The membrane technology is one of Japan’s advanced elemental technologies in the water business. Japanese companies are offering various kinds of membranes for water treatment including those for seawater desalination, for purified water production for industrial purposes, for the elimination of pathogenic microorganisms in purification, and for the membrane bioreactor (MBR) method to produce high quality treated sewage. The pore diameter of a membrane varies with purpose. For example, the reverse osmosis membrane for seawater desalination has a pore diameter as small as 0.1 nanometer. Besides the precision and well-regulated pores, membranes need to be durable against pressure and chemical cleansing, not to mention that they should be stain resistance to prevent clogging.
Japanese companies, such as Nitto Denko, Toray, and Asahi-Kasei, maintain the leading position in the above technologies. For example, Japanese reserve osmosis membranes have a dechloridation ratio of 99.7% and a life period of 5-7 years instead of the standard 3 years. In addition, they allow for the collection of 60 units of freshwater out of 100 units of seawater, 20 units higher than the standard level. Accordingly, Japanese companies have a combined share of about 70% in the reverse osmosis membrane market and about 60% in the whole market of water treatment membranes including microfiltration membrane. At the same time, Japanese pumps for seawater desalination are enjoying a high popularity thanks to the reliability against continuous operation under high pressure. Torishima Pump has 40% in the world market of pumps for seawater desalination.
Leakage from water pipe is also a big issue for effective management of water resources. The rate of leakage is reportedly as high as 20% in some area of the world, but it is about 7% in Japan. Tokyo achieved a rate of leakage as low as 3.1% in 2008 because it tried hard to reduce it by virtue of the regular observation using leakage detector and acoustic bar besides the regular measurement of minimum flow rates. As mentioned above, the reliability of elemental technology and effective management of water resources are vital to the stable supply of water. All companies involved in the water business need to develop the technological advantage, while making continuous efforts for cost reduction. (To be continued)