A ceramic membrane filtration system with a capacity of 38,900 cubic meters per day was completed at a water purification plant in Oshio, Echizen City, Fukui Prefecture, it was announced on November 22, 2006. This system, the largest of its kind (including polymer membrane systems) in Japan, is the result of a joint venture by NGK Insulators, Ltd. and Ebara Environmental Engineering Co., under contract with Fukui Prefecture. The water purification plant started operation on December 1, 2006, and supplies water to residents in three cities and two towns along the Hinogawa River, which runs through the central part of Fukui.

Before adopting the ceramic membrane filtration system, the prefectural government field-tested six systems: five types of membrane filtration system and one sand filtration system. The ceramic membrane system was found to be superior to the others in terms of reliability, durability, recyclability, and life-cycle costs.

The installed system consists of 18 filtration units, each of which has 100 cylindrical ceramic membrane elements. An element is one meter long and 18 centimeters in diameter, with a surface area of 15 square meters. Using microporous ceramic membranes (pore diameter: 0.1 microns), the filtration system removes various impurities, such as suspended solids, Escherichia coli and Cryptosporidium, a parasite that causes diarrhea.

This system does not require a large site because there is no need for a sedimentation basin or a rapid sand filtration basin. It is fully automatic: all processes, including a backwashing process, are performed without human intervention. Other features include less frequent replacement due to the long-life ceramic membranes and low running costs per water volume filtrated.



Posted: 2007/02/13 09:30:29 AM
Japanese version

TAG Food/Water , Local government , Manufacturing industry