城市道路暴雨径流水质特性及控制对策

由于暴雨径流冲刷引起的城市面源污染已成为受纳水体污染的主要来源。在综合国内外相关文献的基础上,分析了城市道路暴雨径流中污染物的赋存形态,总结了不同环境背景下城市道路暴雨径流污染物的浓度水平,阐述了城市道路暴雨径流水质的影响因素,论述了城市道路暴雨径流污染的控制对策,指出合理确定初期暴雨径流控制量、科学选取/设计控制技术、将暴雨径流控制措施与城市规划有机结合构建调控网络是城市道路暴雨径流污染控制的可行途径。     

滇池柴河小流域暴雨径流中COD的输移特征研究

以滇池柴河小流域为单元,对暴雨径流中污染物颗粒粒径进行了分类,得出径流中COD浓度与污染物颗粒粒径的关系,并从输出源强、输移过程、汇集入河这几个方面对暴雨径流中的COD进行了从源到汇的输移特征研究,以确定暴雨径流中COD的入河负荷.结果表明,形成的暴丽径流中的大部分COD经适当沉淀(30min以上)可以有效去除,暴雨径流中的COD主要分布在粉粒和粘粒中,2场暴雨径流均在沉淀的5～30 min去除的COD最多,这部分污染物的颗粒粒径在0.008～0.020 mm,属于容易沉淀去除的部分,沉淀30 min时的COD平均去除率在52.19％,沉淀240 min左右可去除的主要为粒径在0.003～0.008 mm的污染物,沉淀240 min时的COD平均去除率在63.41％；而沉淀2 880min后仍未去除的为粒径小于0.000 8 mm的微小颗粒,仍无法去除的COD平均占23.26％；降雨强度越大,对地面的冲刷能力越强,形成的径流量更多,输出源的COD含量越高.2场暴雨径流的输出源、输移过程和最终入河的COD浓度存在一定的相关性,但由于污染物输移过程中会受各种因素影响,且本研究监测的暴雨场次有限,由此暴雨径流中COD的入河负荷影响因素还有待进一步研究.     

双基质层绿化屋面的雨水水文水质特征分析

绿化屋面作为低冲击开发的常用措施之一,能有效削减暴雨径流、延缓产流时间,从而缓减城市市政管网的压力。但绿色屋面暴雨径流的水质特征依然存在很多不确定性。在天津市气候条件下,通过搭建不同厚度的"双基质层"绿化屋面小试实验装置开展人工降雨实验,着重研究分析了不同降雨条件下,绿化屋面的产流过程以及绿化屋面暴雨径流中污染物的平均出水浓度与吸附基质层厚度、降雨强度的关系。结果表明,产流阶段的产流速度与降雨总量无关,只与降雨强度有关,径流累积量与降雨强度无关,与填料层厚度和降雨总量有关;污染物径流平均浓度与吸附基质层厚度、降雨强度有关;绿色屋顶能够有效降低雨水的COD和浊度,且对酸雨有较好的中和作用。     

沸石床处理农田暴雨径流氮磷中试研究

对沸石床去除农田暴雨径流中氮磷进行了人工模拟中试研究。结果表明 ,沸石床对暴雨径流有较好的净化作用 ,系统水力负荷介于 0 2 4m3 /m2 ·d和 2 4m3 /m2 ·d之间时 ,暴雨径流中主要氮磷污染物的总去除率可达 :TN 4 5 % ,NH4 N 6 0 % ,NO3 N 2 0 % ,TP 38%。平均去除能力为TN 8 14g/m2 ·d ,NH4 N 3 6 4g/m2 ·d ,NO3 N 1 17g/m2 ·d ,TP 0 5 9g/m2 ·d。茭草床的效果明显好于芦苇床 ,植物床的效果明显好于空白对照床。系统在最大进水能力 31L/min下 ,对氨氮仍然能保持4 0 %以上的去除率     

植草沟在城市面源污染控制系统的应用

暴雨径流造成的城市面源污染已引起广泛重视,为控制和削减进入受纳水体的径流污染负荷,各种技术措施得到发展,植草沟便是其中之一.植草沟是景观型地表沟渠排水系统,从植草沟定义、类型、设计计算、参数确定、运行维护及应用实例方面作了较详细介绍.植草沟在条件合适时可代替传统的雨水管道,具有很好的推广应用前景.     

