Synchronously enhancing biogas production, sludge reduction, biogas desulfurization, and digestate treatment in sludge anaerobic digestion by adding KFeO.

In order to enhance the efficiency and benefits of the sludge anaerobic digestion process, KFeO was added to a sludge anaerobic digestion system, and its effects on the system were comprehensively investigated. Results showed that sludge anaerobic digestion was greatly improved by adding 500 mg/L KFeO. Biogas and methane productions were increased by 26.6 and 28.4%, respectively. Sludge reduction, protein removal, and the conversion efficiency of dissolved organics were all improved. The mechanism revealed that the disintegration of sludge flocs, enhancement of protease activity, and decrease of soluble sulfide toxicity on microorganisms contributed to biogas production and sludge reduction. Biogas quality was improved, benefitting from the decreasing HS content in biogas; as additionally, the cost of biogas desulfuration was reduced. In the biogas slurry treatment, the PO-P concentrations were decreased by 39%, which also reduced the cost of the dephosphorization processes at certain extent.