Hydrolysis and acidification of dewatered sludge under mesophilic, thermophilic and extreme thermophilic conditions: effect of pH.
This study investigated the effect of pH (uncontrolled, 8.0, 10.0 and 12.0) and temperature (mesophilic, thermophilic and extreme thermophilic) on hydrolysis and acidification of dewatered sludge in 7-day batch fermentation experiment. Solublization of COD, protein and carbohydrates as well as concentration and composition of VFAs were investigated. Sludge hydrolysis was enhanced with higher pH and temperature. The maximum SCOD, soluble protein and carbohydrates was observed at pH 12.0 at extreme thermophilic condition. The maximum VFAs yield was obtained at thermophilic and was 2.15 times that at mesophilic condition, but it took more time to reach the maximum. The VFAs consisted of acetic, propionic, iso-butyric, n-butyric, iso-valeric, and n-valeric acids, and acetic acid was the prevalent product in most cases except for uncontrolled pH and pH 8.0 at mesophilic condition. The methane production was as follows: pH 8.0>pH 10.0>uncontrolled (0.015)>pH 12.0; mesophilic>thermophilic>extreme thermophilic.
State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
Xiaoguang
X
Liu
Bin
B
Dong
Xiaohu
X
Dai
D000143:Acids / Q000737:chemistry*; D001419:Bacteria / Q000378:metabolism*; D002241:Carbohydrates / Q000737:chemistry; D005232:Fatty Acids, Volatile / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008697:Methane / Q000096:biosynthesis; D011506:Proteins / Q000737:chemistry; D012722:Sewage / Q000382:microbiology*; D012995:Solubility; D013696:Temperature; D014867:Water / Q000737:chemistry*
D000143:Acids; D002241:Carbohydrates; D005232:Fatty Acids, Volatile; D011506:Proteins; D012722:Sewage; D014867:Water; D008697:Methane
Acidification; Dewatered sludge; Hydrolysis; Temperature; pH