Client: Irish Water / Limerick City and County Council

Location: Co. Limerick, Ireland

Project Value: €4.5m

Description: Ward & Burke delivered a turnkey solution including all civil, process and MEICA works for the upgrade works to Limerick Main Drainage, Co. Limerick, Ireland

Limerick Main Drainage is a municipal wastewater treatment plant designed to treat a population equivalent of 130,000.

Ward & Burke in conjunction with STR secured the project to upgrade the existing wastewater and sludge treatment facilities at Bunlicky to receive additional loads at the works. The additional loads are resulting from the connection of a new Pharmaceutical plant in the city, with the works completed in two separate phases.

Phase 1

Design and build of upgrades to Bunlicky WWTW and STC to cater for 50% of Regeneron’s flow and loads. Works involved the design, supply, installation, commissioning and testing of:


  • A Chemical Enhanced Precipitation Treatment Process to cater for the additional flows and loads. This included 2 No. Chemical Storage Tanks (25m3 each), Dosing Systems, Controls etc.
  • Sludge dewatering facility to process the additional sludge being received at the plant.
  • Modifications to the existing sludge process to accommodate the new sludge treatment unit.
  • New Control System & Integration to the existing SCADA System.

Phase 2

Design and build of upgrades to Bunlicky WWTW and STC to cater for 100% of the Regeneron flow and loads. The project comprises of a New Anaerobic Digestion (AD) facility to treat the additional sludge being received at the plant with two digesters proposed for the site with a capacity of 4,000m3 each. A new Combined Heat & Power (CHP) Plant was installed to generate power on the site. Other components of the project plant include:


  • Modifications to existing tankage
  • Gas Mixing System for AD Tanks
  • Heating System for AD tanks
  • Gas Flare
  • Sludge Dewatering System
  • Siteworks and Piling for AD tanks

The new Anaerobic Digestion Process resulted in significant benefits to the clients including:

  • Production of biogas – which could be reused on the site to reduce reliance on imported energy. 450kW Generator on site producing 40-50% of Total Energy required for the site
  • Reduction in sludge solids thereby freeing up capacity in the dryer and other elements of the STC
  • Increased stabilisation of sludge
  • Revenue stream from power generated on site