基于入渗产流分析的透水砖地面铺装结构试验

为了找出有利于降雨入渗、削减径流的透水地面铺装结构,通过人工降雨试验,研究不同铺装垫层结构透水地面的降雨入渗与产流特性。根据8种铺装结构在径流削减、入渗量增加、开始产流时间滞后等方面的效果比较,推荐透水砖地面自上而下的铺装结构为"透水砖面层+无砂混凝土+单级配碎石"形式。     

透水性铺装在城市雨水下渗收集中的应用

针对城市透水性铺装在推广方面所面临的问题,对透水性铺装地面下渗雨水收集、雨水径流污染物去除等情况进行试验研究。结果表明:实施透水性铺装既可有效增加下渗雨水量,下渗雨水的入渗率与降雨量基本呈线性关系;还可降低天然降雨中的污染物浓度,下渗雨水中NH3-N、BOD5、CODMn等水质指标浓度明显降低,下渗雨水水质可满足景观环境补水的水质要求。试验研究为地面透水性铺装技术的推广提供参考。     

深圳光明新区透水沥青道路与滞留带对径流水质水量控制效果研究

通过现场监测分析,研究了深圳光明新区国家低影响开发雨水综合利用示范区内透水沥青道路与滞留带对路面径流水质和水量的控制效果。研究结果表明:与传统沥青道路相比,透水沥青道路径流中的SS、COD、NH3-N、NO-3-N、TN和TP等污染物浓度分别降低了94.76%、83.84%、70.59%、33.33%、50.00%和65.96%,对径流总量和峰值流量的平均削减率分别达76.70%和74.92%。道路滞留带对COD、NH3-N、NO-3-N、TN和TP也具有一定的去除效果;在小雨事件下不外排雨水,在中雨、大雨和暴雨事件下,对径流总量和峰值流量平均削减率分别达65.71%和57.69%,同时具有明显的延迟峰值作用。     

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。     

基于多目标评价的市政道路径流污染控制生物滞留设施填料优化

为优化面向市政道路径流污染控制的生物滞留设施填料,运用多目标评价方法对填料的渗透性能、污染物去除效果和经济成本进行综合评估.以我国华北地区的地理特征和市政道路径流污染特征为依据,开展生物滞留柱试验研究,得到填料优化配比为土壤、河沙、草炭土、给水厂污泥(含铝盐)、蛭石、沸石的质量比为30:24:6:20:10:10,该填...     

汶川震区滑坡堆积体降雨入渗产流特征人工模拟实验研究

5.12汶川地震引发了大量的滑坡堆积体,在雨水的冲刷下,不仅会造成山体崩塌,还会发生次生灾害。本文以汶川震区滑坡堆积体为研究对象,采用室内人工模拟降雨方法,探讨了不同降雨强度和土石比条件下滑坡堆积体坡面产流与入渗规律。结果表明:(1)除土石比1∶4的滑坡堆积体在所设计的降雨强度(1.0,1.5和2.0 mm/min)和土石比为1∶2滑坡堆积体在降雨强度为1.0 mm/min时没有出现产流,其他条件下的滑坡堆积体的产流时间随着降雨强度的增大而减小,而产流率随着降雨强度的增大而增大,且土石比为1∶1的平均产流率比土石比为1∶2的滑坡堆积体大。(2)根据3种入渗模型的对比分析,可知Horton模型为最适合震区堆积体的入渗模型。(3)在降雨强度为1.5 mm/min时,土石比1∶1的滑坡堆积体累积产流量比土石比为1∶2的堆积体大;在降雨强度为2.0 mm/min时,土石比1∶1和1∶2滑坡堆积体累积产流量的变化规律几乎相同。本研究可为汶川震区滑坡堆积体的灾后修复提供实验依据。     

填充沟对轨道交通荷载被动隔振效果的BEM-FEM耦合法分析

采用时间域边界元数值方法,分析了隔振沟对列车交通荷载引起建筑物振动的减振效果.2D计算模型中土—结构体系包含铁路路基、地基土体、隔振沟及六层框架建筑物.考虑了土—结构相互作用对填充沟隔振效果的影响及填充沟的几何形状、填充材料特性对结构振动的影响也做了数值分析,计算结果表明:采用隔振沟,可使建筑物框架结构的杆内力减小80%;随填充沟深度、宽度的增加,填充材料相对于周边的土体越软,隔振效果越好.     

