透水路面与生物滞留组合系统的径流体积控制效能

透水路面与生物滞留组合系统为典型的低影响开发雨水控制设施,通过实验室人工模拟降雨,对道路1%横、纵坡条件下透水路面与生物滞留组合系统的径流雨水体积控制效能进行了研究。结果表明,变径流系数法-等流时线法更适合试验条件下透水路面的产汇流理论计算;随着降雨重现期由1年增加至20年,透水路面的径流雨水体积控制率由30. 69%降低到10. 21%;高降雨重现期下组合系统增加蓄水层深度对雨水体积控制率的改善效果不如低降雨重现期下显著;随着降雨重现期由3年增加至20年,组合系统中生物滞留设施对雨水体积控制率的贡献比例从71. 56%增加至86. 31%;当组合系统中滞留带蓄水层深度为15 cm时,10年和20年重现期下的雨水体积控制率为75. 73%和74. 59%,径流雨水控制效果较好;影响组合系统雨水体积控制率的主要因素相关性排序为蓄水层深度降雨量峰值雨强。     

硫铁矿基质生物滞留系统对雨水径流的处理效能

针对传统生物滞留系统因缺乏有机碳源而导致的脱氮性能不稳定问题，开发了一种基于自养反硝化的硫铁矿改良生物滞留系统，研究了以硫铁矿代替电子供体的生物滞留系统对无碳源雨水径流的脱氮除磷效能，并对系统中的微生物种群结构进行了分析。结果表明，在雨水径流中无有机碳源的情况下，硫铁矿基质生物滞留系统仍可实现反硝化脱氮，对NO₃^--N和TN的平均去除率分别可达到89%和86%，同时亦有高效稳定的除磷效果，TP去除率达到81%。硫铁矿基质可提高生物滞留系统内部微生物的反硝化能力，反硝化相关菌种Pseudomonas和Thiobacillus的相对丰度分别为5.7%和1.6%。     

生物滞留设施对城市雨水径流热污染的削减效应

径流热污染是水污染的重要方面,也是城市水体生态环境破坏的重要原因,生物滞留是缓解城市雨水径流热污染最有效的措施之一。通过不同填料的生物滞留实验,在人工模拟均匀降雨的条件下,探究了在不同降雨特征下不同填料生物滞留设施对城市雨水径流热污染的削减效果。结果表明,不同填料生物滞留设施热负荷削减效果从大到小依次为:炉渣、石英砂、陶粒、沸石;径流温度越高,所携带的热量越大,生物滞留设施的径流热污染负荷削减率也越高;体积削减对生物滞留设施削减雨水径流热污染的贡献大于热交换。     

乌鲁木齐道路生态排水系统案例研究

介绍了道路雨水生物滞留带—蓄水池集成技术在乌鲁木齐市某道路生态排水系统中的应用,比较了传统管网排水系统、生态排水系统、生态排水与传统管网排水组合系统的投资与效益,利用SWMM暴雨管理模型对生态排水系统的径流控制效果进行了模拟分析。结果表明,城市道路生态排水系统对提升道路排水标准及缓解半干旱地区缺水压力的效果显著,对我国干旱地区雨水控制利用系统的构建具有很好的借鉴意义。     

道路生物滞留带削减雨水径流的实测效果研究

通过对深圳市某道路生物滞留设施进行雨水径流监测试验,研究生物滞留设施对道路雨水径流的削减效果及影响因素。结果表明,当降雨总量为3.3~76.7 mm、平均雨强为0.03~0.67 mm/min时,生物滞留设施对道路雨水径流的场次径流总量控制率为50.5%~100%,峰值流量削减率为53.4%~100%,滞峰时间可以达到2 min以上。生物滞留设施对场次降雨量小且平均降雨强度小的道路径流削减效果较好。     

蓄水层对绿色屋顶径流削减能力的影响分析

提出了耦合HYDRUS-1D与蓄水层蒸发模块的绿色屋顶模型,基于绿色屋顶试验和水文监测数据对模型进行了率定及验证,利用该模型分析了深圳市不同雨强、雨前干旱时间(ADP)和水文年下,蓄水层对绿色屋顶径流削减能力的影响。结果表明,随着次降雨强度的增加,绿色屋顶径流削减量先增加,在达到最大值后保持稳定,蓄水层厚度的增加可以显著提高绿色屋顶的最大径流削减量;随着ADP的增加,绿色屋顶对下次降雨径流的削减能力逐渐恢复,由于蓄水层蒸发对土壤层的补水作用,带蓄水层屋顶的径流削减能力恢复的速度远慢于无蓄水层屋顶;绿色屋顶对年径流削减量:枯水年平水年丰水年,且随蓄水层厚度的增加而增加。     

