For large public swimming pools, counter-current circulating water supply system should be adopted; according to the water quality characteristics of sea water; reasonable selection of water treatment equipment; good anti-corrosion work of equipment and control of initial investment; at the same time, good human health inspection should be done, and reliable auxiliary disinfection measures should be taken to prevent the spread of disease.Key words: large public swimming pool, seawater, anticorrosionTake a 2400m swimming pool in a swimming pool as an example.1, swimming pool water supply system selectionThere are three common pool water supply systems: direct current water supply system, periodic water exchange water supply system, circulating water supply system.The DC water supply system requires abundant water sources, the cost of water purification facilities is lower than that of circulating purification facilities, and the water quality is required to keep fresh. The cost of special water intake and transportation for seawater is higher, about 100 yuan / m. Therefore, the project is not suitable for the use of DC water supply system.Regular water supply systems require that all used and contaminated water be removed every 1 to 3 days and fresh water be refilled into the pool. The system can save the investment of purification equipment and is easy to maintain and manage, but the water quality is seriously polluted and easy to spread diseases. It needs to stop using for several days for each water exchange. For profit-making purposes such as the seawater swimming pool, and seawater with high cost is not suitable for use.The circulating water supply system has solved the problems of the above two systems, which can not only save seawater, but also ensure the water quality standard. Therefore, the scheme is adopted.2. Selection of swimming pool water circulation mode
The common circulation modes are downstream and countercurrent.
The scheme can meet the requirement of uniform distribution of water, but the bottom is easy to deposit dirt, and the sanitary condition is poor.
The counter-current type feeds water from the bottom of the pool to the swimming pool, and overflows water from the upper edge of the pool or both sides. The scheme has the advantages of uniform water distribution, no fouling on the bottom of the pool, and timely removal of fouling on the surface of the water by overflow. At the same time, the scheme adopts the circulation method recommended by FINA.
The characteristics of the above 2 schemes are summarized. In the design of the seawater swimming pool, 72 adjustable water distributors are evenly arranged at the bottom of the pool, 24 overflow outlets are set in the overflow troughs on both sides, and 3 main drains are set at the bottom of the pool. In addition, in order to ensure the personal safety of swimmers, the main drainage system with anti swirling function should be adopted.
3. Selection of major equipment
The equipment selected in this project should not only meet the design requirements of the system itself, but also do a good job in anti-corrosion of the equipment according to the characteristics of seawater.
(1) circulating water pump
The circulating water pump provides the power guarantee for the whole water treatment system. Whether it can operate safely and reliably is very important to the whole water treatment system. The formula for calculating the flow rate of circulating water pumps is Q=aV/T. In the formula Q is the circulating water flow (m_/h), A is the water volume coefficient of pipes, purification equipment and water supply tank, which can be taken from 1.1 to 1.2; V is the water capacity of the swimming pool (m'); T is the cycle (h), then the flow of the swimming pool circulating water pump is Q = aV / T = 1.2 x2400/6 = 480 (m_/h). The lift of the circulating water pump is determined by the calculation of the resistance of the circulating pipe, purification equipment, heating equipment and the difference between the pump and the water level. The lift of the circulating water pump is 18 M. The design uses 6 circulating pumps (Cheng Renchi) and a single station with a flow rate of 80m /h. The choice of material pump is directly related to the operation of the system and the initial investment of the equipment. In view of the corrosive characteristics of the seawater swimming pool, the anti-pressure, anti-corrosion plastic pump is selected as the circulating water pump. Six pumps are used at the same time, with a flow rate of 80 m/h, a head of 18 m and a motor power of 7.5 KW.
(2) hair aggregator
The function of the hair aggregator is to remove the larger suspended matter in the water, including paper, plastic bags, hair and so on. The equipment material is also made of organic synthetic materials with anticorrosion function.
(3) filter sand cylinder
There are two types of filter sand cylinders suitable for seawater swimming pool. One is a double-layer filter sand cylinder with large volume for seawater swimming pool. The second type of product has a small circulating flow rate, usually at 30 m_/h. If the second type of product is selected for use in the system, the number will be as high as 16, and the system with pipes, valves and other components will occupy a larger room area. In addition, the system backwashing is more frequent and brings inconvenience to operation management. Taking into account, the project chooses three double-layer filtration sand cylinders with a diameter of 1 400 mm, a single circulation flow of 242 m_/h (the selection of the flow rate of the sand cylinder is a little larger), and the filter media is high-quality quartz sand, which is divided into several layers according to the size of the particle.
(5) disinfection device
The disinfection of seawater swimming pool mainly considers the anticorrosion function, and adopts the special mercury lamp ultraviolet sterilizer. 6 mercury mercury lamp ultraviolet sterilizer with a flow rate of 80m /h and UV power 225W.
Conclusion:
1, because of the high salt content in seawater. The corrosion of equipment and pipeline is serious, therefore, the choice of equipment and pipeline material must consider its anti-corrosion performance, the use of seawater corrosion-resistant materials in the course of use, but also to avoid desalination of seawater, to prevent changes in water quality conditions.
2. For large public swimming pools (e.g. standard swimming pools), counter-current circulation should be adopted. At the same time, filtration sand tanks with large circulation flow should be selected, and the number of them should be 3-4.
3. In order to avoid the occurrence of infectious diseases, it is suggested that the auxiliary disinfection facilities (such as footbath and mandatory leaching margin) should be considered in the design and put into use in the actual operation. In addition, the customers can be physically quarantined if conditions permit.