Kells Oldcastle Water Supply Scheme, Meath

The Kells/Oldcastle Water Supply Improvement Scheme supplies water to Kells, Oldcastle, Crossakiel, Drumone, Kilskyre, Carlanstown and surrounding areas. The original WTP was constructed in the 1980s and included abstraction and treatment (disinfection and fluoridation) of water from Lough Bane. A second abstraction from the River Blackwater and interim treatment at Clavin’s Bridge were subsequently added. Following an audit of the scheme by the Environmental Protection Agency (EPA) in April 2009 the Lough Bane Water Treatment Plant was designated as ‘high risk’ to human health as it is a surface water source with no barrier for Cryptosporidium and the EPA placed the scheme on its Remedial Action List (RAL). The EPA Audit made recommendations, which included: (i) Upgrade of Water Treatment Plant to include a treatment barrier capable of removing or inactivating Cryptosporidium and (ii) Upgrade of the chlorine disinfection system.

We were appointed to take the scheme from preliminary design through detailed design, tendering, construction supervision and handover. The upgrade of the existing Lough Bane WTP (capacity 4,683 m3/day) to provide effective treatment of Cryptosporidium included:

• Bypass Chamber and valves on the existing 600mm intake pipe
• Intake Chamber to house a mechanically operated self-cleansing Intake Screen and manually operated/cleaned coarse and fine screens
• Two pumps (in duty/standby mode) at the end of the new Intake Chamber to pump screened water to the new pressure filter units
• Three pressure filter units together with associated backwash arrangement and backwash pumps
• Three Ultra Violet (UV) Treatment units (in duty/duty/standby mode)
• New backwash water settlement tank and outfall structure for the supernatant water
• Replacement of the existing chlorination and fluoridation units
• New sodium hypochlorite and hydrofluorosilicic storage tanks
• Three No. 55Kw high lift pumps
• New MCC and SCADA systems
• Refurbishment of the existing buildings and new treatment building & storage areas

A key feature of this project us the provision of new treatment units whilst operating the existing 4,683m3/day water treatment plant.