title: Contribution of the ozonation pre-treatment to the biodegradation of aqueous solutions of 2,4-dichlorophenol.
abstract: The effect of ozonation on the biodegradability of 100-ppm aqueous solutions of 2,4-dichlorophenol has been investigated. BOD at 5, 10 and 21 days, BOD/COD and BOD/TOC ratios and the average oxidation state are presented. Biodegradability measured as BOD5/COD ratio was increased from 0 of the original solution to 0.25 at the moment of removing all the initial compound (corresponding to an ozone dose of 0.12 g L-1, 0.48 for BOD21/COD ratio). To test the effect of this pre-treatment, the biological oxidation of these pre-ozonated solutions was performed in two semi-continuous stirred tank reactors, one with non-acclimated sludge and one with acclimated-to-phenol sludge. The study showed that the TOC content of the pre-treated solution could be removed up to 68% by an aerobic biological treatment as well as co-digested with municipal wastewater (TOC removal up to 82%), with similar operating retention times to a municipal wastewater plant (12-24 h). Kinetic studies based on Monod model have also been carried out. Pseudo-first-order kinetic constants were found to be in the range of 0.5-0.8 L g TVSS-1 h-1.
mesh_terms: D000871:Anthelmintics / Q000737:chemistry / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019149:Bioreactors; D002733:Chlorophenols / Q000737:chemistry / Q000378:metabolism*; D010083:Oxidants, Photochemical / Q000737:chemistry*; D010126:Ozone / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D000871:Anthelmintics; D002733:Chlorophenols; D010083:Oxidants, Photochemical; D010126:Ozone; C004762:2,4-dichlorophenol