植物碳源添加对人工湿地水质净化效果和温室气体排放的影响  

Impact of plant carbon addition on water quality purification and greenhouse gas emissions in constructed wetlands

作　　者：苟永祥 郝庆菊[1] 刘康乐 陈芳慧[1] 王珣郦 江长胜 GOU Yongxiang;HAO Qingju;LIU Kangle;CHEN Fanghui;WANG Xunli;JIANG Changsheng(College of Resources and Environment,Southwest University,Chongqing 400715,China;Institute of Innovation and Entrepreneurship,Southwest University,Chongqing 400715,China)

机构地区：[1]西南大学资源环境学院,重庆400715 [2]西南大学创新创业学院,重庆400715

出　　处：《环境工程学报》2024年第7期1913-1925,共13页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金面上项目(41977186);重庆市大学生创新训练项目(S202310635103)。

摘　　要：人工湿地在处理低C/N污水时存在碳源缺乏而严重限制反硝化进行的问题。为了补充反硝化需要的碳源,选择稀碱加热后的玉米芯(下称玉米芯(预))和普通玉米芯作为外加碳源引入湿地系统,开展了两个阶段的实验,分别为植物碳源预处理和不同碳源投加量(C/N=6、5、4)对人工湿地水质净化效果和温室气体排放的影响。第1阶段实验结果表明,人工湿地投加植物碳源后,会降低COD和NH_(4)^(+)-N的去除率,投加了玉米芯(预)和玉米芯的人工湿地出水COD值分别在19.25~25.97 mg·L^(-1)和22.22~23.56 mg·L^(-1),COD平均去除率分别在82.61%~87.12%和84.22%~85.13%,NH_(4)^(+)-N的平均去除率分别在82.44%~92.53%和78.27%~92.86%,而对照组NH_(4)^(+)-N的平均去除率均在90%以上。投加碳源后,系统对NO_(3)^(-)-N的平均去除率都在99%以上。植物碳源的添加并没有显著增加CH_(4)的排放通量,但会明显增加N_(2)O的排放通量(P<0.05)。第2阶段实验结果表明,随着C/N的增加,出水COD值也逐渐增加,C/N=6、5、4的COD平均去除率分别为86.38%、88.76%和92.38%;C/N=6、5、4的出水NH_(4)^(+)-N质量浓度都极低,去除率均达99%以上,出水TN主要以NO_(3)^(-)-N为主,C/N=6、5、4下的NO_(3)^(-)-N平均去除率分别为62.75%、58.41%和47.70%;人工湿地N_(2)O的排放通量随着C/N的增加而增加,而CH_(4)的排放通量相比第1阶段均有所降低,C/N=6、5、4的人工湿地表现为CH_(4)的弱源。以上研究结果表明植物碳源的添加提高了系统对氮素的去除,随着C/N的增加,系统对氮素的去除效率也在增加;但植物碳源的添加增加了温室气体N_(2)O的排放,且N_(2)O是综合GWP的主要贡献源,贡献率占90%以上。Constructed wetlands have the problem of severely limiting denitrification by the lack of carbon sources when treating low C/N wastewater.To supplement the carbon source for denitrification,dilute alkalineheated corncobs(hereinafter referred to as precorn)and common corncobs were selected as the additional carbon sources of the constructed wetlands.Two stages of experiments such as plant carbon sources pretreatment and the different amounts of carbon sources added(C/N=6,5,and 4)were conducted to study their effect of water purification and greenhouse gas emissions from constructed wetlands.The results of the first stage experiments showed that the constructed wetlands with plant carbon sources dosing decreased the removal rates of COD and NH_(4)^(+)-N.The COD of the effluent from the constructed wetlands with precorn and corncobs dosing were 19.25~25.97 mg·L^(-1)and 22.22~23.56 mg·L^(-1),and the average COD removal rates were in the range of 82.61%~87.12%and 84.22%~85.13%,respectively.The average removal rates of NH_(4)^(+)-N were82.44%~92.53%and 78.27%~92.86%,respectively,while those of the control groups were above 90%.After adding carbon sources,the average removal rates of NO_(3)^(-)-N in the system were all above 99%.The addition of plant carbon sources did not significantly increase the emission flux of CH_(4) flux,but it significantly increased the N_(2)O flux(P<0.05).The results of the second stage of the experiment showed that the effluent COD increased gradually with the increase of C/N.The average COD removal rates were 86.38%,88.76%,and92.38%when C/N ratios were 6,5,and 4,respectively.The effluent NH_(4)^(+)-N concentrations at C/N ratio of 6,5,and 4 were all extremely low,and their removal rates were higher than 99%,the effluent TN was mainly dominated by NO_(3)^(-)-N.The average removal rates of NO_(3)^(-)-N were 62.75%,58.41%,and 47.70%at C/N ratio of6,5,and 4,respectively.The N_(2)O flux from the constructed wetlands increased with increasing C/N.The CH_(4)flux was lower compared to that at the

关 键 词：人工湿地 植物碳源 玉米芯 C/N 温室气体 

分 类 号：X703.1[环境科学与工程—环境工程]