The rapid growth of Galway city and environs now means that the existing Mutton Island Wastewater Treatment Plant is nearing design capacity and with growth projected to continue, there is a requirement to increase its capacity to cater for both residential and industrial expansion within the catchment area. TheMutton Island Wastewater Treatment Plant, completed in 2003, was designed to cater for 91,600 population equivalent. The upgrade works involve a design and build upgrade to the plant to increase capacity to 170,000 population equivalent.

Working for Siac, Trench Control designed and installed a series of temporary works schemes for a number of structures for the project including two pumping stations and flow meter and discharge chambers. The temporary works typically involved sheet piles and bespoke propping scheme owing to the constraints associated with the retrofitting of existing structures in the existing facility.