Roof runoff pollution control with operating time based on a field-scale assembled bioretention facility: Performance and microbial community dynamics

Abstract

Bioretention facilities are essential, low-impact development measures to treat roof runoff pollution. To explore the effects of roof runoff pollution control and internal influencing mechanisms of field-scale bioretention facilities, a newly assembled bioretention facility (ABF) comprising volcanic rock and coconut coir was constructed. The results of the 21-month experiment showed that the peak concentrations of total suspended solids (TSS), ammonia nitrogen (NH4+–N), and chemical oxygen demand (COD) of roof runoff were 332.50 mg∙L−1, 3.46 mg∙L−1, and 122.33 mg∙L−1, respectively, indicating that the roof runoff was seriously polluted and needed urgent treatment. The removal rates of TSS, NH4+–N, and COD within the facility were 86.50 ± 7.31 %, 79.40 ± 19.28 %, and 51.84 ± 26.24 %, respectively. However, continuous and high-intensity rainfall decreased pollutant removal performance by weakening the adsorption effect of the media. Continuous pollutant input decreased the abundance of Arthrobacter and Hyphomicrobium within the media, and functional bacteria, such as KD4–96, Roseiflexaceae, Vicinamibacteraceae, and Gaiellales, played dominant roles in NH4+–N and COD removal to ensure the long-term stability of the facility. This study provides theoretical guidance and a practical basis for enhancing the application of ABF in mitigating roof runoff pollution.