Effectiveness of Vegetative Filter Strips (VFS) for Controlling Pathogen Loads and Antibiotic Resistance in Dairy Wastewater

摘要

A vegetative filter strip (VFS) was assessed for controlling pathogen loads and antibiotic resistance (AR) in dairy wastewater. The VFS was divided into two equal sections, and wastewater was applied to alternating sections in a crossover design every6 months. Dairy wastewater and surface water surrounding the VFS and a negative control (NC) site were collected every two weeks and after rain events (>1 in. per 24 h) during the study. Fecal coliform (FC) and fecal streptococci (FS) were measured as pathogen load indicators, and AR of the FS was tested with the antibiotics: tetracycline, oxytetracycline, neomycin, streptomycin, erythromycin, ciprofloxacin, and vancomycin. Pathogen loads (CFU logic per 100 mL) and AR data were analyzed using SAS MIXEDprocedures, and the model included site, season, rain event, effluent application, and the interaction of site by season. Data on AR of FS from animals was analyzed using the SAS MDvED procedures with the model including species. Site and season affected FC and FS loads (P < 0.05). Fecal coliform loads decreased from wastewater (10~6) to surface waters (10~1-10~5). Fecal streptococci loads decreased from wastewater (10~8) to surface waters (10~2-10~6). Antibiotic resistance was affected by sampling site and season (P < 0.05). Streptomycin and neomycin exhibited the greatest levels of AR while vancomycin exhibited the least. Movement of AR to streptomycin, tetracycline and oxytetracycline may have been affected by animals that habitat the VFS and not the dairy cattle. VFS systems can effectively reduce pathogen loads in dairy wastewater.