Treatment methods for heavy metal exceeding standards in coking wastewater

The treatment methods for heavy metal exceeding standards in coking wastewater need to comprehensively consider the characteristics and treatment requirements of the wastewater. The following are some common treatment methods:

1. Activated carbon adsorption method:

Principle: Activated carbon has a large specific surface area and a special microporous structure, which can effectively adsorb organic matter and some heavy metal ions.

Application: By using activated carbon adsorption columns to remove organic matter and heavy metal ions from coking wastewater. However, this method has limited processing effectiveness and can only remove a portion of organic matter and heavy metal ions.

2. Chemical precipitation method:

Principle: By adding appropriate chemical reagents such as calcium hydroxide, ferric chloride, etc., heavy metal ions in wastewater undergo precipitation reaction, and after precipitation, they are separated from the wastewater.

Application: It can remove most heavy metal ions from wastewater, but the remaining wastewater still needs further treatment.

3. Membrane separation method:

Principle: This includes technologies such as ultrafiltration and reverse osmosis, which separate heavy metal ions from wastewater through membrane pore size and molecular sieve effect.

Application: Reverse osmosis technology can remove most of the organic matter and heavy metal ions in wastewater, but the process is complex and the cost is high.

4. Electrolysis method:

Principle: Metal ions can be separated from relatively high concentration solutions during electrolysis and then utilized.

Application: The electrolysis method is mainly used for the treatment of electroplating wastewater, but the disadvantage is that the concentration of heavy metal ions in the water cannot be reduced very low.

5. Ion exchange method:

Principle: By exchanging heavy metal ions with ion exchangers, the goal of removing heavy metal ions from wastewater is achieved.

Application: Suitable for treating wastewater with low concentration of heavy metal ions.

6. Dissolution and evaporation treatment:

Principle: Removing most of the solid pollutants from coking wastewater helps to isolate toxic substances, and can also adjust the pH value of the wastewater to a more acceptable range.

7. Exposure treatment:

Principle: By irradiation, harmful substances such as viruses can be effectively disinfected in wastewater, while also having a decolorization effect, making the wastewater cleaner and more transparent.

In addition, to ensure that coking wastewater treatment meets standards and is safely discharged, the following measures can also be considered: