生物炭对潜流人工湿地污染物去除及N_2O排放影响  

Influences of Biochar on Pollutant Removal Efficiencies and Nitrous Oxide Emissions in a Subsurface Flow Constructed Wetland

作　　者：邓朝仁 梁银坤 黄磊[1,2] 方丹丹 陈玉成 杜刚[3] DENG Chao-ren;LIANG Yin-kun;HUANG Lei;FANG Dan-dan;CHEN Yu-cheng;DU Gang(College of Resources & Environm ent,Southwest University,Chongqing 400715,China;Chongqing Engineering Research Centerof Rural Cleaning,Chongqing 400716,China;School of Urban Construction and Environmental Engineering,Chongqing University,Chongqing 400045,China)

机构地区：[1]西南大学资源环境学院,重庆400715 [2]农村清洁工程重庆市工程研究中心,重庆400716 [3]重庆大学城市建设与环境工程学院,重庆400045

出　　处：《环境科学》2019年第6期2840-2846,共7页Environmental Science

基　　金：国家自然科学基金项目(51408493);重庆市基础与前沿研究计划项目(cstc2016jcyjA0523)

摘　　要：生物炭作为一种生物质废弃物的热解产物,逐渐被应用于受污染水体治理.生物炭具有提高孔隙、吸附氮磷、控制温室气体排放等作用.通过在温室内构建生物炭投加比为40%、30%、20%、10%和0%的微型潜流湿地系统(分别命名为BW-40、BW-30、BW-20、BW-10和CW-K),探究生物炭投加对湿地污染物去除及N_2O排放的影响.结果表明,投加生物炭可以提高出水氧化还原电位(oxidation-reduction potential,ORP),降低电导率(conductivity,Cond),但影响均不显著(P> 0. 05).5组湿地系统中化学需氧量(COD)去除率均达到90%,但随着生物炭投加比的增加,氨氮(NH_4^+-N)和总氮(TN)的去除效果显著提高(P <0. 05).湿地NH_4^+-N平均去除率为(34. 76±14. 16)%～(57. 96±10. 63)%,TN平均去除率为(70. 92±5. 68)%～(80. 21±10. 63)%.各湿地系统N_2O的平均释放通量在13. 53～45. 30 mg·(m^2·d)^(-1)之间,生物炭投加可以通过减少亚硝态氮(NO_2^--N)累积浓度和积累时间,实现N_2O减排,并显著减少湿地中N_2O排放占TN去除的百分比(P <0. 05). 40%的生物炭投加比可以实现70. 13%的N_2O减排效果.Biochar,pyrolyzed from agricultural biomass wastes,has been widely used as an improver in wastewater treatment to regulate the oxygen distributions and microbial communities because of its extended surface area and porous structure. In addition,biochar has been shown to play a role in enhancing the porosity,adsorbing ammonium(NH4+-N),and reducing nitrous oxide(N2O)emissions. In this paper,five groups of constructed microcosm wetlands(CW) were built in a greenhouse with different biochar doses of 40%,30%,20%,10%,and 0%(named as BW-40,BW-30,BW-20,BW-10,and CW-K,respectively) to investigate the influences of biochar on pollutant removal efficiencies and N2O emissions. The results showed that the concentration of effluent dissolved oxygen(DO) was less than 0. 5 mg·L-1,and the p H was stable at around 7. 2 in every CW. Additionally,the effluent oxidation-reduction potential(ORP) was found to have moderately increased with the increases in the quantity of biochar,and the conductivity(Cond) test results showed the opposite trend. However,the effects of biochar on DO,p H,ORP,and Cond were not significant(P > 0. 05). The chemical oxygen demand(COD) removal rates were up to 90% in all CWs. On the other hand,significantly higher removal efficiencies for NH4^+-N and total nitrogen(TN) were found in CWs filled with biochar(P < 0. 05). The average NH4+-N removal rates were(57. 96 ± 10. 63)%,(51. 12 ± 11. 74)%,(48. 55 ± 8. 75)%,(43. 95 ± 9. 74)%,and(34. 76± 14. 16)% in BW-40,BW-30,BW-20,BW-10,and CW-K,respectively,while the total nitrogen(TN) average removal rates were(80. 21 ± 10. 63)%,(78. 48 ± 5. 73)%,(76. 80 ± 4. 20)%,(75. 88 ± 5. 85)%,and(70. 92 ± 5. 68)%,respectively.Nitrate(NO3^--N) was not detected in the CWs for there were sufficient carbon sources and suitable denitrification environments.Moreover,the average fluxes of N2O ranged from 13. 53 mg·(m^2·d)^-1 to 45. 30 mg·(m^2·d)^-1 in the experimental systems.Compared with the control,the reduction rates of N2O in the BW-40,BW30,BW20,and BW10 were 70. 13%,

关 键 词：潜流人工湿地 生物炭 有机污染物去除 脱氮 N2O排放 

分 类 号：X16[环境科学与工程—环境科学]