Sewer construction work

Tender description

Irish Water is responsible for the treatment and distribution of drinking water and the provision of sewer collection systems in Cork City and Co. Lot 1: A number of Combined Sewer Overflows (CSOs) have been identified for removal from the sewer network in Mallow as they are currently in breach of the Urban Wastewater Treatment Directive and are the subject of an European Court of Justice (ECJ) infringement notice. The removal of these CSOs will necessitate new trunk sewers to be constructed within the town. Lot 2: As part of the implementation of a Water Conservation Project for the city, watermains in the network have been identified for rehabilitation. These include watermains that: • are not suitably responsive to active leakage control measures; • have water quality issues; • have reached the end of their service life; • have insufficient hydraulic capacity and are impacting on the efficient operation of the existing network. As per PQQ document. Irish Water proposes to upgrade sections of the sewerage network in Mallow, County Cork to facilitate the removal of a number of Combined Sewer Overflows (CSOs) to the River Blackwater. • removal of 9 No CSOs; • design, Construction and commissioning of new combined sewers and associated access manholes, total length approximately 5.5 km (375 mm-1500 mm diameter), installed using open cut techniques; • trenchless construction of 35 m of 450 mm diameter sewer, 100 m of 750 mm diameter sewer at and 30 m of 1 200 mm diameter sewer; • design, construction and commissioning of a 1400 mm ID combined sewer beneath the bed of the River Blackwater for a length of approximately 60 m installed via an open cut methodology • ancillary fittings and connections on above pipelines; • maintenance of flows to existing pumping station until the completion of the contract or the commissioning of the new pumping station (by others). Cork City Watermain Rehabilitation – Eastern Strategic Link Phase 2 Contract. Irish Water proposes to replace the existing 450 mm diameter cast-iron water main between Shanakiel Reservoir and Popes Quay with a new 600 mm diameter trunk water main, in order to increase its hydraulic capacity and performance and increase security of supply to the city centre. In conjunction with the proposed trunk main replacement, Irish Water proposes to replace selected elements of the existing distribution network that are in poor condition and/or exhibit poor performance.2.4 km of 600 mm diameter trunk water main between Mulgrave Road and Shanakiel Reservoir, including all valves, fittings and connections; 300 m of 150 mm diameter distribution water main at the North Mall including all valves, fittings, mains tie-ins and water service connections. Cork City Water Supply Scheme (G) Network (Western Trunk Main) Irish Water proposes to lay a 600 mm diameter trunk water main between the Cork Harbour and City Water Supply Scheme (WSS) at Curraheen and the Lee Road Water Treatment Plant (WTP) which supplies the Cork City WSS. This trunk main will provide a strategic link between the two water supplies to ensure security of supply and also reduce the current demand on the Lee Road WTP. • 5.5 km of 600 mm diameter trunk watermain from Curraheen north of the N40, to the Lee Road Water Treatment Plant, including all valves, fittings and connections; • connection to 1 500 mm diameter Cork Harbour and City trunk water main at Curraheen; • Trenchless crossing of the River Lee; • Cork City Water Supply Scheme (G) Network (Shanakiel Rising and Distribution Mains). Irish Water proposes to replace the majority of the rising mains that supply the high, intermediate and low-level city reservoirs with a staged pumping system from the Lee Road WTP. In addition, it is proposed to replace three existing low-level distribution mains from Shanakiel reservoir with a single trunk main and provide an extension to the Western Trunk Main beyond the Lee Road WTP to connect it directly to the existing Shanakiel Reservoir’s trunk distribution network. • 780 m of 1 000 mm diameter rising main, including all valves, fittings and connections; • 300 m of 700 mm diameter trunk Main, including all valves, fittings and connections; • 240 m of 600 mm diameter rising main, including all valves, fittings and connections; • 480 m of 500 mm diameter trunk water main, including all valves, fittings and connections; • 50 m of 450/400 mm diameter pipework at the new Harbour View Road pump station, including all valves, fittings and connections; • a new pumping station at the Shanakiel Road low level reservoir, which will supply the Harbour View Road intermediate level reservoir; • a new pumping station at the Harbour View Road intermediate level reservoir, which will supply the Churchfield high level reservoir; • upgrade of existing access to Shanakiel Reservoir to improve visibility of vehicles egressing the site; • demolition of an existing building.