Analysis of disinfection process for swimming pools

Puzzle-solving class: The "patron saint" of swimming pool water quality - a complete analysis of common disinfectants

On a hot summer day, a pool of blue water is the best choice to cool off. However, as a public place shared by many people, how can the swimming pool effectively kill bacteria and viruses that may be present in the water and protect the health of every swimmer? This is inseparable from a scientific and efficient disinfection system. Chongqing YuanGan Technology will take you to have an in-depth understanding of the common "water quality guardians" in swimming pools - disinfectants, and see how they show their special powers to protect a clear place.

On a hot summer day, a pool of blue water is the best choice to cool off. However, as a public place shared by many people, how can the swimming pool effectively kill bacteria and viruses that may be present in the water and protect the health of every swimmer? This is inseparable from a scientific and efficient disinfection system. Chongqing YuanGan Technology will take you to have an in-depth understanding of the common "water quality guardians" in swimming pools - disinfectants, and see how they show their special powers to protect a clear place.

1. The "main force" of swimming pool disinfection: chlorine disinfectants

Chlorine-based disinfectants are currently the most widely used and technologically mature category in swimming pools. They continuously kill microorganisms by forming "free residual chlorine" in the water.

1. Sodium hypochlorite - a safe and convenient "universal player"

• Form and dosage: Commonly known as "bleach" or "84 disinfectant", it is a liquid chlorine-containing disinfectant. It can be added directly and accurately into the swimming pool circulation system through a metering pump.
• Advantages: Non-toxic, non-explosive, safe to store and operate, it is the most mainstream choice for public swimming pools and community swimming pools.
• Disadvantages: The aqueous solution is unstable and the available chlorine content will decrease over time and needs to be stored properly; it will increase the pH value of the water and needs to be adjusted by adding acid.

2. Calcium hypochlorite - a stable and efficient "solid choice"

• Form and dosing: White powder or granular solid is usually prepared into a solution and then added through a metering pump. A special dry powder dosing device can also be used.
• Advantages: The solid form is more stable and easy to store and transport; when dissolved, it will release chlorine and produce calcium hydroxide, which helps to increase the pH value of the water body.
• Disadvantages: It will increase the calcium hardness in the water, and long-term use may form calcium scale on the pool walls and equipment; it needs to be dissolved first, and the adding steps are relatively cumbersome.

3. Trichloroisocyanuric acid – slow-release “sustained-release capsules”

• Form and dosage: White flake or granular solid, commonly known as "swimming pool chlorine tablets". The mainstream and standardized dosing method is to use a special automatic dosing device for swimming pools, or place it in a floating dosing device to allow it to dissolve slowly and evenly in the circulating water flow.
• Advantages: High chlorine content, stable properties, can achieve slow and continuous release, saving time and effort. It is acidic in nature and helps offset the pH increase caused by sodium hypochlorite.
• Disadvantages: During the dissolution process, cyanuric acid is released simultaneously as a stabilizer. Too high a concentration of cyanuric acid will "lock" residual chlorine, causing its disinfection ability to drop significantly. Regular monitoring and partial water changes are required to control its concentration.

2. The "alternative solution" to chlorine disinfection: bromine disinfectant

• Form and dosage: It is usually a tablet or powder of bromide salt, and the dosage method is similar to that of trichloroisocyanuric acid. It needs to be activated by oxidants (such as chlorine) in water to produce bromine with disinfecting activity.
• Advantages: Maintain good disinfection effect in a wider pH range; the bromamine produced still has disinfection ability and is less irritating than chloramine, so the water body is more comfortable to the senses and less irritating to the eyes.
• Disadvantages: The cost is higher than chlorine disinfection; it decomposes faster under high temperatures and strong ultraviolet rays, and is more suitable for indoor heated swimming pools or hot springs.

