Clearing The Air
By Connie Sue Centrella
Protecting the health and safety of pool-goers continues to be the number-one concern for aquatic-facility managers and operators.
By June, the season has begun, and the majority of recreation facilities are in full operation. All sanitizing equipment should be operational to meet bather demand.
Chlorine demand will dictate the design of the sanitizing systems for a facility. The demand is based on various parameters:
Average water temperature
Presence of cyanuric acid
Direct sunlight/UV exposure
Surrounding vegetation and airborne debris
Chemical dilution from source water
Filter turnover and circulation patterns.
In addition, local and state codes must be reviewed to be sure the systems meet the standards.
Over the past several years, changes by regulators have increased the need for controllers and additional components to ensure bather protection from recreation water illnesses.
New standards also are on the rise for chlorine treatment in response to the science behind disinfectant by-products and their effect on bather health.
Make A Full Equipment Review
Early in the season operators should initiate a thorough review of the existing equipment and recommend any changes or upgrades so the expenditures can be included in budgets.
Maintaining accurate records of chemical purchases, daily chemical additions, and fluctuations in chlorine readings will go a long way in helping to analyze what needs to be improved.
This is also the time to examine existing equipment for age, and to note increased repair activity.
Many facilities are “greening” their pool environments by eliminating toxic chemicals. If the operators are trying to achieve an environmentally friendly facility, a review of the current sanitizers used, as well as chemical storage areas, should be made. Additionally, operators should be confident the sanitizers used are EPA-rated and -approved.
More facilities are adding new bather attractions, such as interactive water features, which require additional chemical demand, so sanitizing equipment should be upgraded to meet regulations.
If the facility is in a renovation stage, look into the new standards imposed by codes to meet higher sanitizer demand.
New sanitizing systems include electrolytic chlorine generation (ECG), Ozone and Ultraviolet (UV) as secondary sanitizers, and controllers that monitor chlorine activity, pH, and Oxidation Reduction Potential (ORP) monitoring. These controllers will interface with the chlorine feeders to achieve the optimal sanitizer levels at all times.
Advancements in salt chlorine-generation systems for commercial use are on the rise, and more aquatic facilities are embracing this technology. As the demand grows, ECG manufacturers are providing technology that achieves the most efficient and effective means of chlorination in the public (commercial) pool arena.
While the popularity of chlorine generation is mounting, there is often a lack of understanding about how the system operates--specifically, how to maintain a “salt” pool and the conditions necessary to ensure successful operation year after year.
Safety is the number-one advantage of installing an ECG system. It provides a safe and reliable method of sanitization; there is no need for bulky, heavy containers of powdered chlorine or tablets, or liquid bleach carboys.
There is no possibility of a chlorine leak or inexperienced personnel mixing chlorine with other dangerous chemicals. Erosion feeders--the cause of many accidents--are eliminated from the process.
The installation of the ECG system has proven to eliminate exposure to gaseous fumes, which has plagued operators for years. Facility safety and risk reduction are key reasons to consider this system.
Simple To Operate
Very few chemical adjustments are necessary. Organic sanitizers--such as trichlor--have a pH range of 2.8 to 3.5, which inherently lower the pH of the pool water, requiring the addition of sodium carbonate (soda ash) to raise the pH. In some cases, however, it will be necessary to lower the pH with the addition of muriatic acid or sodium bisulfate.
Another ECG benefit is that the equipment installation is easy and does not take up much room in the mechanical area. There are only four components to the system: a power supply, an electrolytic cell, a flow-protection device and, of course, salt, which is dissolved in the pool water.
Bathers Love It
Finally, patrons can enjoy a feeling of soft, silky water without red eyes, itchy skin, faded swimwear, or a chlorine smell. They cannot taste the salt, as the concentration range is 3,000 to 3,500 parts per million (ppm)--below human taste levels.
The comfort level of pool users and employees is improved, since there is no chlorine smell in indoor installations.
Recreational Water Illnesses (RWI) are a major threat to visitors of aquatic facilities, and thus a liability to the facility itself. Outbreaks of Cryptosporidium, Pseudomonas aeruginosa, E. coli, Staphylococcus aureus, andGiardia are on the rise.
This has compelled operators to reach out to secondary disinfection systems, such as Ozone and UV, to help kill these chlorine-resistant microorganisms.
Aquatic managers seek to eliminate risks by improving public safety, enhancing water quality, and reducing operating costs. This is driving the growing acceptance of Ozone technology as an effective means to prevent RWI.
