尾菜批式中温发酵和高温发酵过程对比试验研究

Comparative Experimental Study of Mesophilic and Thermophilic Batch Fermentation Process of Vegetable Waste

尾菜的快速无害化处理已成为高原夏菜产业发展的“瓶颈”。针对目前尾菜规模化处理厂普遍存在厌氧发酵过程不稳定,而国内外缺少尾菜恒温发酵过程研究的现状,在0.56 m^(3)的恒温发酵罐中开展了尾菜批式中温发酵和高温发酵过程的对比试验,对比了两个过程中沼气产气量、氨氮量、pH值和溶解性总固体的变化过程,并用修正的Gompertz方程分析了恒温厌氧发酵产甲烷过程,研究结果表明:在接种量30%、总固体含量(Total Solid,TS)2.2%的30天批式发酵过程中,中温发酵过程和高温发酵过程均可稳定进行,与修正的Gompertz方程拟合结果吻合度R^(2)均大于0.99。高温组累积产气量、产甲烷量分别为3939 L、2034.2 L,比中温组分别高出11.3%和15.5%,同时高温组甲烷体积分数达到50%的时间较中温组提前了3 d;中高温两试验组对应的最低pH值分别为6.66和6.52,后期均逐渐升高并稳定在7.30左右;两试验组氨氮浓度呈前期快速上升后持续上下浮动趋势,整体高温组大于中温组。试验研究为使用恒温厌氧发酵稳定快速无害化、规模化处理尾菜提供了借鉴和参考。

The rapid and harmless treatment of vegetable waste has been a"bottleneck"in the development of the plateau summer vegetable industry.In view of the instability of the anaerobic fermentation process in the existing large-scale treatment plants of vegetable waste,and the lack of study on thermostatic fermentation processes both domestically and internationally.Comparative experiments of mesophilic and thermophilic batch anaerobic fermentation were conducted in two 0.56 m^(3) thermostatic fermentation tanks.The experiments compared the biogas production,ammonia nitrogen concentration,pH value,and changes in total dissolved solids(TDS)during both processes,meanwhile,the modified Gompertz equation was used to analyze the methane production process by thermostatic anaerobic fermentation.The results showed that during the 30 day batch anaerobic fermentation process with the inoculum concentrations of 30%and the total solid(TS)content of 2.2%,both mesophilic and thermophilic fermentation processes could proceed stably,the fitting results of the modified Gompertz equation were all in coincident degree with R^(2)greater than 0.99.The cumulative biogas production and methane production of the thermophilic group were 3939 L and 2034.2 L,which were 11.3%and 15.5%higher than that of the mesophilic group;at the same time,the time for the methane volume fraction of the thermophilic group to reach 50%was advanced by 3 days compared with that of the mesophilic group.The lowest pH values corresponding to the mesophilic and thermophilic test groups were 6.66 and 6.52,respectively,and gradually increased and stabilised at about 7.30 in the later stage.The concentration of ammonia nitrogen in two test groups continued to fluctuate after a rapid increase in the early stage,and the thermophilic group was greater than that of the mesophilic group on the whole.This experimental study provides a reference for the stable,rapid and harmless large-scale treatment of vegetable waste by using thermostatic anaerobic fermentation.