Enhanced volatile fatty acids accumulation in anaerobic digestion through arresting methanogenesis by using hydrogen peroxide.

Volatile fatty acids (VFAs) can be accumulated as a final product of anaerobic digestion via arresting methanogenesis. Herein, hydrogen peroxide (H O ) was studied to inhibit methanogenesis for enhancing VFA accumulation with glucose as a substrate. The addition of 0.06 wt.% H O significantly reduced methane production and led to a VFAs concentration of 1233.1 ± 55.9 mg L , much higher than 429.3 ± 5.6 mg L in the control that did not have H O addition. The dominated VFAs with H O were acetic acid and propionic acid. A low H O dosage of 0.03 wt.% produced 466.3 ± 3.9 mg L more VFAs than that of O addition at the similar (theoretical) dosage, but when the dosage was relatively higher, the VFA accumulation with O addition became more than that with H O addition, likely because of stronger oxidation of VFAs by the overly added H O . A hypothetical mechanism for H O inhibition suggests that at a low H O concentration the inhibition is mainly toward methanogenesis to limit their consumption of VFAs and a high H O concentration starts to inhibit hydrolysis and acidogenesis and/or oxidize VFAs. Those results encourage further exploration of H O -based arresting methanogenesis for VFAs production.