United States
                Environmental Protection
                Agency
Office of Solid Waste and
Emergency Response
(5102G)
EPA 542-F-01-020
December 2001
www.epa.gov/superfund/sites
www.cluin.org
&EPA     A Citizen's Guide  to
               Activated  Carbon  Treatment
  The Citizen's Guide Series
 EPA uses many methods to clean up pollution at Superfund and other sites. If you live, work, or go to school near
 a Superfund site, you may want to learn more about these methods. Perhaps they are being used or are proposed
 for use at your site. How do they work? Are they safe? This Citizen's Guide is one in a series to help answer your
 questions.
                 What  Is activated carbon treatment?

                 Activated carbon is a material used to filter harmful chemicals from polluted air and water. It
                 looks like tiny granules of black sand. As polluted water or air flows through an activated
                 carbon filter, chemicals sorb or stick to the surface and within the pores of the granules.
                 Most tap water filters and fish tank filters at home contain activated carbon and work the
                 same way. Activated carbon filters are often used as part of a pump and treat system to
                 clean up polluted groundwater (See^4 Citizen's Guide to Pump and Treat [EPA 542-F-
                 01-025]).

                 How does it work?

                 An activated carbon filter generally consists of one or more containers or columns of gran-
                 ules. It is designed to sorb the specific hazardous chemicals found at a site. Water or air is
                 usually pumped through a column from the top down, but upward flow also is possible. As
                 the polluted water or air flows through the column, the chemicals sorb to the porous surface
                                     Columns containing

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For more
information
write the Technology
Innovation Office at:

U.S.EPA(5102G)
1200 Pennsylvania Ave.,
NW
Washington, DC 20460

or call them at
(703) 603-9910.

Further information also
can be obtained at
www.cluin.org or
www.epa.gov/
superfund/sites.
                         of the granules. The water or air that exits the column is cleaner than the water or air that
                         entered it. If the water or air isn't clean enough, it is pumped into another column or cleaned
                         using another method.

                         When the available surface of the activated carbon fills up with chemicals, the carbon is said to
                         be spent. Spent carbon must be replaced or cleaned so the filter can be reused. If spent carbon
                         is replaced, the carbon and the sorbed chemicals are burned or disposed of in an approved
                         landfill. Cleaning spent carbon involves heating the carbon and pumping clean air through it. The
                         heat loosens the chemicals from the carbon, and the air sweeps them out of the column. Air
                         pollution control equipment then collects the chemicals, which are disposed of or destroyed.

                         Is  activated  carbon  treatment  safe?

                         Activated carbon treatment is quite safe to use. The columns are equipped with detectors that
                         alert cleanup workers 1) if leaks occur; and 2) when it is time to replace the activated carbon.
                         The columns are cleaned or replaced with care to avoid releasing chemicals. Larger filters are
                         often preferred because they do not have to be replaced as often as small ones.
                           How long will it take?
                          The time it takes to complete activated carbon treatment depends
                          on several factors:
                          •  amount of polluted water or air
                          •  type and amounts of harmful chemicals present
                          •  size and number of columns
                          Depending on the site, cleanup can take just a few days or as long as many years. Since
                          activated carbon treatment is often used with other cleanup methods, the length
                          of time may depend on how fast the other methods work.
Why  use activated carbon treatment?

Activated carbon treatment can provide good results for a wide range of chemicals like fuels,
PCBs, dioxins, and radioactive wastes. It also can remove some types of metals, if they are
present in small amounts.
Activated carbon treatment can be cheaper than other cleanup methods. However, activated
carbon does not destroy chemicals. The chemicals and spent carbon eventually must be dis-
posed of in a landfill or removed from the carbon and destroyed by other methods.
                        NOTE: This fact sheet is intended solely as general guidance and information to the public. It is not intended, nor can it be relied
                        upon, to create any rights enforceable by any party in litigation with the United States, or to endorse the use of products or services
                        provided by specific vendors. The Agency also reserves the right to change this fact sheet at any time without public notice.

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