Influence of total solid concentration and dilution rate on hydrogensis and acidogenesis of kitchen food waste

Key words: 
• kitchen food waste /
• hydrogenesis and acidogenesis /
• total solid concentration /
• dilution rate

Abstract: In present study, the effects of initial total solid (TS)concentrations(10%, 12% and 14%) and dilution rates(0.25 d－1 and 0.33 d－1) on pH value, solid digestion, leachate production and fatty acid concentration and composition were investigated for hydrogenesis and acidogenesis of anaerobic digestion of kitchen food waste in batch leachatebed reactors. The percents of total solid removed, the cumulative dissolved COD per mass of waste (ACODm) and the cumulative dissolved COD per volume of reactor (ACODv) were compared for the systems with initial TS concentrations of 10%, 12% and 14%, the results show that the systems with initial TS concentration of 12% have the appropriate digestion efficiency considering the waste digestion and the treating capacity of reactor. The systems with dilution rate(D) of 0.33 d－1 have clear advantages in pH value, solid digestion and leachate production in comparison with those with D of 0.25 d－1. Ethanol, acetate and butyrate are the main products in acidogenesis. The concentrations of propionate in the total volatile fatty acids are in the range between 14.6% and 17.1%, which indicates that no propionate inhibition should occur in the following methanogenesis.