This article appeared in the July/August issue of Athletic Business. Athletic Business is a free magazine for professionals in the athletic, fitness and recreation industry. Click here to subscribe.
Today's commercial swimming pools — whether built for competition, recreation or wellness — are complex operations. And that's before anybody takes the plunge. Add swimmers, each introducing a paper clip's worth of organic material to the water, and you have a recipe for what one pool professional calls "homo sapiens soup." Large bather loads bring even greater challenges to the delicate but critical process of keeping the water clean, disinfected and safe for users.
A facility unable to meet these demands will bear the telltale sign of its struggles — an unmistakable scent of chloramines, byproducts of the water chlorination process that have off-gassed into the air. They signal an imbalance in the pool's water treatment system that could hold more dire consequences for the facility and its users than mere unpleasant odor. A report released in May by the Centers for Disease Control and Prevention found that one in eight public aquatic venues out of more than 48,000 inspected in 2013 were closed immediately due to serious health and safety violations. A quarter of all violations (including those that didn't force closure) involved water chemistry. "No one should get sick or hurt when visiting a public pool, hot tub or water playground," said Beth Bell, director of the CDC's National Center for Emerging and Zoonotic Infectious Diseases, in the release. "That's why public health and aquatics professionals work together to improve the operation and maintenance of these public places so people will be healthy and safe when they swim."
AB asked a handful of industry experts how pools can improve their water quality. Here's what they said:
1. KNOW YOUR SOURCE WATER
The contents of the water used to fill and refill the pool will greatly influence treatment effectiveness. "Some communities have a lot of minerals or metals in their water, and at their water-treatment plants they add products that mask various molecular complexes," says Doug Whiteaker, president of aquatic facility design firm Water Technology Inc. "Source water comes into the facility, and it seems like there are no metals in the water, but as soon as it hits chlorine — boom — metal precipitates out of the water and that becomes an operational challenge."
"We have a list of cities now that have gone to chloramination, rather than chlorination, so they're artificially introducing ammonia into the water source," says Mick Nelson, USA Swimming's club facilities development director. "When we use make-up water, which we do at any large facility every day, we're actually adding chloramines into our pool. So that's become a problem. We've had to install activated-carbon filters to remove those chloramines before we refill our pools."
2. DETERMINE YOUR INTENDED USER BASE
It is important to assess the intended programmatic uses of the facility, as well as its desired user demographics and attendance. There are a plethora of ways to provide sanitation to the pool water, with chlorine — either stored on site or site-produced — representing a significant segment of the market.
Chlorination levels will vary depending on whether the pool will host swimming competition or practices, if it's a smaller warm-water wellness pool, or if it's designed to provide what Whiteaker calls "watertainment" in the form of a leisure pool or larger water park. "If you have a competition pool with a large volume of water, you need a lot of pounds of chlorine available to sanitize," Whiteaker says. "But when you get into smaller volumes of water, since pool sanitizers are measured in parts per million, less actual residual sanitizer is available in the water." In addition, maintaining the water's pH balance is critical to ensuring optimal effectiveness of the pool water sanitizer.
Different users will bring different disinfecting challenges. "Younger users and older users can have higher organic loads on their bodies," says Whiteaker, referring to children age six and younger and active-aging adults 60 and older. "You can influence the design with higher turnover rates so that your sanitation and supplemental sanitation systems can adapt to the varying user demands on the pool and adjust water sanitation and pH levels optimal to maintaining water quality."
Facilities that regularly operate at full user capacity may opt to clear the pool every hour so the next 200 patrons can use it. "The problem with that is you have another 200 sweaty, dirty bodies" that the disinfection system must address, says Robert Burrows, vice president of sales and marketing at SureWater Technologies Inc. "Not everybody is sweaty and dirty, but they're carrying whatever they have on them to the pool, so it's a new bather load every hour. That's a real issue."
3. SIZE YOUR SANITATION SYSTEM PROPERLY
To keep up with those types of bather loads, or even the single heavy surge of a swim practice taking over a 50-meter pool, the sanitation system must be sized properly, and Burrows believes bigger is better. "The standards in the past have really focused on what a pool is going to require during the course of a day, what the facility's consumption of chlorine in going to be in 24 hours, and that's really not a good way to do it," he says. "We take from that how much supply is going to be required on hand at the facility, so we don't run out during the course of a day, but the problem is there isn't any given standard for minute-by-minute or peak use. Better standards are starting to come."
In the meantime, a majority of existing high-end commercial aquatics facilities may be operating with undersized sanitation systems, according to Burrows, and even newly constructed facilities can fall short. The reason? Cost savings. "This is changing," Burrows adds. "We've worked with design firms and owners whose goal is to make sure that the water park, for instance, is going to be on the money all the time. They can't afford to close even one body of water during the course of a business day, and they're looking to high-capacity feed systems that are very efficient at getting that product into the water."
4. UTILIZE SUPPLEMENTAL SANITATION
Codes invariably require some form of halogen (typically chlorine) to serve as a pool's primary sanitizer, but supplemental sanitation in the form of ultra-violet light, ozone or other hydroxyl-based advanced oxidation equipment has become commonly accepted as a necessary system component within the past 10 years. "We need to have supplemental sanitation to remove the byproducts of chlorination — the chloramines — from pool water and help minimize their off-gassing into the environment, as well as add another layer of disinfection to protect user safety and create a healthy user experience," Whiteaker says.
