By Allan Finney,
Chlorine byproducts found in swimming pools are linked to higher incidences of asthma, lung damage, stillbirths, miscarriages and bladder cancer, according to research conducted in the U.S., Canada, Norway, Australia and Belgium.
One researcher noted that 10-year-old children spending an average of 1.8 hours per week in a swimming pool environment suffered lung damage she would expect to see in an adult smoker.
For conscientious swimming pools managers, the question this raises is are there viable alternatives to chlorine?
Ozone and ultraviolet are the two most commonly cited technologies.
Dr. John Marshall, of the Pure Water Association, an American consumer group campaigning for safer drinking water, states: “It shows we should be paying more attention to the chemicals we put in our drinking water and we should be looking for other alternatives to chlorination. A number of safe, non-toxic options exist, such as treating water with ozone gas or ultra violet light.”
Is Ozone viable for swimming pools? Recently Mainstream installed a chemical-free public swimming pool in Fairhope, Alabama. It uses Ozone technology and avoids the use of chlorine altogether. This is a first for public pools in North America.
The United States Navy Dolphin program has switched to Ozone technology over the last several years. A spokesman there stated that these systems have delivered the best water quality they have seen out of any systems they tried.
Numerous other private, public, commercial, waterpark and hotel and motel pools have switched to Ozone technologies as people become more concerned about chlorine and chlorinated byproducts. Other than the issue of carcinogens and other health problems, what are the relative benefits of Ozone vs. chlorine?
One of the main problems with adopting Ozone is that there is a higher initial capital cost to the swimming pool compared to chlorine. However, over the life of the pool Ozone and ultraviolet technologies reduce the on-going operating and maintenance costs. These costs can be significant. Chlorine is famous for destroying pool infrastructures, rusting out ventilation systems and destroying pool liners etc. Ozone poses no such problems.
The Ozone pool will be much cleaner, which means dirt, grease, oils, organics and other materials will wind up in the filter system much faster than with chlorinated systems. If the filter and strainer maintenance is not stepped up accordingly, the pool recirculating system will slow down and the pool will actually look dirtier than with Chlorine. However, proper maintenance of the filter system will solve this problem.
Part of the problem in adopting Ozone is that engineers, architects, pool builders and designers are not familiar with the technology. Some applications of Ozone, particularly systems installed 10-15 years ago were plagued with technical problems. Even though Ozone systems have been in regular use in Europe and other areas of the world since the 1950’s, pools here have generally relied on chlorine. Since our engineering, architectural and other technical training have all been geared to Chlorine, it takes re-education to now apply Ozone. Many people in these industries are reluctant to “shift gears” and take the time to educate themselves about the proper application of Ozone.
What is the difference in technologies? Chlorine is a complex man-made chemical that found original use in the infamous “mustard gas” of the First World War. Ozone has been in use for over 100 years, primarily in Europe and was first put to use for water purification, odor control and in medical hospitals (it is still being used medically today, though not commonly in North America).
Ozone is made from Oxygen or O2, which is converted through electricity to Ozone or O3. Ozone is a much more powerful oxidant than chlorine. However, the “shelf life” of Ozone is limited. It must be manufactured and used on-site. This is done through Ozone Generators which convert Oxygen in the air into Ozone.
As well, Ozone is considered a “short-term” disinfectant (although a continuous residual will guarantee disinfection) and chlorine is considered a “long-term” disinfectant. Chlorine is also an entrenched technology. It has been widely used in North America and was first adopted at the turn of the century. It is still the reigning champion of disinfection and has many supporters in the chemical and swimming pool industries.
However, as we’ve seen in this series, there are numerous problems associated with chlorine. And viable alternatives do exist. Some of the issues surrounding these technologies will be dealt with in the next article in this series.