Abstract
To improve volatile fatty acids (VFAs) production from spent mushroom compost (SMC), the effect of total solid (TS) content was studied. The protein and polysaccharide solubilization, ammonium (NH4+-N) and phosphate (PO43−-P) release, and VFAs production were analyzed. Results showed that the optimal fermentation time was 4 day for VFAs production, longer fermentation time led to VFAs consumption and methane production. Within the TS range from 6% to 18%, a TS of 15% was the optimal for VFAs production, the highest VFAs concentration reached 2781 mg/L, and acetate and propionate acids accounted for about 71% of total VFAs. In addition, the maximum concentration of soluble protein and polysaccharide reached approximately 1648 mg/L and 1394 mg/L, respectively. The NH4+-N and PO43−-P release was in a range of 2.11–7.59 mg/gVS and 0.26–1.13 mg/gVS, respectively. If the NH4+-N and PO43−-P can be removed, the application of VFAs utilization might be significantly enhanced.
•TS content influenced VFAs yield and composition during SMC anaerobic fermentation.•The maximum VFAs concentration was 2781 mg/L with a TS content of 15%.•NH4+-N and PO43−-P were released during SMC anaerobic fermentation.