Reusing existing assets alongside great communication and collaboration helped the @one Alliance complete a project at Wymondham Water Recycling Centre to a tight timescale as well as achieving 'Deep Green' status.
The re-use of existing assets helped the Project Delivery team at the Wymondham Water Recycling Plant project to significantly reduce costs and carbon. The challenge was to ensure that the Anglian Water site could cope with future demand and meet new Environment Agency regulations. Under the Water Framework Directive No Deterioration (due in 2021), the Environment Agency requires phosphorous levels from plant to be reduced to 0.8mg per litre (currently 2mg per litre), and Ammonia to 1mg (currently 4mg per litre) before discharge into rivers.
The team initially looked at constructing a new building for the scheme but, following analysis, it was decided that it would save time, costs and carbon to refurbish the existing empty 1930s building.The Norfolk project was transitioned over in June 2016, with the team moving onto site in August 2017.
Dirk Binns, Project Delivery Manager, said: “There was recognition that the assembly programme time was tight at eight months. But detailed process analysis, in-depth technical evaluation, open stakeholder discussions and great delivery teamwork – plus excellent communication and collaboration – helped maintain the obligation date of 31 March 2018. We evaluated all process treatment options, selecting the FSAF – Fixed Media Submerged Aerated Filters – process, and agreed to refurbish the existing 1933 brick building. We carried out an asbestos survey, bricked up doors and windows, repaired cracks, screed the floor and gave the building a lick of paint internally ready for the new FSAF Motor Control Centre. Using this asset rather than building new meant no planning permission and made cost and carbon savings.”
Using existing assets and off-site assembly were major features at Wymondham. The team incorporated the 1933 trickling filters, adding new motorised filter arms, and six FSAF units using biological filtration and aeration to reduce ammonia. The nine-metre high units arrived pre-fabricated and allowed flow to gravitate directly to the existing BAFF (Biological Project Delivery Manager Dirk Binns and Site Manager Trevor Middleton. Aerated Flooded Filter) plant without needing secondary pumping. The existing BAFF process was incorporated into the final design.
“The FSAF filters offered many benefits," said Dirk. “As well as arriving in one piece, they had very few moving parts, reduced assembly time, lower maintenance and with temporary pumping and aeration equipment could be seeded offline, giving early beneficial use of the new process stream.” This also reduced the risk of the plant not being ready for March.
Partners FLI Water, Bell Formwork, RG Carter, Waveney and CEMA were all vital to achieving the goals. The strategy helped to reduce carbon from 3,207 tonnes to just 260 tonnes. Meanwhile, the project was due to come in under the solution cost of £4.9million. “That’s £5.7million less than the £10.6million affordability, with all stakeholders benefitting across the business,” added Dirk. “A lot of efficiency was created by using off-site build and reusing existing assets, helping us to complete the project in the tight timeframe and well under budget.”
Site Manager Trevor Middleton said continual communication was extremely important. Trevor explained: “There were some hiccups but talking kept things on track. The supply chain and site team worked well together on a live water recycling centre that still needed to meet its current EA Regulations. During the project, everyone within the delivery team – our operational colleagues, site team, supply chain partners and designers at Thorpe Wood House – kept communicating. This was critical. There were a number of design changes but everyone pulled together to make them work.”
Andy Pope, Anglian Water Treatment Manager, added: “The project will make a huge impact on the water and river quality and will benefit all river users, specially those downstream such as farmers, and aquatic life. The new technology is now there to allow us to do this – I think we’re going to see more of this in the coming years.”
In October 2019, the project was awarded Deep Green status by delivery partner Skanska after achieving a near-zero impact on the environment by reducing carbon in construction by 83 per cent. After considering constructing an entirely new treatment process and site building, the team opted to instead completely refurbish the existing site, saving almost 3,000 tonnes of carbon. Reuse of materials as part of the design meant that the redundant 1930s trickling filter was given a new lease of life with new mechanical arms to make use of the existing filtration process. The existing Biological Aerated Flooded Filter (BAFF) feed pump station was also reused, reducing energy use by 53 per cent.
Paul Fletcher, Director of the Anglian Water @one Alliance said: “Carbon reduction only happens when all partners in the supply chain are committed to reducing their footprint and saving costs. Huge carbon savings like these clearly demonstrates that commitment and the strength of the collaboration between our suppliers and partners on our journey to carbon neutrality.
“By continuing to set ambitious carbon targets, we can disrupt established practice, drive innovation, and significantly reduce costs and environmental impacts – a win-win all round.”
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