改性沉积物除藻对水质改善的效果研究

通过生态模拟箱(1m×1m×1m)模拟天然湖泊环境,研究了改性沉积物的除藻效果和对水质的改善作用.改性沉积物除藻后,测定和分析了除藻箱体和不除藻箱体内的叶绿素、浊度、DO、TN、TP、DIN、DIP等水质指标.在改性沉积物投量为43mg·L-1时,4h除藻率可达到85%以上.除藻2d后,水体中叶绿素和浊度降低90%,总氮、总磷分别降低70%、80%,这些指标在15d的连续监测期间变化不大.除藻后2箱体中DO都有不同程度的下降,但除藻箱体中DO明显高于不除藻箱体.并且在此实验期间,除藻箱体DIN降低,DIP稳定在较低水平,而不除藻箱体中DIN与DIP均有明显升高.说明改性沉积物除藻能有效减缓水体的厌氧情况,在短期内能抑制营养盐的释放.以上结果表明了改性沉积物在除藻的同时能有效改善水质,可用于水源地的水质保护.

Study of the effect on water quality improvement by removal of algal blooms using modified sediment

The effects of flocculation and removal of algal blooms using modified sediments and its consequent water quality improvement after the removal were investigated through ecological simulation experiments in 1 m3 boxes simulating natural lake environment. Water quality parameters, such as Chl-a, turbidity, DO, TN, TP, DIN and DIP, were measured and analyzed after the removal. More than 85% of algal cells were removed in 4 hours when 43mg·L-1 modified sediments were added. The turbidity, Chl-a, TN and TP were decreased by 90%, 90%, 70% and 80% respectively after 2 days of removal. The above parameters remained relatively stable within the 15 days of observation. DO in both experimental boxes declined, but DO in the treated box was obviously higher than that of the control. Moreover, DIP in the treated box remained at a relatively low level while DIN reduced, however DIN and DIP in the untreated box increased substantially, indicating that the removal of algal blooms using modified sediment could effectively alleviate anaerobic condition and restrain the release of nutrients in short term. The above results suggested that the water quality could be improved obviously after the removal of algal blooms using modified sediment, which could be applied in the protection of water source.