城市河道底泥疏浚深度对氮磷释放的影响

Effects of depth of sediment dredging in urban rivers on release of nitrogen and phosphorus

利用苏州市古城区南园河底泥柱状样,研究了不同疏浚深度下,底泥中营养物氮和磷的释放规律.结果表明:不同层位底泥样中氮的质量分数随着沉积深度的增加而减小;底泥中TOC的质量分数及释放量对总氮的累积与释放有较大影响;底泥中氮和磷的释放量与疏浚深度有关,当疏浚深度为5 cm或15 cm时,从泥水界面向水中扩散的氮和磷的通量均较小.

The regularities of nitrogen and phosphorus nutrients released from the sediment of the Nanyuan River in Suzhou City at different depths of sediment dredging were studied by use of cylindrical specimens from the sediment. Some conclusions are drawn： the mass fraction of nitrogen decreases with the increase of the depth of the sediment; the mass fraction of TOC in the sediment and the amount of its release are of great influences on the accumulative release of the total amount of nitrogen; the release of nitrogen and phosphorus is closely related to the depth of sediment dredging, and the fluxes of nitrogen and phosphorus released from the interface of sediment and water are small when the depth of sediment dredging is 5cm or 15cm.