Sewage treatment services

Tender description

Yorkshire Water (YW) manage the collection, treatment and distribution of water in Yorkshire, supplying around 1 240 000 000 litres of drinking water each day. At the same time collecting, treating and disposing of about one billion litres of waste water safely back into the environment. The contract will support service delivery in maintaining key operational activities. A range of specialist technical services will be selectively employed across YW’s estate to support applications and processes for raw water, treated water, waste water, sewerage treatment and clean and sewer networks. These services are vital to supporting safety and compliance across YW’s business. This directly links to the business commitments and performance measures contained within Yorkshire Water’s business plan. YW therefore intends to establish a framework for providing/upgrading diffuser systems. Yorkshire water (YW) has multiple activated sludge plants (ASPs) located throughout the region. The ASPs range from small rural sites comprising of a handful of diffusers, to large scale sites treating some of the UK’s largest cities and industries, incorporating 600+ diffusers in each lane. ASPs are a key part of the waste water treatment process. The incoming effluent is a mix of both domestic and industrial waste at varying strength. The scope for each site will vary, however the services will generally involve: (a) like for like replacement of existing systems, where only the diffusers and minimum pipework would be replaced; and (b) more substantive upgrades where the diffusers and below and above water level air pipework, valves and blower configuration may require replacement or alteration. During the course of the contract life the services will support AMP7 delivery period where there will be an expected requirement for around 10 000 000 GBP worth of installations or upgrades to diffuser systems. The current anticipated programme allows for the replacement/upgrade of 64 ASP lanes, equating approx. 18 000 diffusers. The contract will be single source with the successful supplier being able to provide all the required services across the entire range of YW’s assets. The works will consist of mainly upgrades/replacements but there will also be the need for small scale cleaning of ASPs and also for whole new diffuser system which will require a full design and build service. The contract value allows for the likelihood of new lanes being required and therefore additional diffusers within the next AMP. Diffused aeration systems will need to comply with both UK and EU standards and laws as well as YW Asset standards and the YW Engineering specification. The general requirements of the type of system needed for this contract will be: — rectangular basins with either a single straight leg or double ‘U’ shaped design, — typical tank depths are 6 to 8 m, — air is provided by multiple blowers into a common air main which is then split between basins, this is then situated above the wall top with the air being distributed via stainless steel tapered air feed pipes with multiple discharge points, — varying basin widths and lengths, — air flow is controlled by modulating control valves linked to a PLC and SCADA network or by manual adjusting valves.