Ferrous-Iron-Activated Sulfite-Accelerated Short-Chain Fatty Acid Production from Waste-Activated Sludge Fermentation: Process Assessment and Underlying Mechanism

To break the bottlenecks of slow hydrolysis and low acid production efficiency waste-activated sludge (WAS) in traditional anaerobic fermentation process, this study investigated employment ferrous-iron (Fe(II))-activated sulfite to produce hydroxyl, sulfate, other highly oxidizing radicals on WAS floc cracking short-chain fatty (SCFAs) during fermentation. The effect dosage ratio Fe(II)/S(IV) was also studied. Results showed that combined pretreatment Fe(II)-activated significantly promoted exfoliation extracellular polymers subsequent SCFAs production. highest concentration reached 7326.5 mg COD/L under optimal 1:2 for Fe(II)/S(IV), which 1.1~2.1 times higher than research groups. Meanwhile, analysis by 3D fluorescence spectroscopy EPR (electron paramagnetic resonance) had a synergistic rupture cells stripping polymers, with SO4− OH as key generated being much stronger 1:1 High-throughput sequencing system changed functional microbial diversity. bacteria sulfate-reducing were enriched. underlying mechanism oxidation molecular ecological network microbiomes unveiled.