How to treat the heavy metal chromium wastewater?

Now the whole people focus on environmental protection aiming to protect green hills and clear waters. The state environmental supervisions have being take a zero-tolerance attitude towards enterprises those discharge "waste water, waste gas and waste residue" into the environment when they fail to meet the discharge standards. The zinc sulfate industrial grade produced by our ferrous sulfate factory is widely used in the treatment of waste water and residues. Among the customers who buy ferrous sulfate industrial grade from Rech Chemical Co. Ltd, there are some buyers who use ferrous sulfate as reducing agent to treat the wastewater with heavy metal chromium. This is a common industrial wastewater treatment process in industry. 

Heavy metal wastewater containing hexavalent chromium is generally treated in chromium reduction method. The principle of this method is to reduce hexavalent chromium to trivalent chromium under acidic condition by adding reducing agent ferrous sulfate, and then add sodium hydroxide, calcium hydroxide, lime and others to adjust pH values to make it form trivalent chromium hydroxide precipitation from the wastewater.

     
       The treatment process is as follows: containing Cr6+ wastewater → regulation pool → reduction reaction pool → coagulation reaction pool → sedimentation pool → filter →pH callback pool → discharge

     
 Condition controls of this reduction reaction: add sulfuric acid to adjust pH value at 2.5 ~ 3, add reducing agents to carry out the reaction, and the control point of the reaction ends at 300 ~ 330mv with ORP instrument. The specific needs to be determined by field debugging, and the reaction time is about 15-20 minutes. Stirring can be proceeded mechanically, or barometric or hydraulically.

       
Coagulation reaction conditions control: PH value: 7 ~ 9, reaction time: 15 ~ 20 minutes.

All information above is about the industry application principle of ferrous sulfate industrial grade, ferrous sulfate water treatment grade to treat  the heavy metal chromium wastewater. Not only for that, ferrous sulfate industrial grade is widely used in other industries such as waste residue treatment, soil remediation, cement and mineral processing.

Copyright：

All texts,images,illustrations on this website are subject to copyright held by Rech Chemical Co. Ltd. Any reproduction,dissemination,transmission,forwarding,and publishing of the articles is strictly prohibited without Rech Chemical's permission, or please indicate the source from http://www.rqsulfates.com