Enhanced short chain fatty acid production from sludge anaerobic fermentation by combined pretreatment with sodium hyposulfide and thermal hydrolysis

Enhancing the anaerobic fermentation efficiency of waste-activated sludge toward preferable resource recovery would be essential. This study demonstrated the synergic effect of thermal hydrolysis and sodium thiosulfate on prompting WAS solubilization toward harvesting short-chain fatty acids . The results showed that SCFA production from TH-STS co-pretreatment was 1.86 times higher than the control groupand significantly increased the proportion of acetate, whereas the proportion of propionate was decreased. TH STS co-pretreatment promoted SCFA accumulation by increasing enzyme activities and enriching acidifying bacteria. Mechanistic explorations suggest that STS induces cell lysis through osmotic pressure and reducing power after TH disrupts extracellular polymers. In addition, TH STS co-pretreatment enhanced the activity of the electron transport system , which positively promoted the biotransformation of SCFAs. This study provides an effective strategy for increasing SCFA production of AF with potential economic benefits.