Viltra’s OXTEC PLUS is a 3-stage sewage treatment system in a single tank structure that uses a biological process to effectively treat sewage. It provides a very efficient, reliable and cost-effective solution to sewage disposal for larger applications within sectors such as commercial and industrial, education, conservation and tourism and hospitality, where there is no access to a main sewer.


  • Manufactured in the UK and Ireland from strong robust, impact resistant tank grade polypropylene

  • Single tank up to 300 PE (population equivalent) - larger systems available in modular basis

  • Extremely low maintenance and running costs

  • Complete system can be manufactured to suit individual sites

  • Process tested and certified to EN12566-3 European standards (up to 50 PE)

  • Bespoke construction for deep and shallow inverts

  • Customisable for non-standard applications, for example schools, restaurants, hotels, glamping sites and conservation areas

  • Reliable and compact

  • No complicated control panels within design of the system

How it works

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

Primary Settlement Tank (PST)

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

Biozone (BZ)

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, achieving 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, which is 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 this is treated through suspended aeration.

Final Settlement Tank (FST)

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 also to ensure continuous flow during periods of low or no flow, thereby keeping the biomass in prime condition.

Key features

  • Single tank installation to minimise costs

  • Robust polypropylene construction for easy and cost-effective installation

  • Non-mechanical recirculation

  • Flat, flush ground-level access covers

  • Failure alarm systems included as standard

  • No mechanical or electrical parts within unit

  • Our unique flow buffering technology (ALF) ensures a constant steady flow 24 hours a day through your system with a gradual release to the natural environment

  • Removal efficiencies up to 99%

  • It is important to note that the new standard relates to all units in the range from 6 persons, (residential equivalent) and includes process and structural testing, including installation in groundwater conditions.

Environment Agency Standard

Why choose a Viltra sewage treatment plant?

  • Specially designed products that are manufactured in the UK and Ireland

  • Superior products and services that are designed to our customer's requirements

  • Esteemed reputation in delivering cost-effective sewage treatment plants within the wastewater market across the UK and Ireland

  • Our larger commercial and industrial products are always backed up by our process warranty

  • Wide-ranging mechanical and electrical fitting with technical support from proposal through to installation and completion

  • We organise the Consent to Discharge process for you, liaising with the all-regulatory bodies to ensure obedience with any requirements enforced

  • At Viltra we have a team of dedicated and accomplished process, civil, electrical, mechanical and environmental engineers with an impressive portfolio of combined experience in the wastewater industry

  • Day-and-night emergency breakdown care only a phone call away

  • Committed after-sales care to ensure customers are reassured

  • Servicing and maintenance packages obtainable at good rates to ensure your system is accomplishing expected functions all year long

  • Viltra have an admired in-house civils team who can deliver an all-encompassing process when vital. This service can implement a complete installation pack from start to finish, saving you the disturbance of executing each element individually.

Our latest projects

How Viltra provided a wastewater solution for the upgrade of a large award-winning garden centre

A flagship design for a brand-new state of the art vegan and vegetarian factory

A bespoke sewage treatment solution for a beauty spot popular with visitors and campers in Scotland

Start an OXTEC PLUS sewage treatment plant project with us

At Viltra, we are specialists in separating waste and water. Whether you have an individual household, a business or a development, we all need and rely on water, we all create and dispose of waste and we all must keep these two worlds apart.

Viltra are a dedicated team who design, manufacture and install wastewater treatment solutions for a wide range of sectors across the UK and Ireland, including the commercial and industrial sector, education sector, conservation sector, domestic sector, agricultural sector and the tourism and hospitality industry. Offering an end-to-end service, the experienced team at Viltra ensure our customers receive a premium service and a robust solution to their wastewater management requirements.

To make an enquiry or to book a FREE site visit by our expert engineers who will find a solution for you, please get in touch with Viltra through the contact form provided.

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