Characterization of water sorted organic fraction of municipal solid waste for anaerobic digestion
作为厌氧发酵原料的水分选有机垃圾特性分析

The solid organic fraction (SOF) and air-flotation sludge (AFS) from the water sorted organic fraction of municipal solid waste (MSW) were sampled and their composition and biochemical characteristics were analyzed. A pilot-scale (30 L) anaerobic digestion experiment was also carried out. The analysis showed that 18% of SOF was inert fraction, 72% was biodegradable (volatile solids) including 40.4%, 21.8% and 9.8% carbohydrates, proteins and lipids respectively. For AFS, 2% was inert, and 82.4% was biodegradable, including 53.5%, 19.2% and 9.7% carbohydrates, proteins and lipids, respectively. The metal content of SOF was higher than that of AFS. The main metal elements were Ca, Fe, Al, K, Na and Mg. Heavy metal element contents (Zn, Mn, Ni, Hg and Cr) were higher than the limits on compost products. The theoretical methane potential of the water sorter organic fraction of MSW was 484 m3 ·t-1 (based on volatile solids), the experimental methane yield was 273 m3 ·t-1, pilot-scale methane yield was 245 m3 ·t-1. One ton of the wet organic fraction can produce 32 m3 methane. Heavy metals, volatile fatty acids and ammonia inhibition were not found during the whole anaerobic fermentation process, however, a long start-up period of 20 d was necessary.