山地城市暴雨径流污染特性及控制对策

为了解山城重庆的暴雨径流污染特性,充实国内仍然薄弱的基础资料,对4种用地类型的4场暴雨进行了监测,测试指标包括TSS、COD、TP、TN和NH3-N。结果表明,对于坡度2.5%的交通干道和坡度30%的校园人行道,从污染物浓度降幅的角度考虑初期径流的控制量应分别为2～3 mm和1.8 mm。随降雨时间的延长,路面污染物浓度迅速降低,坡度越大,降低速率越快。对于平均浓度,校园屋顶和草坪的各污染物浓度均达到地表水环境质量Ⅴ类标准(总氮和氨氮除外)。交通干道和校园人行道的总磷平均浓度也满足地表水环境质量Ⅴ类标准,但2种下垫面的COD、TN和氨氮平均浓度分别超出地表水环境质量Ⅴ类标准的2～8倍、1.9～3.1倍和1.9～4.3倍。对于交通干道,场次降雨径流的总氮、总磷和氨氮平均浓度与初期浓度的比值和污染物浓度20 min降幅接近(分别为0.5～0.53和50%～55%)接近,而COD和TSS平均浓度与初期浓度的比值和污染物浓度20 min降幅相近(分别为0.35～0.37和78%～84%)。对于校园人行道,污染物浓度20 min降幅均达到90%以上(90%～96%),场次降雨径流的总氮、总磷、氨氮、COD和TSS的平均浓度与初期浓度的比值接近(0.3～0.4)。研究结果为山地城市暴雨径流的污染控制提供了参考。     

锅炉烟气联合脱硫脱氮技术

硫氧化物和氮氧化物是燃煤锅炉排放的主要污染物 ,传统分步脱硫脱氮设备昂贵且效率不高 ,而联合脱硫脱氮技术具有很大的优越性 ,如可以减小系统的复杂性、具有更好的运行性能、较低的成本及较小的占地面积 ,因此实现在一个系统内同时脱硫脱氮的工艺成为国内外烟气净化技术的研究重点。对近年来国内外各种联合脱硫脱氮技术的脱除原理、研究现状、应用情况和主要优缺点进行了论述 ,并对各工艺的经济技术指标给予了多方面的比较。通过对两类烟气联合脱硫脱氮技术 (炉内联合脱除和烟气中联合脱除 )的分析、综合和比较 ,找出了我国今后脱硫脱氮技术的研究重点 ,从而为脱硫脱氮技术的进一步开发和改进提供参考     

生物脱氮在污染治理中的应用

生物脱氮作为一种新兴技术，已经在国内外开展了广泛的研究和应用，为环境领域的脱氮处理提供了一个实用而节能的新途径，因此，集中对生物脱氮技术在废气和废水中的应用进行了介绍，分别介绍了这两个方面的进展，并简单比较了各种技术的优缺点，还探讨了生物脱氮技术的今后发展方向。     

日本净化槽技术在农村生活污水处理中的应用

引进日本净化槽技术在中国浙江农村污水处理中应用,探索净化槽技术在浙江农村地区的推广应用前景。膜式净化槽污水处理系统应用先进的浸没式平板膜组件,采用MBR工艺,实现对污水中有机物、氮和磷营养盐类的有效去除。正常工况条件下,监测结果表明,处理系统对COD、BOD5、氨氮、总磷和悬浮物的平均去除率分别为83.64%、84.46%、97.94%、94.13%和93.95%。膜式净化槽系统处理出水水质好且稳定,可直接回用,适宜对水质要求较高和经济条件较好的地区选用。今后在中国农村推广应用净化槽,需加强维护管理制度建设。     

军山湖流域农业非点源污染氮、磷入湖负荷估算

参照国内外相关湖泊研究的方法,在开展流域调查的基础上,按照畜禽养殖污染、农业种植业流失、水产养殖污染和农村生活污染4类途径,结合各乡镇流域面积所占比例、污染源产生量、排放系数和流失系数等估算了军山湖流域农业非点源污染氮、磷的入湖负荷.结果表明,农业种植业流失和畜禽养殖污染是军山潮流域农业非点源污染入湖氮的主要来源,分别占入湖氮总量的37.5％和34.7％,其次为水产养殖污染,占23.2％；畜禽养殖污染是入湖磷的主要来源,占50.8％,其次为农业种植业流失和水产养殖污染,分别占24.4％和20.0％;农村生活污染对入湖氮、磷的贡献率最小.     

