Ozonation of the trace organic compounds in different municipal and industrial wastewaters: kinetic-based prediction of removal efficiency and ozone dose requirements

Abstract For the wide application of ozonation in (industrial and municipal) wastewater treatment, prediction of trace organic compounds (TrOCs) removal and evaluation of energy requirements are essential for its design and operation. In this study, a kinetics approach, based on the correlation between the second order reaction rate constants of TrOCs with ozone and hydroxyl radicals (·OH) and the ozone and ·OH exposure (i.e., ∫[O3]dt and ∫[·OH]dt, which are defined as the time integral concentration of O3 and ·OH for a given reaction time), was validated to predict the elimination efficiency in not only municipal wastewaters but also industrial wastewaters. Two municipal wastewater treatment plant effluents from Belgium (HB-effluent) and China (QG-effluent) and two industrial wastewater treatment plant effluents respectively from a China printing and dyeing factory (PD-effluent) and a China lithium-ion battery factory (LZ-effluent) were used for this purpose. The ·OH scavenging rate from the major scavengers (namely alkalinity, effluent organic matter (EfOM) and NO2-) and the total ·OH scavenging rate of each effluent were calculated. The various water matrices and the ·OH scavenging rates resulted in a difference in the requirement for ozone dose and energy for the same level of TrOCs elimination. For example, for more than 90% atrazine (ATZ) abatement in HB-effluent (with a total ·OH scavenging rate of 1.9×105 s-1) the energy requirement was 12.3×10-2 kWh/m3, which was lower than 30.1×10-2 kWh/m3 for PD-effluent (with the highest total ·OH scavenging rate of 4.7×105 s-1). Even though the water characteristics of selected wastewater effluents are quite different, the results of measured and predicted TrOCs abatement efficiency demonstrate that the kinetics approach is applicability for the prediction of target TrOCs elimination by ozonation in both municipal and industrial wastewater treatment plant effluents.