Effect of inoculation time on the bio-drying performance of combined hydrolytic–aerobic process

The study aimed at investigating the effects of inoculation time on the bio-drying performance of combined hydrolytic–aerobic process. Results showed that the addition of inoculating material at different time exhibited various effects not only on the degradation rate of total organics, but also on the performance of water removal and water content reduction. The beginning of aerobic stage (day 5) was suggested to be the optimal time for inoculation. Under this operational condition, 815 g/kg-W0 (W0 = initial water content) was removed and the water content reduced from the initial 72.0% to 48.5%. Adding inoculating material at the start of hydrolytic stage (day 0) reduced water removal and water content reduction rates. The addition of inoculating material at day 7 or 9 could not improve the bio-drying performance significantly. Additionally, the inoculation at days 0, 5, 7 and 9 enhanced lignocelluloses degradation rate by 3.8%, 11.6%, 7.9% and 7.7%, respectively.