HARNESSING BACTERIAL BIOLOGICAL DENITRIFICATION WITH ZERO-VALENT IRON FOR THE SUSTAINABLE REMOVAL OF NITRATE IN WATER SOURCES
DOI:
https://doi.org/10.58445/rars.2871Keywords:
Nitrate contamination, Zero-valent iron, Biological denitrification, Betaproteobacteria, Water purificationAbstract
Nitrate contamination of water sources poses severe environmental and public health risks. Excess nitrogen affects 59.5 million people in the US, and 46% of streams are contaminated. Traditional nitrate removal technologies like reverse osmosis, ion exchange, and nanofiltration are costly and often inaccessible in underserved areas. This study investigates the use of zero-valent iron (ZVI) granules as a low-cost electron donor to support Betaproteobacteria-driven denitrification. ZVI's high reduction potential and cathodic hydrogen generation make it a sustainable substitute for industrial electron donors like methanol at 984% lower cost. In this two-month experiment, two media systems (Media-1 and Media-2) supported Betaproteobacteria and were supplemented with ZVI. Nitrate concentrations (~25 mg/L initial) were measured using Hach 353 N (PP) tests. Results showed a consistent nitrate reduction of 78.32%, with final concentrations well below the EPA threshold of 10 mg/L. Positive bacterial growth was observed across all growth periods, with clear signs of acclimatization and increasing metabolic efficiency over time. Additionally, a custom-designed shaker system maintained uniform bacterial suspension, improving reliability and consistency. This study presents ZVI-supported denitrification as a scalable, statistically significant (p<0.0045), and affordable solution to nitrate contamination.
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