不同物料厌氧共发酵产甲烷特性研究

Synergistic Effect on Methane Production of Anaerobic Co-digestion with Mixed Materials

针对我国农业废弃物种类多、产量大、利用率低及单一物料厌氧发酵产气效率不高且不稳定等问题,本研究选取了典型农业废弃物牛粪、玉米秸秆和城市污水处理厂脱水污泥作为底物,两两混合进行批式厌氧共发酵实验。实验结果表明,不同底物厌氧共发酵较单物料发酵甲烷产量显著提高,底物的混合比例能够明显影响厌氧发酵的产甲烷特性,当脱水污泥与玉米秸秆以3∶1比例(以挥发性固体质量计)混合,脱水污泥与牛粪以1∶2比例混合,牛粪与秸秆以1∶1比例混合时,30天的累计甲烷产量最高,厌氧共发酵产生了协同效应,协同效应指数大于1。厌氧共发酵体系处于稳定状态,缓冲能力增强,溶解性化学需氧量、氨氮处在正常范围,没有发生氨抑制和挥发性脂肪酸的积累。

The modernization and intensification of agriculture considerably increases the production of agricultural wastes.Anaerobic digestion of mono-substrate is inefficient and instable.This study selected typical agricultural wastes such as cow manure,corn straws and dewatered sludge from municipal wastewater treatment plants as substrates to carry out batch anaerobic co-digestion experiments.The experimental results showed that methane production of the anaerobic co-digestion of different substrates,which was affected by the mixing ratio,is significantly higher than that of mono-substrate digestion.The optimal ratio was of 3∶1(dewatered sludge to corn straw,in terms of volatile solid mass),1∶2(dewatered sludge to cow dung) and was 1∶1(cow dung to straw).Synergistic effect were shown in anaerobic co-digestion with a synergistic effect index greater than one.The anaerobic co-digestion of agricultural waste stabilizes the fermentation system,making the buffer capacity of the system stronger.The dissolved chemical oxygen demand and ammonia nitrogen are in the normal range,and no ammonia inhibition and accumulation of volatile fatty acids occur.