Removal of Alkylphenols from Industrial and Municipal Wastewater

The results of the study of removal of nonylphenol, octylphenol and their ethoxylates from real industrial and municipal wastewater are presented. Industrial wastewater was pre-treated by coagulation with FeCl3 and adsorption on zeolite, before discharging into municipal sewer system. Their removal efficiencies in primary sedimentation tank of municipal WWTP were very low. From the practical point of view, the highest and the most significant removal efficiencies within the whole WWTP were observed for nonylphenol and nonylphenol ethoxylates. Dominancy of abiotic mechanisms of alkylphenols removal follows from adsorption measurements. Activated sludge cultivated in lab-scale extended aeration tank accounted for relatively high adsorption affinity to these substances. Activated sludge sampled from municipal wastewater treatment plant (MWWTP) receiving industrial wastewater containing alkylphenols accounted for very low adsorption affinity to these pollutants. Significantly higher removal efficiency of octylphenol ethoxylates was observed with the O3/granular active carbon (GAC) process compared to the ozonation process alone. Lower toxicity impact of intermediates and products of ozonation treatment on Vibrio fischeri was measured in comparison to the O3/GAC process. Actually, the municipal WWTP effluent discharge concentration values complies with EQS values, including nonylphenols.