Effects of N/C, P/C and Fe/C ratios on dark fermentative hydrogen gas production from waste paper towel hydrolysate

The effects of N/C, P/C and Fe/C ratios on dark fermentative hydrogen gas production from activated carbon treated WPT hydrolysate were investigated using Box-Behnken statistical experiment design. N/C, P/C and Fe/C ratios were chosen as independent variables while the H2 yield and SHPR were set as the objective functions. H2 yield and SHPR functions were described by two quadratic model functions. The addition of a proper amount of N, P and Fe to the fermentation media was found to be essential to enhance the H2 production performance. Linear and interaction terms of N/C and Fe/C did have a significant effect on the H2 yield in the model function. However, the SHPR was significantly affected by the linear and interaction terms of N/C and P/C. The most convenient N/C, P/C and Fe/C ratios resulting maximum H2 yield (0.656 mol H2/mol glucose) and SHPR (241.64 mL H2/g biomass.h) were determined as 0.05, 0.09 and 0.003 (w/w), respectively.