无限深透水地基上土石坝坝基垂直防渗的保角变换渗流计算

近年来,在无限深透水地基或深厚覆盖层地基上修建土石坝的水利工程日趋增多,且有很多采用倒悬挂式防渗墙进行渗流控制.对于这种坝型的渗流计算,尚缺乏精确而简捷的理论公式,常采用近似的估算或经验公式.本文采用保角变换的方法,通过建立数学模型推导出在均质且理想边界条件下,土石坝基垂直防渗的渗透压力、渗流量和出逸坡降计算公式.公式简单,不仅可以计算渗透坡降和坝基渗流量,还可以计算渗透压力的分布,且相对于有限元和边界元计算模型,其计算量要小的多,计算结果的精度也能满足要求.     

Full-cyclic control strategy of SBR for nitrogen removal in strong wastewater using common sensors.

A full-cyclic automatic control strategy for sequencing batch reactors (SBR) was proposed using only common sensors such as ORP, DO and pH. The main objective was to develop a generally applicable and robust control strategy. To accomplish this, various control schemes found in the literature or suggested by authors were examined at diverse ammonia loads and SCOD/NH4(+)-N ratios. Advantages and constraints of each scheme were discussed and compared. Ammonia load was estimated with DO lag time during the aerobic stage, and then the influent pump was manipulated to meet the desired load at the next anoxic stage. A partial denitrification scheme was chosen for the anoxic stage period control, to save anoxic time and external carbon. For external carbon dosage control, intermittent feeding at each anoxic stage was concluded to be a suitable scheme. The anoxic stage period could be successfully controlled by the combination of pH increase and DO increase. Every suggested control scheme was incorporated into a full-cyclic control strategy and tested at 0.02, 0.035, 0.08 kg NH4(+)-N/m3/sub-cycle. From the results, it is expected to perform unmanned automatic SBR operation with this strategy.     

Groundwater as a source and pathway for road salt contamination of surface water in the Lake Ontario Basin: A review

In Ontario, there is limited comprehensive research regarding the contribution of chloride in groundwater to surface water systems. The delivery of chloride via groundwater can contribute to the degradation of the Great Lakes and their tributaries. Thus, this review intends to fill or identify knowledge gaps regarding assessing groundwater as a potential source of road salt, the single largest use of salt in urban cold region environments, contamination to surface water by synthesizing existing groundwater chloride research in the Lake Ontario Basin. Knowledge regarding source characterization, properties, pathways, and impacts of chloride in the environment is essential to evaluate the contribution of chloride via groundwater. Past groundwater chloride research in the basin is primarily concentrated in highly urbanized areas and has identified localized trends of increasing groundwater chloride concentrations in these regions; however, few investigations have been conducted in varying land uses (e.g., rural or less urbanized watersheds) or at sufficient temporal and/or spatial scales. Significant chloride accumulation is occurring in watersheds and aquifers within the basin. Concentrations are expected to increase until equilibrium is obtained, thus resulting in sustained yearlong elevated concentrations in tributaries. Recently, chloride loading to Lake Ontario has increased significantly, with groundwater inputs having the potential to support long-term increases in chloride concentrations in the lake. However, few studies have evaluated the explicit contribution via groundwater to Lake Ontario, and therefore a knowledge gap continues to exist. We provide a synthesis of additional research priorities to better understand the magnitude of groundwater chloride issues in the basin.     

人类活动对黄河河源区水沙变化影响评价

河流水沙变化同时受到气候变化和人类活动的影响,在相同的气候条件下,水沙变化的影响主要是人类活动引起的。采用1961-2010年唐乃亥水文站以上河源区的气象数据,通过反距离加权平均法对潜在蒸发量和降雨量进行空间插值,选择气候相似年组,计算了组内唐乃亥站的年径流量和年输沙量的变化,并结合土地利用和NDVI变化分析了原因。结果表明:研究区共有12个相似年组,在时间上涉及到研究时段的所有年代和降雨量特征;分别有11组和9组的年径流量和年输沙量减小,反映出河流水沙整体减少的整体特征;不同相似年组人类活动对河流水沙的影响幅度差异较大。该方法可以明确判定人类活动的影响程度,并显示出人类活动对水沙影响的复杂性,可以帮助我们区分气候变化和人类活动的不同影响。     

