REMOVAL EFFICIENCY OF HORIZONTAL SUBSURFACE FLOW WETLANDS FOR VETERINARY PHARMACEUTICALS

摘要

This study was undertaken to assess the removal of commonly used antibiotics on poultry and livestock farms, i.e., monensin, salinomycin, and narasin, in a horizontal subsurface flow (HSSF) treatment wetland. The tested wetland supported a stand of reed canary grass (Phalaris arundinaceae L.) and cattails (Typha latifolia L.) on sandy soil. Of the three compounds evaluated, monensin was found to be the most mobile, and the wetland exhibited an average removal efficiency of 40%. The removal rates for both salinomycin and narasin approached 50%. The effect of the applied concentration of antibiotics on wetland removal efficiency was found to be highly significant (p < 0.0001) only at the first two concentration levels (10 and 50 mu g L-1) versus the two higher levels (0.5 and 1.0 mg L-1). Even though raw data on temperature, dissolved oxygen (DO), oxidation reduction potential (ORP), and pH suggested a microbial contribution to overall antibiotics removal, the effect of these parameters was found to be non-significant (p < 0.05). However, the removal trends were found to be in line with our previously reported laboratory work on biodegradation of these pharmaceuticals.