Usage Requirements for Ultrapure Water Pretreatment

Ultrapure water systems are equipped with pretreatment devices to remove impurities from the water, protecting the equipment. There are many types of pretreatment, and different methods are required for different water qualities. So, what are the requirements for pretreatment in ultrapure water systems?

1. When the suspended particulate matter content in the raw water is less than 50 mg/L, contact coagulation or filtration can be used. This involves adding a coagulant and then directly injecting the water into the filter via a pump or pipeline. Currently, multi-media filters are commonly used.

2. When the carbonate hardness of the raw water is high, lime can be added for pre-softening while removing turbidity. Of course, the most common method currently is to use cation exchange resin or add scale inhibitors.

3. When the organic matter content in the raw water is high, chlorination, coagulation, and clarification filtration can be used. If these methods still do not meet the influent requirements of subsequent processes, activated carbon filtration or other measures to remove organic matter can be added.

4. When the free chlorine content in the raw water exceeds the influent standards for subsequent processes, activated carbon filtration or the addition of sodium sulfite can be used for treatment. 5. If subsequent treatment processes use reverse osmosis or EDI equipment, an additional precision filtration device (or set of filtration units) should be installed before the raw water enters the equipment as a protective measure for the reverse osmosis or similar equipment.

6. If subsequent processes have high requirements for colloidal silica, magnesium oxide can be added along with lime to remove silica.

7. When the raw water has high iron and manganese content, aeration and filtration devices should be added to remove iron and manganese.

The above is an introduction to the pretreatment requirements for ultrapure water systems. When selecting a pretreatment device, choose a suitable one based on the requirements of the influent and effluent water quality.