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PCB Bulk Process Waste Disposal Options

Polychlorinated Biphenyls (PCBs) are a synthetic organic compound once extensively used in applications, ranging from paints to plastics. Due to their high toxicity, PCBs were banned in 1979 by the Toxic Substances Control Act. Storage and disposal of bulk PCB waste thus requires approval from the relevant authorities. Several options are available for treating and disposing of PCBs; alkali metal reduction, plasma ARC and gas phase chemical reduction are commonly used to dispose of bulk waste.

  1. Alkali Metal Reduction

    • Alkali metal reduction is applied to bulk waste that contains more than 10,000 mg per kilogram of PCB. The technique utilizes a dispersed metallic alkali, such as sodium, potassium or an organo-metallic compound. The alkali metal acts as a reducing agent and removes chlorine to produce a non-halogenated product. The process is conducted under atmospheric pressure and temperatures, ranging between 194 and 329 degrees Fahrenheit.

    Gas Phase Chemical Reduction

    • Gas Phase Chemical Reduction (GPCR) uses gases, such as hydrogen and steam, to reduce PCBs into hydrogen chloride, which is then neutralized with caustic soda. The process consists of three operating units: the front-end system, the reactor and the gas scrubbing and compression system. Bulk waste is placed into a thermal reduction batch processor at the front-end system, which removes all contaminants and transfers them to the reactor where they are destroyed.

    Plasma ARC

    • This process utilizes ionized argon gas, carbon and oxygen at extremely high temperatures and a DC current of 150kW. PCB is directly injected into the plasma system and heated to around 5,612 degrees Fahrenheit, where it undergoes heat decomposition in the reaction chamber for approximately 20 minutes. At the end of the chamber, the waste is cooled, and all contaminants are removed and transported to the destruction unit.

    Recycling

    • These processes often form part of a recycling program as they all produce nonhazardous, PCB-free waste capable of reuse. This provides both environmental and economic benefits over dumping PCB waste into landfills. Landfill disposal impacts food and drinking water quality by contaminating soil and groundwater, which poses significant health risks. Also, the cost of removing PCB contaminants from landfill sites is considerable.

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