Improved volatile fatty acids production from proteins of sewage sludge with anthraquinone-2,6-disulfonate (AQDS) under anaerobic condition

► This work for the first time applied anthraquinone-2,6-disulfonate (AQDS) for enhancing VFA production from sewage sludge. ► The VFA was enhanced by 1.9 to 2.7-fold principally composed of acetate and propionate. ► The acidification step is the rate-limiting step in which AQDS molecules shuttle electrons to accelerate the redox reactions. ► The AQDS-assisted VFAs are renewable organic carbon sources, except in anaerobic digestion processes.