高架道路降雨径流水质的污染控制试验研究

通过模拟上海高架道路降雨径流水质,基于生物滞留设施的原理设计小试和中试反应器,对比了以陶粒和沸石为介质的生物滞留设施对高架道路雨水径流的处理条件及效果,初步讨论了介质层结构对处理效果的影响。结果表明,基质强化生物滞留设施的水力负荷应不大于1m~3/(m~2·d);沸石基质对COD、TP和NH_3-N的去除效果好于陶粒,其相应去除率分别为74%、87%和71%,装置运行期间出水水质达到《地表水环境质量标准》(GB 3838—2002)中Ⅲ类标准;沸石基质适应水力负荷范围较大,更适于处理水力负荷变化较大的雨水径流;添加沸石层后单位时间内污染物去除效率提高40%左右。     

生物滞留槽径流污染物运移规律研究

通过实验研究生物滞留槽径流污染物运移规律,包含污染物削减系数计算公式,之后对生物滞留槽减控径流污染技术进行试验示范.结果 表明,生物滞留槽可削减径流15％～85％,污染物排放量可削减35％～95％,同时具有较好的生态景观效果.通过本研究,能够为海绵城市建设中道路生物滞留槽的设计方法提供参考,并为后续城市雨水径流综合管控平台的构建,水质水量综合措施的布局优化提供基本技术方法和参数.     

生物滞留池净化雨水径流中氮磷的研究进展

生物滞留池作为雨水管理的技术措施之一,在雨水径流净化和调蓄方面具有较好的功效,因此受到研究者广泛关注。分析了传统生物滞留池对氮和磷的去除效果,并从填料组成、池体结构两个方面,对改良型生物滞留池的污染物去除效果进行了分析。基于目前改良型生物滞留池的研究现状,分析了这方面仍存在的问题及推动改良型生物滞留池技术应用的几个主要研究方向。     

基于模型的海绵型道路年径流总量控制率影响因素研究

采用SWMM模型模拟研究了道路长度、道路红线宽度、人行道及非机动车道宽度、人行道及非机动车道中透水铺装比例、绿化带中生物滞留设施比例、生物滞留设施下沉深度、绿化带宽度、车行道宽度等因素对海绵型道路年径流总量控制率的影响,以期为道路年径流总量控制率目标的合理确定提供依据。结果表明,道路红线宽度、人行道及非机动车道宽度、人行道及非机动车道透水铺装比例、绿化带中生物滞留设施比例、生物滞留设施下沉深度、绿化带宽度、车行道宽度会影响海绵型道路的年径流总量控制率。在海绵设施设计参数和设置比例一定的情况下,影响道路年径流总量控制率的主要因素是道路红线宽度、绿化带宽度和车行道宽度。制定道路年径流总量控制率目标时,应根据道路红线宽度、绿化带面积与车行道面积的比值合理确定。     

垃圾填埋场毛细阻滞型腾发封顶工作机理及性能分析

毛细阻滞型腾发封顶目前主要用于国外干旱、半干旱地区,在湿润气候区的研究很少。在杭州市露天构筑毛细阻滞型腾发封顶模型,量测18个月中降水、蒸发和植被蒸腾下土柱透水量、地表径流量和土体含水率,得到该封顶在不同季节的响应,分析了毛细阻滞作用机理及其性能,使用水量平衡模型(HELP)和土壤–植被–大气相互作用模型(VADOSE/W)对试验过程中的水量平衡进行模拟,探讨了数值模拟存在的问题。试验过程中,共降水2361 mm,产生地表径流88.4 mm,透水67.4 mm,其他降水均在土层吸持与腾发交替作用下最终返回大气,由于试验地区多雨期与植被腾发旺盛期重合,毛细阻滞型腾发封顶在该地区具有良好性能。由于毛细阻滞作用,使得上部黏土中存储了更多水分用于后期腾发,从而减少了透水量,当毛细阻滞界面附近土体的体积含水率超过临界含水率时毛细阻滞界面被击穿,击穿是连续强降雨作用的结果。HELP和VADOSE/W均高估了地表径流和透水量、低估了腾发量,因为VADOSE/W能考虑毛细阻滞的机理,所以大致上VADOSE/W的模拟结果比HELP更合理和准确。     

