The effect of intermittent drying and wetting stormwater cycles on the nutrient removal performances of two vegetated biofiltration designs.

摘要: Vegetated biofiltration systems (biofilters) are now a well-established technology for treatment of urban stormwater, typically showing high nutrient uptake. However, the impact temporal variability rainfall events (further exacerbated by climate change) on nitrogen and phosphorus removal processes, within different designs, is still unknown. Hence, laboratory-based study was conducted to uncover mechanisms behind in biofilters across drying wetting regimes. Two sets experimental columns were based (1) standard design (unsaturated zone only), (2) combination unsaturated saturated (submerged) (SZ) with additional carbon source. Columns watered synthetic stormwater according three schemes, exploring 1, 2, 3, 4 7-week drying. Hydraulic performance, soil moisture pollutant monitored. The results show that hydraulic conductivity SZ experiences less change over time compared design, due slower media drying, crack formation lower plant die-off. Varied lengths challenged both designs differently, 2-week resulting significant drop performance most pollutants (except ammonia), while able retain up four weeks sustaining microbial Increased oxygenation during short-term beneficial ammonia removal. While showed better quicker recovery removal, regions inter-rain event shorter than two weeks, (no zone, no source) can achieve similar if not results.