A study on Improvement of an Urban Lake by Bottom-Filtration

我们进行了改善富营养化湖泊水质的小试实验和底滤模拟。“底滤”是指湖水通过安装在湖底的过滤器进行过滤，滤液循环到湖水中。本实验采用分解花岗岩和黑土(安藤土)作为滤料。流通率设定为无流通率。14天和3.5天。我们发现，随着循环率的提高，水质变得更好，但滤料的差异不大。将对流传质引入滤池，对水体-沉积物富营养化模型进行了改造，并进行了数值模拟。实验结果与仿真结果吻合较好。通过模型的长期模拟，可以根据湖泊的水质指标给出最佳的循环率。

We have carried out the bench-scale experiments and the simulations on Bottom-Filtration for improvement of water quality in eutrophic lakes. "Bottom-Filtration" means filtration of lake water through the filter which is installed on the bottom of the lake, and the filtrate is circulated to the lake water. In the experiment we used decomposed granite and Kuroboku Soil (Ando soil) as the filter media. And circulation rates were set as no circulation. 14 days and 3.5 days. We found that water quality becomes finer as higher the circulation rate, but the filter media do not show much difference. Introducing mass transport by convection to the filter, we remake the Water-Sediments Eutrophication Model, and have carried out the simulation. The results of the experiments and simulations show quite good accordance. The long term simulation by the model can show the best circulation rate according to the target of the water quality of a lake.