Optimization of Fenton pretreatment for 2-chlorophenol solution.

Fenton oxidation was used as the pretreatment of 2-chlorophenol wastewater with the objective of dechlorination, as it was considered that after breakage of aryl-Cl bond, the generated intermediates may be easily biodegraded. Hence, the optimization of pH and the low Fenton reagent doses for dechlorination was investigated. More than 99% dechlorination is obtained at the optimal pH 4 and the Fenton reagent doses of 86 mmol/L HO and 2.87 mmol/L Fe. The corresponding 2-chlorophenol is degraded completely, 80.02% COD is also removed, and the biodegradability, evaluated in terms of the BOD5/COD ratio, is increased up to 0.41. To test the effect of this pretreatment, the pretreated 2-chlorophenol wastewater was fed to a sequencing batch reactor (SBR). The results show that complete mineralization is achieved. It is demonstrated that, for the treatment of recalcitrant compounds like 2-chlorophenol, the Fenton pretreatment could be quite effective and economical for enhancing the biodegradability in a Fenton-biological coupled system. [ABSTRACT FROM AUTHOR]