Application of Activated Carbon Adsorption Technology in Water Treatment

Activated carbon comes in different forms, and currently granular and powdered forms are still the main ones used in water treatment. Powdered carbon is used for intermittent adsorption, that is, the powdered carbon is added to the water to be treated in a certain proportion, mixed evenly, and the carbon and water are separated by precipitation or filtration. This method is also called static adsorption. Granular carbon is used for continuous adsorption. The treated water passes through the carbon adsorption bed to purify the water. This method is exactly the same as the fixed bed in form and is also called dynamic adsorption. There are many substances that can be adsorbed by activated carbon, including organic or inorganic, ionic or non-ionic. In addition, the surface of activated carbon can also play a catalytic role, so it can be used in many different occasions.

Activated carbon has a strong adsorption capacity for dissolved organic matter in water, and is effective in removing most organic pollutants in water, such as phenol and benzene compounds, petroleum, and many other synthetic organic matter. Some organic pollutants in water are difficult to remove by biochemical or oxidation methods, but they are easily adsorbed by activated carbon.

Because the cost of activated carbon adsorption treatment is higher than other general treatment methods. Therefore, when the concentration of organic matter in the water is high, other more economical methods should be used to reduce the content of organic matter to a certain level before treatment. In wastewater treatment, the activated carbon adsorption process is usually placed behind the biochemical blowing, which is called activated carbon three-level wastewater treatment, to further reduce the content of organic matter in the wastewater, remove those pollutants that are difficult for microorganisms to decompose, and make the water after activated carbon treatment It can meet the requirements of discharge standards, or the treated water can be returned to the production process for reuse, achieving the purpose of closed circulation of production water.

The ability of activated carbon to adsorb organic matter is very large. In the third-level wastewater treatment, the COD adsorbed by each gram of activated carbon can reach dozens of percent of its own mass. Adding three-stage wastewater treatment to the wastewater treatment plant can achieve a BOD removal effect of 95%. Activated carbon removes organic matter from water in the form of physical adsorption. The adsorbed properties do not change before and after adsorption. If appropriate desorption methods can be used, valuable substances in the water can also be recovered. If powdered activated carbon is put into the gas explosion equipment, the carbon powder and microorganisms form an agglomerate, which can make the treatment effect exceed that of the general secondary biological treatment method, and the effluent water quality is close to the tertiary treatment.

In addition, it can also make activated carbon sludge dense and solid, reduce effluent turbidity, and increase the hydraulic load of secondary treatment. Powdered carbon can be added intermittently, which can improve the treatment effect of existing secondary treatment plants without increasing investment in tertiary treatment.