Investigating biotic and abiotic degradation of emerging contaminants in surface water-sediment batch systems

Four emerging compounds including estrone, progesterone, sulfamethoxazole and trimethoprim were investigated for their degradation in water/sediment systems exposed to a variety of biotic and abiotic conditions. Both the water and sediment were sampled from River Yamuna. The experiments were conducted in batch mode for 40 days. The degradation kinetics were described using a pseudo first-order reaction model. Among the four exposure conditions, bio-photodegradation led to higher removal of emerging contaminants. Comparing photodegradation in sterile surface water and distilled water showed the impact of interfering ions on the photochemical reactions thereby slowing the reaction. All the four target compounds underwent rapid degradation in batch 4, consisting of distilled water exposed to sunlight. The identification of transformation products suggested degradation pathways except for estrone, for which only one transformation product was identified. The study also detected the transformation products in Yamuna surface water samples confirming the presence of the proposed degradation pathways in the environment.