PUNCH Murnane was appointed by Limerick County Council as Employer’s Representative for the Kilmallock Sewerage Scheme.  The works were procured under a 20-year Design Build Operate (DBO) contract awarded to Coffey Water Ltd., Athenry, Co. Galway.  

The project included the design and construction of a new wastewater treatment works, a sludge treatment facility, a main lift pump station and rising main, a storm tank and a new gravity trunk sewer from the town.  The treatment works cater for a design population from the town of 4,000 in Phase 1 and 8,000 in Phase 2.  Kilmallock is designated as a sludge hub-centre under the Regional Sludge Management Plan and the works  incorporate sludge reception and processing facilities to cater for imported sludge from 12 villages in the surrounding hinterland.

The new treatment plant include the following elements:

• Inlet works including screen chamber and grit trap.
• Two tank Sequencing Batch Reactor extended aeration process.
• Ferric sulphate dosing facilities
• Secondary effluent flocculation tank
• Two tertiary micro-screens
• Final effluent re-use pumping stations
• Picket fence thickener
• Sludge Dewatering Centrifuge
• Control building, sludge, reception, dewatering and storage facilities, SCADA control system, Odour control system and Backup power generation

The plant includes tertiary treatment and releases a highly polished effluent to the River Loobagh to comply with strict discharge standards set by the EPA.  The existing treatment plant in the town was decommissioned and demolished as part of the DBO contract.

The collection and pumping elements of the sewerage scheme included the following:

• A new combined gravity trunk sewer from the town (600mm diameter precast concrete sewer) laid in public roads over a distance of approximately 0.6km as far as the new main line pumping station.
• A new main line pumping station incorporating duty and standby pumps, screening, telemetry and emergency back-up power generation.
• A storm overflow tank at the main line pumping station site with a capacity of 337m³, incorporating screening, wash-down systems, return pumps, odour control system and emergency overflow pipework to the River.
• 285m of 225m diameter HPPE rising main to transfer pump flows from the main lift pumping station to the treatment work site.

PUNCH Murnane Consulting Engineers undertook the role of Employer’s Representative for the contract.