北塘水库底泥盐分释放的影响因子研究

Impact Factors on Salt Release from Beitang Reservoir Sediment

为研究北塘水库作为天津市南水北调调节和事故备用水库的水质安全性,2005年7月～2006年1月,取北塘水库0～20cm混合底泥及0～60cm的圆柱状底泥,在实验室模拟了温度变化、风浪扰动、换水、下渗等条件下底泥Cl-的释放过程和释放强度,分析了Cl-释放对水库水质的影响。结果表明,温度越高,底泥中Cl-的释放速率越快,但释放量的差别随时间变得越来越小。在扰动条件下,10d以后,0～20cm混合底泥中的Cl-几乎全部释放出来。每换一次水,底泥中Cl-的释放量都会明显下降。释放和下渗将导致水库底泥中Cl-的含量不断降低,南水北调通水后,如果能保证一定的供水频率以及换水周期,北塘水库水质将越来越好。

To determine the security of water quality of Beitang Reservoir,Tianjin City as a regulating and accident standby reservoir for water transfer project,samples of 0~20cm mixed sediment and 0~60cm original state sediment were taken from July of 2005 to January of 2006 to simulate Cl-release process and intensity in the condition of temperature variation,wind disturbance,water exchange and seepage. The effect of Cl-release on water quality was analyzed. Results showed that with rise of temperature,release rate of Cl-increased,while the release amount and release difference in various temperatures became smaller with time. When water was disturbed continually,Cl-almost released totally from 0~20cm mixed sediment after 10days. The water renewal experiment indicated that the content of released Cl-decreased obviously after water was exchanged. The release and seepage of Cl-resulted in decrease of salinity content in sediment continuously. Water quality of Beitang Reservoir will become better in condition of water supply and water renewal periodically.