Securing the safety of the water supply to over 200,000 people

Stillorgan Reservoir Disinfection Upgrade

Uisce Éireann commissioned our team to design and administer the Stillorgran Reservoir Disinfection Upgrade Project. The reservoir had been included on the Environmental Protection Agency’s (EPA’s) Remedial Action List (RAL) due to the absence of a Cryptosporidium barrier. Our responsibilities included the design and commissioning of a wide scope of works adjacent to the existing outlet valve house at the site.

We commissioned and installed flow meters and strainers on each of the 700-millimetre (28-inch) supply mains from the existing screen house, along with a 900-millimetre (35-inch) diameter manifold inside the reservoir outlet valve house. The manifold accommodates three new ultraviolet (UV) piped streams along with associated UV ballast panels and supervisory control and data acquisition (SCADA) control panels.

Our team also adapted the existing chlorine disinfection system at Stillorgan. This included the necessary relocation of the existing chlorine dosing points to locations downstream of the UV reactors. Complete with flash mixing as the secondary disinfection system for chemical residual generation, this helps maintain the drinking water quality throughout the distribution system to the consumer tap.

Our scope also included a new 630-kilovolt-ampere electricity substation, complete with metering switch room and associated electrical works and replacement of existing 700–1200-milimetre (28–47-inch) diameter electromagnetic flow meters.

The successful implementation of the project, which involved the construction of the largest UV disinfection plant in Ireland, is protecting the safety of the water supplied to over 200,000 consumers in the Dublin region.