Enhancement of organic matter degradation and methane gas production of anaerobic granular sludge by degasification of dissolved hydrogen gas.

A hollow fiber degassing membrane (DM) was applied to enhance organic matter degradation and methane gas production of anaerobic granular sludge process by reducing the dissolved hydrogen gas (D-H) concentration in the liquid phase. DM was installed in the bench-scale anaerobic granular sludge reactors and D-H was removed through DM using a vacuum pump. Degasification improved the organic matter degradation efficiency to 79% while the efficiency was 62% without degasification at 12,000mgL of the influent T-COD concentration. Measurement of D-H concentrations in the liquid phase confirmed that D-H was removed by degasification. Furthermore, the effect of acetate concentrations on the organic matter degradation efficiency was investigated. At acetate concentrations above 3gL, organic matter degradation deteriorated. Degasification enhanced the propionate and acetate degradation. These results suggest that degasification reduced D-H concentration and volatile fatty acids concentrations, prevented pH drop, and subsequent enhanced organic matter degradation.