Most useful in indoor aquatic environments, supplemental sanitation is particularly effective at addressing the challenges of peak usage periods and in facilities catering to children that must handle the biological issues brought on by fecal accidents.
"They're no longer being considered Band-Aids; they're being considered standard operating equipment," Burrows says of today's supplemental sanitation options. "So when somebody's designing a facility, they're looking right up front at UV as a requirement in the system." He is quick to add, however, that while supplemental sanitation can work well in tandem with the chlorination process, it's still secondary. "If you're not chlorinating sufficiently, you have to get that right first."
5. ENSURE EFFICIENT FILTRATION
Pool water contaminants come in all shapes and sizes, from tiny viruses and bacteria to long strands of hair, and the more of these particulates a filter can capture the better. Sand filters offer ease of use and low cost when compared to regenerative filters featuring replaceable media, but they are far less efficient at capturing contaminants. That means a pool's chemistry is confronting the same contaminants over and over as water cycles through the system. "The smaller the particulate matter you can remove, the more efficient your filtration system is," Whiteaker says. "At one pass, if you can remove particles down to two or three microns, you're much more efficient than if you have a system that's only filtering particles from 30 to 70 microns."
Unlike regenerative media systems, sand offers a relatively permanent filter media, but may require the addition to pool water of flocculation and sequestering agents that bind particulate for easier capture, or additives that reduce the porosity of the filter media to improve efficiency. "I know there are still a lot pools out there that have very functional sand filters that are going to have harder issues to solve because they're not filtering as effectively as the new-age filters," says Nelson.
Manually skimming and vacuuming pools — particularly outdoor pools subject to organic and inorganic material (bird waste, leaves, dust and other debris) — will also help to unburden the sanitation and filtration systems.
6. PROGRAM FOR ADEQUATE WATER TURNOVER
Most large pools, including competition pools, cycle their entire water contents through the system a minimum of once every six hours, but circumstances may dictate adjustments to that schedule, provided the pool is equipped with a variable-frequency drive and sufficient filtration capacity. "You can turn it over faster," Whiteaker says. "If you're going to have a big event with much higher use, you may have to go beyond the health department code minimum. If we know that there's going to be heavy use with some pools — even 50-meter pools — for the 12 hours a day that they're open, we can go to a four-hour turnover rate, because we know water quality and safety is a higher priority than operational costs."
Pools catering to toddlers with zero-depth entries and two feet of water at its deepest will require more frequent turnover. "We will actually use 15 — and at most 30 — minutes of turnover time for those areas just to be able to have that water filtered, analyzed by the water analyzer and then adjusted to get good sanitary conditions in this high-user-load area," Whiteaker says.
In addition, treated water should be returned to the pool evenly. "The distribution system includes both the capture of the water and returning it back to the filtration system and then the inlets in the pool returning the sanitized water back to the pool as the purest water in the system," says Whiteaker, pointing out that most codes call for pool inlets to be placed every 15 or 20 feet, but pools requiring more frequent turnover should be equipped with more inlets. "It's important to distribute that water over the pool so that you can effectively reach any part of that pool with the distribution of sanitized water in a short period of time."
7. ENFORCE USER RULES
Perhaps the most basic measure to improve pool water quality is minimizing the introduction of contaminants in the first place. "Somewhere along the line — maybe 20 or 30 years ago — we lost control of how the people prepare to get in the swimming pool," Nelson says. "They quit taking showers."
USA Swimming advocates the posting of signs that encourage users to shower before entering the pool and discourage urination once they're in the water.
Research and anecdotal evidence shows that a 15-second warm-water rinse without soap can go a long way toward sparing the sanitation system from having to combat chemicals in deodorants, cosmetics, shampoos, conditioners and lotions that didn't exist 25 years ago, according to Nelson. Even showers that offer soap may be dispensing a product harmful to the pool's chemistry. "What we're starting to find out is that these chemicals are just as much the culprits in causing chloramines as peeing in the water and sweating in the water," he says.
Urination is not limited to the kiddie pool, either. Nelson says that one in 10 adults admits to urinating while in the pool out of convenience. "They figure one person isn't going to hurt. Well, one person can affect 10,000 gallons of water for nine days. All of a sudden, we have 20 people doing it? We've got a water-quality problem."
None of these measures alone represents a sufficient solution to pool water quality concerns. They are all part of the puzzle. Burrows speaks of a "layered" system when he says, "Just like with drowning prevention, the more you can do, the more things you have in place, the safer your water is going to be and the safer your customers are going to be."
"Like anything else in life, it's all about balance," adds Whiteaker. "You have to balance the entire system to have a good user experience and a safe user experience. It starts with understanding what the goals and objectives of the owners are and to be able to make sure you can design a system that aligns with those priorities. Otherwise, there are going to be long-term operational challenges."
This article originally appeared in the July/August 2016 issue of Athletic Business with the title "7 steps to ensure proper pool water quality"