The design is based on the established principles of primary settlement, biological oxidation and secondary settlement to produce an effluent to comply with Environment Agency requirements for discharge to a watercourse.
‘Biological oxidation’ takes place in a submerged filter bed, with distribution and aeration being achieved by the use of patented venturis and a small submersible pump - which is the only moving part in the whole system.
Speculative reductions in load are ignored and ‘worst case’ figures adopted to produce a plant fully capable of achieving the required standard. The depth below inlet invert has also been kept to a minimum to reduce the likelihood of encountering difficult ground conditions during installation.
The smallest ‘SAFE’ plants are designed to serve one or two houses and are extremely compact. Larger plants can be supplied as single structure units with or without primary settlement capacity, which provides the option of installing a complete treatment plant, or using a filter/secondary settlement unit only to improve the discharge from an existing septic tank.
The plant is installed completely below ground, leaving only the inspection cover(s) visible at the surface. It is virtually silent in operation and with no kiosk or housing remains totally unobtrusive.