News Release

Japan's highest concentration air-feed ozone generator starts operation
- Advanced water treatment facilities for the Ishikawa Water Treatment Plant run by the Okinawa Prefectural Enterprise Bureau -

METAWATER Co., Ltd. (Headquarters: Tokyo, Japan; President: Tomoyasu Kida; hereinafter referred to as "METAWATER") is pleased to announce that it has delivered and completed an air-feed ozone generator to the Ishikawa Water Treatment Plant (Uruma City) run by the Okinawa Prefectural Enterprise Bureau. This ozone generator produces very-high-concentration ozone for advanced water treatment facilities.

There was a plan to expand and relocate the Ishikawa Water Treatment Plant due to the aging of its former facilities (150,000 m3/day) after 40 years had passed since its construction. Based on this plan, a new water treatment plant (routine treatment facilities) with a capacity of 165,600 m3/day was launched in November 2011. With the completion of the ozone treatment machinery and equipment, the advanced water treatment facilities are now ready for operation.

The main feature of the new facilities is the generation of high-concentration ozone, 50 g/Nm3, compared to the rated ozone concentration of 20–40 g/Nm3 produced by the existing air-feed ozone generator. This increased concentration will contribute to increasing the treatment efficiency and reducing system energy consumption.

The keys to generating high-concentration ozone using METAWATER's silent discharge ozone generator are the high accuracy of electrodes and cooling efficiency. The newly delivered ozone generator has significantly improved the accuracy of electrodes using a new approach. In Okinawa Prefecture, where water temperature remains high throughout the year, a chiller is used as part of cooling water equipment to supply low-temperature water. As a result, in addition to increasing the ozone concentration, the new facilities have improved ozone generation efficiency by about 15% compared to before.

In addition to air-feed ozone generators, the technology can be applied to oxygen-feed ozone generators. METAWATER is planning to expand into the ozone market both in Japan and abroad.


Outline of the Construction

1.Construction name: Construction of ozone treatment machinery and equipment for the New Ishikawa Water Treatment Plant
2.Location: Ishikawa Higashi Onnazaki, Uruma City
3.Period: October 1, 2013 to May 29, 2015
4.Ozone generator specifications: ・Ozone generation: 5 kgO3/h × 2 units
・Ozone concentration: Maximum of 50 g/Nm3
・Water cooling temperature: 15℃
・Ozonated air generation: 100 Nm3 /h (per unit)

High-concentration ozone generator

Full view of Ishikawa Water Treatment Plant

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