icon-arrow-right icon-play icon-close


The Widnes contract consists of quality improvements to the existing treatment to meet more stringent EA requirements.

This will be achieved by increasing the capacity of the existing works through the construction of an FBDA treatment unit and chemical dosing equipment and modifications to existing plant as listed below:

  • Modifications to the existing Selector Tank (breaking into, repositioning and repairing concrete walls)
  • Gravity feed pipe from the Selector Tank to the proposed Fine Bubble Dissolved Air (FBDA) Distribution Chamber.
  • New Outlet Pipework from the FBDA Distribution Chamber to the new FBDA Aeration Tank.
  • The construction of a new FBDA Aeration Process Tank.
  • Installation of a gravity return pipe from the FBDA Tank to the existing Activated Sludge Plant (ASP) Collection Chamber and associated repairs to wall.
  • The construction of a new ‘Blower Building' to house blowers and diffusers serving the FBDA Tank.
  • A new Caustic (Sodium Hydroxide) storage and dosing package plant.
  • M&E Modification and refurbishment to the existing Orbal Tanks gearboxes and drives.
  • Provision of boxed spare RAS/SAS pump.
  • Electrical and ICA installations including power and control cabling.
  • Automation of the existing final tank de-sludging bellmouths and sludge blanket detection instrumentation.
  • Re-surfacing of roads and erection of new security fences.
  • Construction of access staircases and walkways to the new structures and modifications to the existing.
  • Provision of Motor Control Centres for the FBDA and Sodium Hydroxide Dosing.
  • Provision of new SCADA system.
  • An extension to the existing HV ring main.

Facts and figures

  • Client:
    United Utilities
  • Value:
  • Commencement Date:
    February 2011
  • Completion Date:
    December 2011
  • Project categories
    Water and utilities