Should I choose powdered carbon or granular carbon for water treatment?

In the water treatment process, the selection of activated carbon is crucial to the treatment effect. Different types of activated carbon are suitable for different process requirements and conditions. Powdered activated carbon and granular activated carbon have their own advantages and disadvantages in performance, applicable occasions and economy.

 

In the water treatment process, the selection of activated carbon is crucial to the treatment effect. Different types of activated carbon are suitable for different process requirements and conditions. Powdered activated carbon and granular activated carbon have their own advantages and disadvantages in performance, applicable occasions and economy. Xingnuo Activated Carbon will combine the actual application of water treatment to discuss in detail the factors that should be considered when choosing powdered activated carbon or granular activated carbon, to help readers better understand how to make appropriate choices in different situations.

Basic characteristics of powdered activated carbon and granular activated carbon

1.Characteristics of powdered activated carbon Powdered activated carbon has a small particle size, usually in the micron level, and the commonly used specifications are 200 mesh and 325 mesh. It has a large specific surface area and can quickly adsorb pollutants in water. Due to its fine particle size, powdered activated carbon shows a higher adsorption rate in water treatment, especially in cases where the concentration of pollutants is high and rapid treatment is required.

 

Powdered activated carbon is mostly used for one-time treatment and usually cannot be regenerated and reused. Its rapid processing ability makes it suitable for emergency treatment or short-term treatment processes, but due to its powdery properties, more sophisticated dosing equipment is required during operation.

2.Characteristics of granular activated carbon

Granular activated carbon has a larger particle size, generally ranging from 0.5 mm to several millimeters. Common specifications are 8-30 mesh. Due to the large particles, the resistance to water flow is small, so granular activated carbon is suitable for water treatment processes that require long-term continuous operation. Granular activated carbon has a relatively slow adsorption rate, but its durability and renewability make it a preferred solution for lightly polluted or long-term water treatment.

 

Granular activated carbon can be regenerated thermally or chemically and reused multiple times, which offers economic advantages for large-scale water treatment plants or long-running industrial wastewater treatment.

Selection of different applications

1. Application of granular activated carbon In water treatment systems with continuity and stability, granular activated carbon is often a better choice. For example, drinking water treatment, industrial wastewater treatment and large sewage treatment plants usually use granular activated carbon because it is not easy to lose and can be kept running for a long time through the filtration system, reducing the trouble of frequent replacement. In addition, granular activated carbon can be regenerated and reused, which is suitable for processes with light pollution load and low overall operating costs.

The main applications of granular activated carbon include:

Deodorization and dechlorination in water plants

Removal of organic matter in industrial wastewater

Decolorization treatment in wastewater

2. Application of powdered activated carbon

Powdered activated carbon is suitable for applications with large pollution loads and high treatment requirements. Due to its fast adsorption rate, it can effectively remove high concentrations of organic pollutants in a short time, so it is often used in some intermittent treatment or emergency treatment processes.

Powdered activated carbon is used in the following situations:

Short-term treatment of acute pollutants

Emergency treatment of pollution peaks

Water bodies that require rapid treatment of organic matter, color or odor

In some cases, such as sudden water pollution incidents, the use of powdered activated carbon can quickly control pollution, but because it cannot be regenerated, the cost of one-time use is high, and a balance needs to be considered between economic costs and treatment needs.

Treatment effect and operational convenience

1. Adsorption speed and treatment efficiency

Powdered activated carbon has a faster adsorption speed, and thanks to its large specific surface area, it can capture more pollutants in a short time. Therefore, for those occasions where pollutant concentrations need to be reduced quickly, powdered activated carbon is a very effective choice.

In contrast, granular activated carbon has a slower adsorption speed, but it is more suitable for systems that require stable and long-term treatment. Due to the size and shape of the particles, it has less resistance in the water treatment system and does not affect the passage of water, so it is suitable for large-flow water treatment processes.

2. Operational convenience

The operational advantage of granular activated carbon lies in its stability and easy regeneration. When replacement is required, granular carbon can be achieved by simple backwashing or replacement of the carbon bed, and the process is relatively simple.  

The treatment of powdered activated carbon is more complicated, and usually requires special equipment for addition and separation. During the treatment process, powdered carbon is easy to lose, and additional filtration or precipitation equipment is required to recover the activated carbon particles. In addition, the use of powdered carbon may also affect the hydraulic conditions of the system, increasing the maintenance and operation complexity of the system.

Cost-Benefit Analysis

In water treatment, cost is always an important consideration. Granular activated carbon can be reused and has a high adsorption capacity after regeneration. In the long run, the use of granular activated carbon can reduce the overall operating cost of the treatment system.

 In contrast, powdered activated carbon is a one-time use material. Although its use is necessary in some special cases, its cost is higher from a long-term operation perspective, so it is more suitable for emergency treatment or special high-pollution load treatment.

The choice of powdered carbon or granular carbon needs to be evaluated based on the specific needs of water treatment, such as the amount of water to be treated, the type of pollutants, the treatment process requirements, and the economic budget.

Generally, granular carbon is more suitable for large-scale continuous operation systems, while powdered carbon is a better choice for intermittent treatment or where efficient removal of pollutants is urgently needed.  

Water quality requirements and carbon characteristics

In treatment systems with high water quality requirements, the chemical properties of the activated carbon itself should also be considered when choosing the type of activated carbon. For example, the high ash content of some granular carbons may affect the final effluent water quality. As for powdered activated carbon, due to its small particle size, it is easier to disperse during the addition process, and the residual carbon powder in the water may affect the clarity of the effluent water.

In addition, some specific applications in water treatment may require activated carbon to have a higher purity and a lower ash content. For example, in the process of drinking water treatment, the selection requirements for granular carbon will be more stringent. In occasions such as industrial wastewater treatment, the purity requirements for granular carbon are relatively low, but the requirements for adsorption performance are higher. Therefore, the treatment process should select the appropriate type of activated carbon according to the actual water quality.