We know that in major swimming pools, in order to achieve the disinfection effect in the swimming pool water treatment process, various disinfectants (TCCA, SDIC, Calcium Hypochlorite) and swimming pool water treatment equipment are used. These limits are obtained under the premise of water quality microbial safety, better Maintain people's health and meet people's sensory requirements. Because the bactericidal effect of most disinfectants depends on pH, but too high a pH value will make swimmers feel uncomfortable. Therefore, in swimming pool water treatment, it is necessary to keep the pH within the optimal effective range of a disinfectant. The pH value of the relevant national standard swimming pool is between 6.5-8.5, but the most suitable pH value for the human body is 7.2-7.6.
A. When the pH value of the water is greater than 8.0
At this time, most of the pool water is hypochlorite OCl¯, while hypochlorite HOCl (residual chlorine) only accounts for a small part, which will undoubtedly greatly reduce the activity of disinfectants in water, and then affect the algae and bactericidal effects. As a result, it will eventually lead to the proliferation of green algae in the pool water and repeated prohibitions; it will also lead to low or even undetectable residual chlorine when you detect it, so this is not a problem with the quality of the disinfectant, but the result of improper control of the pH value. The high pH value of swimming pool water treatment indicates that the water is alkaline. The principle of the treatment method is very simple, which is to use the principle of acid-base neutralization.
1. Acidic substances can be added to swimming pool water. The nature of hydrochloric acid is slightly acidic. Generally, the pH value of swimming pool water quality is as high as 8.2. You can add hydrochloric acid in an appropriate amount, and the dosage should be used according to the actual test. Example: PH value = 8.2, 5-10 kg can be put into every 1000M3 water to restore the best status (saline alkali has a strong corrosive property, and the dosing pump should be used for automatic dosing).
2. You can add water to dilute the alkalinity in the water. In most cases, the water in the swimming pool will be acidic (for the south), and the sweat of the swimmers themselves is also acidic.
B. When the pH of the water is less than 7.0
At this time, most of the pool water is hypochlorous acid HOCl (residual chlorine), and hypochlorite OCl ¯ only accounts for a small part, that is to say, the activity of the disinfectant in the water is very high, and the disinfectant you put in has a large amount. A portion is wasted, so soon your residual chlorine will be low. The key to solving the problem is to adjust the PH to the most suitable value for the disinfectant to play its role: that is, PH=7.5. In this way, about half of the disinfectant will be hydrolyzed into residual chlorine to play a disinfection role after the disinfectant is put into the water. When the residual chlorine drops, hypochlorine The acid radicals will combine with the hydrogen ions in the water to form (OCl¯) + (H+) ↔ HOCl, so that the disinfectant can be used for a long time. Therefore, the pH value of our swimming pool water quality should be kept at 7.5 as much as possible, which can not only ensure disinfection but also save costs to the greatest extent. Swimming pools generally use sodium hydroxide or sodium carbonate to raise the pH of the pool water.
1. Use sodium hydroxide at a dose of 10 grams per cubic water for every 1.0 degree increase. (For example: 1000 cubic meters need to add 10 kilograms of sodium hydroxide to increase the pH to 1).
2. Use sodium carbonate (Ph Increaser) at a dose of 15 grams per cubic water for every 1.0 degree increase. (For example: 1000 cubic meters need to add 15 kilograms of sodium carbonate if the pH is increased to 1).
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