Effect of granular activated carbon on the enhancement of cometabolic biodegradation of phenol and 4-chlorophenol

Enhancement of the cometabolic biotransformation of 4-chlorophenol (4-cp) and phenol were studied using chemically and thermally granular activated carbons (GAGs). It was found that both chemically activated and thermally activated GAG effectively adsorb phenol and 4-cp. More than 800/0 adsorped substrates were later desorpted, showing a reversible sorption behaviour in the GAG. For each activated carbon type, 4-cp was preferentially adsorbed over phenol and the desorption efficiencies of both phenol and 4-cp were found to increase linearly with the initial mass of adsorbate in the adsorbent. The biodegradation of 500 mg/L phenol by Pseudomonas putida took 24 h while the biodegradation of 4-cp took 32 h. Inhibitions during the cometabolic biodegradation of 4-cp and phenol were alleviated by the addition of the GAGs. The system with chemically-activated coconut type GAG had better system stability over thermally-activated peat type GAG. The results show that GAG can be regenerated by the cells enhancement of the cometabolic biotransformation of 4-cp and phenol can be accomplished using chemically-activated coconut type GAG.