Treatment of liquid fraction separated from liquidized food waste in an upflow anaerobic sludge blanket reactor

Thermochemical liquidization as a pretreatment for anaerobic digestion of f ood waste was studied using a laboratory-scale upflow anaerobic sludge blan ket (UASB) reactor for a period of 82 d. Model food waste (approximately 90 wt% moisture content) was thermochemically liquidized at 175 degrees C for I h, The liquidized food waste was separated into a solid phase (6-10 wt%) and a liquid phase (85-89 wt%). The diluted liquid phase was continuously treated by anaerobic digestion using a UASB reactor at 35 degrees C The vol umetric loading rate was increased stepwise to 6.4-7,2g total organic carbo n (TOC)/l-reactor/d. Methane production was found to be approximately 0.35- 0.61 l/g-TOC removed. The range of TOC removal efficiencies was 67-69% at a n influent TOC concentration,of 10.1-11.1, g/l and a volumetric loading rat e of 4.8-5.3 g-TOC/l-reactor/d. This treatment process using an UASB reacto r could be suitable for resource recovery from food waste.