Integrated digitally enabled design for manufacture and assembly approach for efficient and safe delivery of renewable energy

Project summary

Launched during Asset Management Programme 6 (AMP6), the Minworth Sewage Treatment Works (STW) Thermal Hydrolysis Plant (THP) stands out for its remarkable contribution to sustainable energy generation, reducing carbon emissions and supporting the community it serves. Covering an extensive catchment area that includes Birmingham and its surrounding counties, the facility was delivered within the forecasted £37 million budget and ahead of schedule with significant operational advancements, including gas exportation.

The background

The site, originally designed to manage the waste treatment demands of Birmingham and the surrounding regions, had reached a pivotal moment. Evolving environmental legislation, alongside a substantial increase in local population and the corresponding waste output, had outstripped the facility’s capacity. Moreover, the requirements laid down by the Water Industry National Environment Programme (WINEP) for AMP6 set ambitious targets for renewable energy production and carbon footprint reduction, far beyond the capabilities of the existing set-up.

Because of this pressing need to adapt and transform, Severn Trent Water recognised the imperative to not only expand the facility’s operational capacity but also incorporate sustainable practices that could significantly reduce environmental impacts. To meet these goals, a visionary overhaul of the Minworth infrastructure was essential. The project had the dual objectives of increasing the plant’s capacity to treat and process sludge from a wider catchment area and to harness innovative technologies that could enhance the quality of biosolids. Central to this initiative was the installation of a THP, a technology proven to increase the generation of biogas – a renewable energy source – as well as improve the dewaterability of sludge, yielding a product that could be used beneficially, thus aligning with the principles of a circular economy. A collaboration between Severn Trent Water and RSK company MWH Treatment, the Minworth STW THP project marks a significant milestone in wastewater treatment innovation in the UK.

The challenges

Faced with the constraints of a finite spatial footprint and the necessity to integrate new solutions into the existing facilities without causing disruptions, the project necessitated not only an expansion but also a reimagining of the treatment works. The project’s core challenge was incorporating the Cambi THP technology within the spatial constraints of an existing and operational infrastructure. This necessitated meticulous management of space to amplify sludge treatment capacity and escalate biogas yields without expanding the physical footprint of the facility. Additionally, achieving an ‘enhanced’ status for the treated biosolids was imperative, requiring adherence to stringent regulatory standards while pushing for sustainability and cost-efficiency. The integration of the new technology with the older systems was critical, ensuring a continuous and seamless treatment process. These innovations had to align with the constrained timelines set by AMP6 objectives, which included significant reductions in the carbon footprint and a transition to more sustainable operational practices. Furthermore, the entire operation had to be executed without interrupting the functioning of the existing STW, ensuring that service to the population equivalent of 2.3 million was not compromised during the transition to more advanced THP technology.

Overcoming these challenges required seamless collaboration among engineering expertise, operational functionality and environmental stewardship to enhance the site’s capability to meet and exceed the stringent targets of AMP6 and to set a new benchmark for sustainable treatment operations in the industry.

The solutions

MWH Treatment developed a comprehensive strategy that merged mechanical and biological treatment processes with the pioneering Cambi THP technology. At the heart of the project’s success was a highly sophisticated digital delivery strategy that leveraged laser scanning and 3D and 4D modelling to ensure precision in the design, efficiency in the construction and safety throughout the project life cycle. These digital tools were instrumental in creating a virtual environment where potential issues could be foreseen and addressed before real-world implementation, significantly reducing the risks of costly and time-consuming errors.

The design for manufacture and assembly (DfMA) approach enabled a substantial portion of the project’s components to be prefabricated in a controlled factory setting. This was enabled by the digital delivery strategy, which created the necessary virtual environment to support and optimise the DfMA process. This approach not only streamlined the assembly and installation processes on-site but also elevated the quality of the output and enhanced safety for the workforce. By moving significant portions of construction from the site to factories, the time taken on-site to construct and integrate was substantially reduced. Full utilisation of MWH Treatment’s digital delivery toolbox saved 50,000 work hours, reflecting a major shift towards more efficient and safer project execution. Approximately 70% of the equipment was manufactured and assembled off-site, improving project efficiency and quality and shortening the programme. Off-site manufacturing proved to be a game-changer, particularly in compressing project timelines, optimising resource allocation and mitigating on-site construction hazards.

The impact

The Minworth STW THP now exemplifies the pinnacle of environmental innovation in wastewater treatment within the UK. The plant not only significantly escalates biogas yields but also stands as a testament to Severn Trent Water’s commitment to achieving its AMP6 environmental goals. Minworth has set a new benchmark in sustainable practices and operational efficiency, consistently producing the targeted 8 MW of renewable electricity with over 95% availability.

The success of the project highlights MWH Treatment’s expertise in engineering and project management, offering a replicable blueprint for future developments in large-scale wastewater treatment operations. This project has paved the way for a new era in combining advanced technology and traditional processes, championing the cause for a sustainable future in energy and wastewater management.