Optimization of Acidibility and Acidifying Degree in Anaerobic Digestion

Abstract-Acidibility and acidifying degree were important indicators for acidification process in anaerobic digestion. Four factors affecting acidibility and acidifying degree termed temperature, sludge inoculum, mixing speed and substrate concentration were investigated on the basis of an orthogonal test. The order of the four factors affecting the acidification process was temperature > sludge inoculum > substrate concentration > mixing speed. The optimal temperature and sludge inoculum were 37°C and 0.5 mL/L, respectively. The stability and repeatability of the values of acidibility and acidifying degree under various substrate concentrations proved their potential application as indicators for acidification process in anaerobic digestion.