河泥与海泥陶粒填料生物滞留设施径流控制试验

为探讨河道疏浚泥(河泥)和海洋疏浚泥(海泥)资源化用于生物滞留填料的可行性，分别以河泥和海泥为主要原料制备陶粒，并以两种陶粒为填料搭建了生物滞留试验柱，通过径流雨水渗滤模拟试验，研究了两种试验柱在不同降雨重现期、不同降雨历时和不同污染物质量浓度条件下的运行效果。结果表明：河泥与海泥陶粒作为填料时，生物滞留柱中COD、TP、TN和NH₃-N的淋失量较低，污染物淋失风险较小；在降雨重现期为0.5 a时，河泥与海泥陶粒填料生物滞留柱出流时间分别为49 min和48 min,平均水量削减率分别为34.36%和44.87%,比传统砂土填料生物滞留柱分别提高了34.75%和75.96%;河泥与海泥陶粒填料生物滞留柱对污染物的削减效果明显，对COD、TP、TN、NH₃-N平均负荷削减率分别为50.27%、99.08%、50.72%、79.15%与54.20%、99.58%、55.43%、80.86%,均高于传统砂土填料生物滞留柱。     

道路生物滞留带径流削减效果的试验研究

道路积水是当前我国城市发展面临的突出问题,而设置生物滞留带是典型的道路雨水减排措施之一。为研究不同降雨强度和溢流高度条件下道路生物滞留带的径流削减效果和渗流规律,利用人工降雨装置和模拟道路-生物滞留带平台设计试验,并根据试验结论,结合实际案例进行水文效应计算,对道路生物滞留带设计提出优化建议。结果表明:试验条件下重现期P≤10年时,滞留带可延迟6～10 min的径流峰值时间;不同试验条件的径流削减率和峰值削减率分别为41%～100%和38%～100%;提升溢流高度对径流总量削减效果明显,并对渗流过程有较大影响;渗流流量与滞留带表面水头高度存在一定函数关系。基于试验结果,对道路-生物滞留带系统径流削减率公式进行了推导,为部分参数选取提供了参考值。     

生物滞留池水文水质效应模拟分析

为研究生物滞留池措施对雨水水文水质的调控作用,以宜兴市城区某试验区为研究区域,利用SWMM模拟软件,在5年、10年、100年设计重现期下,分别模拟城市化后有无生物滞留池措施的水文水质状况,并将两者比较分析。研究发现:占研究区域总面积10.75%的生物滞留池措施下,雨水径流量减少了12%左右,峰值流量降低了8%左右,入渗量增加了22%左右;污染物SS、COD、TN、TP总负荷量的削减率分别在10%、7%、9%、8%左右。结果表明:随着城市化进程日益加快,生物滞留池可有效地降低雨水径流量、增加雨水入渗量,削减雨水径流的峰值流量;同时还可以拦截一定量的颗粒悬浮物、营养物质、重金属等污染物。研究成果对海绵城市建设和雨水资源调控利用具有参考价值,对城市水生态建设具有重要意义。     

复合填料生物滞留设施对径流污染物去除效果

填料类型对生物滞留系统水质净化效果具有重要影响。通过生物滞留柱试验,以天然土壤、建筑砂为基本填料,以木屑堆肥、沸石和无烟煤为改良材料,研究了种植土砂土比例、种植土中添加木屑堆肥、砂滤层中单独及同时添加沸石和无烟煤等不同填料组合对径流中COD、TP、NH~+_4-N及NO~-_3-N的去除效果,并对传统砂土填料及复合填料生物滞留设施在不同进流特征下的水质处理效果进行了系统评价。结果表明:在6种填料组合中,种植土中添加木屑堆肥及砂滤层中同时添加无烟煤和沸石对各污染物的处理效果最好;在7种进流工况下,砂土填料生物滞留设施对COD、TP、NH~+_4-N、NO~-_3-N的去除率分别为70.5%～87.5%、50.0%～79.3%、84.7%～96.7%、-110.5%～23.3%,复合填料生物滞留设施的去除率分别为84.0%～93.0%、82.0%～92.0%、80.0%～94.7%、24.3%～90.4%,复合填料生物滞留设施对污染物综合处理效果明显增强,且与传统砂土填料相比,复合填料生物滞留设施受进流特征的影响相对较小。     

