Water has MWRA bubbling with joy

It is flowing, 275 million gallons a day into our homes, and, boy, is it delicious, state officials say.

Tap water flowing to 2.3 million people in Greater Boston is now dramatically better tasting, officials say, thanks to a new treatment plant in Marlborough that uses ozone to remove contaminants with a decrease in chlorine.

''It's clean, and it's crisp, and it's refreshing, and it's a great product; we'd put the taste of our water up against any bottled water," said Frederick A. Laskey, executive director of the Massachusetts Water Resources Authority. ''Put our water in the refrigerator, and it's great. And our water is great out of the tap."

The ozone treatment not only affects taste, it also makes the water safer and cleaner than the stuff Greater Bostonians have been quaffing for generations, Laskey said.

A 2001 federal appeals court ruling spurred the MWRA to use ozone as a water purifier. The US Environmental Protection Agency had asked the authority to build a more sophisticated water filtration plant to remove contaminants. But the MWRA successfully argued that an ozone system could be built that would make the water safer and cleaner, and cost $180 million less.

On July 27 at about 11:45 p.m., a water treatment worker clicked a mouse and activated the massive $340 million John J. Carroll Water Treatment Plant, a looming stone structure on a hill 38 miles from Boston. Silently and with little fanfare, ozone-treated water began flowing for the first time into faucets, showers, toilet tanks, and water fountains in 41 communities, from Arlington to Boston, Swampscott to Quincy.

Bubbled through the water supply, ozone, which occurs naturally in the atmosphere, degrades and destroys the cell walls of bacteria, germs, and other organisms, including cryptosporidium, a potentially deadly waterborne pathogen that comes from animal waste.

''The ozone shreds, burns, and destroys any organic matter or contaminants in the water," Laskey said. ''It is highly effective."

Yesterday, the results got mixed reactions from a panel at a water fountain on Castle Island in South Boston.

''It tastes like Poland Spring water," said an approving Daquari Young, 10, of Dorchester, who took a sip after his cousin, Daslyn LaGrande, 6. ''It's fresh, like the air."

Victoria Strojwas, 12, of Dorchester, nodded thoughtfully after taking a big gulp.

''It tasted pretty fresh, yeah," she said. ''I like it."

But Laurie Joyce, 27, a bus driver from Malden who takes bottled water on her rounds, was unimpressed.

''I guess it tastes fine, nothing I can tell," she said with a shrug and a wipe of her chin. ''I don't know if it tastes better than Poland Spring, I don't know about that one."

The MWRA still adds chlorine to the water, along with fluoride for teeth, ammonia as a disinfectant, carbon dioxide to adjust the pH, and sodium carbonate to prevent leaching from lead and copper pipes.

The water, as always, comes from the Quabbin and Wachusett reservoirs in Central Massachusetts.

Since officials started using ozone three weeks ago, customer complaints about the taste of the water have plummeted, Laskey said, from about 50 a day to just one or two.

He credited the ozone's algae-killing properties, but the amount of chlorine added to the water has also been reduced by about a third, he said, along with chlorine byproducts.

Besides its pool-like aftertaste, chlorine in high concentrations has been linked to health problems, including birth defects, specialists say.

''Just viscerally, if you think about Clorox or any type of chlorine that you might use to disinfect your pool or to clean your laundry, it's nothing that anyone would want to drink, at least not in concentrated form," said Christopher Kilian, director of the clean water and healthy forest program at the Conservation Law Foundation, an environmental advocacy group.

Ozone should help reduce the problem, he said.

''It is definitely a step in the right direction," said David A. Reckhow, a civil and environmental engineering professor at the University of Massachusetts at Amherst. ''They're going to have much higher quality water as a result of the ozonation."

About 400 of the approximately 100,000 water treatment plants in the United States use ozone as a purifier, Reckhow said. Its cleansing properties were first discovered in Europe in the 19th century, Laskey said.

In Massachusetts, Amherst, Andover, North Andover, and Worcester have built ozone purification systems, Reckhow said. Worcester started using ozone in 1997, for health and taste reasons, a city official said.

''Ozone is a potent disinfectant," said Dino Eliadi, director of water and sewer operations in Worcester. ''Anything living, it kills it dead a lot better than any other disinfectant, and the disinfectant byproducts are not as controversial as chlorine.

''With ozone, you get 99.99 percent of any impurities removed, short of a crocodile coming in."

In Marlborough, production of the atmospheric gas takes place deep inside the treatment plant, named for a former MWRA board member who is now general manger of the town of Norwood.

There, powerful electric charges convert liquid oxygen into gaseous ozone, which is bubbled slowly through Greater Boston's water, stored temporarily in vats.

The results, Laskey said, are bound to please.

''Let it run and let it get nice and cold," he recommended.

Michael Levenson can be reached at mlevenson@globe.com.