Is it necessary to add alkali when treating dye factory wastewater with ferrous sulfate?
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Is it necessary to add alkali when treating dye factory wastewater with ferrous sulfate?
Adding alkali depends on the pH value of the wastewater; it is not necessary to add it always.
It is generally better to use it in combination with lime.
It depends on the alkalinity of the reclaimed water; if the alkalinity is low, iron cannot undergo hydrolysis to form iron oxide, and thus no flocculation effect occurs. Too high an alkalinity is also not good.
Adding alkali is used to adjust the pH value, and it is added depending on the quality of the water
If it is merely for adjusting pH, liquid alkali can be used； If the removal of organic matter is also to be achieved, lime is recommended; a combination of lime and ferrous sulfate yields good results, with a COD removal rate of around 40%.