摘要
生物滞留是工程设计的土壤-植物-微生物共同作用的系统,可有效收集和处理城市地表径流。但是,对城市地表径流氮污染去除变化范围大。由于缺乏直接定量生物滞留反硝化微生物丰度和活性以及工程设计的影响,限制了提高氮去除的工程设计优化。我们在海绵城市建设试点常德选择了15个土壤基质质地和汇流比设计不同的生物滞留设施(湿式生物滞留和干式生物滞留),通过采集土壤基质,测定生物滞留土壤基质反硝化潜势(DEA)和硝化潜势(PN),采用qPCR定量硝化基因(amoA)和反硝化基因(narG、napA、nirS、nirK、norB和nosZ)丰度,研究生物滞留土壤质地与汇流比对微生物硝化与反硝化过程的影响。结果表明,生物滞留土壤质地与汇流比对土壤基质微生物反硝化潜势与反硝化功能基因丰度具有重要的影响。土壤基质为粘壤土和高汇流比设计的湿式生物滞留微生物反硝化功能基因与反硝化潜势显著高于壤土基质与低汇流比的干式生物滞留。湿式和干式生物滞留DEA分别为2.47 mg·kg^(-1)·h^(-1)和0.17 mg·kg^(-1)·h^(-1),总反硝化功能基因丰度分别为1.80×10^(9)copies·g^(-1)和5.70×10^(8)copies·g^(-1)。土壤基质反硝化菌群与反硝化潜势随基质粘粒含量和汇流比升高而增加。滞水设计或处于饱和淹水状况明显可提高微生物反硝化功能。另外,微生物反硝化功能基因丰度与反硝化潜势也与土壤基质中有机碳和TN呈明显正相关。通过改进生物滞留工程设计可增加反硝化作用并减少氮向受纳水体的输出。本研究结果可为提高城市地表径流氮污染去除效果提供工程案例参考。
Bioretention systems(BRs)are systems of interaction of soil,plants,and microorganisms,designed to intercept stormwater runoff and reduce loads of water and contaminants discharged to surface waters.However,nitrogen removal efficiency is highly variable,which may be related to the nitrogen complex biogeochemical process that occur within bioretention systems.The nitrogen performance cannot be enhanced by a lack of data directly quantifying the abundance or activity of denitrifying microorganisms in BRs and how they are controlled by engineered designs.Six wet and nine dry bioretention cells(WBRs and DBRs)of different engineered designs in Changde City,including soil media texture and watershed area ratio,were sampled to measure potential nitration(PN)and denitrification enzyme activity(DEA).Nitrification gene(amoA)and denitrification genes(narG,napA,nirS,nirK,norB and nosZ)were also quantified by the quantitative polymerase chain reaction(qPCR).Results showed that BRs design factors,including soil media texture and watershed area ratio,had the greatest effects on variation in denitrifier abundance and activity.Denitrifying populations and denitrification potential increased with soil media clay content and watershed area ratio.Denitrification potential was higher in the wet bioretention systems(2.47 mg·kg^(-1)·h^(-1))compared to dry bioretention systems(0.17 mg·kg^(-1)·h^(-1)).The WBRs also had significantly greater total denitrification genes copies than the dry WBRs,1.80×10^(9)vs 5.70×10^(8)copies·g^(−1),respectively.Furthermore,denitrifying populations and denitrification potential increased with soil organic carbon and nitrogen concentrations.These results suggest that soil media texture and watershed area ratio improvement still have great potential when building bioretention systems that can enhance denitrification and reduce nitrogen loading to receiving waters.
作者
闫玉清
李立青
马旭高
YAN Yuqing;LI Liqing;MA Xugao(School of Environmental Studies,China University of Geosciences,Wuhan 430074,China)
出处
《环境工程学报》
CAS
CSCD
北大核心
2023年第8期2484-2493,共10页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金资助项目(41977155)。
关键词
城市地表径流
生物滞留设施
工程设计
反硝化潜势
反硝化功能基因
urban stormwater runoff
bioretention systems
engineered designs
denitrification potential
denitrification functional genes
