Castlemoyle Water Treatment Plant – Upgrade Contract

Project Summary

The project consisted of an upgrade to the existing Castlemoyle Water Treatment Plant (WTP) by providing a second treatment stream complete with sand replacement and upgrading of existing treatment facilities. The contract included ancillary works at the existing Aughananagh and Pollmounty River Intakes, Dranagh Raw Water Storage Reservoir and Ballyleigh Raw Water Balancing Tank. The existing plant capacity was 170 m3/hr and the upgraded plant has a minimum net treated water output capacity of 349.3m3/hr.

The existing treatment process at Castlemoyle involved Coagulation, Flocculation, Dissolved Air Flotation (DAFF), Rapid Gravity Filtration, Disinfection and Fluoridation. The existing treatment process was retained. The treatment process for the 2nd stream fit within the footprints of the existing Flo-filter units and flocculation chambers to ensure that our process did not require planning approvals. The Water treatment plant was designed such that sedimentation of raw water would take place at the inlet reservoir at Dranagh. The Design/Build (DB) Contract for the Castlemoyle WTP included the design, construction, mechanical and electrical installation, followed by testing and commissioning of the following elements:

  1. Aughananagh Intake and Dranagh Raw Water Storage Reservoir
  2. Pollmounty Intake and Pumping Station
  3. Ballyleigh Raw Water Balancing Tank
  4. Castlemoyle Water Treatment Plant Works – Provision of new treatment stream and modifications to existing stream.

Coffey Group installed and tested a specialist, monolithic concrete rapid gravity filter floor system.  The system is a “cast in-situ” design that becomes part of the surrounding civil structure. The filter floor was installed with over a thousand filter nozzles that retain the filtration media in the filter while letting the filtered water going forward for public supply.   Coffey Group also installed, as part of the project, a silt trap as well as laying sections of new and replacement ductile iron pipework.   Project management and design functions for all aspects of the project were carried out by Coffey Group.

Raw Water Source: River (Aughananagh River and Pollmounty River)

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