不同曝气方式对城市重污染河道水体氮素迁移与转化的影响  

Effect of Different Aeration Ways on Migration and Transformation of Nitrogen in Heavily Polluted Urban River

作　　者：刘波[1,2] 王国祥[1] 王风贺[1] 杜旭[1] 凌芬[1] 夏劲[1] 

机构地区：[1]南京师范大学地理科学学院,南京210046 [2]南通大学地理科学学院,南通226007

出　　处：《环境科学》2011年第10期2971-2978,共8页Environmental Science

基　　金：江苏省科技厅科技支撑计划项目(BE2008677);住房和城乡建设部科技项目(2010-K7-7)

摘　　要：以南京仙林大学城的重污染河道水体为对象,利用模拟方法研究不同曝气方式(底泥曝气、水曝气)对水体氮素迁移与转化的影响.结果表明,在缺氧和温度升高条件下,底泥氮素主要以NH 4+-N形式向上覆水释放;上覆水NH 4+-N的最大累积量表现为:水曝气<底泥曝气<对照,3种工况下上覆水中NH 4+-N的最高质量浓度分别为9.40、11.24、19.30 mg.L-1;曝气通过2种途径不同程度地消减系统中的氮素,一是通过氨挥发作用,二是通过硝化-反硝化作用;从上覆水、间隙水和底泥中氮素的消减效果来看,底泥曝气均要优于水曝气;实验结束后底泥曝气组间隙水中NH 4+-N的浓度和底泥中NH 4+-N的含量分别减少了64.36%和58.73%,水曝气组分别减少了39.53%和38.78%;从上覆水的氮素转化过程来看,曝气工况下的硝化作用启动比较缓慢,水曝气经历了9 d,底泥曝气经历了16 d;在曝气工况下,上覆水中均出现了NO 2--N累积现象,水曝气和底泥曝气的NO 2--N累积持续时间分别为17 d和14 d.Water and sediment samples were collected from a heavily polluted urban river in the Xianlin University Town of Nanjing.We examined the effects of different aeration ways（aerating to sediments,aerating to water） on migration and transformation of nitrogen,using the indoor experimental method.The results showed that： nitrogen release from sediments in the form of NH＋4-N that will accumulate under anaerobic conditions with increasing temperature;the maximum accumulation of NH＋4-N in overlying water showed that aerating to water groupaerating to sediment groupcontrol group and the maximum concentrations reached 9.40 mg·L-1,11.24 mg·L-1 and 19.30 mg·L-1,respectively;nitrogen compounds were generally eliminated from experiment system by a process of ammonia volatilization and a combination of two processes,i.e.nitrification and denitrification under aerating conditions;aerating to sediment was more effective for nitrogen removal than aerating to water,which was removed from overlying water,pore water and sediment;at the experimental endpoint,the concentrations of NH＋4-N in pore water and sediment were significantly decreased by 64.36% and 58.73% respectively compared with those before aeration in aerating to sediment group and that were decreased by 39.53% and 38.78% respectively in aerating to water group;during nitrogen transformation process in overlying water,start-up of nitrification was slowly under aerating conditions;it took 9 days to realize nitrification under aerating to water conditions and 16 days under sediment aeration conditions;the NO-2-N accumulation took place in overlying water under the condition of aeration;the sustain time of NO-2-N accumulating was 17 days in aerating to water group and that was 14 days in aerating to sediment group.

关 键 词：曝气方式 氮释放 氨挥发 底泥 硝化作用 

分 类 号：X552[环境科学与工程—环境工程]