Stormwater runoff quality from different surfaces in an urban catchment in Beijing, China

Urban stormwater runoff quality, widely investigated around the world, has been monitored less in Beijing, China, which impedes the municipal government to use best management practices to protect surface water. In this study, rainwater and stormwater runoff samples from roofs, roads, and a lawn on the campus of the Research Center for Eco-Environmental Sciences (RCEES) (Beijing, China) and from a ring road, with heavy traffic, have been sampled and analyzed for 31 storm events from June 2004 to August 2005. Total suspended solids (TSS), chemical oxygen demand (COD), 5-day biochemical oxygen demand (BOD5), total nitrogen, and total phosphorus concentrations in rainwater and runoff ranged over 2 or more orders of magnitude, meaning that the highest concentration of a certain pollutant did not always occur in a certain kind of runoff. Runoff contained significantly higher concentrations of pollutants than rainwater. On the campus of RCEES, TSS and total phosphorus in runoff samples from the lawn and roads were significantly higher than those from roofs, while the COD, BOD5, and total nitrogen concentrations were not significantly different in runoff among surfaces. Compared with runoff from the roads on campus, runoff from the ring road contained more COD and total nitrogen, but less TSS, BOD5, and total phosphorus. All pollutants measured in runoff from roofs on campus and from the ring road showed a peak concentration in starting runoff, which then decreased sharply. The peak concentrations of COD, BOD5, total nitrogen, and total phosphorus in the roof runoff increased with the increase in time of the antecedent dry period. Thus, urban stormwater pollution control, especially for first-flush control, is of great importance for the full use of rainwater and prevention of water pollution.     

Nitrogen removal from urban stormwater runoff through layered bioretention columns.

Bioretention is a low-impact technology used for the treatment of stormwater runoff in developed areas. The fates of mineral nitrogen compounds in two bioretention columns (RP1 and RP2) with different media-layering characteristics were investigated under multiple loadings of simulated urban runoff. The immediate capture of nitrogen was evaluated, with nitrogen transformation reactions that occurred during the drying periods between rainfall events. A greater proportion of ammonium was removed from runoff in RP2 (68 +/- 16%), which had a high permeability layer over a lower permeability layer, than in RP1 (12 +/- 6%), which had the inverse configuration. Both column systems demonstrated nitrate export (9 +/- 32% and 54 +/- 22% greater than input for RP1 and RP2, respectively), attributed to washout of nitrate resulting from nitrification processes between runoff loading events. Bioretention media with a less permeable bottom soil layer could form an anoxic/anaerobic zone for promoting nitrification/denitrification processes.     

城市道路沉积物氮、磷溶出特性

国内外众多研究表明,城市不透水表面沉积物是雨水径流中污染物的重要来源。以北京市某道路沉积物为研究对象,对城市道路沉积物的粒径分布进行了分析,并通过批量实验,研究了不同粒径道路沉积物中氮、磷营养物及有机物(COD)的溶出特性。实验结果表明,粒径较大的沉积物中氮含量较高,而粒径较小的沉积物中磷含量较高;虽然TP、PO3-4、TN、NO-3、NH+4、COD的溶出浓度、溶出速率变化特征各不相同,但总体趋势是粒径越小氮、磷及COD溶出浓度和溶出速率越大,且最大溶出速率都出现在前5 min。因此,为实现对城市雨水径流污染的有效控制,应采用源头控制措施对小粒径道路沉积物和初期雨水进行有效控制。     

不同地表雨水径流冲刷特性分析

选择北京市某城区典型地表(校园、自行车道、商业街和高架桥)的雨水径流作为研究对象,系统分析了不同地表雨水径流的冲刷特性。分析结果表明:不同地表初期冲刷现象都比较明显,控制不同地表20%的初期雨水可以削减污染物总量的40%～60%,高架桥初期雨水径流中COD、SS和TP浓度最高,校园初期雨水径流中TN浓度最高。不同地表雨水径流的水质优劣顺序为:校园>商业街>自行车道>高架桥。校园和自行车道在整个降雨过程中D50和D90粒径大小相近,分别为30μm和50μm左右,且变化幅度都较小。高架桥和商业街在雨水径流初期D50和D90粒径有明显减小,但后期均出现较大幅度的波动,其粒径明显大于校园和自行车道。上述研究成果对于城市不同地表雨水径流污染控制和场地开发具有重要意义。     

Feasibility of constructed wetlands for removing chlorothalonil and chlorpyrifos from aqueous mixtures

Chlorpyrifos (an insecticide) and chlorothalonil (a fungicide) are transported in stormwater runoff and can be lethal to receiving aquatic system biota. This study determined removal rates of chlorpyrifos and chlorothalonil in simulated stormwater runoff treated in constructed wetland mesocosms. Using sentinel species, Ceriodaphnia dubia and Pimephales promelas, observed declines in toxicity of the simulated runoff after treatment were 98 and 100%, respectively. First order removal rates were 0.039/h for chlorpyrifos and 0.295/h for chlorothalonil in these experiments. Constructed wetland mesocosms were effective for decreasing concentrations of chlorpyrifos and chlorothalonil in simulated stormwater runoff, and decreasing P. promelas and C. dubia mortality resulting from these exposures. The results from this study indicate that constructed wetlands could be part of an efficient mitigation strategy for stormwater runoff containing these pesticides.     

