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Response of low-strength phenol-acclimated activated sludge to shock loading of high phenol concentrations


J-W Lim
C-E Seng
P-E Lim
S-L Ng
K-C Tan
S-L Kew

Abstract

(ii) investigate the degradation pathways and (iii) model the growth and biodegradation kinetics, all under the condition of increasingly higher phenol concentrations (step-up shock loading). With the use of activated sludge acclimated to phenol concentration of 140 mg∙ℓ−1 (low-strength phenol-acclimated activated sludge), complete degradation of phenol with a COD removal efficiency of more than 95% was achieved up to 1 050 mg∙ℓ−1 of initial phenol concentration. At low initial phenol concentrations, the experimental results were indicative of the meta-cleavage pathway for phenol degradation. When the initial phenol concentration was above 630 mg∙ℓ−1, the degradation results were indicative of both meta- and ortho-cleavage pathways. The values of the Haldane kinetic parameters indicated a low degree of inhibition exerted by the presence of increasing phenol concentration. This was substantiated by the observation that the rate constant of phenol removal decreased by only 33% even though the initial phenol concentration was increased by 15 times from 70 to 1 050 mg∙ℓ−1.
Thus, the activated sludge acclimated to only 140 mg∙ℓ−1 of phenol could successfully treat up to 1 050 mg∙ℓ−1 of phenol without experiencing complete inhibition during the degradation process.

Keywords: Phenol removal, low-strength phenol-acclimated activated sludge, degradation pathway, Haldane kinetic parameter


Journal Identifiers


eISSN: 1816-7950
print ISSN: 0378-4738