潜流型人工湿地硝化和反硝化作用强度研究_黄娟

潜流型人工湿地硝化和反硝化作用强度研究黄娟,王世和,鄢璐,刘洋,王峰(东南大学市政工程系,南京210096)摘要:对芦苇、美人蕉、空白潜流型人工湿地中硝化、反硝化作用强度进行了对比研究.结果表明,潜流型湿地硝化作用强度受温度影响显著,且与总氮、氨氮去除率显著相关.各湿地硝化、反硝化作用强度的空间分布具有明显分层现象,湿地表层高于深层.芦苇湿地表层硝化作用强度呈中间高、两端低的变化趋势;深层则沿程递减;反硝化作用强度沿程变化不明显.垂直流湿地平均硝化作用强度高于水平流湿地;有植物湿地高于空白湿地;芦苇湿地高于美人蕉湿地.植物根系分泌物直接影响硝化作用强度,根际硝化作用强度由根面至非根区递减.潜流湿地具有较强的反硝化潜力,反硝化作用强度明显高于硝化作用强度.关键词:潜流;人工湿地;硝化反硝化作用强度中图分类号:X52文献标识码:A文章编号:0250-3301(2007)09-1965-05收稿日期:2006-09-26;修订日期:2006-12-05基金项目:国家自然科学基金项目(50278016)作者简介:黄娟(1980～),女,讲师,主要研究方向为水污染控制.IntensityofNitrificationandDenitrificationinSubsurface-flowConstructedWetlandsHUANGJuan,WANGShi-he,YANLu,LIUYang,WANGFeng(DepartmentofMunicipalEngineering,SoutheastUniversity,Nanjing210096,China)Abstract:Torevealthenitrogenpurificationmechanisminsubsurface-flowconstructedwetlands,nitrificationanddenitrificationintensitieswerestudiedinreed,cannaandunplantedwetlandsrespectively.Theresultsshowthatnitrificationintensityinsubsurface-flowwetlandsisremarkablyinfluencedbytemperatureandcloselycorrelativewithtotalandammonianitrogenremovalefficiency.Itappearsinuprightdirectionthatnitrificationanddenitrificationintensitiesinupperlayerarehigherthanthatinthelower.Forthereedwetland,nitrificationintensityislowinbothendsbuthighinthemiddleofupperlayer,whileitdecreasesgraduallyalongdistanceinlowerlayer.Thechangeofdenitrificationintensityalongdistanceisnotobvious.Averagenitrificationintensityishigherinvertical-flowwetlandthanthatinhorizontal-flowwetlands,higherinplantedwetlandsthanthatinunplantedwetlandandhigherinreedwetlandthanthatincannawetland.Thesecretionfromplantrootsdirectlyresultsinthegradualdecreaseofnitrificationintensityinplantrhizosphere.Resultsalsoshowthatintensityofdenitrificationisobviouslyhigherthanthatofnitrification.Thereby,subsurface-flowwetlandhasstrongdenitrificationpotential.Keywords:subsurface-flow;constructedwetland;nitrificationdenitrificationintensity目前,潜流型人工湿地已广泛应用于污水处理,但其脱氮效果却存在较大差异[1,2].一些中试规模的潜流型湿地处理生活污水可达90%的脱氮率,但也有部分湿地脱氮率低于40%[3].这是由于湿地脱氮是一个复杂的生态过程,受多因素综合影响,其机理仍未完全探明,故导致效果差异显著[