中水回用对社区景观水体叶绿素a变化的影响

Influence of treated wastewater reuse on variation of chlorophyll-a in community landscape water body

由于中水的营养盐含量较高,以中水为补水水源的社区景观水体存在较大的水华暴发风险.基于中水回用于景观水体的换水控制实验,建立了中水景观水体的富营养化模型,模拟了连续换水时和终止换水后叶绿素a的变化过程,分析了中水水质和换水周期对水体藻类生长的影响.结果表明,提高中水水质可以降低水体的叶绿素a峰值;在连续换水期,随着换水周期的缩短,水体的叶绿素a峰值降低,并且从开始换水至达到峰值的时间增长;在连续换水期后终止换水,叶绿素a会重新达到峰值,并且原来的换水周期越短,水体的叶绿素a峰值反而越高,达到峰值所需时间越长.模型应用可为中水回用于社区景观水体的水量水质设计与维护提供依据.

Treated wastewater provides potential water source for landscape water bodies in a community. However,these water bodies are at risk for developing algal blooms because of high nutrient levels of treated wastewater. Based on the data from water exchange experiment in an artificial landscape water body supplemented by treated wastewater,a eutrophication model was calibrated and validated. The model was furthermore applied to simulate chlorophyll-a variation in landscape water body during the period with continuous water exchange （period-1） and when water exchange was consequently suspended （period-2）. Effects of treated wastewater quality and water exchange cycle on algae growth were analyzed. The results indicate that：improvement of treated wastewater quality may reduce the peak concentration of chlorophyll-a; in period-1,the shorter water exchange cycle period is,the lower peak concentration of chlorophyll-a the water body has,and the longer time it needs to reach the peak; in period-2,the concentrations of chlorophyll-a will reach peak again,however,the shorter water exchange cycle in period-1 is,the higher chlorophyll-a peak concentration the water body has,and the longer time it needs to reach the peak. The application of the model can provide support for design and daily maintenance of community landscape water body supplemented by treated wastewater.