Severn Trent Water can now generate more energy from waste following Costain's upgrade of a Rugby sewage treatment works.



The £3.2 million project involved the installation of sludge thickening and mixing equipment to improve digester performance at the plant’s sludge treatment facility. This increased its gas yield, enabling Severn Trent Water to generate more renewable energy. The energy is used to power the sewage treatment works, with any surplus sold to the local electricity grid.




The project's focus was on sludge quality – increasing the density of the sludge from the settlement tanks to provide a thicker, homogenous sludge to the digesters. This allows the digesters to operate more efficiently, improves the gas yield and so increases the efficiency of the Combined Heating Power (CHP) engines on site. Improving the performance of the digesters also has the added benefit of reducing the number of sludge tanker movements at the site.



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