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Creating a lower carbon future in the Lower Aire Valley

Creating a lower carbon future in the Lower Aire Valley

Project Name
Knostrop Energy & Recycling Facility
Yorkshire, Great Britain
Yorkshire Water

Yorkshire Water’s £72 million Knostrop Energy & Recycling Facility turns sewage into energy, generating sufficient electricity to power 7,600 homes. The project, according to local member of parliament Hilary Benn, “is helping to create a lower carbon future in the Lower Aire Valley.”

The project to create the facility, which saves the water company £1.6 million a year in operating costs by replacing the aging incineration plant and meeting 55 percent of the site’s energy needs, was delivered on time and to budget.

This successful outcome demonstrates the benefits of using a delivery partner with the ability to add value at multiple points during the asset’s lifecycle.

Early engagement reaps benefits

Black & Veatch’s involvement began early, working with Yorkshire Water’s Sludge Team in a collaborative feasibility study to review sludge treatment technologies and identify the best location for the new facility. Mesophilic anaerobic digestion, a robust proven digestion technology able to generate renewable energy using biogas, was identified as most suitable for Yorkshire Water’s needs. Knostrop wastewater treatment works, serving the northern city of Leeds, was assessed as the optimum location for the new asset because of the available space, transport links and the ability to decommission an aging incinerator.

With technology and location agreed, Black & Veatch helped Yorkshire Water progress the project by developing and outline design, and undertaking site investigations. The latter work allowed the team to identify and mitigate risks early in the project. For example disused mine workings and contaminated ground were avoided by revising the site layout.

Other preliminary support included an Environmental Impact Assessment to assist the utility’s planning department, in consultation with Leeds City Council planners, in understanding the visual impact of the large storage tanks and structures on the local area.

Designed with efficient operation in mind

Following a mini competition, and negotiated tender, Yorkshire Water awarded Black & Veatch with the contract to design and build the Knostrop Energy & Recycling Facility. With client and delivery partner having already collaborated on earlier phases of the project’s lifecycle relationships and trust had been established, and there was already a clear understanding of the utility’s goals for the project, extending beyond construction and into the asset’s operation and maintenance.

Looking ahead, detailed design was undertaken with future operations and maintenance in mind. Intelligent piping and instrumentation diagrams (iP&IDs) were used to link asset data from the design and commissioning phases to a data base via the P&ID symbol, such as a pump or valve. A Reliability Centred Asset Maintenance workshop was held to identify critical plant and create maintenance plans. QR coded tags were attached to equipment allowing maintenance teams to scan the tag and download asset data to hand-held devices displaying maintenance details. This planned maintenance regime greatly improves the asset’s resilience.

Ensuring efficiencies in construction

Black & Veatch was also able to add value during the construction and procurement phase. The company negotiated a number of single-source subcontracts for civil engineering, tanks and electrical suppliers during the tender. Collaborative working with these key supply chain partners allowed procurement time and cost on the project to be reduced. Several subcontracts were placed with local companies providing economic and social value to the area.

Offsite manufacture was used for chemical dosing equipment, access metalwork and the combined heat and power units. This improved construction productivity, quality and allowed for manufacture in a controlled environment. The boiler house was subcontracted as one package for all the MEICA equipment eliminating the need to manage construction interfaces.

The scope for the tank packages included the construction of the bases eliminating an interface, which along with specialist formwork allowed successive productivity improvements on the four digesters.

One key innovation was to raise the gas bag on a platform so that the condensate pots on the gas pipework were not located below ground level. This innovation avoided a confined space for maintenance and, by way of legacy, is now included in Yorkshire Water’s asset standards.

The project’s embedded carbon footprint was reduced by recycling 120,000 cubic metres of filter media as bedding material rather than being disposed of in landfill. 

Yorkshire Water and Black & Veatch also worked closely together to ensure this was a safe project: more than 810,000 man hours have been worked on the project with 1 reportable accident.

Leaving a sustainable legacy

The completed facility treats up to the maximum throughput of 131tons dry solids/day (tds/d) and regularly exceeds the design average of 82tds/d. As well as generating renewable energy the facility’s environmental benefits includes reducing the number of tanker movements Yorkshire Water makes as part of its overall biosolids management programme.

According to Mark Baker, Head of Asset Solutions for Yorkshire Water, “Black & Veatch have worked collaboratively with our Asset Management business unit to deliver a flag ship project for Yorkshire Water. Knostrop STF not only address’s the bio resources requirements of the business in relation to sludge disposal, but also significantly contributes towards our Performance Commitment for energy generation and carbon reduction.”

“This successful outcome demonstrates the benefits of using a delivery partner with the ability to add value at multiple points during the asset’s lifecycle.”

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