Impact of ammonia, organic matter, and microbial activity on biodegradation of pharmaceuticals in aerobic batch mode Sungman Lee

Abstract

Impact of ammonia, organic matter, and microbial activity on biodegradation of pharmaceuticals in aerobic batch mode Sungman Lee Department of Civil and Environmental Engineering The Graduate School, Hanyang University Presence of pharmaceuticals (PhACs) in the environment has raised concerns over their potential impacts on ecosystems and public health. To better understand the biodegradation patterns of eleven PhACs [atenolol (ATL), caffeine (CAF), candesartan (CAD), cimetidine (CIM), diclofenac (DCF), losartan (LOS), metformin (MET), naproxen (NPX), olmesartan (OLM), sulfamethoxazole (SMZ), and valsartan (VAL)] by aerobic microbes such as heterotrophs and nitrifiers, sets of batch tests were conducted. The results revealed significant variations in the biodegradability of PhACs, suggesting specific degradation mechanisms individually. Nitrifiers demonstrated proficiency in degrading MET, CIM, VAL, and LOS, while heterotrophs were more efficient for CAF, ATL, and NPX, indicating distinct metabolic pathways. CAD, OLM, SMZ, and DCF showed reduced biodegradability, possibly due to resistance factors. A negative correlation was observed between the biodegradation rate and the initial NH4 concentration for those PhACs dominated by nitrifiers in the biodegradation, suggesting possibilities of competitive inhibition. Biodegradation occurred regardless of the presence of an initial primary substrate, except for persistent PhACs. The study has also found that the biodegradation rates of PhACs were especially sensitive to nitrification activity. Utilizing statistical methods such as principal component analysis (PCA) and K-means clustering, distinct clusters of PhACs were identified, providing insights into their biodegradation patterns. Novel parameters were proposed, which could potentially enhance our understanding of the biodegradation process and improve the removal efficiency of PhACs under various environmental conditions.