Determination and characterization of pharmaceuticals in sludge from municipal and livestock wastewater treatment plants

This study investigated 24 pharmaceuticals compounds belonging to the classes of analgesics, stimulants, anti-seizures, non-steroidal anti-inflammatory drugs (NSAIDs), and antibiotics in the sludge of 12 municipal sewage treatment plants (S-sludge) and 4 livestock wastewater treatment plants (L-sludge) located across Korea. Over 70% of the target compounds were detected in at least one sample of S-sludge and L-sludge. The total concentration of the target pharmaceutical compounds detected in S-sludge was 2.622-422.8 mg kg^-1and the most dominant compound was acetylsalicylic acid (ASA: 0.374-367.0 mg kg^-1) whereas in L-sludge, the total concentration was 43.87-156.8 mg kg^-1and the most abundant compound was oxytetracycline (OTC: 34.54-86.39 mg kg^-1). Cluster analysis revealed two distinct groups: group A, which were S-sludge samples including ASA, carbamazepine (CBM), and others, and group B were L-sludge samples, dominated by antibiotics (CTC, OTC, LIN). The total daily load amount of the target pharmaceuticals in S-sludge was 0.010-268.9 kg day^-1 while the L-sludge was 0.021-0.529 kg day^-1. The estimated amounts of the target pharmaceutical discharged from S-sludge and L-sludge into the Korean environment were 150.2 ± 47.94 ton yr^-1 and 15.05 ± 5.671 ton yr^-1 respectively, but the discharged amount of antibiotics from S-sludge (6.945 ton yr^-1) was lower than that from L-sludge (9.234 ton yr^-1).