Targeted synergy of cation exchange-driven extracellular carbon release and lysozyme-catalyzed intracellular carbon release for maximizing carbon source recovery from waste activated sludge

Abstract

Short-chain fatty acids as superior carbon recovery from waste activated sludge have received rising attentions. This study quantified contributions of cation exchange (CE) and lysozyme on the targeted carbon source migration. The innovative targeted pattern for extracellular and intracellular carbon source release was proposed. The 1-day synergetic treatment at optimal CE resin dosage of 1.75 g/g SS and lysozyme dosage of 10 % drove considerable carbon source release and particulate carbon source solubilization, which occupied 35.31 % of total sludge solid carbon sources. The CE dominantly contributed to extracellular polymeric substances disruption and extracellular carbon source release, with the percentage of 39.47–48.13 %. In this case, The Lyso was the strongest contributor to microbial cell lysis and intracellular carbon source release, with the proportions of 49.53–75.76 %. Subsequently, approximately 56.54–58.49 % of the originally dissolved carbon sources (mostly proteins and carbohydrates) were bio-degraded into micromolecular carbon sources with high bioavailability in a short-term anaerobic fermentation (2 days). Correspondingly, satisfactory carbon recovery rate of 23.06 % was obtained, which was 7.30 times higher than the control. The synergy of CE and lysozyme greatly improved kinetic speeds and performances of endogenous carbon source migration and recovery. Such synergetic treatment of CE and lysozyme not only provided novel insights into carbon fate in anaerobic fermentation, but also achieved remarkable carbon source release and recovery benefits with economic incomes of 190.8–283.4 CNY/ton sludge.