生物滞留槽的径流污染削减特性试验研究

生物滞留槽作为一项能有效改善水质的低影响开发设施LID,在我国海绵城市建设中得到了广泛的应用。通过对生物滞留槽进行模拟试验,监测了排水管出水污染物浓度变化,研究了生物滞留槽的污染物浓度和总量削减效果。结果显示,生物滞留槽对总磷TP、氨氮NH3-N、总氮TN、生化需氧量BOD、化学需氧量COD的平均浓度削减率为66.55%、22.57%、-118.55%、51.64%、29.29%,总量削减率为81.90%、58.23%、-15.67%、73.89%、60.80%;生物滞留槽对污染物总量的去除效果要好于对浓度的去除效果。试验结果表明,生物滞留槽能有效去除雨水中的污染物,达到净化水质的目的。     

4种生物滞留填料对径流污染净化效果对比

为提高生物滞留系统净化效果,探讨了绿沸石、蛭石、活性炭、珍珠岩等材料用作特殊填料时对道路径流雨水中NH_4~+-N、TN、TP、COD等污染物的吸附性能。静态摇床实验研究了填料对各污染物的吸附能力,并建立了各填料等温吸附模型。结果表明沸石的综合吸附性能较好,活性炭次之,4种填料的等温吸附过程拟合结果基本符合朗格缪尔(Langmuir)吸附模型。以沸石作为特殊填料的小试结果表明,生物滞留系统对NH_4~+-N、TN、TP、COD的负荷削减率可分别达到70.59%、85.83%、79.98%、66.02%。从净化性能及经济性方面考虑,沸石作为生物滞留系统特殊填料是一种较好的选择。     

基于SWMM模型的海绵城市径流量控制有效评估方法

当前，我国海绵城市管理出现诸多问题，传统的流量控制方法，难以科学有效的实现流量控制分析，使其流量出现评估不准确的情况。为了解决上述问题，提出了基于SWMM模型下的海绵城市径流量控制效果评估方法，该方法引入SWMM模型，实现实时跟踪模拟，确定SWMM模型在城市排水系统中的组成结构。SWMM模型主要由水文模块、水质模块、水力模块三个部分组成，分别对地面径流量和污染物累积进行计算，并得到水力模块的连续性方程。同时，也考虑到路面工程建设的改建、生物滞留设施、雨水花园、透水铺装几个方面对雨水径流关系的影响，对多个角度进行控制评估。实验结果表明，通过建立基于SWMM模型的连续降雨下的海绵城市径流量控制效果评估方法，针对连续降雨天气进行分析，海绵城市径流量提高了40%以上，对于保证城市维稳和运营有着显著的效果。     

海绵城市生物滞留设施关键技术研究进展

海绵城市生物滞留设施是适用于分散式雨水处理与利用的代表性生态技术,但目前仍旧存在一些问题制约其运行效率及寿命。综述了海绵城市建设中生物滞留设施关键技术及国内外研究进展,指出高效净化能力填料的研制、污染物迁移转化模型的建立及设计参数的优化、有机微污染物累积风险评价及修复技术的构建等将成为海绵城市生物滞留设施未来的研究热点。     

生物滞留技术在道路雨洪控制利用中的应用研究

生物滞留技术是目前应用较为广泛的雨洪控制利用措施,在美国等发达国家得到了广泛的认可和应用,但在国内的研究和应用较少。道路作为城市主要下垫面和重要的排水通道,雨水问题尤为突出。本文通过总结国外对生物滞留设施的相关研究成果,对生物滞留设施在道路雨洪控制利用中的应用进行分析,为生物滞留设施在我国的推广应用提供相应的借鉴。     

红壤区填料沙土配比对生物滞留池环境水文效应的影响

提高填料透水性能以平衡其水文调节和污染物去除性能是红壤区生物滞留池构建的关键。研究设计红壤填料中掺入不同比例的河沙以改变其透水性,比较分析其在不同的重现期降雨强度下对生物滞留池的水文调节和污染物去除效果。结果表明:同一降雨强度重现期下,地表径流处理率随着掺沙比例的增加而增加,峰值削减率随沙土配合比的增加变化不明显,峰值延迟时间随掺沙比例增加而减少;硝氮的去除率随着掺沙比例的增加而增加,但对COD的去除率则随着掺沙量的增加而下降,对氨氮和总磷的去除率影响不大;综合考虑生物滞留池的水文调节和污染物去除效果,20%红壤土与80%河沙混合是红壤区生物滞留池填料较为科学的沙土配比。     

Multiple-event study of bioretention for treatment of urban storm water runoff.

