Case Study
     17
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December
    2007
                                                      Researchers have created bricks from fly ash that look and perform like normal bricks.
                                                      Credit: Henry Liu, FPC
                        Follow the "Green" Brick Road?
       Bricks Made From Coal-Fired Power Plant Waste Pass Safety Test

Researchers   have  found   that
bricks  made  from fly  ash—fine
ash particles captured as waste by
coal-fired power plants—may be
even safer than predicted. Instead
of leaching  minute amounts of
mercury as some researchers had
predicted,  the bricks  apparently
do  the  reverse, pulling  minute
amounts of the toxic metal out of
ambient air.

Each year, roughly 25 million tons
of fly ash from coal-fired power
plants are recycled, generally as
additives in building materials such
as concrete, but 45 million tons go
to waste.  Fly ash bricks both find
a use  for some  of that  waste and
counter the environmental impact
from the manufacture of standard bricks.

"Manufacturing  clay brick requires kilns fired to high temperatures," said Henry Liu, a longtime National
Science Foundation (NSF) awardee and the president of Freight Pipeline Company (FPC), which developed
the  bricks. "That wastes energy, pollutes air and generates greenhouse gases that contribute to global
warming. In contrast, fly ash bricks are manufactured at room temperature. They conserve energy, cost less
to manufacture, and don't contribute to air pollution or global warming."

Once colored and shaped, the FPC bricks are similar to their clay counterparts, both in appearance and in
meeting or exceeding construction-material standards.

Supported by NSF's Small Business Innovation Research (SBIR) program, Liu has been working since
2004 to develop the bricks. The first phase of support enabled him to make fly ash bricks more durable by
engineering them to resist freezing and thawing due to weather. Liu is now working from a second-phase
SBIR award to test the brick material's safety and prepare it for market.

Most recently (in August 2007), the NSF project completed two other environmental tests on the fly ash
brick, conducted by Dr. Shankha Banerji, Professor  Emeritus at the University of Missouri—Columbia,
an expert in  solid waste management. One of the two tests is the EPA-developed TCLP  (method 1311),
which determines whether any solid waste may be treated as non-hazardous waste for disposal in a sanitary
landfill. The other test, conducted with a fly ash brick  immersed in  a bath of distilled water under continued
aeration for 5 days, is to simulate leaching of pollutants from fly ash bricks caused by heavy rain. According
to Dr. Banerji, the fly ash brick passed both tests. In the TCLP test, all the dissolved metals were found to
be at least one order of magnitude less than the maximum allowed. In the rain simulation test, it was found
that after the 5 days the water quality still met the EPA standard for drinking water.

"Green manufacturing is a focus for the nation," said Tom Allnutt of NSF's SBIR program, who oversaw
Liu's award.  "Liu's innovative use of fly ash to manufacture high quality building materials will potentially
decrease some of the negative environmental impact of coal-fired power generation while meeting increasing
demands for greener building materials."
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                                                                                            Follow the "Green" Brick Road?
Case Study
     17
While researchers need to study the bricks further to determine how the mercury adsorption occurs and how
tightly the metal is trapped, the new findings suggest the bricks will not have a negative impact on indoor
air quality.

On average, air contains low amounts of mercury that can range from less than 1 nanogram per cubic meter
(ng/m3) to tens of ng/m3—a small fraction of the Environmental Protection Agency limit for continuous
exposure.

Inside a confined experimental chamber, the bricks did not raise the mercury levels in the surrounding air
(originally more than one nanogram), and instead appeared to lower the concentration down to roughly half
a nanogram.

Engineers from FPC of Columbia, Mo., developed the bricks with NSF support and reported their findings
on mercury leaching at the  May 7-10, 2007, World of Coal Ash Conference in Cincinnati, Ohio.

Henry Liu has received a number of NSF awards since 1980 and founded FPC after retiring as professor of
civil engineering and director of Capsule Pipeline Research Center, a state/industry university cooperative
research center established by NSF at University of Missouri-Columbia in  1991 to research and develop
capsule pipeline technology.

-NSF-
                   Submitted By:

                   Media Contacts
                   Joshua A. Chamot, NSF
                   Tel: (703) 292-7730
                   Email: jchamot@nsf.gov

                   Program Contacts
                   Thomas Allnutt, NSF
                   Tel: (703) 292-5332
                   Email: tallnutt@nsf.gov

                   Principal Investigators
                   Henry Liu, Freight Pipeline Company
                   Tel: (573) 442-0080
                   Email: fpc_liuh@yahoo.com
                   COAL COMBUSTION
                   PRODUCTS PARTNERSHIP
                         This coal ash utilization case study is a selection of the Coal Combustion Product Partnership. For
                         more information, consult C2P2 web site at http://www.epa.gov/epaoswer/osw/conserve/c2p2/

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