The proper treatment of wastewater is becoming more and more
important as the number of toxic and biologically recalcitrant organic compounds
continues to increase. Current treatment systems are sequentially coupled, in
that they involve a two-step process of advanced oxidation followed by
biodegradation. In the ideal case of sequential coupling, advanced oxidation is
controlled so that the recalcitrant organic compounds are only transformed to
the point that they are rapidly biodegradable, at which point they would be
passed to the biodegradation stage. Chemical transformation beyond this point
generally wastes oxidant and increases operation costs with no further benefit.
Advanced oxidation processes are inefficient for simple organics and bacteria
are not suitable for biodegrading recalcitrant compounds. Coupling the processes
effectively utilizes the strengths of both.
Researchers at the Biodesign Institute of Arizona State
University have recently devised a wastewater treatment scheme that intimately
couples the advanced oxidation processes (AOP) with the biodegradation
processes. It has been shown to be useful and effective on large scale activated
sludge systems and in systems with toxic concentrations of contaminants. This is
accomplished by the use of a photo-catalytic circulating-bed biofilm reactor
(PCBBR). The PCBBR employs macro-porous carriers that accumulate biofilm in
their interior. The AOP takes place in bulk solution with UV light photolysis or
TiO2 photocatalysis. In this unique design, the bacteria are well
protected from UV light, toxic substrates, and free radicals, but are close
enough to the AOP reactions so they can immediately biodegrade the
photo-catalytic products.
Potential Applications
Examples of manufacturing processes that would benefit from
this technology include:
- Municipal / industrial Wastewater treatment
- Food processing
- Elastomer processing
- Textile dye removal / leather tanning
Benefits and Advantages
- Faster processing times
- Efficiency – Offers complete
mineralization of toxic and recalcitrant organic contaminants
- Cost Savings – Less waste of added
oxidants
- Simplicity / Robustness – A single tank
reactor is easier to manage than multiple tanks
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For more information about the inventor(s) and their
research, please see
Dr.
Rittmann's directory webpage
