Biogas production by thermal hydrolysis and thermophilic anaerobic digestion of waste activated sludge
Abstract This chapter presents a review of biogas production from activated sludge using thermal hydrolysis (TH) and thermophilic anaerobic digestion (AD) Due to the sewage sludge complex floc structure and the presence of a cell wall, the rate limiting step of AD is hydrolysis. This discussion includes general information about a number of methods used to enhance sewage sludge hydrolysis and biogas production. The mechanism of the disintegration process and its effect on AD are also presented. Upgrading the anaerobic biodegradability of activated sludge by thermal pretreatment methods is the main topic of this chapter. The recent research achievements in this area, as well as commercially implemented technologies (e.g. CambiTHP, BIOTHELYS) are included, as are the economic aspect of implementation of TH pretreatment and thermophilic AD in wastewater treatment plants (WWTPs)