Project Outline

This design, build and operate (DBO) project saw Irish Water engage Murphy to deliver a major refurbishment of Leixlip Wastewater Treatment Plant with a phased expansion in capacity from 80,000 PE to 150,000 PE.

This project included:

• New preliminary treatment works and 4,200m³ flow balancing tank to blend domestic and industrial influent streams.
• Refurbishment and expansion of primary treatment with 100% increase in capacity.
• Refurbishment and expansion of activated sludge plant with 60% increase in capacity.
• Refurbishment and expansion of secondary settlement with 30% increase in capacity.
• Refurbishment and expansion of tertiary filtration with 100% increase in capacity.
• Refurbishment and expansion of sludge thickening and sludge dewatering plants.
• Refurbishment of existing anaerobic digestion plant including installation of new biogas conditioning system, 2 no. new 150kW CHP units and 2 no. new 260kW dual fuel gas boilers.
• Upgrade of electrical infrastructure.
• Completely new SCADA system for the expanded and refurbished works

Key Challenges

Leixlip Wastewater Treatment Plant discharges effluent treated to a very high quality into the River Liffey. The key challenge which was met on this project was to ensure that we succeeded in delivering the upgrade of the plant without any interruption in either available capacity or performance.

Project Delivery & Innovations

Some key aspects of project delivery and innovations included:

• Murphy executed over 25 planned overnight shutdowns of the works to deliver upgrades during low flow periods where retention in the plant ensured operational performance standards were continuously maintained.
• Lamella tube settlers installed in the new primary treatment tanks allowed the new tanks double capacity while taking less than 50% of the footprint of the existing tanks. 

Key Facts 

• Murphy operated and maintained the plant throughout the upgrade and for a period of two years after completion.
• This plant hands influent flows from the Intel manufacturing facility, a key customer of Irish Water and driver of foreign direct investment into Ireland.