Products & Solutions

Frequently Asked Questions

How is spent carbon reactivated?

Spent carbon is reactivated in the same manner that it is manufactured. In multiple hearth furnaces or rotary kilns, the spent carbon is heated to temperatures above 1,700°F utilizing steam as a selective oxidant. Adsorbed organics are either volatilized or pyrolysed to a carbon char. The high- temperature steam reaction serves to develop the pore volume of the activated carbon and restore its adsorptive capacity.

How are the emissions from the reactivation process treated?

Reactivation furnaces are maintained under negative pressure ensuring there will be no leaks to the outside environment. The furnace off-gas is passed through an afterburner to destroy any unburned organics that remain. The emission stream is then passed through a chemical scrubber to remove any acidic gases that may have formed. A final treatment is through baghouse filters that remove any particulate matter that remains in the stream.

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Will reactivated carbon work for my application?

In most applications, reactivated carbon will perform nearly as well as virgin carbon. Calgon Carbon can provide an assessment of the standard reactivated carbon products against virgin carbon for most applications using computer modeling programs. Details can be submitted by clicking here to complete an Application Questionnaire. If required, laboratory evaluation by accelerated column testing or pilot scale trials can be conducted.

What is the advantage of reactivating spent carbon?

The reactivation process recycles the spent carbon for reuse. Adsorbed organics are destroyed and the activated carbon’s adsorptive capacity is restored. The cost and long-term liability of disposal are avoided. Reactivated carbon also represents a cost savings over virgin carbons. The adsorptive capacity of the spent carbon can be restored at a lower cost than the manufacture of activated carbon from raw material.

Is reactivated carbon suitable for use in drinking water?

Spent carbons from drinking water and other food grade applications can be reactivated for reuse in their prior applications if these carbons are segregated for custom reactivation at a food grade facility. Reactivated carbon from industrial applications or reactivated at a non-food grade operation is classified as non-food grade as a general practice.

If spent carbon is returned, can it be replaced with virgin carbon?

Yes, Calgon Carbon will reactivate the spent carbon and supply this later to a non-food grade application. The spent carbon can be replaced with a variety of virgin carbons that would suit the needs of the application.

Can hazardous spent carbons be returned for reactivation?

Yes, in most cases. The Catlettsburg, KY and Pittsburgh, PA plants are fully permitted to accept RCRA hazardous wastes. There are a few RCRA codes such as some characteristic hazards that are unacceptable by permit. Some compounds such as PCB’s are also not approved for return.


Carbon Acceptance Frequently Asked Questions:

What is Carbon Acceptance?

Calgon Carbon cannot accept the return of any spent carbon until the material has been tested and approved for reactivation. This is necessary to ensure that the spent carbon can be handled and reactivated safely and that the quality of our reactivated carbon products is maintained. This process is called Carbon Acceptance.

How long does the approval process take?

Carbon Acceptance testing on routine samples typically requires 2-3 weeks from receipt of the sample and completed profile document to assignment of a Carbon Acceptance Number and notification to the customer that the spent carbon may be scheduled for return to our reactivation facility. If the customer has requested TCLP testing to aid in making the RCRA declaration, additional time will be required.

What is the cost of the testing?

The fee for carbon acceptance testing is $400 (USD) for non-hazardous projects and $1,000 (USD) for RCRA-hazardous projects.

How often must the carbon acceptance process be repeated?

Carbon acceptance is a recertification process that must be completed every five years. When a project has been approved for reactivation at one or more of our reactivation facilities, it is assigned a unique Carbon Acceptance Number (CAN) which will be used to identify the project throughout its lifetime.

How can I determine whether my spent carbon is RCRA-hazardous or not?

The customer is to declare the classification of the spent (exhausted) carbon as hazardous or non-hazardous under RCRA (Resource Conservation and Recovery Act) regulations. Specific questions of applicability should be addressed to the RCRA Hotline or an environmental consultant; however, the following general guidelines may be helpful. In general, the spent carbon could be deemed hazardous if it has treated a listed waste or if it is a characteristic waste.

If the spent carbon has been used to treat a listed waste, it could be considered RCRA-hazardous by the "mixture and derived from rule." These hazardous waste codes begin with the following letters:

"F"– Non-specific sources
"K"– Specific sources
"P" and "U"– Discarded commercial chemical products, off-spec species, container residues and spill residues.

The spent carbon could be deemed hazardous by characteristic if it is Ignitable (D001), Corrosive (D002), Reactive (D003) or Toxic (D004 - D043). Toxic wastes are determined by TCLP testing (Toxicity Characteristic Leaching Procedure).

The TCLP analyses are performed on a sample extract which is prepared in a manner to simulate the climatic leaching action expected to occur in landfills. The solid sample (spent carbon) is extracted with one of the appropriate aqueous extraction (leaching) solutions described in the test method.

Analyses for specific metals, volatile organics, semivolatile organics, pesticides and herbicides are performed on the leachate. If the concentration of any of the specified compounds are found to be present in the leachate above the regulatory level, the waste (spent carbon) is a CHARACTERISTIC WASTE and must carry the appropriate "D" code.

TCLP TESTING IS NOT PART OF THE STANDARD CARBON ACCEPTANCE TEST PROTOCOL. We can, however, have the test performed for you to assist you in making the RCRA determination for their spent carbon. Additional costs are incurred for this testing and the cost is dependent upon the particular compounds of interest. Contact your Applications Engineer for more information.

What is the proper DOT shipping name for spent carbon?

Although "Activated Carbon" is listed in the DOT Hazardous Materials Table as a spontaneously combustible material, all Calgon Carbon products manufactured for use in industrial, municipal or remediation projects have been tested, and it has been specifically determined that the products do not meet the definition of this hazard class. (See the Material Safety Data Sheet (MSDS) for Calgon Carbon activated carbon for more details.) The shipping name "Activated Carbon" and its associated shipping description from the DOT table must not be used to ship spent carbon to Calgon Carbon’s reactivation facilities. Our plants are not permitted to accept shipments bearing that description.

The proper DOT shipping name for non-hazardous spent carbon is "Not Regulated" or "Scrap Carbon."

The proper DOT shipping name for RCRA hazardous spent carbon not meeting an RQ (Reportable Quantity) is: "Hazardous Waste, solid, n.o.s., 9, NA 3077, III, (plus waste codes)".

The proper DOT shipping name for RCRA hazardous spent carbon which contains an RQ (Reportable Quantity) of a hazardous substance is: "RQ, Hazardous Waste, solid, n.o.s., 9, NA 3077, III, (plus waste codes or the words 'contains substance name(s)')".

Click here for more information on Carbon Acceptance.