Thames Water has developed a prestigious new sewage treatment plant at Kingston Upon Thames. Jointly designed with Thames Water and constructed by Kvaerner Water, it has been created to serve one third of a million people and as such is the largest built by Thames Water in the last 30 years. Via cogeneration and inorder to maximise cost effectiveness and efficiency at the site, the waste biogas created by the process is utilised to generate the heat and power necessary for the process to be executed. One of the major considerations in building such a plant is the effective protection of the environment. A by-product of sewage treatment is biogas, which is difficult to handle because of the high but variable proportion of methane.
Thames Water selected Knowsley-based Clarke Energy Ltd to provide gas engine generators, which would take the biogas and convert it into power and heat for the site. Commenting, Mr Leigh, project manager for Kvaerner Water, said “As a company, we provide a world class service to all of our customers, and we therefore must demand that of our suppliers. We were on a very tight progamme for this project – two years from start to completion. Clarke Energy ensured that the installation and commissioning would be completed within the deadline and that the system was supplied at a competitive cost. More importantly, the Thames/Kvaerner project team had confidence in the company’s technical ability. The Jenbacher engines supplied by Clarke Energy are sufficiently robust to withstand the hostile properties of biogas, in particular the hydrogen sulphide, and the controls sufficiently accurate to handle the variable properties of the gas”.
Jenbacher engines are purpose designed gas engines, not converted diesel engines. As such they have a sophisticated carburation system which makes them ideal for handling the variations in quality experienced in biogas applications. These engines have also been designed for constant duty baseload operation. In consequence, they will run reliably at full load for many years