Meiwa Industry in Kofu city of Yamanashi Prefecture developed a water purification system to filter water of rivers and lakes without an aggregating agent. The filtered water can be drinking water. The company laminated filtering materials including sands of different diameters in its own method. It wishes to have this system patented to market it through licensing agreement not to mention through sales distribution channels.
The system adopted the sandwich laminating method. Water is supplied in the bottom of the equipment and purified as it goes up from the bottom. The finest filtering materials smallest in diameter are put in the middle, and the filtering materials grows bigger in diameter as the layer stack goes upward and downward. The company successfully increased the durability of the system by preventing the filtering materials from falling to pieces when water pressure is applied. The finest filtering material is 20 micrometers in diameter. In the experiment, the company confirmed that the system filtered water of 139-degree turbidity to water of less than 0.1-degree turbidity that is totally acceptable as drinking water. A product description is available in a pdf file.