Urbanization and the Geoenvironment - Sustainable Practices in Geoenvironmental Engineering - page 235

Since CCA-treated wood was exempt from the Toxicity Characteristic Leaching
Procedure (TCLP) developed by the EPA, few reports concerning tests on these substances
are available. Wilson (1997) tested CCA-treated wood and found that it failed to meet safety
requirements for arsenic and barely passed for chromium. Since the ash also failed the
test, one would conclude that CCA-treated wood cannot be burned in incinerators since
the metals will remain in the ash. Arsenic can vaporize and be captured by air control
equipment or escape into the atmosphere, but chromium and copper will stay in the ash.
Mixing the CCA-wood with mulch for landscape purposes is also problematic because of
the potential for arsenic leaching. Wood-burning power plants cannot accept this type of
wood if they use their ash for application onto agricultural ields. The ash becomes haz-
ardous if 10.7% or more of the wood is CCA treated. Although landilling in municipal
landills is an option, it is not uncommon to ind the waste (ash) sent to unlined construc-
tion and demolition ( C&D ) landills—a practice that leads to contamination of groundwater.
Recently, an alternate method was examined involving acid digestion followed by ethanol
production by fermentation (Moghaddam, 2010). A slightly lower amount of ethanol from
CCA treated than untreated wood was produced (6 and 7 g/L, respectively). In general,
it suggests that production of ethanol from a hazardous waste (CCA treated wood) could
assist in the disposal of CCA treated wood while generating a clean fuel as a source of
e n e r g y.
Attempts at the removal of CCA treatment in the wood before reusing the wood
have not been very successful. However, disposal of these products in the future is still
uncertain. As landilling in lined landills is the only current option, the production
of CCA-treated wood will be limited and was phased out from consumer application
at the end of the year 2003 in the United States—as an agreement with manufactur-
ers and the EPA. European countries had already banned this type of treated wood.
Other alternatives such as ammonium copper quatenary (ACQ) and copper boron azole
(CBA), alkaline copper quaternary compounds (ACQ), copperazole(CuAz), ammoniacal
copper zinc arsenate (ACZA), copper citrate, and copper HDO (CuHDO) preservatives
may be used.
7.4.1.2 Waste Reduction
Reduction of the wastes or reduction of the source of waste is the key to reducing emis-
sions from landills and other waste management techniques. Life cycle analysis (LCA)
has been identiied as a tool to help achieve sustainable consumption as it accounts for
the emissions, and resource uses during production, distribution, use, and disposal
(ISO, 1997). Three steps are involved: (1) the processes of the life cycle, (2) the envi-
ronmental pressures of the processes (Figure 7.8), and (3) the environmental impact
of the use, including the use of impact indicators. Although ISO 14040:2006 (reviewed
and conirmed in 2010) deines the inventory analysis and impact assessment steps, the
other steps involving deinition of the process and the interpretation of the results are
not necessarily simple “steps.” Several databases such as EcoInvent (version 3.0) and
SimaPro are now available for some materials, but data are lacking. Other LCA soft-
ware include Aveny GmbH, AMEEdiscover, eBalance, EMIS, GaBi, iPoint Compliance
Agent LCA Module, Life Cycle Tracker, opn LCA, Quantis Suite 2.0, Regis, TEAM
5.1, and Umberto. In addition, life cycle impact assessment methods are being devel-
oped for minerals, land use, and toxic chemicals. Life-Cycle Initiative , a joint initiative
of UNEP and the Society for Environmental Toxicology and Chemistry (SETAC) was