Replacing Conventional PFAS Water Treatment by GAC with Plasma Treatment to Improve Sustainability

Per and poly-fluoroalkylated substances (PFAS) are carcinogenic compounds which make their way into water systems and are difficult to remove. Currently, PFAS is removed from drinking water at an industrial scale using granular activated carbon (GAC), a solid particulate which removes PFAS from water through adsorption. However, in recent years, a new method utilizing a plasma reactor to mineralize the PFAS has been designed and tested at small scales. This project aims to increase the scale of existing plasma reactor designs to treat the same volumes of water that traditional GAC plants are capable of treating. A specific well in New Castle County, Delaware was identified as the treatment site, and both processes were designed to treat 2.33 million gallons of water per day by reducing the PFAS concentration from 4,500 parts per trillion to the US EPA health advisory level of 70 parts per trillion. The GAC process was estimated to have a capital cost of $6.73 million and an operational cost of $6.32 million each year. The plasma process was estimated to have a capital cost of $14.8 million and an operational cost of $5.93 million each year. Based on a number of economic and environmental factors, this project found that the plasma system was a more effective and sustainable method for achieving the desired reduction in PFAS concentration.