Chaobai River is one of the important urban river sources in Beijing,and its Shunyi river section is a typical re-claimed water channel.It is of great significance to study the nutrient release rules and influencing factors at the bottom-mud-water interface in natural and reclaimed river reaches represented by different points.In this study,through indoor soil column simulation experiments,the release regularity of ammonia nitrogen in sediment at different sections of river channel under dif-ferent pH,DO and temperature conditions was analyzed,and the release flux of ammonia nitrogen at the mud-water interface was estimated.The experimental results show that the release trend of NH4+-N is obvious in overlying water and interstitial water of downstream confluence(S1),tidal subtraction junction(S2)and natural river channel(S3),while the release of NH4+-N is not obvious or the adsorption of NH4+-N occurs in the middle part of reclaimed water channel(S4)and reclaimed water outlet(S5).In the simulation of soil columns with different sections,the NH4+-N flux in interstitial water is 2.5～66.7 times that of overlying water,which verifies the process of nitrogen in the sediment being first released to the interstitial water and then diffused to the overlying water.The effects of different environmental factors(pH,DO and temperature)on the release of NH4+-N from the sediment showed different rules:with the increase of pH,the release flux of NH4+-N from the sediment first decreased and then increased.When pH=7,the release flux of NH4+-N reached the lowest value.With the increase of DO con-centration,the release flux of NH4+-N decreases,and the maximum release flux is reached when DO concentration is 3 mg/L.The higher temperature,the larger NH4+-N release flux.Under acidic or alkaline conditions,the lower the DO concentration and the higher the temperature,the greater the NH4+-N release flux.The results of this study can provide reference for the im-provement of water quality in Chaobai River.
关键词
环境因子/自然河段/再生水河段/氮释放/底泥-水界面/潮白河
Key words
environmental factors/natural river reach/reclaimed water reach/nitrogen release/sediment-water interface/Chaobai River
维普
万方数据