Competitive removal of phenol and 2,4-dichlorophenol in biological activated carbon system

Laboratory scale experiments were conducted to evaluate the removal capacities of the major competitive components in a biological activated carbon (BAC) system. Adsorption, desorption, biodegradation, biosorption, and bioregeneration were considered as the major target reactions. Phenol and 2,4-dichlorophenol were used in a single and bisolute system. The adsorption experiment showed that 2,4-DCP was a stronger adsorbate than phenol both in single and bisolute systems. On desorption of 2,4-DCF, the small fraction of sorbed compounds was reversible but phenol had comparatively high reversibility. All solutions exhibited high degrees of irreversible adsorption as hysteresis. Desorption in background organics showed high reversibility. The biomass sorptions of phenol and 2,4-DCP were both negligible so that the removal of these compounds could be disregarded in the BAC system. Meanwhile, the biodegradation of phenol was higher than that of 2,4-DCP in both as a single and bisolute systems. The biodegradation of phenol was higher than that of 2,4-DCP in both single and bisolute systems. Although, the biodegradation capability of phenol was suppressed in the presence of 2,4-DCP but it induced the biodegradation of 2,4-DCP. In single solute, the degree of bioregeneration in terms of phenol and 2,4DCP in single solute were 76.28% and 56.80%, respectively. In bisolute system, they were 74.46% and 60.20% for phenol and 2,4-DCP, respectively and degree of bioregeneration was corresponding to degree of hysteresis.