组合型生态浮床对上覆水和沉积物之间氮磷的影响

Influence of Combined Ecological Floating Bed on Nitrogen and Phosphorus Between Overlying Water and Sediment

在天鹅湖水体中构建以水生植物和陆生喜水植物为实验植物,浮法控制器、水循环增氧系统和造浪-输送系统为辅助设备的组合型生态浮床.组合型生态浮床运行期间改变了水体的理化环境,影响了上覆水-沉积物中氮磷形态的迁移转化,跟踪监测在组合型生态浮床影响下上覆水和沉积物TN、NH4+-N和TP含量的浓度变化规律,探讨了在组合型生态浮床作用下,DO、Eh、pH对上覆水和沉积物中营养盐的影响,以及上覆水和沉积物中氮磷之间以及和各环境因子之间的相互关系.结果表明,实验期间上覆水中TN、NH4+-N和TP的去除率分别达到61.92%、63.09%和80.0%.沉积物中TN和NH4+-N的去除率分别达到23.79%和37.04%,沉积物中TP含量上升了43.71%.组合型生态浮床对上覆水环境因子如DO、Eh、pH等产生不同程度的影响,处理区上覆水中DO和Eh均高于对照区,DO由原来的8.7～8.9 mg·L-1上升到9.3～10.4 mg·L-1,Eh由原来的163～178 mV上升到191～198 mV,通过提高上覆水中DO和Eh有效抑制沉积物磷的释放并促进沉积物对上覆水中磷的吸附.pH的波动性较小,维持在7.51～8.32之间,并未促进沉积物磷释放.上覆水中TN、TP和NH4+-N以及与沉积物中的TN、NH4+-N之间呈极显著正相关,与沉积物中的TP极显著负相关;pH与上覆水和沉积物中的TN、TP和NH4+-N都无相关性;上覆水中的DO与Eh显著正相关,与沉积物中的TP显著负相关.

A new type of combined ecological floating bed was developed on Swan Lake. It was combined with aquatic and hydrophilous plants and ancillary equipments that included floating controllers, water-cycling aerator systems and wave-making systems. Combined ecological floating bed changed the physical and chemical environment of Swan Lake and had an effect on the transportation and transformation of TN, NH~ -N and TP between overlying water and sediment during the experiment. The concentration change of TN, NH~ -N and TP and the effect of DO ~ Eh and pH on the nutrient in the overlying water and sediment were investigated. The results indicated that： in overlying water, the removal efficiencies of TN, NH4＋ -N and TP were 61.92% , 63.09% and 80. 0% , respectively; the removal efficiencies of TN and NH4＋ -N were 23.79% and 37.04% , respectively; the concentration of TP increased by 43.71% in sediment during the experiment. The combined ecological floating bed influenced environmental factors such as DO, Eh and pH in overlying water in some degree. DO concentration rose from 8.7-8.9 mg＇L-＇ to 9.3-10. 4 mg.L-~ , and Eh concentration was from 163-178 mV to 191- 198 inV. Both of them were higher than those in the contrast area. Phosphorus release was inhibited, and phosphorus adsorption was promoted through improving DO and Eh of the overlying water. The pH volatility was less and maintained between 7.51 and 8.32, and did not promote phosphorus release in sediment. TN, TP and NH4＋ -N in overlying water and TN and NH;-N in sediment were significantly positively correlated with each other and with TP in sediment. The pH had no significant correlation with TN, TP and NH4 -N in overlying water and sediment. DO was significantly positively corrected with Eh in overlying water and was significantly negatively corrected with TP in sediment.