Abstract
In recent years, recycling has become the first best option
of dealing with waste before landfilling is considered in cases of
handling difficulties. In South Africa however, 41,000 tons of solid
waste is destined for landfills daily; which includes huge chunks of
waste from construction and demolition activities. The continued
reliance of South Africa on the landfilling system could extend a
while until economical recycling alternatives are introduced.
Leachate generation and percolation is expected in these landfills on
account of infiltration of water into the waste body from rain and/or
runoffs. Although, it has been documented that arsenic, copper and
chromium percolate soil systems, it however noted that occurring
physical, chemical and biological activities may influence mobility of
metals from generated leachate. This is particularly evident in cases
where Chromated Copper Arsenate (CCA)-treated wood are disposed
in monofills with consequential impacts on the environment.
Laboratory investigation using a bespoke device to explore the
environmental risk of depositing CCA-treated wood in monofills
and/or open dumps was done; with a view to simulating worst case
scenario of an unlined disposal facility that relied on the geology of
the site. This scenario best indicates high concentrations and
maximum formation of heavy metals. The bespoke device was
assembled with chopped untreated wood and CCA-treated wood in a
bottom chamber respectively, and de-ionized water was allowed to
seep through from a reservoir forming leachate. The targeted
chemical ions (arsenic, copper and chromium) from the leachate were
analyzed by way of full spectral method on the effluent and were
compared to South African standard of drinking water. The study
therefore, revealed that CCA-treated wood formed hazardous
concentration levels of chromium and arsenic which if not properly
contained in real cases, could inflict severe contamination
consequential to human and environmental health.