Enzymatic hydrolysis of food waste and methane fermentation using UASB reactor

摘要

This study was conducted to investigate the effect of enzymatic hydrolysis on the solubilization of volatile suspended solid (VSS) in food waste (FW) with commercial enzymes; carbohydrase, protease and lipase, and also to estimate methane production potential of FW liquor hydrolysed by enzymes with an upfolw anaerobic sludge blanket (UASB) reactor. In single enzymatic reaction, the protease exhibited the highest hydrolysis rate of VSS among the three types of enzymes. At a mixed enzymatic hydrolysis, the mixture ratio of 1:2:1 with carbohydrase:protease:lipase, and 0.3% (w/w FW) of its mixture dose showed the highest VSS reduction and chemical oxygen demand (COD) generation. A methane fermentation using FW liquor was carried out with stepwise increase of organic loading rates (OLR) from 1.6 to 13.2 g COD/L/d. Over 95% of COD removal efficiency and 67-75% of high methane content were consistent up to the loading rate of 9.1 g COD/L/d but significantly decrease at over 11.1 g COD/L/d. 0.35 L CH4/g-CODremoved of high methane yield was obtained at 9.1 g COD/L/d. These results indicated that enzymatic hydrolysis in conjunction with methane production by UASB reactor could provide a novel alternative in conventional methane production system from FW.