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Effect of PAC on COD removal rate

During water treatment, we often encounter some difficult problems. From the determination of agent by test to the dosing process to the reaction of effect after treatment, each step is very critical. Once the control is not good, the effect of effluent will be directly affected. Today we will take a look at the influence of the application of PAC on COD

Polyaluminium chloride reduces COD by 20-40%. However, only some colloidal COD and suspended COD are removed by liquid PAC, and the removal rate of soluble COD is still low. If the soluble COD in water increases, the flocculation precipitation can not be removed. In addition, the water quality PH is too low, flocculation and precipitation effect is poor after adding PAC, and suspended substances in water lead to poor COD removal effect.

Polyaluminium chloride actually contains a certain amount of ferrous sulfate, generally light yellow, the darker the color, the higher the content, and ferrous ions in water will cause high COD results. Oxidizer oxidizes the reductant, ferrous oxide acts as reductant, and measures the reducing substance in water. When added to water, chloride ion is free. Mercury sulfate is needed to shield chloride ion during COD test. If mercury sulfate is not added or used in small amount, it may also cause high COD.

Another reason for the increase of COD may be that PAC itself contains a small amount of reducing substance. With the increase of product consumption, COD in sewage reaches a certain value while the incoming COD increases continuously, so COD in water increases instead. It can be simply understood that PAC contains chloride ion. If the dosage is too high, the chloride ion content will increase and COD will also increase

Thank you for your attentionHenan aierfuke Chemical Co., Ltd：Focus on water treatment, only for the healthy world! Our company is committed toPolyaluminium chloride、Polyferric sulfateThe R & D, manufacturing and sales of series of water purification materials are willing to create success with our customers and friends.