Antibiotic residuals in dairy manure have different characteristics that facilitate sorting by solid-liquid separation. Partitioning of antibiotic residuals, oxytetracycline and sulfadimethoxine, was measured in an on-farm study of a screw press solid-liquid separator finding that the majority of the antibiotic residual mass in the influent manure partitioned with the separated liquid stream. The study also found that 39% of the influent oxytetracycline residue mass was reduced after screw press solid-liquid separation.