Physicochemical Processes for Wastewater Treatment

Overview

• Lecture focuses on wastewater generation and treatment in petroleum refining industry.
• Previous studies covered sugar, distilleries, and fertilizer industries.
• Petroleum refineries are crucial for fuel production, impacting industrial, commercial, and domestic uses.

Refinery Operations

• Crude Distillation Unit: Two columns - Atmospheric and Vacuum.
  • Atmospheric Distillation Column: Operates at atmospheric pressure, producing methane, ethane, LPG, naphtha, aviation fuels, kerosene, and diesel.
  • Vacuum Distillation Column: Operates under vacuum, producing vacuum gas oils, bitumen, varnishes, etc.
• Refineries also engage in chemical conversion processes to remove impurities (e.g., sulfur).

Wastewater Management

• Large volumes of water are needed, primarily for steam and cooling processes.
• Wastewater characteristics differ based on refinery operations and crude oil properties.

Sources of Wastewater and Pollutants

• Leaks, spills, and runoff contribute to wastewater.
• Contaminants include BOD, COD, oil, phenolics, sulfides, ammonia, suspended solids, and heavy metals.

Treatment Strategies

• In-Plant Source Control: Reduces pollutant load before it reaches main wastewater streams.
• End-of-Pipe Treatment: Primary, secondary, tertiary treatments, and advanced oxidation processes.
• Use of activated carbon filters for tertiary treatment.

Physicochemical Treatment

• Processes to reduce water volume: evaporation, membrane technologies.
• Processes to reduce pollutant concentration: carbon filters.

Typical Wastewater Treatment Systems

• Oil-Water Separation: Primary and secondary stages.
• Biological Treatment: Followed by clarification and tertiary treatment.
• Advanced Oxidation Processes: For persistent pollutants.
• Chemical Oxidation: For specific contaminants using oxidants.
• Membrane Filtration and Reverse Osmosis: For removing dissolved pollutants.

Compliance and Standards

• MINAS standards guide treatment processes.
• Emphasis on controlling COD, BOD, oil, phenols, sulfides, ammonia, heavy metals, and other pollutants.
• Refineries must meet environmental standards for discharge.

Conclusion

• Refinery wastewater management is complex due to varying crude oil and production processes.
• Effective treatment strategies are essential for environmental compliance.