Necessity and Method of Pretreatment in Purified Water Equipment

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2020.06.06 10:00

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No matter the ion exchange system is directly used or the electrodialysis method (EDI) is first used, and then the reverse osmosis system is added, the common tap water, groundwater or industrial water often cannot meet the requirements of ion exchange resin or reverse osmosis membrane for the inflow of contaminated substances. Only after proper pretreatment, the source water can meet the water quality requirements of the water preparation system.

Purified water equipment

In order to achieve an expected index of raw water quality and meet the requirements of the purification process on the source water, the raw water must be pretreated. The main objects of raw water pretreatment are suspended solids, microorganism, colloid, organics, heavy metals and residual chlorine in free state.

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

When the free chlorine in the raw water exceeds the subsequent inflow standard, it can be filtered with activated carbon or added with sodium sulfite.

If the subsequent process has high requirements for colloidal silicon, add magnesium oxide while adding lime to remove silicon.

When the content of iron and manganese in raw water is high, aeration and filtration devices shall be added to remove iron and manganese.