This momentum has also spurred several manufacturers to interface their traditional sanitizers with Ozone technology, delivering the ultimate water-quality treatment.
There are two methods of Ozone production: Corona Discharge (utilizing electrical energy) and UV (utilizing light energy). Either method must be introduced into the circulation system downstream from all operating equipment, and before the injection point of the residual disinfectant.
Corona Discharge generators produce a much higher concentration and quantity of Ozone as compared to the UV Ozone generators. With the Corona Discharge method, as the air is exposed to an electrical current, a ring of energy is created, which looks like a crown (corona). As the air (or oxygen) flows through the corona, the oxygen molecules are split apart and then combine again to form ozone (O3).
Systems are designed so that, when the pump is turned off, the ozonation process ceases.
Ozone is a strong oxidizer of chloramines (chlorine disinfection by-products), which are formed when chlorine reacts with organic matter. Chloramines cause foul odors, irritation of the skin, eyes, and ears, and damage to indoor air-handling systems.
Also, new research is pointing to disinfection by-products (DPBs) as a cause of asthma in those who frequent aquatic facilities, especially those indoors. Installing an ozone-generator system will help to alleviate this concern because the DPBs are oxidized before they can affect bathers.
Ozone sanitizing improves water quality and bather comfort, while providing a safer, more pleasurable swimming experience.
A commonly voiced objection to installing Ozone technology is the upfront cost. As in any secondary sanitation method, the payback is based on savings to the end user.
Ozone destroys biofilm, which linger in filtration systems. By reducing the biofilm in the sand system, there is less cleaning and changing out of filtration media. Chloramines gas off, which can harm HVAC systems. By implementing Ozone technology, the structural corrosion of equipment is reduced.
The major chemical cost in an aquatic environment is chlorine treatment. The oxidation properties of Ozone can eliminate chlorine consumption by 50 percent. The operator no longer needs to “shock” the pool to oxidize--this is done continuously through the Ozone generator.
As state and local codes amend regulations to meet the sanitizer demand, many are now requiring Oxidation Reduction Potential (ORP) devices to measure the activity of the chlorine.
ORP relates to the oxidizing/reducing capability of the water by measuring the electron activity. The ORP probes only measure the ratio of oxidation. The electron activity is measured in millivolts (mV) with a recommended range of 650 mV to 750mV. ORP is only an indirect method to approximate the disinfectant level. Also, ORP measurements are influenced by the fluctuations in pH readings.
Although ORP does not specifically indicate the chlorine concentration in ppm, it does indicate the effectiveness of the chlorine as an oxidizer. An ORP reading will vary as pH fluctuates. As the pH increases, the millivolt reading on an ORP meter will decrease, indicating that the sanitizer is not as effective. Bringing the pH down or adding more sanitizer will raise the millivolt reading.
It is important that the operator calibrate the probes as part of the routine maintenance schedule because residue will build up on the probes and provide false readings. These are some of the reasons that manual testing with a DPD test kit is also required to ensure bather protection.
In order to effectively and efficiently monitor chemical-feed systems, it is vital that controllers be utilized to continuously feed the appropriate dosages. Controllers actually have the capability to read current disinfectant (either in ppm or ORP), pH levels, and alkalinity, sending an appropriate message to the chemical-induction feeders.
The message sent tells the feeders to add the correct chemical in order to achieve water balance, as well as chlorine demand.
The probes, which read chemical parameters, should be cleaned and maintained to remove residue buildup, which may interfere with readings. Operators should consult manufacturers’ instructions on how to properly clean the probes to assure that correct readings are being made.
It’s About Education
Keeping visitors comfortable and returning is the key to operating a successful aquatic facility. Critical to the health and safety of all is staying current with the changes in disinfection equipment, monitoring devices, and code requirements.
It takes time and research to understand the differences between the various systems available; attending as many education venues on these systems is recommended. This technology is the future, and the future is now.
Embracing as much knowledge as possible about these systems will create a safe and healthy environment for swimmers, as well as reducing risk and liability to the facility.
Connie Sue Centrella is a professor and Program Director for the online Aquatic Engineering Program at Keiser University eCampus. She is a five-time recipient of the Evelyn C. Keiser Teaching Excellence Award “Instructor of Distinction.” Centrella is an industry veteran with over 40 years experience in the pool and spa industry. She is a former pool builder with extensive knowledge in pool construction and equipment installation as well as manufacturing.