Simultaneous Removal of Oxytetracycline and Sulfamethazine Antibacterials from Animal Waste by Chemical Oxidation Processes

Simultaneous degradation of oxytetracycline (OTC) and sulfamethazine (SMZ) antibacterials in synthetically contaminated cow manure (20 mg of antibacterials/kg of manure) in the presence and absence of bedding was investigated by the application of ozone, Fenton, and persulfate oxidation processes. Almost the complete removal of antibacterials was attained with all oxidation processes, which were combined with a pretreatment of manure with magnesium (Mg2+) salt desorption. Among the investigated oxidation processes, thermally activated persulfate oxidation with 25 mM Na2S2O8 at 50 degrees C was also applied to the animal feeding operations wastewater, and the pseudo-first-order degradation rate constants of OTC and SMZ were found as 3.22 and 1.25 (1/h), respectively. Thermally activated persulfate treatment resulted in the reduction of 82% inhibition of OTC and SMZ to 7%, indicating the production of almost nontoxic degradation products in the wastewater.