预处理及物料配比对有机垃圾厌氧发酵的影响

针对我国推行垃圾分类政策后产生的大量有机垃圾难以有效消纳的问题，开展了厨余、果蔬与园林垃圾连续式厌氧发酵实验，并通过超声与碱热预处理技术改善产甲烷性能，并以厨余垃圾单独厌氧发酵作为对照实验组。根据进料有机负荷（OLR），将反应周期分为低有机负荷OLR=1，2 g/（L·d）]和高有机负荷OLR=4，6 g/（L·d）]2个阶段。结果表明:在低有机负荷阶段，反应体系均表现出较强的稳定性。其中，厨余垃圾实验组的有机质（VS）去除率和甲烷产率最高，分别可达到90.3%，460 mL/g。并且超声与碱热预处理可以使混合物料甲烷产率分别提高7%~8%和3%~7%；在高有机负荷阶段，厨余垃圾实验组稳定性明显降低，具体表现为pH值降低至6.70，挥发性脂肪酸（VFA）和氨氮（TAN）积累浓度分别达到1230，1519 mg/L，且VS去除率与甲烷产率分别降低了2.8%、11%。此时混合物料反应体系表现出较强的抗冲击负荷的能力。与厨余垃圾相比，混合物料的甲烷产率有所提高，可达到420 mL/g。其中，超声预处理后甲烷产率可进一步提高3%，而碱热预处理后甲烷产率降低了4%。

EFFECTS OF PRETREATMENTS AND SUBSTRATE COMPOSITIONS ON ANAEROBIC DIGESTION OF ORGANIC WASTE

With the implementation of waste sorting policy in China, efficient utilization of organic waste becomes a great challenge in China. In this paper, continuous experiments on anaerobic digestions of kitchen waste, fruit and vegetable waste and garden waste were conducted, while ultrasound and alkali-thermal pretreatment were applied to enhance methane production, with the mono-digestion of food waste served as the control. According to different OLRs, the reaction period was divided into low OLR phaseOLR=1, 2 g/(L·d)] and high OLR phaseOLR=4, 6 g/(L·d)]. The results showed that under low OLR, all reaction systems showed strong stability, among which, kitchen waste had the highest VS removal rate of 90.3% and methane yield of 460 mL/g. Besides, after ultrasonic pretreatment and alkali-thermal pretreatment, the methane yields of co-substrates were increased by 7%~8% and 3%~7%, respectively. Under high organic load, the stability of mono-digestion system was significantly reduced, specifically, the pH value was decreased to 6.70 and the concentration of VFA and TAN was accumulated to 1230, 1519 mg/L, while the VS removal rate and methane yield were reduced by 2.8% and 11% as well. However, the co-digestion systems showed stronger resistance to high OLRs. Compared with kitchen waste, the methane yield of co-substrate was increased to 420 mL/g. After ultrasonic pretreatment, the methane yield was further increased by 3%, while the methane yield after alkali-thermal pretreatment was decreased by 4%.