Paper & Pulp Industry

The paper and pulp industry is known for generating large volumes of wastewater that require proper treatment before being discharged to avoid environmental pollution. The wastewater from this industry typically contains a variety of contaminants, such as lignin, cellulose, hemicellulose, organic matter, suspended solids, and potentially harmful chemicals used in the papermaking process.

Effective wastewater treatment in the paper and pulp industry is essential to meet regulatory standards and reduce the impact on the environment.

Chemicals Used in Pulp and Paper Wastewater

• PAM/Polyacrylamide
• Aluminum Sulphate
• PAC/Polyaluminium Chloride
• Isothiazolinone CMIT MIT
• Caustic Soda/Sodium Hydroxide

Paper Mill Wastewater Treatment Chemical 

Chemical treatments play a vital role in the wastewater treatment process for paper mills. They are used to enhance the removal of specific pollutants, improve treatment efficiency, and meet stringent regulatory requirements. Here are some common chemical treatments used in paper mill wastewater treatment:

1. Coagulants: Coagulants are chemicals that destabilize colloidal particles and promote their aggregation, forming larger particles that can be more easily removed during sedimentation or filtration. Aluminum sulfate (alum) and ferric chloride are commonly used coagulants in paper mill wastewater treatment.

2. Flocculants: Flocculants are chemicals that help to bind fine particles together to form larger, settleable flocs. This process aids in the removal of suspended solids from the wastewater during sedimentation or flotation. Polymers, such as polyacrylamides, are widely used as flocculants in paper mill wastewater treatment.

3. pH Adjustment: The pH of the wastewater is crucial for the performance of various treatment processes. Adjusting the pH with chemicals like lime (calcium hydroxide) or sulfuric acid helps optimize the effectiveness of coagulation, flocculation, and biological treatment.

4. Disinfectants: In some cases, especially if the treated effluent is discharged into sensitive water bodies, disinfection is necessary to kill harmful microorganisms. Chlorine-based disinfectants or alternative methods like ultraviolet (UV) irradiation are employed for this purpose.

5. Antifoaming Agents: Paper mill wastewater may contain foaming agents used in the pulping or papermaking processes. Antifoaming agents are added to control excessive foam formation and prevent operational issues in treatment units.

6. Chelating Agents: Chelating agents can be used to complex and remove heavy metals that might be present in the wastewater as a result of certain papermaking processes.

7. Advanced Oxidation Processes (AOP): AOP involves the use of powerful oxidizing agents like ozone, hydrogen peroxide, or Fenton’s reagent to break down recalcitrant organic compounds that are resistant to conventional biological treatment.

8. Nutrient Addition: In some cases, the biological treatment process may require additional nutrients (nitrogen and phosphorus) to promote the growth of microorganisms responsible for biodegradation. Nutrient supplements like ammonium nitrate or diammonium phosphate may be added when needed.