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Efficient, reliable and cost-effective sewage treatment plant for domestic applications.

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Viltra's OXTEC is a 3-stage biological process sewage treatment plant contained in a single tank structure. It is a highly efficient, reliable and cost-effective way to dispose of domestic sewage where there is no access to a main sewer.



• Very small footprint

• Can be tailored to suit individual sites

• Manufactured in NI from robust, impact-resistant polyethylene – unlike alternatives which are prone to cracking if not handled carefully

• Easily installed due to lightweight material

• Quiet in operation - there are no electrical or mechanical components within the tank. The only mechanical component is a small air compressor

• Extremely low maintenance & running costs – (Energy efficient Air Pump – 38-43W)


Key Features

 Single tank installation to minimise costs

 Strong and secure access cover

 Failure alarm systems included as standard

 No mechanical or electrical parts within unit

 Rotationally moulded in tough, durable polyethylene for easy and cost-effective installation

Sealed unit with no joints below water level


Environment Agency Standard

The OXTEC sewage treatment plant is tested and certified to exceed the current Environment Agency standard of 95%, with an overall average of 96.7%.

BOD removal
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Installation Available
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Service contracts available
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Free commissioning
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CE Certified


How it works

Viltra's OXTEC is a 3-stage biological process sewage treatment plant contained within a single tank structure

Primary Settlement

• The primary settlement tank (PST) is a two-stage tank designed to maximize the removal of gross and suspended solids. The PST also incorporates a sludge storage volume depending on desludge periods.


• The biological treatment phase incorporates two proven principles of biological process in the form of a fixed film reactor and a suspended floc dispersed growth system for high transfer rates and operational control, providing a stable treatment process unaffected by shock loads.

• The heart of the process is a submerged, high rate, plastic media on which a fixed film of biomass is grown.  The film consumes incoming settled effluent and oxygen, provided by a small blower. The media is aerated through HDPE membrane diffusers that provide fine bubble aeration.

• The fine bubble aeration is carefully controlled, providing optimum oxygen transfer rates and scouring to slough off excess biomass while keeping the thickness of the fixed biological film at optimum levels.

• The fact that the media remains submerged means that there will be biomass which is “unfixed” to the media, but treatment is achieved through suspended aeration.

Final Settlement

• The final settlement tank is designed to provide maximum settlement of any suspended solids prior to discharge. The system incorporates continuous sludge return airlift to return sludge from both the final settlement tank back to the primary settlement tank.

• This system also provides for continuous recycling of treated effluent back to  the PST to not only provide dilution of incoming settled effluent, but to also ensure continuous flow during periods of low or no flow, thereby keeping the biomass in prime condition.

Why choose a Viltra sewage treatment plant?

• Custom designed and manufactured in Northern Ireland.

• Fully comprehensive mechanical and electrical installation with technical support from design through to installation and final commissioning.

• At Viltra we have a team of dedicated, skilled engineers with over 35 years' combined experience.

• Proven track record of supplying cost-effective wastewater treatment systems within the wastewater market.

• High quality products and services tailor-made to our customers’ requirements.

• Dedicated after-sales service to give our customers complete peace of mind.

• 24-hour emergency breakdown service only a phone call away.

• Our products are tested and certified to EN12566-3 European Standards.


Country Specific Measures


Call us today to speak to our experts about Viltra's OXTEC sewage treatment plant

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