In Japan, water pollution is a serious problem in many lakes around residential area. The main cause of water pollution is domestic waste water. So, Japanese government has been making effort to raise a sewerage coverage ratio. However, it takes too long time to install sewerage systems into perfectly all houses. Now, a new way to solve the water pollution problems is needed, and Biotope may be the one. The system of Biotope is very simple. Biotope takes water from a lake, and clean up the water through water plants, and get back the water into the lake. By using this system, we can eliminate pollutant directly from water in lakes without using a lot of energy or other resources. It sounds wonderful if it really works.

 Of course the best solution of water pollution is to install sewerage systems into completely all houses and stop domestic waste water flowing into rivers and lakes directly. But I think Biotope can also help a lot to solve water pollution problems.

Reference: http://www.biotope.gr.jp/about/