Treatment of persistent organic compounds by integrated advanced oxidation processes and sequential batch reactor

Alex Christensen, Mirat D. Gurol, Temesgen Garoma

Index: Water Res. 43(16) , 3910-21, (2009)

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Abstract

The objective of this study was to evaluate the extent of improvement in the biodegradability of persistent organic compounds by pre-oxidation by using Sequential Batch Reactors (SBRs). Dichlorodiethyl ether (DCDE), a non-biodegradable compound, was used as a test chemical. Ozonation, Fenton reagent and ultra-violet light coupled with hydrogen peroxide (UV/H 2O 2) were used for oxidation of DCDE at levels of 50–100%. Pre-oxidized DCDE solutions were then subjected to SBR studies using activated sludge to determine the rate and extent of biodegradation of oxidation by-products. The results indicated that the biodegradability of pre-oxidized DCDE increased drastically, reaching an average of 90% for all three oxidation methods versus zero for non-oxidized DCDE. It was concluded that the results of SBR experiments may be better indicators of biodegradability of chemically-oxidized wastewaters due to significant acclimation of microorganisms in SBRs, which cannot be observed in conventional respirometric laboratory studies.