The smell tells: busy indoor parks district and school pool enhances air quality: difficulties maintaining properly balanced water chemistry at the Gurnee Park District and Warren Township High School District indoor swimming pools brought numerous problems over the years.

The smell tells: busy indoor parks district and school pool enhances air quality: difficulties maintaining properly balanced water chemistry at the Gurnee Park District and Warren Township High School District indoor swimming pools brought numerous problems over the years. Swimmers complained about foul-smelling air and irritated eyes, skin and sinuses -- plus high corrosion rates from the chloramine-saturated air brought continuous maintenance headaches for building personnel. The adoption of a new system that automatically controls the rate and types of oxidation reactions in the pool water finally solved the facility's air quality problems. (Aquatics)(Cover Story)

Indoor aquatic facilities experiencing heavy bather loads seem to require constant attention to maintain high air and water quality. Such was the case in Gurnee, Illinois, where Warren Township building management for years battled foul-smelling air and cloudy water caused by the continual formation of undesirable chlorine by-products. To make matters worse, the 180,000-gallon pool's long hours of operation left little time to combat the problem. The installation of a new environmental process control system has finally brought sustained clean air for the first time since the facility opened in 1987.

Chronic Air and Water Quality Problems

The aquatic facility is located at the Warren Township O'Plaine Road campus for freshman and sophomores, and the 75 x 42 foot pool is shared with the nearby junior/senior campus and the Gurnee Parks District. The facility is open 16.5 hours each weekday, 11 hours on Saturdays and eight hours on Sundays. The Parks District schedules its aquatics functions around the school's physical education classes and swim team practices and meets. Due to its busy schedule, the pool's bather loads average several hundred persons per day during the school year, as well as during the summer.

Since the aquatic facility first opened its doors 14 years ago, facility management had received constant complaints about foul-smelling air, and swimmers often had difficulty breathing at the surface of the water. High chloramine levels (1 + ppm) in the Warren Township pool were also resulting in cloudy pool water. In addition, the chloramine-laden air brought a highly corrosive environment, resulting in the formation of rust to the structural steel supports about the pool.

High levels of chloramine in pool water cause skin, eye, and respiratory irritation. In an indoor aquatic facility, the problem is compounded because chloramine vaporize in the air and remain in the confined area. In an effort to control Warren Township's high chloramine problem, facility management installed an expensive ozone system in 1995. The use of muratic acid was also replaced at that time with CO-2 for pH control.

During the next five years, chloramine levels continued to run high, while air and water quality remained, poor despite numerous modifications and expansions to the ozone system. A final upgrade to the ozone system (expanding its ozone-generating capacity to the level where it would supposedly take care of a 1.5 million gallon pool) only brought a small measure of relief. Eventually, the manufacturer of the ozone system went out of business, leaving Warren Township with no way to service and repair the system.

All throughout this period, facility management also attempted to tackle the pool's water quality problem through superchlorination. This was performed every one to two weeks on Saturday or Sunday evenings, when the pool was closed for the longest periods during the week. As much as 40 gallons of sodium hypochlorite were added to the pool during these times in an effort to eliminate high chloramine levels.

During superchlorination procedures, all doors to the outside were opened and large fans blew fresh air over the top of the pool. Early the next morning following superchlorination, sodium thiosulfate was added to bring chlorine residuals down to a safe level before swimming activities began at 5:30 am. Despite these efforts, chloramine levels would quickly shoot back up and swimmers continued complaining about burning eyes and breathing difficulties.

A Solution

In early 2000, Warren Township pool facility management traveled to nearby Buffalo Grove High School to attend a demonstration of a new environmental process control system for indoor pools. The facility at Buffalo Grove is almost identical to the Warren Township High School facility. The chronic problems the facility had experienced with foul, chloramine-laden air were also similar.

After learning of the air quality problems experienced there over the years, attendees were amazed at the absence of "chlorine" odors inside the Buffalo Grove facility, and the exceptional clarity of the pool water. This positive change was attributed to an Environmental Control System (ECS) by Strantrol[R], manufactured by USFilter's Stranco Products, which was installed in May 1999. Based on this site visit, Warren Township decided to install the same system.

The ECS system was installed in July 2000 by Midwest Aquatics, Elgin, Illinois, and paid for by the Warren Township Parks Commission. At startup, the water balance was optimized to achieve a Ryznar Index of 6.5 and an Air Quality Index (AQI) of 100 percent. Almost immediately the air quality of the Warren Township facility improved and within a few weeks odor problems were eliminated.

The new system maintains combined chlorine levels in the pool water at very low levels to prevent chloramine odors. In addition, combined chlorine levels in the pool's dehumidification system are undetectable. The improvement in air and water quality has completely eliminated the need for the time-consuming chore of superchlorination.

Controlling Oxidation Reactions

The ECS feeds the optimum concentration of oxidizer in order to prevent the formation of volatile chloramine. Utilizing High Resolution Redox (HRR) technology, which directly and continuously measures oxidative disinfection activity, the ECS system controls not only the rate of oxidation but also the types of oxidation reactions that take place in pool water.

Through the optimization and control of the rate of oxidation of all organic nitrogen compounds entering the pool, the formation of volatile chloramine is thereby prevented. Swimmers contribute organic-based nitrogen substances to pool water that contain complex substances, which release by-products into the water as the substances oxidize. These by-products place a demand on chlorine. Typically, conventional chlorine control systems respond slowly to sudden changes in demand and may overfeed during low demand. ECS technology, on the other hand, measures true demand, ensuring the appropriate amount of oxidants are present, resulting in optimum air quality and clean, clear pool water.

The process control system also calculates the Ryznar Index, which indicates the corrosive tendencies of the water and computes the required chemical addition needed to balance pool water. By maintaining the proper Ryznar Index, maintenance costs at the facility have been reduced as equipment life is extended, and pool surfaces require less cleaning.

Conclusion

Today, after years of never before experiencing chloramine-free air, Warren Township pool facility management receives only compliments about air and water quality. The pool area is virtually chloramine odor-free, and the water is clear and "feels" clean. The improved air quality and less corrosive atmosphere ensures that the township's investment in air handling equipment is protected. In addition, the township has found cost savings in terms of chemical consumption because the amount of chemicals needed to maintain optimum air and water quality has been reduced with the new system.

Due to facility management's confidence in the new system, Warren Township recently hosted its own ECS demonstration day. Future plans are for a new indoor pool at the other Warren Township campus, and facility management will recommend that ECS technology be utilized there as well.

Paul Monahan, author of "The Smell Tells: Busy Indoor Parks District and School Pool Enhances Air Quality" on page 58, is Director of Buildings and Grounds for two high schools serving the Warren Township High School District #121, and he interfaces regularly with Gurnee Park District to coordinate the sharing of facilities. He is a licensed Aquatic Facilities Operator (AFO) by the National Recreation and Park Association and a Certified Pool Operator (CPO) by the Illinois Department of Public Health. This is his tenth year with the school district.