Feature Article - November 2020
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Safer Swimming, Safer Breathing

Managing Water & Air Quality

By Joe Bush


Hefter said keeping water safe historically has been better known and practiced than maintaining good air quality. Originally facilities were built air-tight because the goal was to keep the heat in for energy saving.

"This caused a lot of problems because when you have people enter your pool they bring a lot of different things, and we get a buildup of combined chlorines which comes from nitrogen in the water and what happens if we don't have good air quality, that buildup in the water will get high," Hefter said.

"We super-chlorinate to get rid of them, and we put in a whole bunch of chlorine and it burns off those chloramines and it starts kind of like a fire in the water and it's like a pile of leaves. If it doesn't have a lot of circulation and oxygen it'll just smolder, but if you have a lot of air and air circulation it'll burn really hot and just dissipate."

She said in an indoor pool without good air circulation, chloramines dissipate and go into the air but if they have nowhere to go, they'll go to the area of least resistance, which is back in the water.

"The only way to get good air circulation was to open up the front doors, open up the back doors and turn on big huge fans to blow the chloramines outside. You see that with a lot of these facilities because they're so air-tight, and they don't have good air circulation. Newer facilities are taking into consideration those types of things."

Building specifications are bolstered by air circulation technology. Markey said his newest air quality hardware and software is a huge improvement from his former unit.

"The ability to evacuate all the air with spectator mode is great to quickly change the air based on current need," he said. "This was a great feature the other unit didn't have. While not used often, it is nice to be able to quickly 'clean up' the air, and would be excellent when having a larger event."

Pearce said chemistry works against the quest for air quality; the chemistry of the water is what creates the air quality issues. Unfortunately, what's used in a pool to make water safe also creates byproducts that create air quality issues.

He said it's impossible to get rid of the byproducts completely, and it's impossible to keep the air completely free of any of these compounds, but there are ways to reduce them. The biggest problem is that the chlorine that is essential to destroy bacteria reacts badly with the ammonia that is introduced with sweat or urine. When that ammonia mixes with chlorine, it creates a chloramine that rises off the surface of the water and creates the smell most people associate with pools.

"Therein lies the problem," Pearce said. "You have people releasing ammonia and you have chlorine, and the only way to successfully reduce those chloramines in the air is by adding additional technology. UV or ozone are typically the most prevalent additions that will reduce the amount of chloramines, but you're never going to completely get rid of them because you're always adding chlorine and you're always adding ammonia."

UV and ozone systems are pass-through systems so pools only get the benefit of those two additional bacteria killers when the water passes through the chamber, Pearce said, but bathers are adding ammonia to the water all the time.

"So the trick for a commercial pool is, how do you keep the air as chloramine-free as possible when the two ingredients to make chloramines are present all the time?" said Pearce. "That really is the trick for all manufacturers, and anyone involved in technology is trying to come up with the magic bullet."

Pearce said that until that magic bullet is invented or discovered, the only answer to improving water quality is to throw UV and ozone technology at it. Attacking air quality is the same, and the process simple.

"Air changeover is a big deal," said Pearce. "The more fresh air you bring in and the more chloramine-infested air you move out, the better the air quality."

The flip side is, because when facilities exchange the air in the winter—cold air brought in and warm air sucked out—the heating bill spikes. The opposite is true in the warmer months. That's the fine line operators must toe—how much fresh air to bring in, how to control the chloramine, with UV or ozone, and finding the break point in wanting to pay for additional heat or air conditioning versus keeping the air as clean as possible.

"Chlorine has got to be in the water, there's just no option," he said. "You have to have bathers, because otherwise what's the purpose of the pool? It's just because of the nature of the way a pool circulation system works, there's turnover times and it takes a certain amount of time for all of that water to get through whatever that technology is to help reduce the chloramine. Until there is something to put into the pool to stop that reaction from happening, it's going to happen.

"Unfortunately you add stuff to the pool to stop that reaction, you stop the chlorine from being effective and then what's the use of having the chlorine because now people get sick because there's not enough chlorine."