Activated carbon waste stream can be classified into a variety of possible categories, including both hazardous and non-hazardous waste. The handling and disposal of activated carbon waste streams can pose a significant economic and logistical burden on the waste generator. The incentives for recycling spent activated carbon wastes include financial benefits and reduced liabilities associated with improper handling or disposal of the activated carbon waste stream.

Many companies offer activated carbon recycling services as part of an overall service arrangement or as a stand-alone service. The specific service offered will depend on such factors as the characteristics of the GAC treatment system, the volume of spent carbon to be handled, and the capabilities of the selected vendor. Spent carbon waste can be handled in either bulk shipments via tanker truck or rail cars, or in drums or alternative containers. Virtually all spent carbon waste to be regenerated is processed using a thermal destruction/scrubbing system, which destroys the organic contaminants as well as regenerates the carbon for reuse. Some vendors offering activated carbon regeneration services will segregate the waste batches handled from each customer, if required, while other vendors will "blend" together waste carbon batches from multiple customers prior to processing. This process can be a significant concern to those seeking to minimize liability associated with mixing and disposal of their waste stream with other unidentified wastes from other sources.

The compliance benefits listed here are only meant to be used as general guidelines and are not meant to be strictly interpreted. Actual compliance benefits will vary depending on the factors involved, e.g., the amount of workload involved.

• Eliminates the cost, handling, and related liabilities associated with spent carbon disposal at off-site facilities.
• Significantly reduces the volume of fresh carbon that must be purchased to regenerate the system.

• Regeneration of powdered activated carbon is typically not practical.
• If carbon is contaminated with PCBs, dioxins, heavy metals, or DCBP (dichlorobromopropane), regeneration may not be an option.
• Special packaging may be required if carbon has certain chemical properties (e.g., 2<Ph>11, halide and sulfur contamination, etc.)
• Regenerate of carbon on-site is not economically feasible unless more than 400,000 pounds of spent AC is generated per year.

One vendor, Envirotrol, Inc., which performs custom segregated reactivation by which the same carbon is shipped back to the original user, offered the following cost comparison.

Assumptions:

• Facility uses 2,000 lbs. of activated carbon per month.
• Spent carbon from the facility is classified as hazardous and must be incinerated.
• Incineration costs $0.60/lb.
• Virgin carbon costs $1/lb.
• Reactivated carbon costs $0.65/lbs.
• Losses during reactivation of carbon equals 15%. This loss is made up for with virgin carbon when carbon is shipped back to user.
• Labor and freight costs are the same for both uses.

Table 1. Cost Comparison of Annual Use of Virgin versus Reactivated Carbon

Economic Analysis Summary:

• Annual Savings for Recycling Activated Carbon: $21,540
  
• Capital Cost for Diversion Equipment/Process: $0
  
• Payback Period for Investment in Equipment/Process: Immediate

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Calgon Carbon Corporation
P.O. Box 717
1500 Calgon Carbon Drive
Pittsburgh,  PA   15230-0717
Phone: (800) 422-7266 or (866) 225-4660
E-mail:  customerrelations@calgoncarbon.com
URL:  http://www.calgoncarbon.com/

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