Enhancement of methane production from anaerobic digestion of waste activated sludge with choline supplement

This study investigated the effects of choline supplement on methane production from anaerobic digestion of sludge. Batch experiment with varied dosages (0.1-1.3 sludge) of choline in terms of methane production, sludge degradation and process stability were carried out. The results showed that the addition of choline could greatly improve methane production, and the highest cumulative methane production of 225.7 mL/g volatile solids (VS) could be achieved with the optimal choline addition of 0.3 g/L, which was 30.0% higher than that of the control. Model simulation indicated that modified Gompertz model and Cone model well fitted the actual evolution of methane production. The parameters analysis showed the promotion of hydrolysis rate and methanogenesis potential of sludge by choline addition. Furthermore, the process lag phase was reduced by 32.8%. This study provided an alternative for efficient biomass stabilization and bioenergy recovery from sludge. (C) 2019 Elsevier Ltd. All rights reserved.