United States Office of Solid Waste and EPA 542-F-01-020

Environmental Protection Emergency Response December 2001

Agency (5102G) www.epa.gov/superfund/sites

www.cluin.org

A Citizen’s Guide to

Activated Carbon Treatment

? ? 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 A Citizen’s Guide to Pump and Treat [EPA 542-F01-025]).

How does it work?

An activated carbon filter generally consists of one or more containers or columns of granules. 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

clean

water

activated

carbon

granules

polluted

water

Columns containing activated carbon

The Citizen’s Guide Series
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.

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 disposed of in a landfill or removed from the carbon and destroyed by other methods.

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.

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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How long will it take?