Antibiotics biodegradation during nitrification: a novel approach to reduce antibiotics load to water environment from nitrogen enriched wastewater

Literature broadly documents that antibiotics are present in surface water and are being removed to very different extend by biological sewage treatment systems. In this study biodegradation capability of five antibiotics clarithromycin, enrofloxacin, sulfamerazine, sulfamethoxazole and trimethoprim by nitrifying activated sludge were investigated. Nitrifying activated sludge was capable to biodegrade the tested antibiotics with different rates. The pseudo first order degradation rates were 9.95, 7.6, 4.11, 3.12 and 2.74 L/gSS/d for sulfamethoxazole sulfamerazine, trimethoprim clarithromycin and enrofloxacin respectively. Sorption contributed less than 10% percent in the overall removal with enrofloxacin an exception (around 15%). The overall removal efficiency was 80% for sulfamethoxazole, 76% for sulfamerazine, 60% for enrofloxacin, 50% for trimethoprim and 44% for clarithromycin. Nitrifiers in the nitrifying activated sludge were mostly responsible for biodegradation and ammonia monooxygenase enzyme of nitrifier played the key role.