Ultraviolet device enlisted in crypto fight

New system for indoor pool 'better' than chlorine

Cryptosporidium is going to have a tougher time living in the tepid water of the city’s Indoor Aquatic Center.

When the competition pool reopens Monday after two weeks of maintenance, a new water-cleaning system — using ultraviolet light — will be in place to help kill bacteria and disease.

Ultraviolet light will “kill the crypto much better than the chlorine can,” Richard Ziesnas, director of environmental health for the Lawrence-Douglas County Health Department, said Thursday.

But the crypto-killing effectiveness of the new system is just a side benefit, pool officials said. They considered the technique long before last summer’s breakout of cryptosporidiosis in Lawrence, hoping to reduce the amount of chlorine used at the indoor pool.

“It’s something we’ve been looking at for two, three years,” said Mark Hecker, the city’s parks and maintenance superintendent.

He added, “this should eliminate crypto … This should eliminate everything. The idea is that you have sterilized water coming through there.”

Under the new process, all the water in the pool will be filtered every six hours. During the treatment, it will be moved through tubes that emit ultraviolet rays to kill bacteria and viruses, then chlorine will be added.

The process uses fewer chemicals than the typical method of “shocking the pool,” which raises chlorine to very high levels before other chemicals are added to make the pool palatable for swimming.

The “shocking” method creates an intense chlorine odor in pools, which fails to dissipate in an enclosed area like the Indoor Aquatic Center. That odor originally was the reason the ultraviolet system was considered.

“At the outdoor pool, excess chlorine burns off in the sun and wind,” Hecker said.

Mark Hecker, Lawrence's superintendent of parks and maintenance, checks out one of two new pieces of equipment that uses ultraviolet rays to kill viruses, bacteria and parasites in the water to supplement the traditional chlorination.

A year ago, a cryptosporidiosis outbreak that started among Lawrence swimmers led to nearly 100 laboratory-confirmed cases in seven northeast Kansas counties, with 89 of the cases in Douglas County. There may have been several hundred more unconfirmed cases, federal health officials reported early this year. No one died from the outbreak, though cryptosporidiosis can be fatal.

So far this year, one case has been diagnosed, and health officials found no connection to city pools.

Chlorine kills most bacteria and other organisms, officials said, but doesn’t do well against the hard-shelled cryptosporidia parasite unless raised to very high levels.

“The ultraviolet will be more effective, because it can penetrate the (shell) and kill the crypto much better than the chlorine can,” Ziesnas said.

But chlorine can’t be eliminated entirely, Ziesnas said, because the water must remain clean between trips through the filter.

“It’s not a cure-all to get rid of the chlorine altogether or be a substitute,” he said.

The new radiation system will cost the city $20,000, Hecker said. The city spends roughly $30,000 annually on pool chemicals; the new process will lead to a reduction in that cost. The family pool at the center had a similar system installed in January 2003.

“Overall this is a good thing the city is doing,” Ziesnas said. “It’s an added safety note.”