Advantages and disadvantages of separation-based water treatment methods for the removal of per- and polyfluoroalkyl substances in drinking water: a review

Per- and polyfluoroalkyl substances, often named ‘forever pollutants’ due to their persistence and very low biodegradability, are contaminating many water sources worldwide, and represent a major health issue because most water treatment plants are not designed to remove these pollutants. Here we review the advantages and disadvantages of removal methods, and we explain how to choose an optimal method. We also compare contamination of drinking water sources and industrial effluents. Removal methods include carbon adsorption, ion-exchange, and reverse osmosis. Filtration-adsorption on granular activated carbon appears as a cheap and efficient method, yet short-chain per- and polyfluoroalkyl substances are little or no retained by the adsorbent. Ion exchange is efficient, and the resins can be regenerated, yet this method highly depends on water composition because the efficiency may be decreased by adsorption competition with other substances. Reverse osmosis is the most effective treatment, yet it is energy intensive. The three methods display other problems such as the disposal of the waste produced.