Efficient removal of Imidacloprid and nutrients by microalgae‐bacteria consortium in municipal wastewater: effects, mechanism, and importance of light

BACKGROUND With the rapid development of society, a large amount of wastewater and pesticides enter the water bodies globally, posing a threat to both the environment and the health of people and other living things. In this paper, an algal strain Scenedesmus sp. was isolated from a municipal wastewater treatment plant (WWTP); its interaction effect with wastewater bacteria on the removal of IMI and conventional pollutants in municipal wastewater was evaluated. RESULTS In this study, an algae-bacteria system was constructed with municipal wastewater, with the aim of exploring the removal effects and mechanisms of the consortium system on Imidacloprid (IMI, 20 mg L-1 and 60 mg L-1) and conventional nutrients from municipal wastewater. The results showed that no IMI was removed under 20 mu mol m(-2) s(-1). However, under 60 mu mol m(-2) s(-1), more than 90% of IMI was removed in the algae-wastewater group (AWG) with Scenedesmus sp.; this value is much higher than the 50.4% (20 mg L-1) and 36.1% (60 mg L-1) achieved by the wastewater group (WG) without Scenedesmus sp. Meanwhile, the removal efficiency of nitrogen was 82.3% (20 mg L-1) and 71.9% (60 mg L-1) in AWG, both of which are higher than the 73.4% and 59.1% in WG, respectively. Moreover, Scenedesmus sp. TXH has a strong resistance to IMI and 4 degradation products (including IMI-urea, 4(5)-hydroxy-IMI, Nitrosimine, and a substance with m/z of 176) were found in AWG. CONCLUSION Using consortium to treat municipal wastewater containing IMI is an effective and safe way. (c) 2022 Society of Chemical Industry (SCI).