Research on Swimming Pool Water Treatment based on Embedded System

Abstract. This paper mainly designs the outdoor swimming pool circulation purification system， introduced the circulation mode selection， calculation of water cycle， and we proposed water purification treatment measures. After filtration and disinfection of swimming pool water， which achieve the "Hygienic standard for swimming place" （GB9667-1996） that regulations on "the quality and hygiene standards" artificial swimming pool， which can be recycled.

Key words： pool； water treatment； filtering； circulation； disinfection

0 Introductions

With the continuous improvement of people's living standards， a swimming pool as water recreation fitness facilities， more and more into people's daily lives. Volume standard swimming pool is approximately 2250m3 [1]， if the pool water is not recycled， it will cause a huge waste. Pool water recycling is a reflection of the water resource， is an effective way to alleviate the shortage of water [2]. Because the pool water is directly related to human health and safety [3]， so the pool water sanitation more people's attention. Currently， the pool water treatment technology research at home and abroad has matured much water treatment plant for the problems that exist in the project， and constantly develop more suitable for swimming pool water treatment equipment. In this paper， based on existing technology， combined with practical engineering， select the appropriate water treatment equipment， and so that the treated water up to standard recycled.

1 Quality standard of swimming pool water

Pool water in direct contact with the human body， water may become a source of infection of the disease. Therefore， the world has a clear pool of water quality requirements， and to develop the relevant health standards. Pool water should comply with national and Technical Supervision and the Ministry of Health jointly issued GB9667-1996 concerning artificial swimming pool water health standards， as shown in Table 1.

2 The process of swimming pool water treatment system

A public swimming pool water treatment process is shown in Figure 1； the processing system is composed of the hair filter， pump set， sand filtration and disinfection tank. The pool water into the conditioning tank through the slot overflow reflux， and by adjusting the bottom of the pool filter pipe into the hair filter， the hair of the filter effect is hair removal and retention and longer fibers in the water， then into the pump set in sand filtration tank the filtered water then filtered by the chlorine dioxide generator in the composition for disinfection sterilization， then chlorine disinfection， pH value of water quality control， and ultimately flows from the bottom of the pool.

2.1 Water cycle principle

Because of the shortcomings of poor health in conditions of regular water supply and source limitation in directly supply water， water swimming pool use loop filter. Setting up independent water purification equipment， the used water extract part of the purification and disinfection and then sent back to the swimming pool circulating use. The cycle of swimming pool water generally has 3 kinds： up flow， downstream type and mixed type in domestic and foreign. Using the up flow type is water supply at the bottom of the pool， pool water， the top periphery overflow； the purpose is to make the drift can quickly spill water. The water supply for the absolute overflow or water treatment cannot be， therefore， in the construction of civil engineering requirements are extremely stringent，

The pool on the top edge surface must be at the same elevation， uneven otherwise it will cause overflow water. To remedy this defect， methods often used are that increase circulation flow that will inevitably cause a waste of energy. On the other hand， because the area difference ratio in pool bottom and water inlet ，The average rising velocity of water is very small， In addition to inlet flow is from the outside， The surrounding water is top-down reflux， Precipitation still， Therefore， the bottom of the pool or easy contamination； Downstream practice is shallow inlet end wall， deepwater bottom end backwater， pool sediment can be discharged smoothly outside the pool into the filter， avoiding the old and new blended excessive water， in addition to increasing the filter sewage capacity to ensure the water quality， but the need for manual drift fishing water. Hybrid is a comprehensive cycle of the above two methods， the bottom and the wall are water， backwater from the bottom back to 40%， representing 60% of the surface of backwater flooding， water distribution uniformity way this cycle， the bottom does not plot sewage， water floats will promptly overflow to go， but the way of construction difficulty， high cost， generally only need to undertake major events of the swimming complex will employ， such as the Olympic Games swimming pool. The design pool use downstream circulation mode based on the above analysis.

2.2 Calculation of circulating water

2.3 The selection of circulating water pump and filtration equipment

Cycle and cyclic flow determines the processing capacity of the system size， height and total operating cost. Therefore the design with the circular flow transforms approach to adaptation due to the seasonal effect， swimming pool water quality change of flow. This design depends on the number of control to reduce the actual running energy consumption， regulating the flow.

