Water quality problems of water park equipment manufacturers
Residual chlorine in water is an important indicator of swimming pool water quality. Insufficient chlorine content means insufficient sterilisation of the water body, which may lead to excessive bacterial content in the pool water, increased particulate matter, and adverse effects on the human body. The swimming pools built by current water park equipment manufacturers generally use chlorine-containing disinfectants to sterilise and purify water. There have been children choking on water, causing a cough and high fever, and the hospital diagnosed it as a respiratory infection caused by bacteria.
Greening is the reason for the growth of algae. Just like Lake Taihu, the following measures are recommended:
1 Prevent the growth and reproduction of algae
Algae are extremely tiny plants, with hundreds of different types. Algae can multiply rapidly in water. First, it consumes carbon dioxide dissolved in the water, leading to a rapid increase in pH. Then, as the dead algae consumes oxygen in the water, the clear pool water becomes a dead water altar within a day. Airborne spores, lawns, and soil scours will bring algae into the water body. This often happens after heavy rains, especially when the water temperature is high.
2 Controlling bacterial and virus pollution
In order to control harmful bacterial and virus pollution, water park equipment manufacturers must add disinfectants to the pool water reasonably. For home users, the most commonly used disinfectants are bromine and its compounds, and chlorine and its compounds.
Bromine and chlorine can kill bacteria, viruses and algae, and can play an oxidising effect. Elemental bromine is a reddish brown liquid at room temperature, and granular methyl compounds containing bromine and chlorine are used for swimming pool disinfection. This compound is added to the circulation system to decompose hypobromous acid and hypochlorous acid. The cost of bromine disinfection is higher than chlorine disinfection, but its applicable pH range is wider. Under soft water conditions, bromine should be used as a disinfectant, and its concentration should be maintained at 4-6 mg/L.
Hypochlorous acid is the main disinfectant. Its mechanism of action is: ①Penetrate the cell walls of microorganisms and destroy the protein and enzyme systems of microorganisms; ②Remove organic and inorganic pollutants in water through oxidation. Hypochlorous acid is the main disinfectant. Its mechanism of action is: ①Penetrate the cell walls of microorganisms and destroy the protein and enzyme systems of microorganisms; ②Remove organic and inorganic pollutants in water through oxidation.
The source of hypochlorous acid is calcium hypochlorite or chlorine. Calcium hypochlorite is a granular substance formed by calcium hydroxide absorbing chlorine gas and is a stable compound. Calcium hypochlorite will release chlorine after being added to the water, so it can be used as a disinfectant for swimming pools. Adding calcium hypochlorite will increase the calcium ion concentration and pH in the water, which is beneficial for swimming pools using soft water. There should be enough chlorination to keep the residual chlorine in the pool water at 0.4-0.6 mg/L.
When the concentration of organic matter in the pool water is high, a mixture of NH 2 Cl, NHCl 2 and NCl 3 will appear. This is caused by the reaction of chlorine molecules with nitrogen compounds in the pool water. This will lose the disinfection effect, especially NCl 3 will make the pool water emit an unpleasant smell. Only by further increasing the chlorine dosage can the NCl 3 be decomposed. At this time, the chlorine concentration in the water will no longer continue to rise. It will continue to rise only after the NCl 3 is decomposed, which is the so-called breakpoint chlorination in the professional.
When the swimming pool has not been replenished with enough fresh water for a period of time, the cyanuric acid content in the water is too high, and the phenomenon of chlorine lock-in will occur, that is, the chlorine mainly exists in the form of a combination of 2 or 3 chlorine molecules, thus losing disinfection effect. It has not been determined at what concentration cyanuric acid will happen. It is generally believed that the chlorine lock-in effect is most obvious when its concentration is around 160 mg/L. After the chlorine lock in the pool water, increasing the chlorine dosage can alleviate this situation, but the long-term solution is to add more fresh water.
On the other hand, cyanuric acid can act as a chlorine stabiliser. It is advantageous to maintain a low concentration in the water to prevent ultraviolet rays from the sun from consuming residual chlorine in the water. It is usually added to water in the form of particulate matter, and can also be produced during the process of dissolving the dichlorine complex or the trichlorine complex into the water: the chlorine complex splits into individual chlorine molecules, and cyanuric acid is produced at the same time. Therefore, if a chlorine complex is added to the pool, there is no need to add additional chlorine stabilisers. However, when sodium hypochlorite or calcium hypochlorite is used as a disinfectant, it is necessary to add a chlorine stabiliser. Care should be taken to avoid mixing the above substances in a dry state, as that would be dangerous.
Under special circumstances, an excessive amount of sodium hypochlorite or calcium hypochlorite can be added to the pool water at one time to form a higher chlorine concentration, inhibit the growth of algae and reduce the unpleasant chloroform odour, and it can also destroy the gathered organic pollution Things. In addition, a one-time introduction of excessive chlorine to make the chlorine concentration in the pool water reach about 10 mg/L can effectively prevent bacteria and algae from multiplying. Family swimming pools can do this treatment once a week.
3 Keep the pool water transparent and clean
The transparency and cleanliness of water can be reflected by the index of total soluble solids. TDS refers to charged chemicals that accumulate in the pool water, especially when the pool water evaporates or there is not enough fresh makeup water added. This substance is difficult to be seen by the naked eye, but due to its conductivity, it will corrode various components of the swimming pool, such as pumps, pipes, filters, etc. These substances usually exist in the form of chlorides or sulfates: long-term use of sodium hypochlorite as a disinfectant will cause chlorides to accumulate; regular addition of aluminium sulfate and sodium bisulfate will increase the sulfate concentration. Periodic backwashing and timely replenishment of fresh water is the best way to control TDS.
4 Stabilise the pH of the pool water
The pH reflects the pool water pH range of 6.5 to 8.5 specified in the “Sanitary Standards for water quality of Artificial Swimming Pools”. In order to protect the reasonable operation of the swimming pool, the users of the swimming pool should pay close attention to whether this indicator meets the standard, and the pH of the water can be measured with a simple test paper. In order to stabilise the pH of the pool water, special stabilisers should be added to keep the pH of the pool water within a reasonable range.
At the same time, pay attention to another index closely related to pH: total alkalinity. The total alkalinity reflects the difficulty of the pH change of the water body. If the total alkalinity is lower than 80 mg/L, the pH stability is not enough and easy to fluctuate; when the total alkalinity is higher than 200 mg/L, the pH stability is too high and it is difficult to adjust. The pH of the pool water should have reasonable stability and can be adjusted without excessive fluctuations, so the total alkalinity should be kept in a reasonable range. In addition, high alkalinity and high pH will cause water turbidity and the formation of sediment; too low alkalinity will cause corrosion of equipment and cause physical discomfort for swimmers.
5 Adjust the hardness of the water
The hardness of the water should be moderate, too high will cause aggregates on the pool wall, and too low will erode the mortar on the pool wall.
Hard water means that the calcium ion concentration in the water exceeds 250 mg/L and the alkalinity is higher than 150 mg/L. The pH in hard water is relatively stable, but the method of increasing the water hardness should not be used to stabilise the pH. For hard water sources, water softeners should be installed at the water supply port for pretreatment. The calcium carbonate concentration of soft water is less than 50 mg/L or the calcium chloride concentration is less than 30 mg/L. It is difficult to maintain a stable pH in soft water. The disinfectant uses calcium hypochlorite to help increase the hardness of the water. There are two main methods to keep the water clean. One is to use a drug pump to automatically dosing, and then to manually spray the drug. If there is sediment, perform underwater dust removal in time until the water quality reaches the standard.