固体碳源生物膜反应器的脱氮性能及机理研究

Nitrogen Removal Performance and Mechanism of Biofilm Reactor with Solid Carbon Source

为研究固相反硝化的脱氮性能及其机理,利用板块状热塑性淀粉/PCL共混固体碳源构建了上流式固体碳源生物膜反硝化反应器,重点研究了固体碳源填充方式、反应器HRT以及进水硝态氮浓度对反硝化效果的影响。结果表明,折流倾斜填充方式比竖直悬挂填充方式具有更好的脱氮效果。当生化池尾水中的TN平均浓度为20 mg/L时,在HRT为3 h条件下,折流式反应器的平均反硝化速率为4.9 mg/(L·h),出水TN和COD平均浓度分别为5.5和12 mg/L;竖直悬挂式反应器的平均反硝化速率为2.5 mg/(L·h),出水TN平均为12.6 mg/L、COD平均为18 mg/L。另外,在折流式反应器中,TN去除率与反硝化速率分别与HRT和进水硝态氮浓度之间存在显著线性相关性,且TN的去除率和反硝化速率随HRT的延长及进水硝态氮浓度的增加而上升。扫描电镜观察结果证明了生物膜的附着及其对固体碳源的降解。PCR-DGGE分析结果进一步证实了Myxobacterium AT3-03和Comamonas granuli是生物膜中主要的反硝化微生物。

In order to explore the nitrogen removal efficiency and mechanism of the solid-phase denitrification process, a laboratory scale up-flow biofilm reactor was developed using thermoplastic starch/PCL plate as solid carbon source. The influence of plate packing method, hydraulic retention time （HRT） and influent nitrate concentration on nitrogen removal performance was investigated. The results showed that the reactor with inclined baffle plate presented higher nitrogen removal efficiency than the re- actor with vertical-fixed plates. When the average concentration of TN in the effluent of the biochemical tank was 20 mg/L, and HRT was 3 h, the average denitrification rate, effluent TN and COD concentrations of the reactor with inclined baffle plate were 4.9 rag/（ L·h）, 5.5 mg/L and 12 mg/L respective- ly ; The average denitrification rate, effluent TN and COD concentrations of the reactor with vertical-fixed plate were 2.5 mg/（ L·h）, 12.6 mg/L and 18 mg/L respectively. In addition, in the reactor with inclined baffle plates, there was an apparent linear correlation between TN removal efficiency and HRT, as well as the relationship between denitrification rate and influent nitrate concentration. The TN removal efficiency and denitrification rate increased with the increase of HRT and influent nitrate concentration. The observed results of scanning electronic microscopy （SEM） proved the phenomenon of biofilm adhesion and biological degradation on the surface of thermoplastic starch/PCL plate, and the PCR-DGGE analysis indicated that Myxobacterium AT3-03 and Comamonas granuli were predominant denitrifying bacteria in the biofilm.