Category Archives: Water Treatment

Get the facts to keep your pool and hot tub safe this swimming season.

It’s  not just about cloudy water.

Ten years ago the term Recreational Water Illness (RWI)  was not even a commonly used term. Based on great pool and spa industry  awareness efforts led by the CDC, when you Google the phrase RWI or Recreational Water Illness, you find 785k results. A lot has  happened in the last 10 years.

Cryptosporidium (Crypto) outbreaks are still increasing.  We finally know how to inactivate Crypto (it’s not easy, but it is possible);  by having many pools go to supplemental disinfectants like UV or Ozone to  mitigate crypto and other stuff. Filtration aids have emerged as well that help  remove crypto from pool water.

Yet, we live in a world that I still ask who the CPO®  certification holder is when I visit a public pool, and I check the pool and  spa water with test strips before I let my family get in. I have teenagers and  they don’t listen to me as often as they should. OK, they rarely listen to me  at all, but I hope it’s seeping in there somewhere. THEY even rely on the test  strip results.

We live in a world where skin rashes and outer and inner  ear infections remain very common from exposure to pool and spa water.  Here’s my RWI Prevention Week tips of the  year.

  • First and foremost, make sure you have the  proper disinfectant level and pH everywhere in the pool and spa at all times.
  • Second, download and review the “Crypto  Tookit Resource” from NSPF.
  • Third, be sure you don’t get in the water if  you have diarrhea. Shocking that I have to say that but, the fact is, too many  people do get in when they are ill and don’t have a clue how ill they can make  the rest of us. This includes swimmers, divers, polo players, coaches,  lifeguards and aquatic managers. Don’t work around the pool or spa and don’t  get in if you are sick.  Let’s keep it  safer this year.


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Pools and Hot Tubs – Does Science Support Pool Water Exposure Causes Cancer or Asthma?

If something was published in scientific literature 50 years ago, you  simply go online (or have a librarian) go online to find the paper.  The upside is that scientific, scholarly  publications never go away!  This is an  awesome thing since today’s scientists can determine the edge of scientific  knowledge and push forward. This reduces wasteful duplication.  The down side is that scientific, scholarly  publications never go away!

How prosperous do you think the pool and spa industry will be in  10 years if every year a handful of publications come out that “suggest”  exposure to pool water (or the air above an indoor pool) may cause cancer or  asthma?  I emphasize the word “MAY!”  Not that it does, it just “may.” That has  been going on for several years; it is not likely to stop. Many of the studies  did not have any information on how the pool was operated (disinfectant level,  type, bather load, filter type, fresh air make up, …). Pretty scary stuff to  have people making life decisions based on a research protocol that can’t be  duplicated.

This year, NSPF jointly funded researchers to develop a questionnaire to  make sure future researchers ask the right questions and give information about  the pool used in the research. With that information, we can start formulating  solutions – rather than being falsely labeled as “bad.”  This questionnaire will be presented at the 2012 World Aquatic Health™  Conference (WAHC). Five leading scientists from around the world (Reynolds – U of  AZ, Blatchley – Purdue, Kogevinas & Villanueva -Barcelona, & Plewa -U  of IL) will help us all understand reality from “news hype” on the relationship  between disinfection by-products and health.

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Decorative Water Features Need Robust Water Treatment

A recent article published by The Washington Post discusses an outbreak of the bacterial infection known as Legionnaires’ disease which reportedly affected eight Milwaukee area people in 2010.  The outbreak has been linked to a decorative water feature located in a hospital lobby that had been visited by all eight of the people who contracted the illness.  This and other similarly documented cases have raised question as to the risk factors associated with operation of such water features in public spaces, particularly those frequented by persons who may be immunodeficient, such as health care facilities.

Legionnaires’ disease is a fairly common topic in the commercial aquatics industry, as this condition is caused by a waterborne pathogen known as legionella bacteria.  The illness is a dangerous form of pneumonia and is contracted by inhaling aerosolized water droplets that contain the legionella bacteria.  Infections have, in the past, been linked to poorly maintained spas or hot tubs (both commercial and residential) as well as other types of public bathing places.

Legionella bacteria is naturally occurring and is commonly found in many water sources, including municipal drinking water, but typically at a concentration below that which would cause infection.  However, if there is a source of the bacteria, and conditions are favorable, the bacteria can quickly multiply to levels that may pose a health risk.  For this reason, it is critical that any water feature, especially those which create aerosolized water, is treated and maintained in such a way to control the presence of legionella bacteria along with other waterborne pathogens.

