Li Jia, Xie Wen-Xia, Jiang Zhi-Hui, Shan Xi-Huan, Liao Yun-Jie, Zhao Hong-Tao, Li Xu-Yong
College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China.
State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Huan Jing Ke Xue. 2020 Sep 8;41(9):4113-4123. doi: 10.13227/j.hjkx.202001170.
Most sponge city constructions in China are carried out in urban parcel-based catchments, and the quality and quantity of surface runoff can be controlled by several low impact development (LID) facilities. However, there are few reports on the generation and control of urban diffuse pollution. In this study, two areas with different hardening rates were compared to analyze the load conditions during the accumulation-wash-off-transport process of particulate pollutants. The results showed that the road surface in the catchment was the main underlying surface that the particulate pollutants contributed to. The road dust accumulation in the medium hardening rate (61.1%) and high hardening rate (73.6%) plots accounted for 88.4% (2.22-12.51 g ·m) and 90.1% (4.99-33.43 g ·m) of the catchment area unit, respectively. The contribution to the suspended solids (SS) load of runoff was 91.7% (0.97-7.34 g ·m) and 90.5% (0.92-18.77 g ·m), respectively. The SS load of road runoff accounted for approximately 95.2% and 83.1%, respectively. The pollution load (SS) after treatment by the LID facilities was approximately 24.0% and 40.2% of the surface runoff, respectively. The particle size distribution of road dust during the accumulation and wash-off processes was>150 μm, while that in surface and output runoff was <50 μm. With the increase in the impervious area, the distribution of finer particles (<105 μm) in the process of accumulation and wash-off increased (24.4%, 106.4%), while the distribution of particles <50 μm in road runoff decreased (12.4%). The particle size distribution of the accumulated, washed dust, and the rain runoff on the roof were roughly similar to those on the road. However, compared to the particle size distribution of road dust, in the accumulation and wash-off processes, the coarser particles (>1000 μm) of the medium hardening rate plot and the particles of size 250-450 μm and <45 μm of the high hardening rate plot increased significantly (>1000 μm: 58.1%, 108.5%; 250-450 μm: 72.9%, 41.8%; <45 μm: 59.2%, 64.8%). The results revealed the entire distribution process (accumulation-wash-off-transport) of particulate pollutants and the effect of LID facilities on the total SS pollution load of the catchment, which can provide an important reference for the scientific assessment of the project performance of LID installation in urban parcel-based catchments.
中国大多数海绵城市建设是在基于城市地块的集水区开展的，地表径流的水质和水量可通过多种低影响开发（LID）设施加以控制。然而，关于城市面源污染产生与控制的报道较少。本研究对比了两个硬化率不同的区域，以分析颗粒污染物在累积-冲刷-输运过程中的负荷状况。结果表明，集水区内道路表面是颗粒污染物的主要贡献下垫面。中等硬化率（61.1%）和高硬化率（73.6%）地块的道路积尘分别占集水区单位面积的88.4%（2.22 - 12.51 g·m）和90.1%（4.99 - 33.43 g·m）。对径流悬浮固体（SS）负荷的贡献分别为91.7%（0.97 - 7.34 g·m）和90.5%（0.92 - 18.77 g·m）。道路径流的SS负荷分别约占95.2%和83.1%。经LID设施处理后的污染负荷（SS）分别约为地表径流的24.0%和40.2%。道路积尘在累积和冲刷过程中的粒径分布>150μm，而地表径流和输出径流中的粒径分布<50μm。随着不透水面积的增加，累积和冲刷过程中细颗粒（<105μm）的分布增加（24.4%，106.4%），而道路径流中<50μm颗粒的分布减少（12.4%）。屋顶累积、冲刷的灰尘及降雨径流的粒径分布与道路上的大致相似。然而，与道路积尘的粒径分布相比，在累积和冲刷过程中，中等硬化率地块的粗颗粒（>1000μm）以及高硬化率地块粒径为250 - 450μm和<45μm的颗粒显著增加（>1000μm：58.1%，108.5%；250 - 450μm：72.9%，41.8%；<45μm：59.2%，64.8%）。研究结果揭示了颗粒污染物的整个分布过程（累积-冲刷-输运）以及LID设施对集水区总SS污染负荷的影响，可为科学评估基于城市地块集水区的LID设施工程性能提供重要参考。
