Magnetic field mitigation of composite fouling through microbial and interfacial disruption

Abstract Composite fouling, arising from microbial and inorganic interactions, compromises the reliability of reclaimed-water distribution systems. We evaluated permanent magnetic fields (PMF; 300–800 mT) and electromagnetic fields (EMF; AC and pulsed DC) in a full-scale reclaimed-water distribution loop. Under the tested conditions, EMF—particularly pulsed DC—reduced total foulant mass by up to 51.7% (p < 0.05) and was associated with lower biofilm biomass, mineral scaling, and particulate accumulation. 16S rRNA profiling indicated co-occurring declines in community diversity and simpler co-occurrence networks under EMF. X-ray diffraction indicated a relative enrichment of aragonite (vs. calcite) and decreases in dolomite and quartz within deposits across all magnetic-field treatments. Field-induced oxidative conditions and interfacial changes were consistent with processes that may hinder microbial attachment and crystal nucleation. Collectively, the results suggest that EMF can outperform PMF for composite-fouling control in reclaimed-water systems and motivate optimization of field strength and waveform and validation across additional water qualities and hydraulics.