Enhancement of the biodegradability of model wastewater containing recalcitrant or inhibitory chemical compounds by photocatalytic pre-oxidation.
m-Dinitrobenzene, diphenylamine and resorcinol, three aromatic compounds found inhibitory or recalcitrant to biological treatments, were chosen as model chemicals for this study on the integration of photocatalytic-biological treatments. The degradation of each of these compounds was achieved by ultraviolet photocatalytic oxidation, leading to the formation of intermediate compounds. The photocatalytic treatment was performed in a TiO2 slurry reactor containing an aqueous solution of one of the three chemicals. The biodegradability of model wastewater treated photocatalytically was measured in terms of BOD1/TOC. Intermediate compounds that appeared at early stages of the photocatalytic degradation of m-dinitrobenzene or diphenylamine seemed to be more inhibitory than the parent compounds but this was not the case for resorcinol. A substantial improvement in BOD1/TOC could be achieved, but it required the mineralization of at least 80% of the organic carbon originally in the water. Microtox toxicity results confirmed the BOD1/TOC trends for diphenylamine.
Bolduc
L
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Department of Chemical Engineering, University of Waterloo, ON, Canada.
Anderson
W A
WA
D001673:Biodegradation, Environmental; D002384:Catalysis; D004136:Dinitrobenzenes / Q000737:chemistry*; D004159:Diphenylamine / Q000737:chemistry*; D007220:Industrial Waste; D010084:Oxidation-Reduction; D010777:Photochemistry; D012118:Resorcinols / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D018505:Waste Management / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
D004136:Dinitrobenzenes; D007220:Industrial Waste; D012118:Resorcinols; D014874:Water Pollutants, Chemical; D004159:Diphenylamine; C017906:3-dinitrobenzene; C031389:resorcinol