The Bio-Pure is a fibreglass conical shaped tank that is used for domestic sewage treatment. The Bio-Pure works on the successful and simple extended aeration method, which means that the solids are treated as well as the liquids. The extended method that we use means that the sewerage is aerated for a minimum of 24 hours. Many other sewage systems only treat the sewage for a few hours. Treating the solids means that the Bio-Pure only needs emptying every 3-5 years typically, making it a simple and easy solution for sewage treatment.

The unit is available in 10 sizes to cater from 1 to 50 persons and can be used for single houses, renovations, barn conversions, small communities, industrial units and camping sites.  The Bio-Pure can therefore serve both domestic and commercial properties that have no access to mains drainage.  The Bio-Pure is also now available with an integrated pumped outlet.


The Bio-Pure is a two chamber unit and consists of a conical tank, with an inner circular aeration chamber inside, which is open at the base. The space between the inner and outer tank is the clarifier chamber.  The draft tube is positioned 100 mm from the base of the clarifier, extends up into the aeration chamber.  Air from the compressor housed under the lid is piped to a diffuser in the draft tube.  Raw sewage enters the aeration chamber through the inlet pipe, flowing into the centre of the chamber.  Air surging up from the draft tube aerates the sewage, causing an aerobic bacterial colony to establish and digest the organic matter.

As more raw sewage enters the chamber through the inlet pipe, an equal amount of effluent displaces through the open bottom into the clarifier (outer tank).  The quiet conditions in the clarifier allow all the suspended solids to sink to the base of the clarifier and they are drawn back up the draft tube by the upward flow of air for further digestion in the aeration chamber.  The clear effluent rises to the top of the clarifier and passes over a weir into the outlet pipe and is disposed of through a water course or soak away.  The Bio-Pure constantly recycles the sewage via gravity and achieves nearly total solids digestion.  Most sewage treatment units consist of three chambers, the first one being a Primary Settlement Tank where the solids form a septic sludge.  They require regular emptying by tanker.  Because the Bio-Pure digests the solids as well as the organic matter in the liquid, the unit has a much longer emptying interval than any three stage unit.  The interval is 3 to 5 years.

The Bio-pure is 96% efficient thus allowing long intervals before de-sludge is required. The waste water is cleaned to a standard of 20 mg/l biological oxygen demand and 30 mg/l suspended solids, meeting the usual discharge level requirement.

The Bio-Pure is fully EN 12566-3 certified


  1. Sewage enters the inner chamber via the inlet pipe
  2. Air surges up from the draft tube to aerate the solids and liquids for a minimum of 24 hours
  3. More sewage enters the inner chamber and an equal amount of effluent displaces through the into the outer chamber (at the bottom of the inner chamber)
  4. Suspended solids sink to the base of the clarifier and are drawn back up the draft tube for further digestion
  5.   A small quantity of settled effluent from the top of the outer ring clarifying chamber, is drawn back into the centre aeration chamber by a simple airlift system for further digestion.
  6.  Clear effluent rises to the top of the clarifier and passes over the weir into the outlet pipe