不同因素对华北地区弱透水层中硝酸盐反硝化作用影响的研究  

Effects of different factors on the denitrification of nitrate in aquitard in North China

作　　者：蔡敏 辛立勋 张旭 崔娜欣 周丽 邹国燕[1,2] 陈桂发 CAI Min;XIN Lixun;ZHANG Xu;CUI Naxin;ZHOU Li;ZOU Guoyan;CHEN Guifa(Eco-Environmental Protection Research Institute,Shanghai Academy of Agricultural Sciences,Shanghai 201403,China;Shanghai Engineering Research Center of Low-carbon Agriculture,Shanghai 201415,China;Shanghai Zhuoyuan Water-Ecological Environmental Engineering Co.,Ltt,Shanghai 200003,China)

机构地区：[1]上海市农业科学院生态环境保护研究所,上海201403 [2]上海低碳农业工程技术研究中心,上海201415 [3]上海琸源水生态环境工程有限公司,上海200003

出　　处：《上海农业学报》2020年第3期82-89,共8页Acta Agriculturae Shanghai

基　　金：上海市科技兴农项目(2019-02-08-00-12-F01136);上海市科委国内科技合作项目(19295801000)

摘　　要：地下水是人类的主要饮用水源,近年来,人口急剧增加及工农业的快速发展加剧了地下水的开采与利用,同时,过量施肥及农业污水灌溉导致大量硝酸盐(NO3--N)通过淋溶等流入地下水中,成为农业灌溉区的主要污染物。水体中过高浓度的NO3--N对人群健康及生态平衡的潜在风险不容忽视。目前,反硝化过程是水体中NO3--N衰减和去除的重要途经,其主要集中出现在地下水弱透水层的厌氧或准厌氧环境下。NO3--N浓度、溶解氧(Dissolved Oxygen,DO)、微生物等是影响反硝化过程的重要因素。本研究选取华北平原弱透水层/含水层互层分布的典型代表——北京市通州区张家湾镇张家湾村的通州试验场为研究区域,采集不同层深的不同类型的原状土样,通过构建实验室条件下的微宇宙系统,比较NO3--N初始浓度、固液比、溶解氧含量、土壤类型及微生物这5个因素对反硝化过程的影响,为确定地下水弱透水层中硝态氮主要的消散场所提供依据。结果表明:(1)NO3--N在20 d内会被完全降解,降解过程符合一级动力学,其反硝化反应速率常数为0.06—0.10 d(-1),在反硝化过程中NO2--N和三磷酸腺苷(ATP)的浓度均呈先增大后减小的趋势;(2)对于不同NO3--N初始浓度(25 mg/L、50 mg/L、100 mg/L)及固液比(1∶10、1∶20、1∶30),反硝化速率常数分别为K(25)>K(50)>K(100),K(1∶30)>K(1∶20)>K(1∶10);(3)反硝化过程主要发生在准厌氧环境下(DO<0.2 mg/L),而在常氧环境下(DO=5—6 mg/L)基本无反硝化过程发生;(4)不同土壤类型(黏土、沙土、粉土)间的反硝化速率没有显著差异,但是粉土中反硝化过程产物亚硝酸盐的累积量最低、降解最快;(5)微生物是参与反硝化过程的重要因素,在灭菌处理中,基本无反硝化发生。本研究探索了NO3--N在弱透水层中的反硝化规律及其主要影响因素,为后续合理评估硝态氮在华北地区地下水中的污染及生态健�Groundwater is the main source of drinking water for human beings.In recent years,with the rapid increase of population and development of industry and agriculture,the exploitation and utilization of groundwater have been intensified.Meanwhile,due to the excessive fertilization and agricultural sewage irrigation,a large amount of nitrate(NO3--N)has flowed into groundwater by leaching and become the main pollutants in agricultural irrigation areas.Excessive concentration of NO3--N in the groundwater poses great threat to human health and ecological balance.At present,denitrification process is an important way to remove and attenuate NO3--N in groundwater,which mainly occurs under the anaerobic or quasi-anaerobic environment in aquitard of groundwater.NO3--N concentration,dissolved oxygen,microorganism are the key factors to affect the denitrification process.In this study,Tongzhou test site located in Zhangjiawan Village,Zhangjiawan Town,Tongzhou District,Beijing,a typical representative of aquitard/aquifer interbedded distribution in North China plain,was selected as the study area,and different types of undisputed soil samples at different depths were collected.By constructing a microcosm system under laboratory conditions,the effects of 5 factors including initial NO3--N concentration,solid-liquid ratio,dissolved oxygen(DO),soil types,microorganism on denitrification process were compared.The results showed that:(1)The NO3--N could be degraded completely within 20 days,which accorded with the first-order kinetics with the denitrification rate constant of 0.06—0.10 d-1.The concentrations of NO2--N and adenosine triphosphate(ATP)increased first and then decreased during the process of denitrification;(2)For different initial concentrations of NO3--N(25 mg/L,50 mg/L,100 mg/L)and solidliquid ratios(1∶10,1∶20,1∶30),the denitrification rate constant was K25>K50>K100,K1∶30>K1∶20>K1∶10,respectively;(3)The denitrification process mainly occurred under the quasi-anaerobic environment(DO<0.2 mg/L),but not u

关 键 词：地下水 硝酸盐 弱透水层 反硝化速率 

分 类 号：X523[环境科学与工程—环境工程]