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

对富营养化湖泊进行了底滤改善水质的实验和模拟。“底滤”是指通过安装在湖底的过滤器对湖水进行过滤，滤液循环进入湖水。在试验中，我们使用分解的花岗岩和Kuroboku土（安藤土）作为过滤介质。循环速率设定为无循环。14天和3.5天。研究发现，随着循环速率的提高，水质变得越来越细，但过滤介质的差异不大。将质量对流输运引入滤网，重新建立了水-沉积物富营养化模型，并进行了模拟。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得出最佳的循环速率。

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.