Following on from Veolia Water Solutions & Technologies’ success in securing the contract for its Biothelys® thermal hydrolysis plant at Esholt Sewage Treatment Works for Yorkshire Water, the company has been awarded a further Biothelys® contract, for Thames Water at Oxford STW.
The Oxford plant will treat a throughput of 25,000 tonnes of dry solids per year composed of a mixture of primary and secondary sludges produced both at the Oxford works itself together with those imported from a number of outlying works.
The treated sludge produced by the thermal hydrolysis process will be fed to the downstream anaerobic digesters at a much higher dry solids concentration (typically 10 – 12%) compared with only 5-6% for untreated sludge. This will, in effect, double the existing digester throughput.
The use of thermal hydrolysis at Oxford will also substantially increase the amount of biogas produced by the existing anaerobic digestion plant. This biogas will then be used to generate “green” electricity via a combined heat and power (CHP) plant.
In addition, due to the higher destruction of volatile matter, there will be less sludge left at the end of the process for final disposal.
Veolia’s contract for the Biothelys thermal hydrolysis plant at Oxford was awarded by Kier Infrastructure and Overseas Ltd., who is the main contractor for the overall scheme which also comprises refurbishment of the existing anaerobic digestion plant and new sludge storage and handling facilities.
The Biothelys plant will be in operation by March 2014.