The intermediate thermal hydrolysis process: results from pilot testing and techno-economic assessment

摘要

Thermal hydrolysis has proven to be an efficient pre-treatment process for sludge before anaerobic digestionrn(AD), by thermally enhancing organic matter hydrolysis. Recent research has shown that a new configurationrnwith the existing technology can further enhance the efficiency of the system. The intermediate thermal hydrolysisrnprocess (ITHP) has been explored and tested in the Sludge and Energy Innovation Centre pilot plant located atrnBasingstoke sewage treatment works for a period of 15 months. The pilot facility has allowed operational considerationsrnto be explored and understood to inform the design and construction of full scale. ITHP resultsrnshowed a volatile solids destruction of 64% and an average overall specific gas production of 503 m~3/TDS. Furthermore,rntechno-economic analysis was used to compare conventional thermal hydrolysis process (THP) withrnsurplus activated sludge (SAS) only THP and ITHP. Data captured from operational sites, laboratory scale experimentsrnand the large scale ITHP pilot plant, was used in the model. The results showed that ITHP offers anrnexcellent solution for energy recovery having the best economic return, but overall the largest CapEx. SASrnonly THP is the cheapest to build but does not perform as well as conventional THP and ITHP. ConventionalrnTHP remains an excellent solution when space and AD volume is constrained.