Enhanced methane production from waste activated sludge by potassium ferrate combined with ultrasound pretreatment

This study explored the effect of potassium ferrate (PF) combined with ultrasound (US) pretreatment on methane generation from sludge by a series of experiments and simulations. Batch experiments showed that the pretreatment of PF coupled with US exhibited positively synergy on the methane yield. And by the pretreatment of 0.05 g/g TSS (total suspended solids) PF cooperated with US (1 W/mL, 25 kHz, 15 min), the methane yield was enhanced from 180.62 +/- 3.26 to 228.83 +/- 4.76 mL/g VSS (volatile suspended solids). Mechanism studies confirmed that the co-pretreatment of PF and US efficiently promoted sludge disintegration, and the biodegradability of sludge organics was obviously enhanced. Microbial community analysis showed that the functional microorganisms participating in sludge anaerobic digestion were enriched by PF cooperated with US pretreatment, with the total abundance enhanced from 12.96% in the control to 17.96% in PF + US pretreated reactor.

Automated summary

The combined pretreatment of potassium ferrate and ultrasound showed a positive synergy in enhancing methane yield from sludge. It efficiently promoted sludge disintegration and increased the biodegradability of sludge organics. Additionally, the microbial community involved in anaerobic digestion of sludge was enriched by this pretreatment.