Sewage treatment processes already release large quantities of carbon and as treatment requirements get more challenging these emissions could increase. We are working with Severn Trent Water to see how these emissions can be reduced.
What we are doing and why
Severn Trent Water’s sewage treatment processes currently release 321,672 tonnes of carbon to the environment. As the requirement for effluent treatment gets more challenging, carbon emissions could increase as old sewage works are replaced with newer, more energy intensive, treatment processes.
We are working with Severn Trent Water on a five year project to identify if it is possible to reduce the carbon footprint from sewage treatment works. This partnership has already realised savings for customers and savings in operational and embedded carbon while protecting and improving the water environment.
The programme is made up of three projects:
Dynamic Trials: We are looking at operating sewage treatment works (STW) in response to the real time conditions in the river, for example, effluent treatment would improve as the river flow reduces. Phase one of this project is taking place at Coleshill STW to demonstrate whether it is possible to dynamically operate a STW. This work will be expanded to other sites in future phases of the project.
Modelling: Using jointly developed catchment models we can better understand the impact of changes across the whole of a river and identify the sites with the greatest potential for carbon savings. By modelling the impact of changes in flows from STWs we can plan for growth. Accounting for all the pressures across a catchment will also help us gain a joint understanding of what work is needed to meet future water quality requirements and the best timing for any improvements (e.g. link to water companies Capital Maintenance Programme).
Regulatory: We are exploring alternative ways to regulate or enforce consents to promote reduced carbon emissions. We need to understand what we can do within the current consenting regime to support ‘dynamic’ operation of STWs.
This exciting work has generated a great deal of interest across the country and we are currently working with other water companies’ and national Environment Agency Policy staff to determine which aspects of this programme could be delivered as part of a new national project.
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