Biological Treatment of Coke Plant Waste Utilizing an Integral Clarification Concept

Authors:

Myrl R. Wear, Senior Environmental Engineer

James A. Grantz, Environmental Engineer

Ronald J. Thompson, Supervising Project Engineer

Armco Environmental Engineering

The paper discusses the biological treatment of coke plant waste at Armco’s Hamilton plant using an integral clarification system combined with pretreated wastewater from ammonia stills and the benzol plant. The treatment process utilizes extended aeration, activated sludge, and careful pH, temperature, and nutrient control to achieve effective removal of ammonia, phenol, and thiocyanate while maintaining stable effluent quality. Operational data over the first year demonstrate that the system performs reliably under variable flow and loading conditions, with minimal emulsified oil impact and efficient sludge management.

Key Learnings

  • Biological treatment of coke plant wastewater can effectively remove ammonia, phenol, and thiocyanate when combined with proper physical-chemical pretreatment.
  • An integral clarification system with aeration allows for efficient sludge recycling, minimizing the need for separate sludge return systems.
  • Extended aeration and completely mixed basins support stable nitrification and carbon oxidation under variable loading conditions.
  • Careful control of pH, temperature, and nutrient addition (phosphorus) is critical for maintaining system stability and microbial health.
  • Emulsified oil in the effluent has minimal negative impact when pretreated and monitored properly.
  • High mixed liquor suspended solids (MLSS) and long sludge ages contribute to efficient treatment and stable effluent quality.
  • Operator training and continuous monitoring of dissolved oxygen, pH, and temperature are essential for smooth plant operation.
  • Capital and operating costs are significant, but proper design and system integration can optimize performance and reduce operational challenges.
  • Seasonal variations can affect nitrification, highlighting the importance of a full year of operational data for evaluating system performance.
  • Startup periods may experience instability, emphasizing the need for phased basin operation and careful system tuning.
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