Milli-QÂ® Lecture | Highlights of Microbial Control Frequently Asked Questions in (Super) Pure Water Systems

Microorganisms are a special type of pollutants in water. They have the ability to reproduce and metabolize, release salt and acid substances, and cause secondary pollution of water quality. Therefore, everyone is paying more and more attention to microorganisms.

1
Why is it recommended to refrigerate the column during the (super) pure water system deactivation?

The ion exchange resin is one of the most important filler components in the purification column, and the activated ion exchange resin is a semi-hydrated form.

If not refrigerated, the ion exchange resin may be dehydrated. Once the ion exchange column is dehydrated, its ion exchange capacity fails. In the wet state, the bacteria remaining in the resin particles can rapidly multiply, and the bacteria remaining at normal room temperature will proliferate and block the entire column. One way to control the rate of microbial growth is through refrigeration.

Therefore, the purification column can be sealed for a short time and placed in a refrigerator (4 Â° C).

2
How does the (super) pure water system remove microorganisms from the water?

The Milli-Q ^Â® Water Purification System controls microbial growth in four ways:

a. The presence of silver-plated activated carbon silver ions can inhibit the growth of microorganisms;

b. The very critical purification technology of reverse osmosis membrane has a very high removal efficiency for all pollutants and can retain more than 99% of microorganisms;

C.265nm sterilizing UV lamp Compared with the traditional 254nm UV lamp, the ultraviolet sterilizing efficiency of this wavelength is greatly improved, and it has been applied to the pipeline and storage system of the 7th generation pure water & ultra pure water machine IQ 70XX series products. ;

d. Screen filtration or ultrafiltration through its interception, intercepting a small amount of microorganisms remaining in the water to ensure that the microbial content of the water intake meets the requirements.

3
How often does the reverse osmosis membrane be washed?

If the reverse osmosis membrane is blocked and needs to be cleaned, then both detergents (cleaner A and cleaner B) can solve most problems. Put the cleaning agent into the disinfection port, then start the cleaning cycle. After the cleaning cycle is over, the system automatically enters the standby mode.

There is also a chlorine reagent tablet for sterilization, which is also supplied from the disinfection port. It produces hypochlorous acid in a neutral or acidic liquid environment, which can effectively kill bacteria. It is recommended to perform chlorine reagent disinfection every month.

4
Why is the final filter aperture only 0.22Î¼m instead of 0.45 Î¼m?

The vast majority of bacteria are 1 Î¼m in size. The smallest bacteria known to date are pseudomonosomal strains grown under specific conditions and have a size of 0.3 Î¼m.

Therefore, the 0.22 Î¼m end filter can be used to remove the known minimal bacterial strain.

5
Can bacteria cause an increase in TOC levels in pure water?

Whether it is a living bacteria or a dead bacteria, the body contains complex and diverse organic molecules, with its metabolism and death, these organic molecules will have different degrees of influence on the TOC, and thus affect the experimental results.

6
What is the most effective way to kill bacteria?

There are a variety of disinfecting reagents and methods to choose from. They can be broadly divided into two broad categories:

âž¤ chemical methods: ozone, chlorine, alcohol, detergents, etc.;

âž¤ Physical methods: heating, osmotic pressure, radiation and filtration:

Â· Chlorine treatment is one of the most effective ways to kill bacteria in water. Chlorine and water react to produce hypochlorous acid:

Cl ₂ + H2O = HOCl + H ⁺ + Cl ^- ;

(low pH is more conducive to the formation of hypochlorous acid)

Â· Equivalent sterilization methods include ozone treatment and UV oxidation.