生物膜复合系统脱氮除磷的特征及微生物群落结构分析

试验研究了序批式生物膜复合系统在不同有机负荷下氮磷等营养物质的去除特性.结果表明,复合系统在COD负荷为0.35kg.kg-1.d-1(以MLSS计)时能够很好解决脱氮除磷的泥龄矛盾,TP、TN、NH4+-N去除率分别能达到96%、89%和96%,高于对照组的SBR工艺.复合系统中,悬浮污泥对硝化起主要作用,悬浮态污泥和生物膜的硝化平均贡献比为1.66;附着态生物膜对反硝化和除磷起主要作用,生物膜和悬浮态污泥的反硝化贡献比为2.19,释磷贡献比为3.5,摄磷贡献比为3.76.利用PCR-DGGE技术发现,复合系统中存在丰富的脱氮功能菌和除磷功能菌,且悬浮态与附着态微生物的相似性仅为73%,区别较大,说明两者存在一定的分工协作,与反应器的处理特性相一致.

Characteristics of nitrogen and phosphorus removal and microbial community structure in hybrid biofilm system

Bench scale sequencing hybrid biofilm reactor (HBR), fed on synthetic wastewater, were used to study the characteristics of nitrogen and phosphorus removal with different sludge loads. It was found that under the condition of the sludge load at 0.35 kg(COD_Cr)·kg^-1(MLSS)·d^-1, the system had a good performance on nitrogen and phosphorus removal, and the total nitrogen (TN), total phosphorus (TP) and ammonia nitrogen (NH₄⁺-N) removal efficiency were 96%, 89% and 96%, respectively, all higher than the counterparts in the sequencing batch reactor (SBR) process. The suspended sludge contributed the main nitrification process with the contribution ratio of 1.66 to the biofilm. However, the biofilm influenced the denitrification and phosphorus degradation processes significantly. The contribution ratio from the biofilm to the suspended sludge on denitrification, phosphorus releasing and uptaking were 2.19, 3.50 and 3.76, respectively. The microbial community structures of the treatment reactor were monitored by PCR-amplified 16S rDNA and denaturing gradient gel electrophoresis (DGGE) analysis of the resultant PCR products. The profiles of DGGE showed that the HBR was rich in nitrogen and phosphorus removal functional bacteria and the correlation coefficient between the suspended and biofilm microbial community was only 73%. The results indicated the close relationships among different microbial communities in the HBR. The relationship between the structure of microbial community and its functions may be characterized with the variation analysis.