Biodegradation of 4-chlorophenol by acclimated and unacclimated activated sludge - Evaluation of biokinetic coefficients


ŞAHİNKAYA E., Dilek F. B.

ENVIRONMENTAL RESEARCH, vol.99, no.2, pp.243-252, 2005 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 99 Issue: 2
  • Publication Date: 2005
  • Doi Number: 10.1016/j.envres.2004.11.005
  • Journal Name: ENVIRONMENTAL RESEARCH
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.243-252
  • Keywords: cometabolism, 4-chlorophenol, acclimation, inhibition, biodegradation, INHIBITORY CO-METABOLITE, COMETABOLIC DEGRADATION, PSEUDOMONAS-PUTIDA, PHENOLIC-COMPOUNDS, BATCH REACTOR, KINETICS, CHLOROPHENOLS, SUBSTRATE, MICROORGANISMS, BACTERIA

Abstract

Unacclimated and acclimated activated sludges were examined for their ability to degrade 4-CP (4-chlorophenol) in the presence and absence of a readily growing substrate using aerobic batch reactors. The effects of 4-CP on the p (specific growth rate), COD removal efficiency, Y (yield coefficient), and q (specific substrate utilization rate) were investigated. It was observed that the toxicity of 4-CP on the culture decreased remarkably after acclimation. For example, the IC50 value on the basis of It was found to increase from 130 to 218 mg/L with the acclimation of the culture. Although an increase in 4-CP concentration up to 300 mg/L has no adverse effect on the COD removal efficiency of the acclimated culture, a considerable decrease was observed in the case of an unacclimated culture. Although 4-CP removal was not observed with an unacclimated culture, almost complete removal was achieved with the acclimated culture, up to 300 mg/L. The Haldane kinetic model adequately predicted the biodegradation of 4-CP and the kinetic constants obtained were q(m) = 41.17 mg/(g MLVSS h), K-s = 1.104 mg/L, and K-i = 194.4 mg/L. The degradation of 4-CP led to formation of 5-chloro-2-hydroxymuconic semialdehyde, which was further metabolized, indicating complete degradation of 4-CP via a meta-cleavage pathway. (c) 2004 Elsevier Inc. All rights reserved.