Removal of veterinary antibiotics in swine manure wastewater using microalgae–bacteria consortia in a pilot scale photobioreactor

Abstract

Scenedesmus almeriensis microalgae–bacteria consortia were evaluated for the removal of a mixture of tetracycline (TET), ciprofloxacin (CIP), and sulfadiazine (SDZ) from the real liquid fraction of pig slurry in a pilot scale photobioreactor. After 15 days of operation, the reactor was spiked with a mixture of 100μg/L of each antibiotic. The experiment ran for 20 additional days. From the liquid phase, antibiotic removal were 77 ± 5 %, 90 ± 14 %, and 60 ± 27 % for TET, CIP, and SDZ, respectively. The antibiotics found in the solid phase were 979 ± 382 ng/g for TET and 192 ± 69 ng/g for SDZ; CIP was not detected in the biomass. The parameters analyzed before and after antibiotic addition showed that the antibiotics did not have a negative effect on the reactor biomass. The removal efficiencies of the analyzed parameters were 64.6 ± 0.6 % for TOC, 56.9 ± 0.6 % for IC, 63.9 ± 0.6 % for TN, 88.6 ± 0.9 % for N-NH4+, 64.9 ± 0.6 % for N-NO3−, and 30.1 ± 0.3 % for P-PO43−. This study demonstrated the good performance of microalgae-based technology for swine manure wastewater treatment, not only in terms of organic matter and nutrient removal, but also regarding the removal of antibiotics. The mass balance analysis of the entire process is presented. Additionally, the present study is a validation of previous laboratory scale batch studies operating in a quasi-continuous mode on veterinary antibiotics (VA) removal efficiencies and kinetics.