Bioretention is a novel best management practice for urban storm water, employed to minimize the impact of urban runoff during storm events. Bioretention consists of porous media layers that can remove pollutants from infiltrating runoff via mechanisms that include adsorption, precipitation, and filtration. However, the effectiveness of bioretention in treating repetitive inputs of runoff has not been investigated. In this study, a bioretention test column was set up and experiments proceeded once every week for a total of 12 tests. Through all 12 repetitions, the infiltration rate remained constant (0.35 cm/min). All 12 tests demonstrated excellent removal efficiency for TSS, oil/grease, and lead (99%). For total phosphorus, the removal efficiency was about 47% the system removal efficiency ranged from 2.3% to 23%. Effluent nitrate concentration became higher than the influent concentration during the first 28 days and removal efficiency ranged from 9% to 20% afterward. Some degree of denitrification was apparently proceeding in the bioretention system. Overall, the top mulch layer filtered most of TSS in the runoff and prevented the bioretention media from clogging during 12 repetitions. Runoff quality was improved by the bioretention column.     

基于Hydrus-1D模型的LID措施雨水径流控制效应研究

为探究LID措施在不同工况下的雨水径流控制效应,选取生物滞留池、下凹式绿地及透水铺装为研究对象,构建Hydrus-1D模型来模拟分析其雨水径流控制效应。结果表明：生物滞留池的径流量削减率与汇水面积比和蓄水层厚度为正线性相关关系,与种植土厚度(20～40 cm)为负线性相关关系;下凹式绿地的径流量削减率与汇水面积比、雨水口高度和种植土厚度为正线性相关关系;透水铺装的径流量削减率与降雨历时和透水砖渗透系数为正相关关系,与雨峰系数为负相关关系。建议生物滞留池的蓄水层厚度取值为30 cm、种植土厚度取值为30 cm;建议下凹式绿地的汇水面积比不小于15%、雨水口高度取值为10 cm、种植土厚度取值为30 cm;当透水砖渗透系数大于0.291 cm/min时,透水铺装产生的雨水径流较少。     

生物滞留系统去除城市地表径流中多环芳烃的研究进展

低影响开发(LID)生物滞留系统是净化城市地表径流的重要措施。多环芳烃(PAHs)作为难降解有机污染物,是城市雨水径流中的重要成分之一。通过总结城市地表径流中PAHs污染现状和国内外应用生物滞留系统去除PAHs的研究动态,系统分析了PAHs类污染物的去除机理、效果和影响因素。研究结果表明:生物滞留系统主要通过填料吸附、微生物降解、植物吸收、挥发等作用去除PAHs,平均去除率在30%~90%。影响去除效果的主要因素包括PAHs性质、系统组成与设计、微生物及环境因子等。建议关注生物滞留系统中PAHs的积累和长期运行效果,并开展系统优化设计和作用机制研究工作。     

Improving bioretention/biofiltration performance with restorative maintenance

One of the most popular Stormwater Control Measures is bioretention, or biofiltration. Anecdotal evidence suggests that well-designed bioretention cells are often not adequately installed and that maintenance is lacking, leading to less-than-adequate water storage volume and/or surface infiltration rates post-construction. In March 2009, two sets of bioretention cells were repaired by excavating the top 75 mm of fill media, increasing the bioretention surface storage volume by nearly 90% and the infiltration rate by up to a factor of 10. Overflow volume decreased from 35 and 37% in the pre-repair state for two different sets of cells, respectively, to 11 and 12%. Nearly all effluent pollutant loads exiting the post-repair cells were lower than their pre-repair conditions. The bioretention systems employed two different media depths (0.6 and 0.9 m). The deeper media cells discharged less outflow volume than the shallower cells, with 10-11% more runoff volume leaving as exfiltration from the 0.9-m than from the 0.6-m media depth cells. This study showed that maintenance is both critical and beneficial to restore otherwise poorly performing bioretention. Moreover, while deeper media cells did outperform the shallower systems, the improvement in this case was somewhat modest vis-à-vis additional construction costs.     