基于改进 abcd 模型的黄河源区径流变化与归因

为改进模型对高寒地区融雪径流模拟不足的缺陷，将融雪模块耦合到传统 abcd 模型。利用 1980—2018 年 逐月实测的径流数据和通过 AnuSpline 方法插值的格网气象要素，驱动改进后的abcd 模型，分析三江源生态保护 措施实施前后（1980—1999 年和 2000—2018 年）黄河源区径流的动态变化，并量化关键气象因素与人类活动对 径流变化的影响程度，即相对贡献。结果表明：耦合融雪模块的 abcd-snow 模型完善了高寒地区水文过程的模拟， 提高对径流的模拟性能，在黄河源区表现出较好的适用性；整个研究时段黄河源区的实测径流呈不显著减少趋势 （?0.80?mm/a，p>0.05），但 2000 年前径流则呈现显著下降趋势（?4.12?mm/a，p<0.05），2000 年后径流则呈显著增加 趋势（3.16?mm/a，p<0.05）；?归因分析表明气候变化是源区径流变化的主导因素。2000 年前，气候变化对径流减少 的相对贡献率为 62.8%，人类活动对径流的贡献为 37.2%；2000 年后，气候变化对径流增加的贡献率达到 120.0?%， 人类活动对径流的贡献为?20.0%。其中：降水的变化是决定径流变化主导因素；其他气候因素的相对贡献较小； 以人类活动为主的生态恢复可显著降低河川径流。本研究有助于理解气候变化和下垫面变化对黄河源区水资源 变化的系统驱动机理，并为流域水资源合理配置提供科学参考依据。     

发电机采用外接直流电源起励升压的技术改造

姚庄水电厂是一座渠道引水式电厂,装机容量2×1 250 kW,发电机出口电压6.3 kV,通过1台主变压器升压至10 kV并入电网.电厂直流系统采用镉镍蓄电池组;发电机励磁装置的型号为BZL-2A.姚庄电厂自投产以来,发电机一直采用的是外接交流起励方式,在厂用交流电源有保证的情况下,采用这种起励方式是没有问题的.但由于并网线路的电压比较低,电网运行的可靠性不高,在两年多的运行实践中,因雷击等引起的电网事故而造成全厂停电已有5次之多.此时,由于电网停电、机组停机,没有交流电源发电机不能起励升压和并网发电,也不能迅速开启泄水闸门放水,如不及时采取措施,就有水淹厂房的危险(因为是渠道式水电站).为此,我们进行了直流起励升压的技术改造.经过研究试验,该方案获得了成功,解决了长期以来一直威胁电站安全的一大隐患,保证了电厂的安全运行.     

城镇径流污染控制技术路线构建与应用效果分析——以太湖流域城镇为例

近年来,由于我国城镇化加快带来的城市不透水下垫面比例逐年升高,降雨径流污染愈发严重.为了有效削减城市径流污染负荷,亟需建立适用于我国不同城区特点的降雨径流污染控制技术路线.通过分析太湖流域典型城区降雨径流污染特征,发现老城区的污染物负荷大于新城区与规划区和工业区,是径流污染控制重点区域.以太湖流域城市径流污染需求和难点...     

Reducing micropollutants with source control: substance flow analysis of 212 pharmaceuticals in faeces and urine.

Pharmaceuticals in the aquatic environment are raising concern. It is expected that many anthropogenic pharmaceuticals are largely excreted via urine; a popular argument for introducing urine source separation. However, to date, this assumption lacks verification. We close this gap with quantitative screening of official pharmaceutical data. We analysed the excretion pathways of 212 pharmaceuticals' active ingredients (AI), equalling 1,409 products. On average, 64% (+/-27%) of each AI was excreted via urine, and 35% (+/-26%) via faeces. In urine, 42% (+/-28%) of each AI was excreted as metabolites. However, these numbers need cautious interpretation. We found an extreme variability (1) between different therapeutic groups, (2) within some groups and (3) sometimes even between products of the same AI. We discuss various therapeutic groups and include Swiss sales' quantities. For instance, urine source separation could very effectively remove the highly sold and non-degradable x-ray contrast media: 94% (+/-4%) are excreted via urine. However, for different pharmaceuticals belonging to cytostatics, excretion via urine was 6-98%. Because of such large variability we advise caution to introduce the still imperfect urine separation technology solely because of pharmaceuticals. Nonetheless, together with other good arguments for this innovation, removal of pharmaceuticals is a welcome side effect.     

中储式钢球磨制粉系统的建模与控制策略

火电厂中间储仓式钢球磨煤机制粉系统具有多变量强耦合、大惯性、大迟延以及时变性等特性，长期以来难以投入自动控制，已成为电力行业自动控制研究的热点。分析了球磨机制粉控制系统的工作原理和任务、控制要求和控制难度，总结了近年来模糊控制、解耦控制、神经网络、自寻优控制、预测控制以及自抗扰控制等各种高级控制方法在球磨机制粉系统中的主要研究成果和应用情况，对各控制方法的优缺点、适用性、控制效果等进行了分析和评述，指出了制粉系统中控制策略和数学模型的发展趋势和研究热点内容，对进一步开展相关研究有一定的指导意义。     

Automatic control of external carbon source addition for nitrogen removal in sewage with low C/N ratios.

