Upper Liffey Valley Regional Sewerage Scheme, Kildare
The project consists of the expansion and upgrade of the Upper Liffey Valley Regional Sewerage Scheme, which serves a number of towns in north Kildare Ireland, including Naas, Newbridge, Sallins, Clane, Kill, and connects the wastewater collection network to a regional Wastewater treatment plant at Osberstown in Naas.
The total catchment area of the combined agglomerations is approximately 3,500 ha with drainage systems comprising combined, separate and partially separate systems. The delivery of the scheme comprised separate contracts, including a contract for the upgrade of the Osberstown WwTP and a few additional contracts for the upgrade of the collection network.
Key features of this project:
- Contract 1A - Upgrade of Osberstown WwTP from 80,000 PE to 130,000 PE whilst ensuring the continuous operation of the WwTP. The upgrade comprised a new preliminary treatment area, 26m diameter primary sedimentation tank, anaerobic and anoxic tanks, three new 40m diameter final sedimentation tanks, tertiary filtration system, gravity belt thickeners, anaerobic sludge digestor and expansion of the sludge dewatering system.
- Contract 1B - A VO was subsequently issued for the replacement of the existing sludge dryer with an alternative thermal hydrolysis process, including nitrogen reduction in the sludge liquors
- Contract 2A – Collection Network - three pumping stations and storm water holding tanks, 4.6km of rising mains and 3.1 km of gravity sewers
- Contract 2B – Collection Network - two pumping stations and storm water holding tanks, nine kilometres of rising mains and 10km of gravity sewers