Mesocosm study of enhanced bioretention media in treating nutrient rich stormwater for mixed development area

A well-designed engineered soil for bioretention is important as it ensures that pollutant removal requirements are met. This laboratory study investigated the nutrient removal efficiency of bioretention media enhanced with 10% (by volume) additives from various waste materials (cockle shell, newspaper, printed paper, coconut husk and tyre crumb) and planted with Red Hot Chinese Hibiscus (Hibiscus rosa-sinensis), a common landscape shrub in tropical countries. The results showed that media enhanced with shredded newspaper demonstrated a significant improvement in total nitrogen (TN) removal (80.4%), compared to standard bioretention media (57.5%) without compromising total suspended solids (TSS) and total phosphorus (TP) removal, when dosed with actual runoff. The thick root system and rapid growth rate of the plant was proven to contribute to TN removal. This study concluded that shredded newspaper can be a potential addition to enhance bioretention media performance in treating stormwater, especially nutrient rich runoff from mixed development areas.     

Snowmelt pollutant removal in bioretention areas

Snow accumulating in urban areas and alongside roads can accumulate high pollutant loads and the subsequent snowmelt can produce high pollutant loads in receiving waters. This paper examines the treatment of roadside snowmelt in bioretention with respect to pollutant removal, pollutant pathways, and major sinks. Bioretention was used to treat snowmelt from three types of urban roads in Trondheim, Norway: residential, medium, and roads with high-density traffic. Metal retention in bioretention boxes had a mass reduction in zinc, copper, lead, and cadmium in the range of 89-99%, and a decrease in outflow concentrations in the range 81-99%. Cadmium was only measured in the water samples, while the other three metals were traced through the system to identify the main sinks. The top mulch layer was the largest sink for the retained metals, with up to 74% of the zinc retained in this mulch layer. The plant metal uptakes were only 2-8% of the total metal retention; however, the plants still play an important role with respect to root zone development and regeneration, which fosters infiltration and reduces the outflow load. Dissolved pollutants in snowmelt tend to be removed with the first flush of meltwater, creating an enrichment ratio with respect to the average pollutant concentrations in the snow. The effect of this enrichment ratio was examined through the bioretention system, and found to be less predominant than that typically reported for untreated snowmelt. The enrichment factors were in the range of 0.65-1.51 for the studied metals.     

Implementation of improved wetland systems as a ‘zero‐discharge‐technology’ in Poland

This paper discusses results from the implementation of a ‘zero‐discharge‐ technology’ primarily for single households, as well as hotels and small residential urban and rural areas. During a 15‐year span, 5600 improved wetland systems (IWS) were built, and approximately 50% of treatment wetlands in Europe are located in Poland. The first section of this paper discusses water and wastewater management and its development trends. Particular attention is paid to creating sustainable water management in rural areas due to increased necessity in these regions. The second section presents the principle of the IWS, which consists of two options. The third section discusses the current requirements regarding the quality of treated wastewater in Poland. The fourth section presents the effectiveness of the implementation of this system by the Institute for Applied Ecology and the further prospects of ‘zero‐discharge‐technology’ development. The last section discusses the obtained results in the reduction of pollution.     

The role of inter-event time definition and recovery of initial/depression loss for the accuracy in quantitative simulations of highway runoff

A long-term runoff monitoring was carried out in a highway drainage system in Winterthur, Switzerland. Several runoff quantity simulations were carried out using the distributed model ‘InfoWorks-CS’. Serial rainfall monitoring data were used for investigation of water runoff behaviour from the highway. The inter-event time definition was calculated from the runoff simulation and applied for better accurate runoff volume determination. Under continuous rainfall condition, the quantity simulation showed a good agreement with the measured hydrograph. However, in some cases where rainfall was not continuous, overestimation of runoff volume and difference in peak height/timing was found after rainfall halting. It was believed that the initial/depression loss on road surface was recovered during the halting period of rainfall and caused the difference in the runoff volume and peak height/timing difference in simulation. The consideration of regenerated depression loss significantly improved runoff simulation results in the on-and-off type rainfall events. This result showed that it was essential to estimate the inter-event time definition to consider appropriateness of the initial or intermediate loss.     

