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 (GACs). It was found that both chemically activated and thermally activated GAC effectively adsorb phenol and 4-cp. More than 80% adsorped substrates were later desorpted, showing a reversible sorption behaviour in the GAC. 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 GACs. The system with chemically-activated coconut type GAC had better system stability over thermally-activated peat type GAC. The results show that GAC can be regenerated by the cells enhancement of the cometabolic biotransformation of 4-cp and phenol can be accomplished using chemically-activated coconut type GAC.