm inlet drainage and a 99-metre drainage field, constructed using slotted pipe bedded in clean washed gravel, overlaid with a permeable membrane and finished with excavated soil in a 900mm-wide trench. This design ensures efficient wastewater dispersal and prevents groundwater contamination.

Finally, the existing tank was emptied and decommissioned by filling with gravel and covering with soil. Surplus excavated material was removed using grab wagons, leaving the site clean and safe.

Percolation tests revealed ground conditions consisting of gravel over sandy clay, which influenced the design and size of the drainage field. This step was critical to ensure the system operates efficiently and complies with environmental standards.

The project was completed successfully, providing a fully compliant wastewater solution tailored to the property’s needs. The new system ensures safe, efficient operation and meets all current environmental regulations. The old tank was responsibly decommissioned and the site was restored to a neat and functional condition.

1. What is a Klargester Twin Stage Septic Tank?
   A Klargester Twin Stage Septic Tank is a high-performance system designed to treat domestic wastewater efficiently. It uses a two-stage process to separate solids and allow effluent to disperse safely into a drainage field.
2. Why are percolation tests important?
   Percolation tests measure how quickly water drains through soil. This determines the size and design of the drainage field, ensuring the system works effectively and avoids environmental issues.
3. How do you decommission an old septic tank safely?
   Decommissioning involves emptying the tank, filling it with gravel to prevent collapse, and covering it with soil. This process ensures the old tank poses no future risk to the property or environment.

RA Dalton Ltd are experts in septic tank installation, drainage field construction, and wastewater compliance. Contact us today for professional advice and a tailored solution for your property.

Call us now or visit www.radalton.co.uk.