餐厨垃圾和稻草两相厌氧发酵及其动力学

Anaerobic co-digestion of food waste and rice straw and its kinetics

采用响应面实验设计对影响酸化相产酸效果的4个因素即有机负荷、酸化时间、F/M(VS/VS)比、餐、草比进行实验研究。在最优的酸化条件下,选取最优的餐、草比与单餐厨和单稻草的产酸效果和产甲烷性能进行比较,并进行产物动力学曲线拟合。实验结果表明,进料负荷为42.95 g(VS)/L,酸化时间为7.92 d,F/M(VS/VS)为2.12∶1,餐、草混合比为3.88∶1时,产酸效果最优,VFA和乙醇总量为16 844 mg/L,比单因素最优水平组合VFA和乙醇总量提高30.4%。一级动力学模型可以很好地表征酸化阶段的VFA和乙醇的产量,餐、草比3.88∶1,餐厨垃圾和稻草的酸化一级产物生成的速率k分别为0.0887、0.0753和0.0625 1/d。修正Gompertz模型也较好地表征产甲烷阶段的负荷累计产甲烷量,拟合曲线的相关系数均大于0.98。

In order to optimize acidogenic phase parameters,organic loading rate( OLR),hydraulic retention time( HRT),feedstock to microorganism ratio( F / M),and food waste to rice straw ratio( FW / RS) were investigated using response surface methodology. Under the optimal acidifying conditions,the yields of VFAs and ethanol and cumulative methane rate were compared among the anaerobic digestion of optimal FW / RS,food waste and rice straw,and were fitting using kinetic models. The results showed that the maximum VFAs and ethanol yield of 16 844 mg / L in the acidogenic phase was obtained under the OLR of 42. 95 g VS / L,HRT of 7. 92 days,F / M(VS/VS)of 2. 12∶ 1 and FW / RS of 3. 88 ∶ 1. The best VFAs and ethanol yield was 30. 4% higher than that of optimal one-factor test. First-order kinetic model could describe the VFAs and ethanol yield in acidogenic phase well. The product formation kinetic coefficient of first-order model of VFAs and ethanol of FW / RS(3. 88∶ 1),food waste and rice straw were 0. 0887,0. 0753,0. 0625 1 / d,respectively. Modified Gompertz equation could describe the cumulative methane rate well,and the correlation coefficient of fitted curve were all higher than 0. 98.