Summary

Per- and polyfluoroalkyl substances (PFAS) are a family of manmade congeners with dual hydro- and oleo-phobic properties, which is why they have been widely used in firefighting foams, as well as in a multitude of other products such as food packaging, paints, pesticides, and microelectronics. Given their extensive use, high water solubility, and resistance to conventional wastewater treatment methods, PFAS have been detected in public water supplies nationwide, raising concerns about potential toxic human health effects due to their environmental persistence. Flocculation is a widely used separation technique for removing suspended solids from water and wastewater. However, traditional flocculants (e.g., inorganic salts and polymeric systems) form aggregate flocs that are usually loosely packed, contain a large amount of water due to their hydrophilicity, and require large settling tanks because of the slow separation process needed to collect the solids. Furthermore, they have seldom been used to remove dissolved species like PFAS. To address these issues, the research team has developed EnviroFloc: an innovative “smart” polymeric flocculant consisting of a temperature-responsive compound, N-isopropylacrylamide (NIPAAm), modified with cationic co-monomers and/or fluorinated co-monomers. This combination results in a polymer that can rapidly capture dissolved PFAS molecules and form insoluble solid aggregates at temperatures above the lower critical solution temperature (LCST). The core advantages of this system include: Low water retention in the sedimented floc: Dissolved PFAS molecules are captured by the dissolved polymer at ambient temperature and then collected into an insoluble densely packed solid pellet above the transition temperature, resulting in a smaller solid waste stream compared to other remediation technologies.

• Fast kinetics: Flocculation occurs within seconds to minutes compared to several hours for other flocculant systems.
• Relatively low energy input required to flocculate: EnviroFloc’s LCST is close to ambient temperature.
• Little-to-no pretreatment needed: The contaminated stream can be applied as secondary treatment for challenging PFAS wastes, RO concentrate, and IX brine.

Specific aims of the project include:

• Development of EnviroFloc polymer flocculants: Optimizing flocculation performance.
• EnviroFloc regeneration evaluation: Using temperature-assisted solid-liquid extraction to determine removal efficiency and reusability.
• Demonstration of EnviroFloc performance efficiency: Testing as a secondary treatment step in multiple case studies (e.g., RO concentrates and IX brine).
• Design, simulation, and feasibility demonstration: Creating a PFAS treatment unit.

This Phase II SBIR project will accomplish the key tasks necessary to prepare for the commercialization of BAM’s EnviroFloc and the associated treatment unit specifically for PFAS water treatment.