Micropollutant elimination by O3, UV and plasma-based AOPs: An evaluation of treatment and energy costs

Abstract

Over the last years, there has been a growing interest in the use of Advanced Oxidation Processes (AOPs) for the elimination of micropollutants. This work attempts to compare the efficiency of conventional UV, O3 and H2O2 based AOPs with a relatively new AOP based on plasma-ozonation, in terms of removal and energy efficiency. The experimental study is performed in a synthetic water matrix spiked with four different micropollutants: atrazine (ATZ), alachlor (ALA), bisphenol A (BPA) and 1,7-α-ethinylestradiol (EE2). For the different processes examined in this study, O3 – based AOPs are more effective compared to UV based techniques in terms of energy efficiency. Although the energy efficiency of plasma-ozonation falls between the energy cost of O3 and UV-based AOPs, the removal kinetics generally proceed faster compared to other AOPs, achieving complete elimination (>99.8% removal) of the target compounds within 20 min of treatment. Moreover, the results suggest that improvement in the mass-transfer in the plasma-ozonation setup permits to further decrease the energy cost of this process up to electrical energy per order (EE/O) values between 2.54 and 0.124 kWh m−³, which is already closer to the energy efficiency of ozonation (EE/O = 0.73–0.084 kWh m−³).