Hydrolysis and acidification of residual sludge is the prerequisite for its consequent energy and resource utilization. As to the low-organic carbon sludge, the characteristics of thermophilic anaerobic hydrolysis and acidification under electron acceptor shocking conditions were examined, especially for hydrolysis, acidification and nitrogen/phosphorus nutrient release. The results showed that under short-term aeration shocking conditions, efficiency of anaerobic hydrolysis and acidification was enhanced significantly, with the volatile suspended solids reduction percentage of 40% compared to 31% without shocking effect. Concurrently, the shock condition enhanced soluble chemical oxygen demand production, especially for protein. By incorporating the electron shock, it mainly affected the hydrolysis efficiency rather than the acidification mode, with the acidification type of butyrate fermentation. The release of ammonia and also measurements by both excitation emission matrix florescence spectroscopy and molecular distribution indicated that the difference of protein-type substances was mainly contributed from hydrolysis rather than acidification. Electron acceptor shocking, especially short-term aeration, is an effective technique to enhance anaerobic hydrolysis and acidification of residual sludge.
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