Make drinking water safer How powerful is the application of UVC LED in water purifiers
 2021/04/23 | View:107




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The potential pollution problems of the water purifier itself are often easily overlooked. In fact, bacteria may potentially breed in each filter unit of the water purifier, such as: PP cotton filter element, carbon in the pre-treatment and post-treatment system of the water purifier Rod filters, pipes, joints and other parts have no antibacterial function and may breed bacteria; purified water treated with microfilters, ultrafilters or reverse osmosis membrane filters may also be contaminated if stored or used improperly. This article will take the reverse osmosis type water purifier as the object to explain the role of UVC LED in the sterilization of the water purifier.


Reverse osmosis water purifier

 

The reverse osmosis water purifier can remove heavy metal ions, bacteria, viruses and other harmful substances in the water through the reverse osmosis RO membrane. However, after installation and use for a period of time, the water purifier may be contaminated by bacteria, and the effluent microorganisms (total number of colonies, total coliform bacteria) Groups, etc.) substandard conditions; if the water purifier is left unused for a long time, the microbial contamination will be more serious. According to GB 5749-2006 "Sanitary Standards for Drinking Water": The total number of colonies in the water from the water purifier should not exceed 100CFU/mL.

 

1. There is a bucket type reverse osmosis water purifier

 

With a water storage bucket, users rarely clean the water storage bucket due to inconvenient disassembly. After the tap water passes through the reverse osmosis membrane, the residual chlorine in the water is filtered and the antibacterial environment is lost. Adhere, multiply, and secrete mucus. Over time, bacteria and mucus accumulate on the surface, which leads to the problem of excessive bacterial colonies in the purified water.

 

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Test with a water tank filled with pure water. After the water tank is placed for three days, the total colony count in the water tank quickly rises from 5CFU/mL to 106CFU/mL, which exceeds the drinking water hygiene standard. The total colony count will continue to rise over time.

 

1. Instant filter type reverse osmosis water purifier

The purified water from the outlet end of the RO membrane to the faucet has to pass through wading materials such as post activated carbon filters and water pipes. Among them, the granular activated carbon material promotes the growth of bacteria and will increase microbial pollution.

 

 Table 1 is the filter type R. After the machine is allowed to stand for 12 hours, there is no sterilization treatment, and the total colony count test in the first glass of water is turned on.


Instant filter RO machine (600G)

The total number of colonies in the first glass of 500ml water(CFU/mL)

Drinking water hygiene standard(CFU/mL)

Total number of colonies exceeding the standard(CFU/mL)

1# Machine

63

100

Not exceeded

2# Machine

80

100

Not exceeded

3# Machine

490

100

390

4# Machine

385

100

285

 

In an experiment, five 600G instant-filter RO machine prototypes were used for testing. After the machine was placed for 12 hours (simulation overnight), there was no sterilization treatment. The machine was turned on and received the first glass of 500ml water. The test found that the total colony count of three machines exceeded Drinking water sanitary standards, one of the prototypes has a total colony count of 538CFU/mL exceeding the standard.

 

UVC-LED smart water purification safe and efficient

 

As a mature technical solution, UV sterilization has been used in the water treatment industry for a long time. UV sterilization is a physical sterilization. It uses ultraviolet rays to efficiently inactivate various bacteria and viruses in the water and prevent the reproduction of bacteria in the water. In order to achieve the purification effect.

 

Traditional UV mercury lamp

Heat source: there is heat radiation;

Short life: only about 1000 hours;

Large size: usually exists as a long tube;

Low efficiency: UVC band ultraviolet light only occupies a part of the light source, which is a serious waste of energy;

Not environmentally friendly: Contains highly toxic substance mercury;

 

UVC-LED

Cold light source: no heat radiation, low temperature rise;

Long life: more than 10 times that of traditional mercury lamps;

Small size: easy to integrate in various product designs;

Efficient sterilization: concentrated wave band, high photoelectric conversion efficiency;

Environmental protection and safety: no mercury, no ozone;

 

UVC-LED is used in barrel-type RO machines. The UVC-LED lamp has a radiation angle when irradiated. The sterilization effect within the radiation angle is good. Outside the radiation angle is called the radiation blind zone, the radiation intensity is weak, and the sterilization effect is poor.

 

UVC-LED is used in the instant filter RO machine, that is, the filtered water is directly discharged from the faucet after the filter RO machine is turned on. The high-intensity ultraviolet lamp must be used to sterilize the flowing water in real time to ensure that the flowing water is effectively sterilized.

 

In order to ensure that the total number of colonies in the first cup of water released by the faucet each time does not exceed the standard, the position of the UV lamp is as close as possible to the water outlet of the faucet to shorten the distance of the non-sterile waterway and improve the sterilization effect.

 

Traditional mercury lamps often appear in the application of instant-filter RO machines-site installation is inconvenient; the faucet is too large and the structural size is difficult to match, which affects the overall appearance design; the peak cannot be reached instantaneously after the lamp is turned on, and the sterilization effect of flowing water is poor; Start-stop causes many problems such as short service life. 

According to the different characteristics of reverse osmosis water purifiers and the prevention and control of potential bacterial growth, XinUV Optoelectronis has developed a variety of uvc led water steriliztion module, all with different implementation schemes, which can better prevent and control potential bacterial contamination of the water purifier problem.


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