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)
✓ 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%.
How it works
• 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.
• 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.