摘要
采用复合垂直流人工湿地(IVCW)系统,研究了系统内部水流方向上各态氮和其它理化参数的变化。结果表明,复合垂直流人工湿地中,硝态氮、亚硝态氮、溶解氧和pH沿水流方向逐渐减小;总氮去除率为43.63%,可使劣Ⅴ类水的总氮指标降至Ⅲ类;氮的去除主要发生在下行池,上行池因溶解氧低、有机碳不足和系统向水中释放氮的原因,脱氮效果不明显。
As a new ecological engineering for wastewater treatment and water quality man agement thrived at 1970' s,with the ad-vantages of low construction fee,l o w daily cost and easy to operation and management,constructed wetland(CW)is popularized all around world.CWpurified sewages by physics,chemistry and biol ogic function between the plant,microorgan ism and soil layer.It is well known that the discharging of sewages including surplus nitrogen will cause eutrophic ation of water body.Akey function of the wetland would be provided additional n itrogen removal.Integrated vertical flow constructed wetland(IVCW)was a new s ewage treatment technology by CW which was proposed together by Institute of Hy drobiology of Chinese Academy of Sciences,German Kalong University and Austria' s Vienna Agricultural University duringthe Ninth Five-Year Planin China. IVCWwas composed of down-flow vertical system and up-flow vertical system pl anted by Canna generalis and Acorus tartarinowii respectively.There was a parti tion wall between two vertical systems whose bottom was fed thr ough.The down-flow vertical system was 10cm higher than up-flow vertical system,that w ater flows in the course did not need motive force.IVCWhad a longer water r est rain time and stronger reply oxygen ability than c ommon wetland sewages treatme nt systembecause of length flow and interm ission inpouring water.Changes of th e nitrogen and physical-chemical characters of different l ayers in IVCWtreatin g sewages were m easured.The results showed that nitrate nitrogen and nitrite n itrogen decreased by 56.96%an d 63.43%along the direction of water i n the constructed wetland because they were deoxidize d to N 2 Oand N 2 by denitrification,and dissolved o xygen and pHalso decreased since the oxy gen consumed by nitrification and life f unction and acid release from organi c compound decomposed and nitrification.The total nitrogen concentration of lake water and effluent water was 2.120mg ·L-1 and 1.195mg ·L-1 respectively.IVCW was a well sewage treating system with the removal rate o f total nitrogen 43.63%and the index of total nitrogen in wetland down f r ombeyondⅤtoⅢ,according to the environmental quality level of surface water in China.T he nitrogen removal mainly happened in down-flow system in construct ed wetland.The denitrification efficiency in up-flowsystemwas not remarkable since the lowdi ssolved oxygen(0.71~1.48mg ·L-1 )and lack of organic carbon(COD Cr ,varied from 20.96to 28.10mg ·L-1 )and the organic nitrogen release fro m wetland system toward water.The am i nation of nitrogen was dominant whil e nitration was shorter for low disso lve oxygen and oxi-dation-deoxidized status in IVCW.I ncreasing reply oxygen an d organic c arbon in up-flow system could advance the nitrification and denitr ification that were crucial function of nitrogen removal in we tland and could i mprove the nitrogen removal efficiency of IVCW.Subsection inpouring water or pr etreatment to transform ammonia n itrogen to nitrate nitrogen were rec ommendato ry means to increase denitrification efficien cy in wetland.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2004年第4期757-760,共4页
Journal of Agro-Environment Science
基金
国家"十五"重大科技专项"受污染城市水体修复技术与工程示范"(2002AA601021)
关键词
垂直流湿地
污水处理
总氮
氨氮
vertical flow wetland
sewage treatment
total nitrogen
ammonia nitr ogen