UF Design a treatment system for CCA Treated Wood Discussion

My professor would like me to create a design that would control the redox chemistry of wetland water to remove Ar, Cu, and Cr from the water once CCA treated wood is placed into the wetlands water. Either by precipitating out of water or absorbed from plant. But the goal is to remove the metals and prevent from polluting down stream water. The dissolved metals are Cr +6, As +5 and Cu +2 once these metals have been leached from my knowledge. Would like some help at making the chemical equations and overall help with the question in general.

QUESTION-1 (100 points).
Chromated copper arsenate (CCA) has been used to pressure treat lumber since the 1940’s, and from the 1970’s,
the majority of the wood used in outdoor residential settings were CCA-treated wood. This is because in CCAtreated woods, chromium (Cr), copper (Cu) and arsenic (As), act as preservative to protect wood from rotting
agents such as insects and microbes. However, and due to toxicity concerns, pressure CCA treated wood is no
longer being produced for use in most residential settings, including decks and play-sets – in fact, it is being
removed from some of the locations where they have been used for decades. Accordingly, researchers have been
thinking of recycling the CCA-treated wood, only if they could clean it to remove the Cr, Cu and As.
Based on your current knowledge of metal biogeochemistry, aqueous redox chemistry in natural waters, and
access to peer reviewed literature:
•
Design a treatment system for CCA-treated wood using wetland(s) as treatment unit(s) and propose a
system concept in which you would control the redox chemistry of wetland water in either a single unit
or a series of connected wetlands to immobilized Cr, Cu, and As as these elements leach out of watersoaked CCA-treated woods. Make sure that the solubilized Cr, Cu, and As are precipitated within the
wetland, and therefore, not detectable in the wetland effluent. Finally, for each step involving either the
leaching or the precipitation of these metals, show all relevant chemical reactions and point out the role
of different microorganisms involved, if any, in your conceptualized remediation process.
1
QUESTION-1 (100 points).
Chromated copper arsenate (CCA) has been used to pressure treat lumber since the 1940’s, and from the 1970’s,
the majority of the wood used in outdoor residential settings were CCA-treated wood. This is because in CCAtreated woods, chromium (Cr), copper (Cu) and arsenic (As), act as preservative to protect wood from rotting
agents such as insects and microbes. However, and due to toxicity concerns, pressure CCA treated wood is no
longer being produced for use in most residential settings, including decks and play-sets – in fact, it is being
removed from some of the locations where they have been used for decades. Accordingly, researchers have been
thinking of recycling the CCA-treated wood, only if they could clean it to remove the Cr, Cu and As.
•
Design a treatment system for CCA-treated wood using wetland(s) as treatment unit(s) and propose a
system concept in which you would control the redox chemistry of wetland water in either a single unit
or a series of connected wetlands to immobilized Cr, Cu, and As as these elements leach out of watersoaked CCA-treated woods. Make sure that the solubilized Cr, Cu, and As are precipitated within the
wetland, and therefore, not detectable in the wetland effluent. Finally, for each step involving either the
leaching or the precipitation of these metals, show all relevant chemical reactions and point out the role
of different microorganisms involved, if any, in your conceptualized remediation process.
1