Why is powdered activated carbon pac used in sewage treatment? What are the functions and process of activated carbon?

With the rapid development of industrialization and urbanization, sewage treatment has become a key area of environmental governance in various countries. In sewage treatment technology, activated carbon is widely used in water plants, industrial wastewater treatment, urban sewage treatment, as well as chemical, pharmaceutical, electronic and other fields due to its excellent adsorption performance and stability. JS Activated Carbon will discuss in detail the characteristics, application methods and typical process of activated carbon in sewage treatment, and analyze its development potential in future sewage treatment.

1. Characteristics and advantages of activated carbon in sewage treatment

Powdered activated carbon pac is a porous material with a high specific surface area and rich pore structure. These characteristics give it great application value in sewage treatment.

Highly efficient adsorption: The specific surface area of activated carbon is generally as high as 500-1500 m²/g or more, which can strongly adsorb organic matter, heavy metal ions, odor substances, chlorides, etc. in sewage. In addition, activated carbon can also effectively remove pigments, grease and microbial residues, making it an ideal material for treating difficult-to-degrade pollutants.

Strong adaptability: The pore size and porosity of activated carbon can be adjusted according to specific needs, so that it can adapt to the treatment requirements of different water qualities and different pollutant concentrations. Its physical adsorption, chemical adsorption and other methods can have a good removal effect on various complex components, and the adsorption rate can exceed 95% under appropriate conditio

Fixed bed adsorption method: When sewage passes through a static activated carbon bed, pollutants are adsorbed on the activated carbon. After saturation, the activated carbon needs to be regenerated or replaced.

Fluidized bed adsorption method: In a fluidized bed, activated carbon particles are suspended in the bed, and pollutants are adsorbed when sewage flows through. This method is more uniform than the fixed bed adsorption method and avoids the formation of "adsorption hot spots".

Moving bed adsorption method: The activated carbon is fixed by a membrane filter, and pollutants are taken away when the sewage flows, effectively improving the adsorption effect.ns.

3. Process flow of activated carbon in sewage treatment

The typical process flow of activated carbon in sewage treatment usually includes pretreatment, activated carbon adsorption, precipitation, filtration and disinfection to ensure efficient removal of pollutants.

1. Pretreatment

Before the sewage enters the activated carbon adsorption device, it must first be filtered through the grid and the sand settling tank to remove large suspended particles, and then the pH value and temperature of the water quality are adjusted in the regulating tank. Pretreatment not only improves the efficiency of the subsequent adsorption process, but also reduces the consumption of activated carbon.

2. Activated carbon adsorption

In the activated carbon adsorption stage, the sewage passes through the activated carbon particles in the bed, and the organic matter, pigments and trace harmful substances in the water are effectively adsorbed. This stage can adopt a variety of methods such as fixed bed, fluidized bed, moving bed, etc. The specific choice depends on the water quality and treatment goals.

Renewable use: After a special process, several cubic meters of saturated activated carbon can be put back into use, significantly extending its service life. This feature has positive significance in terms of sewage treatment cost control and environmental protection.

2. The main application methods of activated carbon in sewage treatment

According to different pollutants and water quality conditions, there are many application methods of activated carbon in sewage treatment, mainly including adsorption method, biological activated carbon method and coagulant-assisted method.

1. Adsorption method

Adsorption method is the most common application method of activated carbon in sewage treatment. Through efficient adsorption, activated carbon can adsorb organic pollutants in sewage on the surface, effectively reducing COD and BOD in water. This method is suitable for a variety of industrial wastewater and domestic sewage, with the characteristics of simple operation and significant pollutant removal effect.

2. Bioactivated carbon method

Bioactivated carbon is a composite material that combines microbial degradation and activated carbon adsorption. Microorganisms attach to the surface of activated carbon and achieve multiple purifications by degrading organic matter, ammonia nitrogen and other pollutants. This method can not only reduce the consumption of activated carbon, but also improve the removal efficiency. It is an innovative application in the field of sewage treatment.

3. Coagulant-assisted method

In the coagulant-assisted method, several cubic meters of activated carbon and coagulants work together to condense suspended matter and colloidal substances in sewage into large particles, which are easier to precipitate and separate. This method is mostly used to remove particulate pollutants and heavy metal ions in sewage, which can further improve treatment efficiency and water quality.

3. Sedimentation and Filtration

After adsorption, the sewage enters the sedimentation tank, where the pollutants and several cubic meters of activated carbon particles gradually settle to the bottom. The subsequent filtration stage usually uses a sand filter to remove the remaining suspended particles and pollutants in the water to ensure clear water.

4. Disinfection and Water Discharge

The sewage treated and filtered by activated carbon will enter the disinfection tank before the water is discharged. Chlorine or other disinfectants are added to kill bacteria and viruses in the water to ensure that the water quality meets the standards for discharge or reuse.

IV. Application Case Analysis

In practical applications, the excellent adsorption performance of activated carbon has significantly improved the quality and efficiency of sewage treatment. The following are some practical case analyses.

Case 1: COD Removal in Municipal Sewage Treatment

A municipal sewage treatment plant uses the A2O process, but the removal effect of COD is not ideal. By introducing the activated carbon fluidized bed adsorption method, the treatment plant treats sewage under a pressure of 0.03-0.04 MPa, controls the COD load at 3.0 kg/d, and increases the COD removal rate of sewage after activated carbon adsorption to more than 90%, significantly improving the effluent effect.

Case 2: Heavy Metal Removal in Industrial Wastewater Treatment

The sewage of a chemical company contains a high concentration of heavy metal ions. The heavy metal concentration was greatly reduced by using the activated carbon and coagulant-assisted method. After testing, the heavy metal concentration in the treated water meets the emission standards, and the consumption of activated carbon is relatively low, and the overall treatment cost is effectively controlled.

5. Evaluation of the effect of powdered activated carbon pac wastewater treatment

Organic matter removal effect: Activated carbon has a significant adsorption capacity for organic matter. By measuring the COD and BOD of the inlet and outlet water, its purification effect can be quantified.

Heavy metal removal effect: Activated carbon has a good adsorption effect on heavy metal ions such as cadmium, chromium, and lead, and the concentration of heavy metal ions in sewage can be significantly reduced.

Decolorization removal effect: Activated carbon has a significant decolorization effect and is mainly used in oils, beverages, food, drinking water and other fields. Activated carbon removes pigment molecules in liquids through adsorption, especially in water where the decolorization effect is the strongest.

6. Importance of activated carbon

The application of activated carbon in sewage treatment covers many aspects. Its high-efficiency adsorption capacity, adaptability and regeneration characteristics make it an important material for sewage treatment. Through reasonable process selection and strict effect evaluation, the application of activated carbon is expected to be further promoted and optimized, providing a solid guarantee for sewage treatment in the process of industrialization and urbanization.