There is an increasing need for large wastewater treatment plants to generate as much electricity as possible from biogas. This not only ensures significant operational cost savings, but also improves the environmental profile of the plant. Enhanced digestion through the use of the ExelysTM continuous thermal hydrolysis process has the potential to help a large wastewater treatment plant move towards electrical energy neutrality. This article aims to use Csepel waste water treatment plant (WWTP) (3.5 million PE) in Budapest, Hungary as a case study to investigate the potential advantages an ExelysTM-DLD process could provide. The results indicate that despite already having an effective and efficient digestion process, through implementation of the ExelysTM-DLD process, Csepel has the potential to cover 65% of its total electrical needs from biogas. This is 33% more than the current situation. This also leads to a significantly improved NPV for the ExelysTM-DLD scenario, an important factor for the operator of a large wastewater treatment plant. When looking to the future, through the optimisation of the wastewater treatment process and the application of the ExelysTM-DLD, Csepel WWTP has the potential to be completely electrical energy neutral. This would be a significant financial advantage as electrical prices rise and carbon taxes are enforced.
Energetic and economic assessment of sludge thermal hydrolysis in novel wastewater treatment plant configurations
