Removal of chlorinated phenols in upflow anaerobic sludge blanket reactors

The dechlorination of chlorophenol (CP) compounds was investigated using up flow anaerobic sludge blanket reactors. A total of five trichlorophenols (T CPs) and a single dichlorophenol (DCP) were individually treated: 2,3,4-TCP ; 2,3,5-TCP; 2,3,6-TCP; 2,4,5-TCP; 2,4,6-TCP; and 3,5-DCP. Synthetic wastew ater composed of sucrose and acetic acid provided an alternate, readily bio degradable carbon source. Each chlorinated compound was concurrently fed to separate reactors. The parameters that were quantified include biogas comp osition, acetic acid concentration, GOD, and VSS. The degree to which CPs w ere sorbed to the granular biomass in actively dechlorinating UASB reactors was found to be insignificant. CP compounds were able to be metabolized to mineral end products to a large extent at loadings where reactor performan ce was not impaired. Ortho chlorine atoms were most readily removed from CP s. CPs containing chlorine atoms in the para position were the most toxic a gents with 2,4,5-TCP being the most toxic compound. Toxicity was reversible . (C) 1998 Published by Elsevier Science Ltd. All rights reserved.