Based on the above data and instructions， the design selected 4 copper pump （pump set before the hair collector， Q=38 m3， H=18 m）， 1～2 pumps running in winter， spring and autumn and summer running 2～3 pump， 3～4 pump operation. We use backwashing water pump and circulating water pump and filtration equipment， and the back flushing requirements to check. Circulating pump infrastructure rubber cutting vibration isolator； water pipe with flexible pipe rubber expansion joint， produce noise to reduce water hammer shock and vibration pump.

Filtration equipment used in physical properties of natural quartz sand， it has small area， and the advantages of large water filter. Sand cylinder with 6 directional control valves， provides a simple procedure， the cylinder is made by the corrosion wear resistance of glass fiber winding， the normal service life of up to 50 A.

The design includes 4 sets of S1200 high-speed filtering sand cylinder. Vessel diameter was 1200 mm， the height of the container is 1600 mm， the effective filtration area of 1113 m2， the rated maximum throughput of 42 m3. Sand cylinder is provided with a pressure gauge， can according to the change of numerical pressure gauge to determine the backwashing time sand cylinder. Sand cylinder is provided with a water mirror， in order to observe the flow condition at any time. For the convenience of repair and out of the water pipeline is provided with a control valve.

2.4 Circulating pipeline design

At present the ideal for swimming pool water circulating pipe has two kinds： 1） thin wall stainless steel pipe. This kind of pipe welding is reliable， stable water quality， the inner wall of the pipe is not easy to scale， but the cost is high； 2） UPVC tube， socket adhesive， has the advantages of light weight， convenient construction； disadvantage is the compression ability than stainless steel tube， and the interface is not temperature， taking into account the swimming pool is pre buried pipeline laying， not easy damage by external forces， and the swimming pool of the scheme is not heated swimming pool， the comprehensive consideration of the design using 110～116MPa water supply pipe with the UPVC.

2.5 Water purification treatment

Water purification using sand cylinder filter （quartz sand particle size 0.8～1 mm）， and the dosing pump water adding different treatments： 1） coagulant. The polymerization aluminum chloride， promote water impurities， settlement， improve the filtering effect， long term quantitative dosing； 2） disinfectant. The two chloro isocyanuric acid or sodium sustained-release chlorine tablets， kill the bacteria in water， ensure the swimmer's health and safety， long-term quantitative dosing； 3） algaecide. The copper sulfate， inhibit algae growth， intermittent dosing； 4） acid agent. Using alkaline sodium， hydrochloric acid， to adjustment pH in pool water， it must intermittent dosing. We use three sets of dosing pump， 1 disinfectant， and 1 set of coagulant and other depending on the situation， adding algaecide or acid-base balance agent.

3 The working principle of the control system

As there are many different types of sensors or monitoring subsystem， taking into account compatibility and scalability engineering requirements， the article uses an embedded real-time operating system， system hardware connections is shown in Figure 2. The circuit is composed of sensors， control circuits and embedded processors and other components. Core of circuit is Samsung S3C2440 processor， the function is responsible for the organization and resource allocation system， mainly including the power supply module， low-voltage protection circuit， a memory unit， communication module， analog signal conditioning modules and other components， and deployment in the transformer voltage sensors and current sensors through various sensors such as I / O interface， IIC interfaces， RS232 interface， JTAG interface to connect and have program download and debugging functions. CPU has sensor data acquisition function and the analog signal convert into a digital signal through power conditioning circuit， and then by the micro-controller obtained the data after processing package packing and to send by RS232.

3.1 The flow chart of main program

Programming is completed by KEIL software platform， modular program design is adopted in the system， will be relatively independent function in the system into functional modules， and then call in the main program， so as to increase the readability of the program， but also reduce the duplication of part of the work of preparation. Brief introduction of the main program and the backwashing function module subroutine flow chart of main program flow diagram is as shown in figure 3 and figure 4.

4 Conclusions

Because S3C2410 has the logic strong control function and high reliability， which can will control the complex system into the control unit small models， the water treatment system can work in automation， visualization and the reliability of the control system， intelligence and security are improved. The whole system has been put into use， and showed good effect. Application of the control system can meet the demand of swimming pool water treatment and has very good popularization value and application prospect.

Reference

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