Parametric analyses of evapotranspiration landfill covers in humid regions

Natural soils are more durable than almost all man-made materials. Evapotranspiration （ET） covers use vegetated soil layers to store water until it is either evaporated from the soil surface or transpired through vegetation. ETcovers rely on the water storage capacity of soil layer, rather than low permeability materials, to minimize percolation. While the use of ET covers in landfills increased over the last decade, they were mainly used in arid or semi-arid regions. At present, the use of ET covers has not been thoroughly investigated in humid areas. The purpose of this paper is to investigate the use of ETcovers in humid areas where there is an annual precipitation of more than 800 mm. Numerical analyses were carried out to investigate the influences of cover thickness, soil type, vegetation level and distribution of precipitation on performance of ET covers. Performance and applicability of capillary barriers and a new-type cover were analyzed. The results show that percolation decreases with an increasing cover thickness and an increasing vegetation level, but the increasing trend becomes unclear when certain thickness or LAI （leaf area index） is reached. Cover soil with a large capability of water storage is recommended to minimize percolation. ET covers are significantly influenced by distribution of precipitation and are more effective in areas where rainy season coincides with hot season. Capillary barriers are more efficient than monolithic covers. The new cover is better than the monolithic cover in performance and the final percolation is only 0.5% of the annual precipitation.     

Effects of rainfall patterns on highway runoff pollution and its control

The magnitude of pollution from highway runoff is highly dependent on rainfall patterns. To demonstrate the effects of rainfall on the characteristics of highway pollution and its control, runoff from two sections of a major highway in Taiwan was monitored, representing respectively the uncontrolled runoff and the runoff treated using a swale system. Event mean concentrations (EMCs) of suspended solids, chemical oxygen demand, total nitrogen, total phosphates, iron, copper and zinc were calculated from monitored data. Annuals loads were also obtained from long‐term simulations using the US Environmental Protection Agency Stormwater Management Model. Results indicated that, despite high traffic volumes, both EMCs and annual loads from the studied highway were low compared with those found in literatures. The lower potentials of runoff pollution were attributed to a pattern of infrequent but intense rainfalls of the study area. The specific rainfall pattern also caused the swale system to be less effective in controlling nitrogen and phosphorus because of significant erosion.     

Performance of grass swales for improving water quality from highway runoff

The performance of grass swales for treating highway runoff was evaluated using an experimental design that allowed for influent and effluent flow and pollutant concentration measurements to be taken at specific intervals through each storm event. Two common swale design alternatives, pre-treatment grass filter strips and vegetated check dams, were compared during 45 storm events over 4.5 years. All swale alternatives significantly removed total suspended solids and all metals evaluated: lead, copper, zinc, and cadmium. The probability of instantaneous concentrations exceeding 30 mg/L TSS was decreased from 41–56% in the untreated runoff to 1–19% via swale treatment. Nutrient treatment was variable, with generally positive removal except for seasonal events with large pulses of release from the swales. Nitrite was the only consistently removed nutrient constituent. Chloride concentrations were higher in swale discharges in nearly every measurement, suggesting accumulation during the winter and release throughout the year. Sedimentation and filtration within the grass layer are the primary mechanisms of pollutant treatment; correspondingly, particles and particulate-bound pollutants show the greatest removal via swales. Inclusion of filter strips or check dams had minimal effects on water quality.     

湿润气候区带膨润土垫ET封顶的性能分析

ET(evapotranspiration,腾发)封顶目前主要用于少雨地区的填埋场,本文考虑1500mm的年降雨量,分析一种加膨润土垫(GCL)的新型土工复合ET封顶在湿润地区的工作性能。建立渗流-腾发耦合模型,计算此新型ET封顶和典型单层土ET封顶的地表径流量、地表蒸发量、植被蒸腾量、最终透水量,对比分析两种ET封顶内的水分运移规律及其工作性能。结果表明:新型ET封顶产生的地表径流总量多于典型单层土ET封顶;新型ET封顶通过膨润土垫的低渗透性使上部土层能够储存更多的水分用于后期腾发,其腾发量大于典型单层土ET封顶,尤其是在降雨高峰期更为明显;在该地区,总厚度1.2m的典型单层土ET封顶并不能有效阻止水分渗透到填埋场中,而新型ET封顶能够满足设计要求。