Steel slag assists potassium ferrate to improve SCFAs production from anaerobic sludge fermentation.

Potassium ferrate (PF) pretreatment in anaerobic sludge and its potential influence mechanisms have received widely attention. This study investigated the coupling effect of PF loading on steel slag (SS) on excess sludge anaerobic fermentation. Results showed that SS loading increase the treatment performance of PF on short chain volatile fatty acids (SCFAs) production from anaerobic fermented sludge. It was showed that the modified PF loaded SS (MPF-SS) promoted the dissolution and release of organic substrates from intracellular to extracellular. Further exploration showed the promotion of PF and MPF-SS exposure to acid production microorganisms was much more than that to acid consumption microorganisms. MPF-SS addition can also effectively reinforce the carbohydrate transport, amino acid metabolism and the key enhanced genes associated with fatty acid biosynthesis pathways. This study fills the knowledge gap about modified PF on sludge treatment and also expands a new perspective for its application for sludge resource recovery.