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Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) are two of the most important indicators of organic pollution in the wastewater. They must be reduced to the normal value before wastewater discharge. In this blog, we will explore what is BOD and COD, and how activated carbon effectively reduces them.
What is BOD and COD?
BOD measures the amount of oxygen required by microorganisms to break down organic matter in water. A high BOD level indicates a significant organic load, which can deplete oxygen in aquatic systems, leading to fish kills and ecosystem imbalance.
COD, on the other hand, measures the total amount of oxygen required to chemically oxidize both biodegradable and non-biodegradable organic compounds. It provides a more comprehensive measure of organic pollution.
Both BOD and COD are critical for understanding the health of wastewater.
How Does Activated Carbon Remove BOD and COD?
With high prorous structure, activated carbon can absorb and remove a wide range of pollutants, including dissolved organic matter, oils, and other compounds that contribute to high BOD and COD levels. These impurities are effectively captured within the tiny pores of the activated carbon, reducing their concentration in the water.
In addition, activated carbon interacts with certain compounds, neutralizing harmful substances and breaking down complex molecules into simpler, less harmful forms. This dual action enables activated carbon to significantly improve water quality, making it an ideal solution for industries looking to meet strict environmental discharge standards.
Different Types of Activated Carbon for COD and BOD Removal
Different types of activated carbon are available for wastewater treatment, each with unique characteristics and applications:
Granular Activated Carbon (GAC):
It is ideal for fixed-bed or deep-bed absorbers, GAC is durable and effective for long-term use in industrial wastewater treatment.
| Parameter | Specification |
|---|---|
| Particle Size | 8×30 mesh, 10×30 mesh, 8×16 mesh or customized |
| Iodine Value | ≥900 mg/g |
| Moisture Content | ≤5% |
| Ash Content | ≤10% |
| Bulk Density | 0.45-0.55 g/cm³ |
| Hardness | ≥95% |
| Surface Area | ≥1000 m²/g |
Powdered Activated Carbon (PAC):
It is best suited for batch processes or when rapid treatment is necessary. PAC is often dosed directly into wastewater.
| Parameter | Specification |
|---|---|
| Particle Size | 200 mesh, 325 mesh |
| Iodine Value | ≥950 mg/g |
| Moisture Content | ≤8% |
| Ash Content | ≤15% |
| Bulk Density | 0.35-0.45 g/cm³ |
| Surface Area | ≥1050 m²/g |
Impregnated Activated Carbon:
Impregnated with chemical agents for specific pollutant removal, such as heavy metals or certain organic compounds.
| Parameter | Specification |
|---|---|
| Particle Size | 4×8 mesh, 10×30 mesh or customized |
| Iodine Value | ≥800 mg/g |
| Moisture Content | ≤5% |
| Ash Content | ≤12% |
| Bulk Density | 0.45-0.55 g/cm³ |
| Impregnated Chemicals | MgO, KOH, NaOH |
| Surface Area | ≥900 m²/g |
At Zhulin Carbon, we provide customizable solutions, offering GAC and PAC with optimized pore structures designed for efficient BOD and COD reduction.
Key Factors Influencing the Efficiency of Wastewater Treatment
The performance of activated carbon in BOD and COD removal depends on several factors:
Temperature: Higher temperatures can increase adsorption rates but may also reduce the adsorption capacity.
pH: The pH of the wastewater affects the surface chemistry of activated carbon. A neutral to slightly acidic pH often yields the best results.
Contact Time: Longer contact time allows for better adsorption, especially in fixed-bed systems.
Pollutant Concentration: High organic loads may require larger quantities of activated carbon or regeneration cycles.
Conclusion
Activated carbon is a highly effective solution for reducing BOD and COD levels in wastewater. Selecting the right type of activated carbon can significantly enhance pollutant removal to ensure the environmental regulations.
At Zhulin Carbon, we are committed to providing high-quality products and expert support to meet your wastewater treatment challenges. Contact us today to learn more about how our activated carbon can transform your wastewater treatment process.