[Enhancement of sewage sludge anaerobic digestibility by thermal hydrolysis pretreatment].

Biochemical methane potential (BMP) experiments of thermo-hydrolyzed sewage sludge are carried out to investigate the effects of thermal hydrolysis on the digestibility of sewage sludge. The results show that thermal hydrolysis pretreatment can facilitate the dissolving of organic solid in sludge, and soluble organics hydrolyzed into low molecular organics, in which volatile fat acids accounted for 30% - 40 % of soluble COD, so the digestibility of sewage sludge remarkably improved. The optimum pretreatment temperature and holding time were 170 degrees C and 30 minutes, under which the total COD removal rate enhanced from original 38.11% to 56.78%, and biogas production rate of COD in feeding sludge from 160mL/g to 250mL/g.