Anaerobic co-fermentation of waste activated sludge with corn gluten meal enhanced phosphorus release and volatile fatty acids production: Critical role of corn gluten meal dosage on fermentation stages and microbial community traits

Abstract

The anaerobic co-fermentation of iron bound phosphorus (P) compounds (FePs)-bearing sludge with corn gluten meal (CGM) and the underlying mechanisms associated with P release and volatile fatty acids (VFAs) production were investigated. The optimal CGM dosage for P release was 0.6 g chemical oxygen demand (COD)/g total suspended solid (TSS), which resulted in an increase in efficiency from 7 % (control sample) to 39 %. However, the optimal CGM dosage for VFAs production was 0.4 g COD/g TSS, and the yield increased from 37.4 (control sample) to 331.7 mg COD/g volatile suspended solid. The addition of CGM enhanced hydrolysis and acidogenesis by supplying abundant organic substrates to promote the growth of hydrolytic and acidogenic bacteria. A higher VFAs/ammonium-nitrogen ratio resulted in a lower pH, which promoted greater FePs dissolution and P release from the sludge. This study provides novel insights into the effects of CGM on P release and VFAs production.