HIRAKATA, Osaka Pref. -- Osaka Prefecture's once moldy-smelling, strange-tasting tap water is now safer to drink and better tasting thanks to three high-tech drinking water filtration plants that went into full operation Wednesday, prefectural officials claim.

With the three plants in the prefectural cities of Hirakata, Moriguchi and Settsu, a maximum 2.22 million cu. meters of water can be processed daily to supply cleaner, clearer tap water to 6 million people in all municipalities in the prefecture other than the cities of Osaka, Toyono, Nose and Shimamoto, which have their own water supplies, the officials said.

Conventional water purification cannot remove the tap water's old moldy smell, which comes from Lake Biwa's poor water quality, and the disconcerting taste of trihalomethane. But ozone processing and activated carbon filters in the new high-tech plants kill germs and take away funky odors, the officials said.

Ozone is a form of oxygen used as an oxidizing, deodorizing and bleaching agent in water purification. The processing method using ozone reduces the amount of trihalomethane to one-third of that produced by the conventional method, the officials said.

The new Hirakata plant, where each of five ozone generators produces 27.5 kg of ozone hourly, is capable of processing about 1.8 million cu. meters of water daily. Construction of the prefecture's three plants started in 1992 at a cost of about 88 billion yen.