硫酸盐还原过程中乙酸型代谢方式的形成及其稳定性

通过产酸脱硫反应器处理高浓度硫酸盐废水的连续流试验,考察了不同试验阶段硫酸盐去除率和产气量稳定期,液相末端产物中挥发酸组成的变化、乙酸的分布特征、微生物种群组成和种群间关系.试验结果表明,各试验阶段液相末端产物中乙酸的分布比例高达50%～82%,微生物群体呈现特定的乙酸型代谢方式.乙酸型代谢方式本质上是产酸相反应器处理硫酸盐废水过程中,硫酸盐还原菌(SRB)与产酸菌(AB)建立起生物链式协同代谢关系,并通过非完全氧化型方式分解有机物,从而在末端产物中积累大量乙酸.乙酸型代谢方式的形成取决于利用乙酸的硫酸盐还原菌(ASRB)的竞争能力和它对乙酸的利用能力.乙酸型代谢方式可以为后续产甲烷相反应器提供适宜的底物,对提高硫酸盐废水处理系统的效率和运行稳定性具有重要意义.

Formation of an Acetic-acid Type Microbial Metabolism Pathway and Its Stability During the Course of Sulfate-reduction

Continuous flow experiment was conducted in an acidogenic sulfate reducing reactor supplied with molasses as sole carbon resource and sulfate sodium as electron acceptor. The composition of Volatile fat acid(VFA) in terminal liquid products, the distribution of acetic acid, the existance of microbial populations and the interspecific relationship between sulfate reducing bacteris (SRB) and acidogenic bacteria (AB) were investigated in different experimental stages when sulfate removal rate and gas production maintained at a relatively stable status. The experimental results showed that an acetic acid type microbial metabolism pathway was formed based on the fact that the proportion of acetic acid in terminal liquid products was as high as 50% to 82%. It was also explained the formation of acetic acid type microbial metabolism pathway was resulted from acetic acid accumulation in the terminal liquid products, which was subjected to the bio chain cooperation relationship between populations of SRB and AB, and the incomplete oxidation of organic substance in acidogenic phase reactor of two phase anaerobic treatment process. It was also presented that the formation of acetic acid type microbial metabolism pathway depended on the capability of acetic acid utilized SRB (ASRB) population competing against other populations and its ability of acetic acid consumption. Furthermore, this kind of metabolism pathway could offer suitable carbon resource for methane producing reactor in the two phase anaerobic treatment process, and has significant effect on the sulfate removal rate of the whole treatment system and its running stability.