预处理对园林垃圾混合物料联合厌氧发酵的影响

采用超声、微波及碱热预处理技术强化园林垃圾、厨余垃圾与果蔬垃圾联合厌氧发酵产气性能，并以未进行预处理的实验组作为对照。结果表明:4组实验pH值在2 d内迅速降低至7.24~7.45，反应后期可稳定在7.7~8.0，表明厌氧消化系统有较强的稳定性。挥发性脂肪酸（volatile fatty acids，VFA）浓度在第2~4天内达到最大值。乙酸和丙酸是4组实验中VFA的主要成分，两者比例之和在70%以上。VFA浓度在第13天后降低到500 mg/L以下，且以乙酸为主。氨氮（TAN）浓度在前4 d内出现一定波动，随后逐渐升高至2190~2410 mg/L。游离氨氮（FAN）浓度呈先降低后增加趋势，并在第13天后逐渐趋于稳定，为144~209 mg/L。沼气中甲烷比例在第2天后均超过50%，并在第11~12天时达到最大值61.4%~63.8%。修正的Gomperts模型模拟结果表明:预处理技术可缩短反应体系厌氧产沼的适应时间，提高前期产气速率。除此之外，超声预处理与碱热预处理可显著提高基质甲烷产率，由未处理时的396 mL/g分别提高到601，536 mL/g，而微波预处理使得反应体系甲烷产量略有降低。

EFFECTS OF PRETREATMENT ON ANAEROBIC CO-DIGESTION OF GARDEN WASTE AND OTHER SUBSTRATES

Ultrasound, microwave and alkali-thermal pretreatment were applied for enhancing biogas production by anaerobic co-digestion of garden waste, kitchen waste and fruit and vegetable waste. The experiment without pretreatment served as the control. The results showed that pH values of the four experiments rapidly decreased to 7.24~7.45 within 2 days and then increased to 7.7~8.0 at the end of reactions, indicating that anaerobic digestion systems were relatively stable. The concentrations of VFA reached the maximum within 2~4 days, of which acetic acid and propionic acid were the main components, accounting for more than 70%. After 13 days, VFA concentrations decreased to below 500 mg/L, and mainly acetic acid remained. There were some fluctuations of TAN concentrations during the first 4 days, which then gradually increased to 2190~2410 mg/L at the end. While the concentrations of FAN firstly decreased, then increased and stabilized to 144~209 mg/L after 13 days. The proportion of methane in biogas all exceeded 50% after the 2nd day and reached the maximum value of 61.4%~63.8% on the 11th~12th day. According to simulation results of the modified Gomperts model, pretreatments could shorten the adaption period and enhance gas production at early stage. Ultrasonic pretreatment and alkali-thermal pretreatment could significantly increase the methane yield, from 396 mL CH₄/g VS to 601 mL CH₄/g VS, 536 mL CH₄/g VS, respectively, while microwave pretreatment slightly decreased the methane yield.