不同SBR系统N_2O排放及微生物群落比较

Comparative Analysis of N_2O Emissions and Microbial Communities from Different Sequencing Batch Reactor Systems

为了解污水脱氮中微生物群落对N2O排放的影响,在相同的工艺条件下,研究了制药厂(A)和啤酒厂(B)2种不同来源污泥在SBR系统中的N2O排放特性.结果发现:①A和B 2个系统总氮去除率在97.5%和98.6%的情况下,脱氮中N2O态氮所占比例分别为6.35%和2.84%,相差2倍以上.②A系统的N2 O排放时期主要集中在好氧硝化段,而B系统则主要集中在缺氧反硝化段.③在1个脱氮周期内,A系统只有1个N2O排放高峰,出现在好氧硝化段(第3小时);而B系统有2个N2O排放高峰,分别出现在好氧硝化段(第3小时)和缺氧反硝化段(第6小时).采用PCR-DGGE技术分析微生物群落特征发现,A系统和B系统的微生物群落有明显差异,表明污水脱氮中微生物群落是影响N2O排放的重要因素.通过优化微生物群落结构,可有效控制污水脱氮中N2O排放.

To understand the effects of microbial communities on N2O emissions from wastewater denitrification systems,two sequence batch reactor（SBR） systems（A and B） seeded with different sources of activated sludge were run under identical conditions.Emission characteristics of N2O and the microbial communities from the two systems were compared.Results showed that 1） when the nitrogen removal efficiencies of the A and B systems reached 97.5% and 98.6% respectively,the amount of N2O emitted from system A was roughly twice as much as that emitted from system B,accounting for 6.35% and 2.84% of the total N removed from the respective systems.2） N2O emissions in system A occurred mainly during the aeration-nitrification stage,while in system B the emissions occurred during the anoxic denitrification stage.3） System A showed only one N2O emission peak in each cycle occurring at the aeration-nitrification stage（the third hour） while system B showed two peaks： one at the aeration-nitrification stage（the third hour） and the other at the anoxic denitrification stage（the sixth hour）.PCR-DGGE analysis showed that the two systems harbored significantly different microbial communities,suggesting that microbial communities were an important factor affecting N2O emissions in nitrogen removal systems.N2O emissions in wastewater denitrification systems could be controlled effectively through the optimization of the microbial community structure.