再生水回用于景观水体氮营养盐对叶绿素a和藻密度的影响研究

Effect of nitrogen nutrients on chlorophyll a and algal density in landscape water supplied with reclaimed water

再生水回用于景观水体是否会带来严重的生态风险,尚需广泛而深入的研究。以北京市某再生水厂出水为研究对象,人工配制各浓度梯度的营养盐,试验研究补给再生水后景观水体水质指标的变化,重点考察氮营养盐(氨氮、硝酸盐氮)对叶绿素a和藻密度的影响情况。试验结果表明叶绿素a和藻密度主要受水体中氮磷比和磷酸盐浓度的影响,与单独的硝酸盐氮浓度增加并无直接的关系。当磷酸盐浓度保持在1mg/L以下,氨氮浓度在4mg/L以下,硝酸盐氮浓度在16mg/L以下,将再生水一次性补给景观水体是可行的,不会产生藻类暴发。

Whether or not reusing reclaimed water for landscape water would result in serious ecological problem still needs to be extensively and deeply investigated. In this study the effluence of a Beijing reclaimed water treatment plant was chosen to investigate the variations in quality indicators of landscape water after the supplies of reclaimed water, especially focused on effects of nitrogen nutrients （ammonia nitrogen, nitrate nitrogen） on the chlorophyll a and algal density. The experimental results showed that the concentration of chlorophyll a and algal density were mainly influenced by N/P ratio and concentration of phosphate in water, but no direct effect by the increasing of nitrate nitrogen concentration. With phosphate concentrations below 1 mg/L, the ammonia nitrogen concentration below 4 mg/L, and the concentration of nitrate nitrogen below 16 mg/L, supplying landscape water with the reclaimed water is feasible and does not cause serious algal outbreak.