Time-Settlement Behavior of Processed Refuse. Part III: Anaerobic Digestion of Milled Refuse

摘要

The objectives of this laboratory investigation were to gain an understanding of the decomposition of milled refuse under anaerobic conditions, the rates of decomposition, and the gas production and composition. The rates of decomposition of cellulose and cellulosic materials, gas production per unit weight of materials digested and the CH4 to CO2 ratios were obtained from the literature for different systems. Similar data from laboratory experiments on the anaerobic decomposition of milled refuse were analyzed and compared with the information obtained from the literature. The rate constant decomposition, Ke at 37C, reported in the literature for the different systems, varied from .000033 to 1.97/day. Gas production ranged from near zero to 14 cu ft per pound of volatile matter digested and the CH4 to CO2 ratio varied between 0.3 and 1.86. For anaerobic digestion of milled refuse in the laboratory experiments, the rate constant (normalized to 37C) for the reduction of volatile matter varied between 0.00105 and 0.00216/day. The low rates were observed for the digesters which were either seeded with a non-acclimatized culture or not seeded at all. Gas production ranged from 6.9 to 12.8 cu ft/lb of volatile matter digested. The averaged CH4 to CO2 ratio, for the initial phase of gas production, varied from 0.13 to 1.09, the lowest ratio being observed for the digester which was operated at the lowest temperature, 20C.