Mantair Conversion Unit

The septic tank conversion unit from Mantair is powered by a small air blower.  The air blower can be located in either an existing outbuilding or in a small remote housing.  The blower can be located up to 25 metres from the Mantair unit and is powered by domestic 240v electrical supply.  It is a connected to the Mantair unit by a small bore MDPE pipe concealed underground.  The blower provides the air that is required for the treatment process and to lift the treated effluent to the discharge point.

Once installed, the Mantair septic tank conversion unit separates the existing tank into two compartments/zones.  The majority of the existing tank is transformed into an Aeration/Mixing Zone.   Air is supplied to this zone via an aerator contained within a draught tube. Within this zone, the aeration and mixing encourage the growth of aerobic microorganisms. This process degrades the sewage and breaks down large and heavy solids.

The contents of aeration/mixing zone where the micro-organisms are maintained in suspension are referred to as ‘mixed liquor’.  As further flow enters the tank, part of the mixed liquor is displaced into the second compartment, referred to as ‘the final settlement zone’.  Here, the microorganisms separate and form a thin sludge.  This is continuously returned to the aeration/mixing zone, thus maintaining the levels of micro-organisms in the mixed liquor.

The liquid, which remains in the upper part of the final settlement zone, is the treated effluent discharged from the Mantair unit via the Final Effluent Airlift.

The final effluent airlift controls the rate of discharge from the system and prevents any shock hydraulic loads from upsetting the treatment process. The use of an airlift enables the Mantair unit to discharge the effluent at a higher level than the tank inlet.

EN12566-3 is the European Standard for ‘packaged sewage treatment plants’ up to 50 population equivalent.  An integral part of the test procedure is structural testing of the packaged plant tankage. As the Mantair conversion unit does not include new tankage, it cannot be tested, and EN12566-3 is not applicable.

As there is no a European Standard for ‘in tank’ Conversion Units, they can’t obtain a CE Mark. However, all components used in the manufacture of the Mantair conversion unit comply with the relevant European Standard.

The Environment Agency recognises the Mantair conversion unit as a sewage treatment system. It authorises its use under Permit Certification, allowing the treated effluent from the system to be discharged directly into natural watercourses.

The Mantair unit should not be confused with other products marketed as ‘conversion units’, which involve the installation of additional tankage downstream of the existing septic tank.  As new tankage is required, these products can be tested under the European Standard.  These products, however, do not ‘convert’ the existing septic tank, but provide biological treatment in additional tankage.