Selection and Evaluation of Model Pollutants for Performance Assessment of Advanced Treatment of Industrial Park Wastewater by Ozonation

Abstract

Ozonation has gradually become a routine process for advanced wastewater treatment. During the technology innovation on the advanced treatment of wastewater by ozonation, researchers have to assess the performance of abundant new technologies, new reactors, and new materials. However, they are usually puzzled by the rational selection of model pollutants to assess the capability of such new technologies to eliminate the chemical oxygen demand (COD) and total organic carbon (TOC) of practical wastewater. It is unclear how well the various model pollutants reported in the literature could represent the COD/TOC removal of actual wastewater. The rational selection and evaluation of model pollutants for advanced treatment of industrial wastewater is of great significance in establishing the technological standard system for advanced treatment of wastewater via ozonation. Herein, the aqueous solutions (including unbuffered solutions and bicarbonate-buffered solutions) of 19 model pollutants and four practical secondary effluents from industrial parks were investigated through ozonation under identical conditions. The similarity in COD/TOC removal of the above wastewater/solutions were evaluated using mainly clustering analysis. The results showed that the dissimilarity among the model pollutants was greater than that among the actual wastewaters, thus enabling the rational selection of several model pollutants to assess the performance of advanced treatment of wastewater using ozonation by different technologies. The errors of predicting the COD removal of secondary sedimentation tank effluent by ozonation in 60 min using the unbuffered aqueous solutions of ketoprofen (KTP), dichlorophenoxyacetic acid (2,4-D), and sulfamethazine (SMT) were less than 9%, and those using the bicarbonate-buffered solutions of phenacetin (PNT), SMT, and sucralose were less than 5%. The evolution of pH by using the bicarbonate-buffered solutions was more similar to that in practical wastewater than by using unbuffered aqueous solutions. In the similarity evaluation of COD/TOC removal between the bicarbonate-buffered solutions and the practical wastewaters, the results were almost the same whether considering different input ozone concentration conditions. Therefore, the protocol proposed in this study based on similarity evaluation to assess the performance treating actual wastewater could be extended to different ozone concentration conditions with certain universality.