Sulfite altered permanganate effects on acetate-enriched short-chain fatty acids production during sludge anaerobic fermentation

Anaerobic fermentation is a promising method for waste activated sludge (WAS) treatment, but ineffective solubilization and hydrolysis limit its application. The current study examined the function of sodium sulfite (SDS) in potassium permanganate (PP)-conditioned WAS fermentation for short-chain fatty acids (SCFAs) biosynthesis. The presence of SDS in the PP system (PP/SDS) reduced the positive effects of PP on total SCFAs yield (2755 versus 3471 mg COD/L), while effectively increasing the proportion of acetate (from 41 to 81 %). Not only did SDS decrease the promoting effects of PP on WAS solubilization and hydrolysis efficiency by 5–42 %, it also shifted microbial metabolic pathways to favor acetate production. In addition, the amino acid metabolism with acetate as end product was enhanced. Moreover, PP/SDS inhibited methanogenesis, resulting in an accumulation of acetate in high quantities. Thus, the current study a provided insight and direction for effective WAS treatment with acetate-enriched SCFAs production.