Zero-valent Iron-Biosand Filtration is Capable of Reducing Antimicrobial and Generic <i>E. coli</i> Concentrations in Unbuffered Conventionally Treated Reclaimed Water: A CONSERVE Project

Kulkarni, Prachi; Kulkarni, Prachi

Wednesday, July 12, 2017

Exhibit Hall (Tampa Convention Center)

Prachi Kulkarni , USDA ARS Environmental Microbial and Food Safety Laboratory , Beltsville , MD

Greg Raspanti , Maryland Institute for Applied Environmental Health, University of Maryland, School of Public Health , College Park , MD

Anthony Bui , Maryland Institute for Applied Environmental Health, University of Maryland, School of Public Health , College Park , MD

Rhodel Bradshaw , USDA ARS Environmental Microbial and Food Safety Laboratory , Beltsville , MD

Eric Handy , USDA ARS Environmental Microbial and Food Safety Laboratory , Beltsville , MD

Cary Coppock , U.S. Department of Agriculture–ARS , Beltsville , MD

Kalmia Kniel , University of Delaware , Newark , DE

Manan Sharma , USDA ARS Environmental Microbial and Food Safety Laboratory , Beltsville , MD

Amir Sapkota , Maryland Institute for Applied Environmental Health, University of Maryland, School of Public Health , College Park , MD

Amy Sapkota , Maryland Institute for Applied Environmental Health, University of Maryland, School of Public Health , College Park , MD

Introduction: If conventionally treated reclaimed water (RW) is to be adopted as an alternative to freshwater irrigation, it is necessary to investigate reuse site-based mitigation options that can further reduce contaminants such as foodborne pathogens and pharmaceuticals and personal care products (PPCPs) that may persist in RW.

Purpose: To examine the efficacy of a zero-valent iron (ZVI)-biosand filter in removing residual PPCPs, specifically antimicrobials, and generic Escherichia coli (E. coli) present in RW.

Methods: Populations of generic E. coli and concentrations of 13 antimicrobials commonly found in RW were quantified using the most probable number (MPN) analysis and high performance-liquid chromatography-tandem mass spectrometry, respectively, in unbuffered chlorinated effluent from a tertiary treatment plant. Testing was conducted before and after filtration through a 50:50; v:v macro-scale ZVI-biosand filter over a two-month period using a greenhouse-based experiment simulating reuse site conditions. The antimicrobials included were ampicillin, oxacillin, penicillin G, ciprofloxacin, oxolinic acid, pipemidic acid, azithromycin, erythromycin, vancomycin, linezolid, sulfamethoxazole, tetracycline and triclocarban. ZVI-filtered RW was then used to irrigate growing lettuce plants in the greenhouse, and lettuce plants were analyzed for the presence of E. coli after multiple irrigation events.

Results: Significant (p-value <0.01) reductions in concentrations were observed after ZVI-biosand filtration for ciprofloxacin, oxolinic acid, pipemidic acid, azithromycin, erythromycin, penicillin, linezolid and vancomycin with 100% reduction achieved for erythromycin. Generic E. coli ranged from 0.36 to 9.3 MPN/100ml in RW and was reduced to between < 0.3 and 2.3 MPN/100ml after ZVI-biosand filtration. No E. coliwas detected on lettuce after irrigation events.

Significance: This greenhouse-based experiment shows promising results for providing a safe alternative to freshwater irrigation by reducing both E. coli populations and potential exposure to antimicrobials in reclaimed water. This study is part of a three-year effort to explore next-generation mitigation treatments to improve irrigation water quality (CONSERVE).

Navigation

P3-216 Zero-valent Iron-Biosand Filtration is Capable of Reducing Antimicrobial and Generic E. coli Concentrations in Unbuffered Conventionally Treated Reclaimed Water: A CONSERVE Project