Treatment of hyper-saline wastewater loaded with phenol by the combination of adsorption and an offline bio-regeneration system

摘要

BACKGROUND: Effective treatment of hyper-saline wastewaters containing phenol is required before their discharge into the sewage system and the environment. An investigation of the feasibility of the use of a combined physical-biological procedure is reported for the treatment of hyper-saline phenol wastewater. This process consists of two stages: first the phenol is removed and concentrated by resin XDA-1 from hyper-saline effluent, and then it is biodegraded in a subsequent stage with microorganisms to regenerate the adsorbent. RESULTS: The removal of phenol by XDA-1 was found to be feasible under acidic and neutral conditions. It was found that decreasing temperatures are beneficial for phenol adsorption. The equilibrium data were well described by the Freundlich model. Increasing the salinity of the effluent improved the adsorption capacity of XDA-1, which is an advantage of the combined process for the treatment of saline wastewater. A pseudo-second-order kinetic model provided the best correlation with experiment results. Results indicate that phenol desorption is the rate-limiting step in the bio-regeneration process under the tested operating conditions. The adsorption and bio-regeneration process was repeated for up to six cycles, with percentage regeneration (PR) values remaining above 81%. CONCLUSIONS: High PR values, good pore structure, and specific surface properties of the six-round-regenerated resin indicated the stability of the combination system in treating hyper-saline phenol wastewater. (C) 2008 Society of Chemical Industry.