Stormwater quality benefits of a porous friction course and its effect on pollutant removal by roadside shoulders.

This project has two main objectives; the first is to documents the effect of a porous friction course overlay on the quality of highway stormwater runoff, and the second is to assess pollutant removal of a vegetated area along the side of a road from both conventional and porous pavements. The quantity and quality of stormwater runoff from a four-lane divided highway in the Austin, Texas, area was monitored before and after the installation of a porous friction course (PFC). Observed concentrations of suspended solids and pollutants associated with particulate material were much lower in the runoff from the PFC compared with runoff from the conventional asphalt surface. The vegetated highway shoulder reduced the concentrations of many stormwater constituents from the conventional asphalt surface; however, the concentrations of these constituents in runoff produced by the PFC were so low that the vegetated area produced no further reduction in concentration.     

Water quality improvement through bioretention media: nitrogen and phosphorus removal.

High nutrient inputs and eutrophication continue to be one of the highest priority water quality problems. Bioretention is a low-impact development technology that has been advocated for use in urban and other developed areas. This work provides an in-depth analysis on removal of nutrients from a synthetic stormwater runoff by bioretention. Results have indicated good removal of phosphorus (70 to 85%) and total Kjeldahl nitrogen (55 to 65%). Nitrate reduction was poor (< 20%) and, in several cases, nitrate production was noted. Variations in flowrate (intensity) and duration had a moderate affect on nutrient removal. Mass balances demonstrate the importance of water attenuation in the facility in reducing mass nutrient loads. Captured nitrogen can be converted to nitrate between storm events and subsequently washed from the system. Analysis on the fate of nutrients in bioretention suggests that accumulation of phosphorus and nitrogen may be controlled by carefully managing growing and harvesting of vegetation.     

Road traffic impact on urban water quality: a step towards integrated traffic,air and stormwater modelling

Methods for simulating air pollution due to road traffic and the associated effects on stormwater runoff quality in an urban environment are examined with particular emphasis on the integration of the various simulation models into a consistent modelling chain. To that end, the models for traffic, pollutant emissions, atmospheric dispersion and deposition, and stormwater contamination are reviewed. The present study focuses on the implementation of a modelling chain for an actual urban case study, which is the contamination of water runoff by cadmium (Cd), lead (Pb), and zinc (Zn) in the Grigny urban catchment near Paris, France. First, traffic emissions are calculated with traffic inputs using the COPERT4 methodology. Next, the atmospheric dispersion of pollutants is simulated with the Polyphemus line source model and pollutant deposition fluxes in different subcatchment areas are calculated. Finally, the SWMM water quantity and quality model is used to estimate the concentrations of pollutants in stormwater runoff. The simulation results are compared to mass flow rates and concentrations of Cd, Pb and Zn measured at the catchment outlet. The contribution of local traffic to stormwater contamination is estimated to be significant for Pb and, to a lesser extent, for Zn and Cd; however, Pb is most likely overestimated due to outdated emissions factors. The results demonstrate the importance of treating distributed traffic emissions from major roadways explicitly since the impact of these sources on concentrations in the catchment outlet is underestimated when those traffic emissions are spatially averaged over the catchment area.     

生物滞留池改善城市雨水径流水质的研究进展

如何有效控制城市雨水径流所带来的面源污染已成为城市管理工作所面临的重要难题之一.作为城市暴雨最佳管理措施(BMPs)中的技术之一,生物滞留池可有效控制城市面源污染.总结了生物滞留池在改善城市雨水径流水质方面的研究进展,简要分析了生物滞留池去除污染物的机制.研究结果表明,生物滞留池对雨水径流中的总悬浮颗粒物(TSS)、重...     

城市旅游区暴雨径流污染过程中的不透水面效应

选取武汉市动物园4种典型的不透水面暴雨径流污染特征进行了系统的研究,以期为旅游区面源污染危害评价和治理提供基本的依据.结果表明,动物园4种不透水面初期径流污染物浓度很高,COD最大值达1140 mg/L,下垫面类型及地表累积污染物是影响径流水质的主要因素.通过无量纲累积曲线的分析,表明旅游区不透水面径流初期冲刷严重,该曲线还为面源治理提供了重要的工程参数.