挥发性有机酸对产沼气效果的模拟试验

两相厌氧生物处理工艺在废弃物资源化利用中得到广泛应用。为了摸清产酸相的主要产物在产气过程中的效应，该文利用甲酸、乙酸、丙酸和丁酸等4种有机酸模拟产酸过程中的主要酸化产物，以活性污泥为接种物，设计单因素试验和正交试验，研究了在中温条件下，4种有机酸单一作用条件下和混合作用条件下，甲烷日产气量和累积产气量的变化。结果表明：单一有机酸作底物时，存在一个浓度阈值，高于此值会抑制甲烷产生，低于此值，产气效果随着酸浓度增大而提高；有机酸共同存在时，可以产生协同优势，其中乙酸的产气优势高于丁酸，丙酸具有抑制作用；4种单一酸中，单位浓度下乙酸产气效果最好，甲酸产气量最大，甲酸积累不易对发酵过程产生抑制作用，而丙酸累积最易造成抑制。因此，建议在沼气工程中适当调整产甲酸、乙酸和丁酸较多的发酵物料浓度，从而提高产气效率。

Simulation experiment of volatility organic acids on biogas-producing characteristics under anaerobic condition

Two-phase anaerobic biological treatment has been widely applied in waste disposal/utilization. In order to study the effects of main products on the biogas-producing process, based on the simulation of four major acidified organic acids (formic acid, acetic acid, propionic acid and butyric acid), the activated sludge was inoculated. Then single factor and orthogonal experiments were designed to study the main and interactive effects of organic acids on dynamics of both daily and accumulative methane production under medium temperature condition. The results showed that there existed a critical threshold of organic acid concentration in single organic acid, where high concentration above the threshold would have inhibited effect on gas production; and gas production got increased with the acid concentration increasing when it below the threshold. There was a significant interactive effect among the four organic acids, and acetic acid had the stronger increasing effect than butyric acid, propionic acid had the constrained effect. Acetic acid had best effect on gas production among the four organic acids under same concentration. Formic acid got the highest gas yield and had less inhibiting effect than propionic acid. It is suggested that the fermented material concentration, which easily produce organic acids, should be adjusted in order to improve gas production efficiency.