Whether it is safe to swim in an ozone-sterilized swimming pool can be divided into two points for analysis: the residual ozone concentration after the first ozone disinfection, and whether the second input ozone disinfection amount reaches the disinfection concentration; the following lists the safe use of ozone in swimming pools:

1. The traditional method of ozone sterilization and disinfection of swimming pool water

The traditional theory of swimming pool ozone disinfection believes that ozone is a very strong oxidant and is toxic, so ozone is absolutely not allowed to enter the swimming pool. Because the specific gravity of ozone is greater than that of air, if it is precipitated from water, it will float on the water surface, forming a high-concentration ozone layer, which can easily be inhaled and cause poisoning. Therefore, before the water reacts with ozone and returns to the swimming pool, it must pass through a deozonation device to prevent the remaining ozone from entering the swimming pool. After the deozonation device, in order to maintain a long-term sterilization effect, chlorine preparations need to be added.

The traditional ozone disinfection method for swimming pool water treatment has the following characteristics:

◆The dosage of ozone is 0.8-1.0mg/1;

◆There must be an ozone reactor with a larger volume to ensure that the contact reaction time between ozone and water is not less than 2 minutes;

◆Ensure that after the ozone reacts with water, the remaining ozone concentration in the water is not less than 0.4mg/1;

◆Use activated carbon to remove all remaining ozone before entering the pool;

◆After ozone disinfection, add chlorine disinfectant to make the residual chlorine reach 0.3-0.6mg/1.

In practical application, the above method has the following problems:

◆Ozone utilization rate problem: The traditional swimming pool ozone disinfection process needs to remove the remaining ozone. The specification requires that the ozone concentration is about 1.0mg/l, and the remaining ozone concentration is greater than 0.4mg/l. The remaining 0.4mg/l ozone is removed without being used, which is equivalent to only about 0.5mg/l of ozone being used. , the rest of the ozone is wasted. Moreover, after the ozone is removed, chlorine needs to be added as a long-term disinfectant.

◆Infrastructure investment problem: According to the traditional ozone disinfection method of circulating water in swimming pools, the contact time between ozone and water is preferably more than 3 minutes. If the shortest contact time is 2 minutes, for a standard pool (about 2400m3), the water treatment cycle The flow rate is 400m3/h, and the flow rate is 13.3m3 in 2 minutes. According to the requirements, the filtration rate of the activated carbon filter tank is 30m/h, which requires an activated carbon filter tank with a filter area of ​​13.3 m3, which will greatly increase the area of ​​the machine room, and the cost of the ozone system will increase by more than 30%.

In fact, if the ozone is not removed, these problems may be solved. Therefore, many units at home and abroad have researched and applied this method.

2. Theoretical analysis of the disinfection method without removing ozone

Analysis and research at home and abroad show that:

◆The ozone concentration in the air is greater than 0.1mg/1 hour, which can stimulate the human respiratory organs. Under this concentration, it has little effect on the human body; when the ozone concentration in the pool water is below 0.15mg/1, it is harmless to the human body.

◆Because ozone decays in both water and air, and the half-life is short, it will not accumulate ozone concentration;

◆Part of the contact reaction area that does not remove the ozone disinfection method is in the swimming pool, so the added ozone can play a role in disinfection;

◆Through the ozone concentration monitor to measure the ozone content in the pool water and output a signal, the amount of ozone generation can be controlled to ensure that the ozone concentration in the pool water does not exceed the fortified value;

◆When using countercurrent circulation, the water containing ozone can reach every point of the pool within 5 minutes, and the half-life of ozone is 20 minutes. When the ozone concentration in the water is 0.05mg/1, the sterilization effect can be guaranteed. ;

◆It should be pointed out that there is no report of death from ozone poisoning in the world, but as many as 100,000 people died from chlorine poisoning. Toxicological experiments show that at the same dose, the toxicity of ozone is lower than that of chlorine. It is difficult to understand that the ozone with low toxicity and good bactericidal effect is removed and the chlorine with high toxicity and poor bactericidal effect is added.

3. The characteristics of ozone disinfection in swimming pools

◆The swimming pool should adopt the counter-current circulating water distribution method. In this case, the influent water containing ozone can be quickly mixed with the pool water, and it may not be necessary to add other chemicals, such as chlorine, flocculant, pH adjuster, etc., in actual operation. Only swimming pool managers can really appreciate other benefits brought by the counter-flow water distribution method, such as easy removal of floating objects on the water surface, water saving and energy saving, and less pool cleaning workload.

◆When the swimming pool water is disinfected with ozone, it is not necessary and should not remove the remaining ozone, and the remaining ozone in the water will not reach the concentration that will cause harm to people.

◆When the countercurrent circulation does not remove ozone, if the pool water can be circulated according to the specifications, under normal passenger flow, when the ozone dosage is 0.5mg/l, it can meet the needs of disinfection, but the design should consider leaving a margin .

◆The ORP controller can be used to monitor the ozone concentration in the water. When the ozone concentration in the backwater of the pool is too high (greater than 0.10ppm), turn off the ozone generator to prevent the ozone concentration in the air from exceeding the standard (0.1ppm).

◆ Filtration plays a decisive role in water quality. When the particle size of the filter material is 0.45-0.8mm, if the thickness of the filter layer (excluding the thickness of the support layer) can reach 900mm, the ozone dosage can be reduced, otherwise, the dosage of ozone can be reduced. No amount of ozone can guarantee water quality.

◆If chlorine preparation is to be added, the disinfection needs can be met when the residual chlorine reaches 0.1ppm.

4. Ozone is better than chlorine preparation for sterilization and disinfection of swimming pool water

◆After adding chlorine preparation, it will inevitably lead to the change of pH value of water, making people feel uncomfortable, so it is necessary to add alkaline or acidic substances to neutralize it. Ozone is a neutral substance and does not cause such problems.

◆Ozone can ensure the stability of water quality during large passenger flow and high temperature season. When high temperature and passenger flow are large, the water quality is often poor. At this time, if chlorine preparation is used, it needs to be added in large quantities, which will bring a series of side effects. Such as the change of pH value, the stimulation to the respiratory tract and the human body, etc.; and a large amount of ozone has no such side effects.

◆Using an ozone generator can greatly reduce the management and operation difficulty of the water treatment process. At the same time, the ozone generator has high safety, while the chlorine preparation has certain dangers during transportation, storage and use.

◆Ozone can decompose organic matter in water and has a micro-flocculation effect, so under normal passenger flow, flocculants can be omitted.

◆Under certain conditions of use, such as countercurrent circulation and no activated carbon filter tank, ozone can be used as the only agent for water treatment without adding chlorine preparations, flocculants, and pH regulators.