Environmental Life Cycle Assessment (LCA) of Treating PFASs with Ion Exchange and Electrochemical Oxidation Technology
Gengyang Li, J. R. Dunlap, Yifei Wang, Qingguo Huang, Ke Li
Abstract
Life cycle assessments (LCAs) were performed for per- and polyfluoroalkyl substance (PFAS) treatment with ion exchange (IX) followed by electrochemical oxidation (EO). For the studied water quality, the global warming potentials (GWPs) for two orders of removal of perfluorooctane sulfonic and perfluorooctanoic acids from 1000 m3 water samples were 72.2 and 84.9 kg CO2 eq., respectively. The major contributors to the GWP were electricity and resin manufacturing. To understand the environmental impacts of different treatment options, the following scenarios are compared: single use of the IX resin followed by incineration (IX + Incin.), single use of the IX resin followed by EO (IX + EO), and regeneration and reuse of the IX resin followed by EO (IX/Re + EO). When the EE/O is less than 192 kWh/m3, the GWPs of the three scenarios are in the order of IX/Re + EO < IX + EO < IX + Incin. When the EE/O is larger than 695 kWh/m3, the order is IX + Incin. < IX/Re + EO < IX + EO. When the EE/O is in the middle of the two numbers, the order is IX/Re + EO < IX + Incin. < IX + EO. A greener energy mix favors the EO options and increases these two numbers. An empirical equation was introduced to estimate the overall GWP of PFAS removal based on the EE/O and adsorption isotherms.