A bioelectrochemical approach for brine management in water reuse plants

Reverse osmosis (RO) plays a critical role in many advanced water reuse projects, producing high-quality water for potable and nonpotable applications. However, the process also generates a concentrated waste stream known as RO concentrate or brine, which can contain elevated levels of salt, nutrients, contaminants of emerging concern (CECs), and PFAS. Managing that concentrate remains one of the biggest challenges facing water reuse facilities today.

A recent peer-reviewed study published in Sustainability explored a potential new approach. Co-authored by Carollo’s Ehsan Khodayari and Graham Juby, the research evaluated whether microbial fuel cells (MFCs) could help treat RO concentrate while simultaneously generating electricity.

Evaluating Microbial Fuel Cells for RO Concentrate Treatment

The pilot-scale study was conducted at the San Jacinto Valley Regional Water Reclamation Facility in Southern California. Researchers tested a modular MFC system that uses naturally occurring microorganisms to break down organic matter and produce electrical current.

The results showed that the system removed an average of 40% of chemical oxygen demand (COD), 52% of biochemical oxygen demand (BOD₅), and 48% of total organic carbon. The MFC also demonstrated the ability to recover a small amount of electrical energy during treatment.

PFAS and Contaminant Removal Results

The study also evaluated the system’s ability to address contaminants of emerging concern and PFAS. Researchers observed reductions in several pharmaceuticals and personal care products, along with a 36% reduction in PFOS. While other PFAS compounds were less affected, the findings suggest that microbial fuel cells may provide an additional treatment barrier for select contaminants in RO concentrate.

A Potential Tool for Sustainable Brine Management

While further research is needed to optimize performance and better understand PFAS removal mechanisms, the study demonstrates the potential of microbial fuel cells as a low-energy, sustainable approach for managing RO concentrate.

As advanced water reuse continues to expand, technologies that can reduce waste streams, lower environmental impacts, and recover resources will play an increasingly important role.

Read the full article in Sustainability to learn more about the pilot study and its implications for future water reuse projects.