Pretreatment of waste activated sludge by peracetic acid oxidation for enhanced anaerobic digestion

This article studied the sludge reduction and supernatant changes during peracetic acid (PAA) oxidation and investigated subsequent anaerobic biodegradation. PAA oxidation treatment effectively leads to a disintegration of sewage sludge. The results suggested that the sludge solid concentration and volatile solid concentration decreased by 24.5 and 39.0% after 120 min, respectively, when the PAA dose was 30 mg PAA/g SS. The VSS to SS ratio dropped from 0.85 to 0.71. The concentration of supernatant soluble chemical oxygen demand, protein, total phosphorus, polysaccharide, and ammonia nitrogen increased by 530, 177, 166, 165, and 222%, respectively. Biogas production was enhanced when PAA was employed as a pretreatment. Compared with the control system, the cumulative biogas production increased by 20.0% after 28 days of anaerobic digestion (AD). The biogas production rate in digester with pretreated sludge reached the maximum on day 8 at 87mL/d, but the peak value was obtained on day 11 at 74mL/d in digester with the raw sludge, which indicated that PAA pretreatment could decrease the retention time of AD and increase biogas yield. (c) 2018 American Institute of Chemical Engineers Environ Prog, 37: 1901-1907, 2018