Lough Egish Regional Water Supply Scheme

Project Summary

Coffey Construction was contracted to work collaboratively with Irish Water and Ryan Hanley Consulting Engineers in the assessment, design, supply, installation, calibration, testing and commissioning a range of process modification works and 1-year operation service of the Kilkit Water Treatment Plant and Corlea raw water intake pumping station.

A summary of works carried out by Coffey Construction includes:

  • Replacement of end-of-design life pumps and motors, electrical panels and improvements to the control system at the intake works.
  • Upgrade the existing coagulation, flocculation and filtration Water Treatment Plant to an enhanced coagulation plant.
  • Construct a 3-cell tank, consisting of 2 No. 354m3 wash water settlement tanks and a 280m3 supernatant tank adjacent to existing tanks
  • Integrate the new and existing MEICA assets.
  • Construct a new chemical building to centralise chemical storage, make-up, transfer and dosing, replacing existing infrastructure.
  • Install UV Treatment system and sludge dewatering centrifuge.
  • Installation and commissioning of the new suite of qualitative instrumentation to control and automate the new coagulation, flocculation, filtration, disinfection and sludge treatment works
  • Implement automatic diversion of clarified water flow to operational filters during a filter backwash sequence and filtration control based on head loss rather than timers alone.
  • Implement automatic filter-to-waste diversion following the backwash.
  • Upgrade the existing SCADA and Telemetry system to allow for all new control and alarm.
  • Interim operation of the existing works during the Design-Build Period thus minimising the disruption to the treatment process.

Some notable challenges and successful outcomes were realised during the operation, design and build of this project.  For the first time in Ireland, settlement tanks were designed and constructed utilising a twin wall system.  This system maximised the on-site efficiencies and minimised space requirements for construction.

During the initial operation and build phase, it was discovered that the existing panels were overheating, and spares and consumables were unavailable. Coffey’s Project Manager collaborated with the client to agree revised programme which included the supply, installation and commissioning of new panels.

Asbestos was found on site during the excavations for the settlement tanks.  Coffey Construction engaged a (preferred) specialist sub-contractor to remove the asbestos from the site with minimal disruption to the programme.

Off-site manufacturing was utilised for items including the internal and external panels of the twin wall tanks, access platforms and the decanter arm systems.

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