Scalable and Durable Brush Electrodes in Locally Enhanced Electric Field Treatment Systems for Water Disinfection

TL;DR

A durable stainless-steel brush electrode improves the scalability and longevity of chlorine-free water disinfection using electric fields.

Contribution

A robust brush electrode design significantly enhances the durability and scalability of LEEFT systems for water disinfection.

Findings

The brush electrode system achieved efficient microbial inactivation at low voltages with minimal metal release.

The system operated effectively for about half a year, a 10-fold improvement in electrode lifespan.

Electroporation assisted by reactive oxygen species was identified as the primary disinfection mechanism.

Abstract

Locally enhanced electric field treatment (LEEFT) has
emerged as
a promising chlorine-free approach for water disinfection. However,
its practical deployment has been limited by challenges in electrode
durability and system scalability. Herein, we report a robust stainless-steel
brush designed to enable long-term operation and scalability of LEEFT
electrodes. A tubular reactor with coaxial electrodes featuring the
brush as the center electrode was developed to combine both macroscale
and microscale electric field enhancements. Operational parameters,
including waveform, frequency, voltage, and flow rate, were systematically
optimized to maximize microbial inactivation while minimizing metal
release. Flow cytometry and control experiments revealed electroporation,
assisted by reactive oxygen species, as the primary disinfection mechanism.
Under optimal unipolar pulse conditions with high duty cycle and frequency,
the system achieved efficient inactivation at voltages in the tens
of volts range. Notably, the LEEFT system with the brush electrode
has remained effective for about half a year with minimal metal release,
representing a 10-fold increase in lifespan compared to previous LEEFT
configurations. This work demonstrates a scalable, durable, and chemical-free
solution for decentralized and sustainable water disinfection.

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