Was pretreatment beneficial for more biogas in any process? Chemical pretreatment effect on hydrogen–methane co-production in a two-stage process

The study focused on the mesophilic anaerobic hydrogen production from PPS (pulp and paper sludge) and FW (food waste) pretreated by NaOH or H2SO4, and the subsequent thermophilic anaerobic methane production with the effluent in a two-stage process. The maximum hydrogen yield (78.35 mL g−1 VSfed) which was 50.21% higher than that of CK, was achieved when 10 g NaOH/100 g TSsubstrate was used. However, the maximum methane yield (383.8 mL g−1 VSfed) was obtained in CK as well as 64% SCOD removal efficiency was achieved. In short, NaOH/H2SO4 pretreatment was suitable to enhance the hydrogen production.