Minworth Wastewater Treatment Works (WWTW) is Severn Trent’s largest sewage treatment works serving a population equivalent of 1.75 million from Birmingham. The plant also treats a high volume of imported sludge from industry and regional works. Average flow is 450 Ml/d (5.8 m3/s) with full flow to treatment of 1,070 Ml/d (12.4 m3/s). The UWWD UID requires 61,000 m3 of additional storm tank capacity which will be achieved by the conversion of existing rectangular primary tanks. A new inlet works and primary tank island has been constructed to improve process performance with the added benefit of increasing the quantity and quality of sludge which will enhance production of renewable energy from the 9MVA generation station. The fisheries directive ammonia consent will be reduced from 5 to 3mg/l to improve the quality of the river tame necessitating upgrade to the existing activated sludge Plant 1-6 and provision of an additional ASP 7 configured for the BNR process in preparation for new drivers in AMP5. The scheme also features an extensive programme of capital maintenance of existing assets.
The intelligent iMCC’s & SCADA have been commissioned to provide extended information and historian trending for energy management and condition monitoring.
Accurate flow control has been achieved using the first radial gate to be deployed on a sewage works in the U.K. Modulation has been tuned during storm conditions demonstrating how well surges are controlled to achieve stable flow to full treatment of 12.4m3/s. The plant shutdown interlocks have been tested and back-up penstocks with fast acting actuators offer dual redundancy.
A scum reception process has been pioneered which blends scum with warm digested sludge to mitigate the risk of handling problems frequently encountered.
3D modelling has been utilised to design man access interfaces on the buildings, inlet works and primary island to ensure a safe workplace for operation and maintenance. 3D helps visualisation of plant areas and secures end user ownership.
Cost Avoidance Drives Value
Cost out plans have focused the designers and contract teams on cost avoidance and value engineering to add value throughout the whole life of the scheme. Production line efficiency has reduced programmes and eliminated waste. £15 million (BBP) of savings have been made across the whole scheme.
Generation Station Green Energy Increase on Target
There has been a significant increase in the power output from the generation station due to the increased gas production from the new primary sludge tanks and sludge route. Average output has risen from 4MVA to 6MVA which is in line with Severn Trent’s strategic intention to maintain their position as the largest producer of green electricity in the water sector.
Environment and Sustainability
Ecological and Environmental issues have been high on the agenda as the site is classified as a nature conservation area. A woodland area has been planted to maintain wildlife biodiversity and a comprehensive bird study identifying 43 species was issued to the RSPB. The deepest bentonite wall in Europe has been constructed around the landfill site to protect the water course from contamination.
- Design and Build
- Value Engineering
- Programme Management
- Public Relations (Corporate Responsibility)
- Procurement Planning
- First Radial Gate to be deployed on a sewage works in the UK
- Winners of the Severn Trent Water Corporate Responsibility Award in the category of Community to honour the commitment to community involvement including charities, academic institutions, Parish Councils, residents, neighbours and the local economy.
- Severn Trent held an annual exhibition – ‘Quality Working Day’ and the team were recognised for their achievements at the “Being the Best Awards”: Bronze for Collaboration, Silver for Highest Standards and Gold for Health & Safety.
- United Kingdom
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