3. Auxiliary and alternative “high-tech means”

1. Ozone – the powerful “pioneer of pretreatment”

• Form and dosage: The gas must be produced by an on-site ozone generator and mixed with the pool water through a special contact reaction tank to ensure full reaction.
• Advantages: It has extremely strong oxidation and disinfection ability, can instantly kill bacteria and viruses, and effectively remove organic pollutants in the water, giving the water a moving "sapphire blue" luster.
• Disadvantages: Unable to maintain residue in pool water, so it must be used in conjunction with chlorine- or bromine-based disinfectants, which provide continuous disinfection protection. System investment and operation and maintenance costs are high.

2. Ultraviolet rays – a pure “instant killer”

• Working principle: Let the circulating water flow through the reactor equipped with ultraviolet lamps, and use ultraviolet rays of specific wavelengths to destroy the DNA of microorganisms and make them inactive.
• Advantages: High efficiency, no chemical residue, and can effectively control chlorine-resistant microorganisms.
• Disadvantages: Like ozone, it only has an instantaneous disinfection effect and no continuous protection capability. It must be used in conjunction with chlorine/bromine disinfectants.

4. Quick Check List for Swimming Pool Disinfectant Characteristics

5. Precise monitoring: the “control core” of intelligent disinfection

No matter which disinfectant is chosen, accurate online monitoring is essential to achieve safe, economical, and stable disinfection effects. Real-time and accurate data is the only basis for the intelligent dosing system to make correct decisions.

Core recommendation: [YuanGan Technology Online Residual Chlorine Sensor]

For swimming pools that use chlorine-based disinfectants, we strongly recommend the use of [film-based residual chlorine sensors].

• Why are membrane-covered sensors preferred? Pool water is a complex system containing sweat, oil, urea, and other organic matter and oxidants that can significantly interfere with traditional exposure sensor measurements. The film-covered sensor adopts an ingenious design: the front end of its measuring electrode is covered with a highly selective, breathable and waterproof special film. This thin film is like a "precision screen" that can effectively block most interfering substances in the water from directly contacting the electrode, allowing only target gases (such as hypochlorous acid molecules) to pass through and participate in the reaction.
• Core advantages: Strong anti-interference ability: greatly reduces the impact of complex water quality on measurement, making readings more stable and reliable. Long maintenance cycle: Membrane protection reduces electrode pollution and loss, reducing maintenance frequency and long-term use costs. More accurate data: Providing trustworthy feedback signals for automatic dosing systems is the basis for achieving precise control.
• Strong anti-interference ability: greatly reduces the impact of complex water quality on measurements, making readings more stable and reliable.
• Long maintenance cycle: Membrane protection reduces electrode pollution and loss, reducing maintenance frequency and long-term use costs.
• More accurate data: Providing trustworthy feedback signals for automatic dosing systems is the basis for achieving precise control.

Alternatives and applicable scenarios: [Exposed residual chlorine sensor]

Exposed sensors (without membrane) are also an option in certain scenarios.

• Working principle: Its electrodes are directly exposed to the water body to be measured.
• Applicable conditions: Only recommended for professional competitions or training venues with excellent water quality maintenance, very advanced circulation filtration systems, and extremely low levels of interfering substances in the water.
• Note: In conventional commercial or public swimming pools, due to large water quality fluctuations and many interferences, exposed sensors are more susceptible to contamination and interference, resulting in data drift and inaccurate readings, requiring more frequent cleaning and maintenance.

We recommend that for the vast majority of public, community and commercial swimming pools, priority should be given to the use of film-type residual chlorine sensors, which help achieve continuous and stable disinfection control with higher reliability. You can choose the most appropriate measurement technology based on the actual conditions on site.

Conclusion

Choosing the right disinfectant and cooperating with a precise automated control system are the core of modern swimming pool water quality management. From the classic chlorine system (sodium hypochlorite, calcium hypochlorite, trichloroisocyanuric acid) to the comfortable bromine system, to the efficient ozone and ultraviolet auxiliary solutions, every choice is related to operating costs, safety and user experience.

The online residual chlorine and other sensors provided by YuanGan Technology are the reliable cornerstone for you to build an intelligent swimming pool water treatment system. We are committed to using precise sensing technology to make every swimming pool a safe, clear and pleasant blue harbor.

—— Chongqing YuanGan Technology Co., Ltd., the water quality safety sensing expert around you