[Influence of temperature on hydrolysis and acidogenesis of kitchen wastes in two-phase anaerobic digestion].

Abstract

The experiment evaluated the solubilization rate and VFA production rate of kitchen wastes with controlled-temperature at 25 degrees C, 37 degrees C, 40 degrees C and 50 degrees C, and subsequently investigated the lactic acid production and constituents of individual organic acids at various temperature levels. Results show that the increase of temperature when below 37 degrees C may improve both hydrolysis and acidogenesis rates and acidogenesis rate decreases while hydrolysis rate increases above 37 degrees C. The maximum VFA concentration of 34.4 g x L(-1) was achieved at 37 degrees C and a higher hydrolysis rate of 82% was obtained at 50 degrees C. Formic and acetic acid were predominant VFA, while propionic and butyric acid took a relatively little part. And lactic acid concentration remained relatively high. Accroding to the experiment an optimum temperature to optimize both hydrolysis and acidification is 37 degrees C.