Response surface analysis to evaluate the influence of pH, temperature and substrate concentration on the acidogenesis of sucrose-rich wastewater

In this study, the central composite design and the response surface methodology (RSM) were applied to determine the optimum physiological conditions for the production of volatile fatty acids (VFA) and H2 from sucrose-rich wastewater by mixed anaerobic culture. The experimental results show the acidogenesis was affected by pH, temperature, and substrate concentration individually and interactively. The interaction between temperature and pH on the VFA and H2 production was significant, whereas there was no interaction between pH and sucrose concentration, temperature and sucrose concentration. The optimum conditions were pH 5.6, temperature 33.5 °C and sucrose concentration 24.2 g l−1 for total VFA yield; pH 5.5, temperature 33.1 °C and sucrose concentration 24.4 g l−1 for butyrate yield; pH 5.5, temperature 35.1 °C and sucrose concentration 26.0 g l−1 for H2 yield. The RSM was demonstrated as an appropriate approach to the optimization of acidogenesis.