Sewage Treatment Plant

Sewage Treatment plant ( STP )

Sewage Treatment plant ( STP ) standards, solution cost saving / M3, more stringent controls, new guidelines and the introduction of new Building Regulations have placed greater importance than ever before on the need to install correctly sized and specified sewage treatment plant ( STP ). Such systems have to deliver high performance, but also be capable of supporting future demand, not just current level of use.
We have drawn on over 10 years of expertise in sewage treatment plant technology in order to meet our own strict criteria in the development of the Envirosafe plant:

Sewage Treatment Plant

Sewage Treatment Plant Extended Aeration System

  • High and medium rate performance options across a range of influent and effluent qualities
  • Adaptable to specific consent requirements including ‘Total Nitrogen’
  • Low head loss
  • Minimal footprint area
  • Single piece tank for rapid installation and reduced costs
  • Variable invert options
  • Minimal visual impact (below ground)
  • Low running costs
  • May be installed in trafficked areas (subject to loading)
  • Compliant with EN-12255
  • Designed for applications selected in compliance with British Water Code of Practice Flows and Loads
  • Low maintenance
  • Alarm protected

Sewage treatment plant Process Design

Sewage treatment plant employ a plug flow combination of aerobic and anoxic processes in a fluidised bed arrangement. This operates in conjunction with an advanced system of air diffusers and selected media to deliver optimum levels of purification.

Substantial BOD reduction takes place here, where the carbonaceous pollutants are removed by presenting the sewage to the micro-organisms in the presence of oxygen. The treatment is achieved by high efficiency air diffusers continually pumping oxygen through the biological media and fluidised effluent. Standard Envirosafe models utilise two aerobic treatment chambers for lower performance applications. Where higher effluent standards are required, the HEQ models employ a third anoxic zone.

This is the initial stage of treatment and simply involves the retention of coarse solids present in raw sewage and wastewater for subsequent gradual breakdown. Envirosafe features two chambers to ensure efficient operation with a flow balancing facility.

A natural by-product of biological treatment is humus sludge and this is separated for further treatment. The treated effluent is discharged via the outlet.

Flow Management

Design incorporates flow management in order to both stabilise influent volume variations and to minimise hydraulic impact on the final settlement process. Such control ensures that final effluent remains at a consistently high quality.


  • Medium and high effluent quality configurations
  • Choice of inverts (from 0.5 to 2.0m)
  • Duty and Standby blowers (as required)
  • Alarm Systems
  • Sample chambers
  • Pumping stations
  • Extension shafts (to 2.0m maximum standard invert)

Control Panel

  • Weatherproof to IP66 rating, can be externally mounted
  • Fully pre-programmed treatment plant control with alarm/fault log
  • Automatic re-start from power failure condition
  • Integrated level protection
  • Visual and audible alarm indicators
  • Technical Specification