Most people, whether aquatic professionals or not, understand the purpose of treating and balancing swimming pool water to maintain a safe environment for swimmers.  Unfortunately, the importance of this protocol is sometimes overlooked in water features such as fountains that are not meant for direct interaction, but nevertheless can expose people to waterborne bacteria.  The health risk is by no means limited to aquatic facilities and water features.  Legionellosis outbreaks have been linked to many other types of water systems, including irrigation, car washes, water softeners, cooling towers, and even showers.  An ASHRAE standard exists for the purpose minimizing Legionellosis risk associated with building water system design and operation.

As for the case described in the previously mentioned article, the culprit was found to be a “water wall” style feature located in a main lobby area of a hospital.  The affected individuals had been exposed to legionella as they sat next to or passed by the feature and presumably inhaled aerosolized water droplets emitted by the cascading effects of the water wall.  This case took place in a hospital, but just as easily could have been a restaurant, or bank, or any other public space with an inadequately maintained water feature.  The point here is that regardless of the water feature type or setting, a method of disinfecting the water and maintaining the feature must be employed to prevent the growth of bacteria and ensure the feature is safe.

There are various options for disinfection of aesthetic water features.  Many of the same technologies that are used to disinfect swimming pool water are applicable to aesthetic water features as well.  These include a halogen residual (chlorine or bromine), ultra-violet light, ozone, and copper-silver ionization.  Selection and design of an appropriate system is typically dictated by the size and type of the feature, including the volume of water it will contain, as well as the setting in which it will operate.  Filtration is also important, particularly in larger scale water features, to prevent build-up of particulate and contaminants that can contribute to bacteria growth.

Beyond the disinfection systems, design of the feature itself also plays a key role in maintaining a healthy water feature.  Stagnant water areas must be avoided by providing adequate circulation throughout the feature – not only for the main body of the feature, but any concealed volume or reservoir as well.  Feature flow types should be considered for the setting in which the feature will be located, minimizing the aerosolizing of water when necessary.  Material selections must be appropriate, avoiding porous materials that can harbor bacteria growth.  The second outbreak case referenced in the Washington Post article mentioned previously describes a “spongelike foam material” used as a base for a bed of decorative rocks that the water feature flowed through.  A porous material such as this foam provides extensive surface area and interstitial space in which bacteria can readily reproduce without being exposed to good water circulation and thus disinfection.  Even when draining down a feature of this type for cleaning, it would be nearly impossible to adequately clean this type of material by any measure short of replacing it.  It is for these same reasons that porous materials should be avoided on swimming pool decks and spray pad surfaces as well.

Observable water features have been popularized in many environments – both indoor and out – for the unique aesthetic, soothing ambiance, and therapeutic presence that can be created by moving water.  These benefits, however, do not come without risk if the prevalence of waterborne pathogens is not properly addressed.  Ultimately, the design of and aesthetic water feature, regardless of type or setting, should be undertaken with the assumption that human interaction will take place – even if it is simply a passer-by taking a breath.  Any feature that maintains a volume of water must also treat that water in order to ensure it is sanitary.  These systems may be very simple, or may consist of multiple, fully automated sanitizing and monitoring components on par with the largest commercial swimming pool systems.  In addition, a testing protocol should be established for the water feature to monitor the water quality, ensure the equipment is operating properly, and the systems are maintained appropriately.  If these criteria are addressed when considering installation of a water feature, it can provide years of safe and sanitary operation.  Such a feature should be able to be enjoyed in a hospital lobby, without prompting a return trip to the hospital due to Legionnaires’ disease.

UV and Chlorine Water Disinfection Research

Purdue University, was awarded a grant of $75,000 as the first step in a three-year program to research combined UV and chlorine swimming pool water disinfection methods. The research will examine the effects of combined treatment on water and air chemistry in chlorinated, indoor pool settings.  The grant, managed and administered under the NSPF industrial research grants category.  The goal of this work is to give industry, regulators, facility operators and management a better understanding of swimming pool disinfection byproduct chemistry and technology options for their control, including Cryptosporidium inactivation. In turn this information will be helpful in reducing human exposure to DBPs in recreational water facilities.