回灌渗滤液C/N对填埋垃圾生物反应器反硝化特性的影响

利用模拟填埋垃圾生物反应器（landfill bioreactor）研究了回灌渗滤液C/N对填埋垃圾堆体反硝化性能的影响,并采用PCR扩增、克隆测序等分子生物学技术,以功能基因nirS为分子标记考察了4次回灌过程中反应器内反硝化微生物群落结构变化.结果表明,回灌渗滤液的COD/NO 3--N比例对反应器的反硝化活性具有显著性影响.当COD/NO 3--N从3.11提高到13.08时,反应器内硝酸盐还原速率可从1.14 mg.（kg.h）-1提高到11.40 mg.（kg.h）-1.当回灌渗滤液生物可利用性COD与NO 3--N比值达到6.37时,可以实现填埋垃圾生物反应器反硝化作用的快速、稳定运行.4次回灌,反应器内的反硝化微生物大部分与β-变形菌纲（β-proteobacteria）细菌相似,少数属于非培养微生物（uncultured bacteria）,其中Thiobacillus denitrificans和Azoarcus tolulyticus是反硝化过程的主要功能微生物,在回灌渗滤液反硝化过程中可能发挥着重要作用.

Effect of Injected Leachate C/N Ratio on the Denitrification of a Bioreactor Filled with Landfilled Refuse

The denitrification capacity of a landfill bioreactor was investigated under different ratios of injected leachate C/N; the denitrifying bacteria community compositions over four injection times were also studied using molecular approaches and functional gene nirS served as marker. Results showed that COD/NO3(-) -N ratio of the injected landfill leachate had a significant impact on the denitrification capacity of the bioreactor. Nitrate reduction rate increased from 1.14 mg x (kg x h)(-1) to 11.40 mg mg x (kg x h)(-1) when the injected leachate COD/NO3(-) -N ratio raised from 3.11 to 13.08. It suggested that a stable and rapid denitrification could be obtained when bioavailable COD/NO3(-) -N ratio in the injected leachate was 6.37. In the bioreactor, the main denitrifying bacteria was similar to beta-proteobacteria, and others belonged to uncultured bacteria. Thiobacillus denitrificans and Azoarcus tolulyticus known as beta-proteobacteria were the dominant species and played an important role in NO3(-) -N consumption during the leachate injection.