As an important intermediate product, short-chain fatty acids（SCFAs） can be generated after hydrolysis and acidification from waste activated sludge, and then can be transformed to methane during anaerobic digestion...As an important intermediate product, short-chain fatty acids（SCFAs） can be generated after hydrolysis and acidification from waste activated sludge, and then can be transformed to methane during anaerobic digestion process. In order to obtain more SCFA and methane,most studies in literatures were centered on enhancing the hydrolysis of sludge anaerobic digestion which was proved as un-efficient. Though the alkaline pretreatment in our previous study increased both the hydrolysis and acidification processes, it had a vast chemical cost which was considered uneconomical. In this paper, a low energy consumption pretreatment method, i.e. enhanced the whole three stages of the anaerobic fermentation processes at the same time, was reported, by which hydrolysis and acidification were both enhanced, and the SCFA and methane generation can be significantly improved with a small quantity of chemical input. Firstly, the effect of different pretreated temperatures and pretreatment time on sludge hydrolyzation was compared. It was found that sludge pretreated at 100°C for 60 min can achieve the maximal hydrolyzation. Further, effects of different initial p Hs on acidification of the thermal pretreated sludge were investigated and the highest SCFA was observed at initial p H 9.0with fermentation time of 6 d, the production of which was 348.63 mg COD/g VSS（6.8 times higher than the blank test） and the acetic acid was dominant acid. Then, the mechanisms for this new pretreatment significantly improving SCFA production were discussed. Finally,the effect of this low energy consumption pretreatment on methane generation was investigated.展开更多
基金supported by the National Science Foundation of China (Grant no. 51408419)the National Key Technology Research and Development Program of China (Grant nos. 2014BAL02B02-03 and 2014BAC29B01)the Key Program for International S&T Cooperation Projects of China (Grant no. 2012DFG91380)
文摘As an important intermediate product, short-chain fatty acids（SCFAs） can be generated after hydrolysis and acidification from waste activated sludge, and then can be transformed to methane during anaerobic digestion process. In order to obtain more SCFA and methane,most studies in literatures were centered on enhancing the hydrolysis of sludge anaerobic digestion which was proved as un-efficient. Though the alkaline pretreatment in our previous study increased both the hydrolysis and acidification processes, it had a vast chemical cost which was considered uneconomical. In this paper, a low energy consumption pretreatment method, i.e. enhanced the whole three stages of the anaerobic fermentation processes at the same time, was reported, by which hydrolysis and acidification were both enhanced, and the SCFA and methane generation can be significantly improved with a small quantity of chemical input. Firstly, the effect of different pretreated temperatures and pretreatment time on sludge hydrolyzation was compared. It was found that sludge pretreated at 100°C for 60 min can achieve the maximal hydrolyzation. Further, effects of different initial p Hs on acidification of the thermal pretreated sludge were investigated and the highest SCFA was observed at initial p H 9.0with fermentation time of 6 d, the production of which was 348.63 mg COD/g VSS（6.8 times higher than the blank test） and the acetic acid was dominant acid. Then, the mechanisms for this new pretreatment significantly improving SCFA production were discussed. Finally,the effect of this low energy consumption pretreatment on methane generation was investigated.
