Why Does the Storage of Water from an Ultrapure Water System Affect Its Water Quality?

The quality of ultrapure water produced by an ultrapure water system gradually declines after being left idle for a period of time. Improper storage and distribution can both contribute to this decline. Below, we'll explain why the storage and distribution of ultrapure water affect its quality.

Ultrapure water quality deteriorates over time. The reasons for this deterioration include:

Storage Container: Because ultrapure water has a very low or even zero concentration of dissolved ions, it readily absorbs ionic contaminants from the external environment. Storage containers made of low-grade plastics and glass can leach ions and organic matter, increasing the water's conductivity and deteriorating its quality. Therefore, it is recommended to use high-grade polyethylene storage containers with low leaching.

Ventilation Port: Most storage containers have an vent for air circulation during water intake. This vent draws in outside air, introducing CO2, bacteria, particles, and volatile organic compounds from the laboratory air. These will contaminate the ultrapure water stored in the tank. Therefore, the vent should be equipped with an air filter to prevent organic matter, bacteria, and CO2 from entering the tank. Design: During the cleaning process, it's impossible to completely drain the water from the flat-bottomed tank. This undrained water is a breeding ground for bacteria. Therefore, we recommend using a conical-bottomed tank to ensure complete drainage. The tank should be blow-molded to prevent uneven surfaces from providing a breeding ground for bacteria.

Distribution: A good distribution pump should not cause temperature increases even after 10 hours of continuous operation, as elevated temperatures promote bacterial growth.

Disinfection: Even the growth of minute microorganisms can form a biofilm, degrading water quality. Therefore, installing a disinfection module (UV lamp) that inhibits bacterial growth is crucial.

This concludes our explanation of why the storage and distribution of ultrapure water affect its quality. As explained above, when using an ultrapure water system, it's essential to properly store the ultrapure water to prevent changes in water quality that could render it unusable and lead to waste. Understand the factors that affect the quality of ultrapure water from your ultrapure water system and avoid these factors.