North London Waste Authority (the authority) is seeking a Contractor for the design, supply, construction and commissioning of sewer diversion works on the existing Angel and Chingford sewers. The sewer diversion works are part of the North London Heat and Power Project (NLHPP) for the development of a new energy recovery facility and associated works at the Edmonton EcoPark pursuant to a development consent order granted to the authority on 24.2.2017. A new Resource Recovery Facility (RRF) will be constructed over the existing Angel and Chingford sewers and their confluence manhole. Following Thames Water requirements on the accessibility and endurance of their asset, the prior diversion of approximately 165 m of the Angel sewer and 115 m of the Chingford sewer including the construction of new manhole access points is required to maintain access and allow the RRF to be constructed over the Thames Water asset. The sewer diversion works are on the critical path for the NLHPP. The sewer diversion works include:
(i) tunnelling works for the installation of a 1 200 mm diameter sewer along a stretch of approximately 115 m diverting the Chingford sewer, and the installation of a 1 200 mm diameter sewer along a stretch of approximately 165 m diverting the Angel sewer;
(ii) installation of a drive shaft at the confluence of the 2 sewers of approximately 9,0 m deep;
(iii) installation of reception shafts at the 2 sewers of approximately 9,0 m deep and
(iv) connection of the new sewers to the existing sewers. Further details of the required works are set out in the Memorandum of Information, forming part of the procurement documents. The works must comply with the Thames Water standards regarding their assets. The site for sewer diversion works, Edmonton EcoPark, is an operational waste management site where LondonEnergy Ltd, a private company wholly owned by the authority, operates an existing Energy from Waste (EfW) facility. Normal operation of the EfW facility is to be maintained at all times during the construction.