Sewage Treatment Plant Installation

Treatment plants are the usual answer where a septic tank will not do: the ground is too heavy for a drainage field, there is not enough room for one, the site is close to a watercourse or borehole, or an old tank has to be replaced to meet the General Binding Rules.

They are also worth considering when a property is being extended or converted and the number of bedrooms takes the existing system past its capacity.

• Replacing a septic tank that discharges to a watercourse
• Clay ground that will not take a drainage field
• Plots too small for the required field area
• Conversions and extensions that add capacity
• Farms, holiday lets and small developments

Plants are rated by population equivalent, and the rating is worked out from the number of bedrooms rather than who happens to live there today. Undersizing is the most common mistake and it shows up as poor effluent quality and complaints.

We specify plants certified to BS EN 12566-3, which means the performance has been independently tested rather than claimed. Beyond that the choice comes down to how the site is used — some plants cope better with holiday lets and other irregular loads, some are quieter, and servicing intervals differ between makes.

The tank is set on a designed base and backfilled to the manufacturer's specification, which for most units means a concrete surround; getting this wrong is what causes tanks to distort or lift. We arrange the power supply to the blower, connect the inlet and outfall, commission the plant and hand over the paperwork you will need if you sell the property.

Plants need servicing at the interval the manufacturer sets, and the desludging record is part of complying with the rules.