Adding a Submerged Layer to the Stormwater Biofilter Design Could Increase Antibiotic Resistance Genes Concentration in the Effluent

• Published in: Journal of environmental engineering (New York, N.Y.) Vol. 149; no. 7
• Main Authors: Ghavanloughajar, Maryam, Borthakur, Annesh, Cira, Marisol, Jay, Jennifer, Stenstrom, Michael K., Mohanty, Sanjay K.
• Format: Journal Article
• Language: English
• Published: New York American Society of Civil Engineers 01-07-2023
• Subjects: Antibiotic resistance; Antibiotics; Biofilters; Coagulation; Design; Drug resistance; Effluents; Genes; Iron; Pores; Stormwater; Survivability; Technical Note; Technical Notes
• ISSN: 0733-9372; 1943-7870
• DOI: 10.1061/JOEEDU.EEENG-7297

AbstractA submerged layer is often added to stormwater biofilters to increase denitrification but the implication of the design on antibiotic resistance genes (ARGs) concentration in the effluent is rarely evaluated, even though the submerged layer could potentially create conditions to proliferate ARGs in biofilters. Here, we intermittently applied stormwater naturally contaminated with ARGs on biofilters with and without a submerged layer in the presence or absence of iron filings and analyzed the effluent concentration of ARGs. The results show that the presence of a submerged layer significantly increased the relative gene abundance in the effluent. We attribute the result to the increased survivability of antibiotic resistance bacteria and the potential proliferation of ARG in saturated pores than that in pores that dry intermittently. The addition of iron filings significantly reduced the ARG concentration in the effluent from submerged biofilters potentially by removing the ARGs by coagulation and absorption. The results are helpful to inform the design of biofilters to minimize the spreading of ARGs from stormwater biofilters.