Comparison of infiltration models to describe infiltration characteristics of bioretention

Bioretention is one of low-impact development measures, which widely used not only because it can reduce stormwater runoff total volume, decrease peak flow rate and delay peak flow time, but also can remove the runoff pollutants. Infiltration is an important hydrological process for bioretention to evaluate its runoff total volume reduction and pollutants removal. So, it is important to find an optimal infiltration model that can well describe the infiltration performance of bioretention. The Horton, Philip and Kostiakov infiltration models were selected to compare their accuracy when using for describe the infiltration characteristics of bioretention, and the errors between the different models simulate results and experiment results were assessed via the maximum absolute error (MAE), bias and coefficient of determination (R²). The experimental results showed that Horton model is fitting well and flexible under different experiment conditions, especially when the hydraulic head was 10 cm, with MAE of 0.50–0.81 cm/h, bias of 0.1–0.23 cm/h and R² of 0.98–0.99. R² of the Philip and Kostiakov models were all over than 0.87 at the initial infiltration period, but the model fitting accuracy decreased significantly with infiltration time elapse. Furthermore, the total runoff volume capture ratio and emptying time were advanced used to evaluate the flexibility of Horton model, and the Nash-Sutcliffe efficiency coefficients of them were over than 0.61 and 0.58, respectively. Therefore, the Horton model can be optimal selected to describe the infiltration process of bioretention and for its hydrological evaluation.     

海绵型公园雨水控制分析计算方法——以成都市活水公园为例

海绵城市建设中,为了实现对雨水控制的定量计算,若采用模型模拟需要详实的数据基础,推广起来存在诸多问题。本文以径流系数为主要分析手段,运用较为简便的方法对成都市活水公园进行海绵型公园改造前后的雨水控制各项指标做了定量计算,利用芝加哥雨型进行雨量分配,对改造前后公园外排水流量进行对比分析,结果表明进行海绵型公园改造后,5年一遇降雨外排水流量削峰率达74%,峰现时间延后25min。外排水流量径流系数为0.278,年径流总量控制率大于85%。对3年和5年重现期的雨水控制效果均较好。此计算方法可用于面积不大的海绵城市试点区域或海绵型公园的雨水控制计算,所需数据量小,操作性强,具有可重复性和实用价值。可对海绵城市建设中的雨水控制指标计算提供一定参考。     

Study on bioretention for stormwater management in cold climate,Part I: Hydraulics

Simulated storm events were applied to four large bioretention columns to approximate 1.6 years of equivalent volume in Edmonton, Alberta’s typical climate. Summer, winter, and spring runoff were simulated in temperature-controlled laboratories with a range of −20 °C to +20 °C. During summer less porous bioretention media (i.e. loam soil) effectively weakened peak flows by >83% for 1:2 year events while more porous bioretention media (i.e. sandy loam soil) maintained hydraulic conductivities >9.1 cm/h. Winter operation consisted of all columns being subjected to −20 °C and then 1 °C repeatedly. Events were applied at an air temperature of 1 °C and, although frozen initially, more porous media experienced faster water breakthrough and ponding disappearance in winter indicating that hydraulic performance during intermittent warming periods in winter may be achievable. All columns’ hydraulic performance rebounded quickly in the subsequent summer. All columns successfully managed 1:2 year events in terms of infiltration rate, ponding depth and duration. Preliminary results also showed that both media have the potential to manage less frequent (1:5 and 1:10 year) events.     

Performance of lot-level low impact development technologies under historical and climate change scenarios

Low impact development (LID) systems have potential to make urban cities more sustainable and resilient, particularly under challenging climate conditions. To quantify performance capabilities, modeling results for an array of combinations of LIDs are described using PCSWMM at lot-level to examine performance of individual LIDs on volume and peak flow reductions. Among the four LIDs studied: rain barrel (RB), vegetative swale (VS), bioretention cell (BC), and permeable pavement (PP), PP at lot-level demonstrated the best capability for reducing surface runoff volumes and peak runoff rates under historical weather conditions, while BC showed similar capability for reduction of runoff volumes but minimal peak flow reduction. With PP as the controlling method at lot-level, the maximum percentage reduction of runoff volume for a 2-year storm is 58% whereas for a 100-year storm, the runoff volume reduction is 20%. These results mean the extent of flooding that may arise from the 100-year storm is reduced, but not eliminated. Effectively, the 100-year storm volumes with LID are devolved to have flooding equivalent to a 25-year storm. Under climate change scenarios, performance for all LIDs declined at various levels, where BC was the most resilient LID for a climate change scenario, such that projected 2-year or 5-year storms with climate change will have its impact devolved with LID in place, to result in similar volumes and peaks without LID under historical conditions. Furthermore, even with an assembly of lot-level LIDs distributed throughout the community, there is not attenuation to substantial degrees of flooding for major events, but there can be effective control for water quantity for small (2- to 5-years in particular) storm events.