For cost-effective nitrogen removal from sewage with low C/N ratios, an automatic control system for the addition of external carbon based on oxidation-reduction potential (ORP) data in an anoxic reactor has been developed. In this study, it was carried out with a pilot-scale modified Bardenpho process. This consisted of anoxic1, aerobic1, anoxic2 and aerobic2 stages with an external recycle ratio of 150% (Q/Qinf), and a media packing ratio of 2.4%-2.9% (v/v) in the aerobic reactor. As a result of applying the automatic control system for the minimization of the external carbon source dosage, the dosage was decreased by about 20%. This estimate was based on ORP compared with a stable dosage of 75 mg/L based on the C/NOx-N ratio of the anoxic influent. It was necessary that the ORP set-value be regulated from -120 mV to -80 mV because influent NH4+-N concentration varied from 12 to 15 mg/L due to rainfall. Correspondingly, the demanded dosages were decreased. Drift of the the real-time value in control system was more stable after changing the ORP set-value from -120 mV to -80 mV.     

Identification of critical control points using water quality as an indicator of hygiene for artisanal fisheries on Lake Malawi

Fish are a highly perishable commodity, and unhygienic fresh fish supply chains have been documented over the past two decades in sub‐Saharan Africa. Fishers spend long hours on boats with no provision of sanitary facilities, and even after landing, they are often in environments without sanitary facilities. The purpose of the present study was to explore the impacts of water, sanitation and hygiene practices in an artisanal fishery on food safety by analysing water samples in close contact with fresh fish at various checkpoints from capture to sale at the local market along the shores of Lake Malawi (Malawi). The four checkpoints included (a) fishing boats at the fishing ground before fishing commenced (n = 85); (b) in the same boats at the landing site before offloading fresh fish (n = 85); (c) with fresh fish transporters at the landing site (n = 71); and (d) among vendors at the market (n = 63). Escherichia coli was found in a high percentage of samples at each of the four checkpoints during the dry, wet and cold seasons. The highest risk for contamination (represented by E. coli concentrations) was the transition from transport to vendor, regardless of the season during which the samples were taken. The product value chain demands food safety. The results of the present study have potential applications in informing future interventions to develop behavioural change strategies regarding handwashing and toileting practices, norms unique for highly mobile fishing communities through the integration of hardware and software solutions and using better‐quality water to store fish on the boat, in transport and at the market.     

Water level change of Lake Tana,source of the Blue Nile: Prediction using teleconnections with sea surface temperatures

Water level change of Lake Tana, the source of the Blue Nile was analyzed. Correlations between the water level change and global sea surface temperature (GSST) were calculated and teleconnections were found. Prediction of water level was performed using a recurrent artificial neural network model. First, the seasonal change of water level was divided into three phases, the rising, recession 1, and recession 2 phases. The water level increased during the rising phase, decreased rapidly during the recession 1 phase, and decreased at a uniform rate during the recession 2 phase. To find teleconnections of the water level change in the rising phase with GSST, correlations between the level change and GSST were calculated. Sea regions on the Pacific Ocean indicated significant correlations with the level change at lag 0–1 month and lag 6–7 months. There was a strongly correlated sea zone over the western Pacific Ocean at time lags of 6–7 months. To predict water level change, SST time series of the correlated zone was applied to a recurrent neural network model. Predictions of changes of the rise of the water level of Lake Tana during the rainy season from teleconnections with SSTs via the neural network model simulated the observed changes well (r = 0.795). Prediction of the changes of Lake Tana’s water level with a lead time of 6–7 months can greatly facilitate management of the lake’s water resources.     

Quality assessment of an aquifer recharged with wastewater for its potential use as drinking source: "El Mezquital Valley" case.

Mexico City, with a population of 18 million, has been sending its wastewater for more than 100 years to the Tula Valley where it is used to irrigate 90,000 ha. Due to the large wastewater volume (60 m3/s) sent through unlined channels, combined with the use of very high irrigation rates, artificial recharge of the local aquifer has been occurring. This recharge is estimated in more than 25 m3/s. As a consequence, the water table has raised and several springs have appeared in the last decades with flows between 100 to 600 L/s. These springs and several wells are the water sources in the region. An evaluation of the Tula Valley aquifer quality was performed to analyze the use of such water as source of drinking water for Mexico City. The work is divided into 5 individual projects: (a) drinking water quality in the Tula Valley; (b) water availability in the Tula Valley; (c) wastewater treatment due to its use for irrigation, (d) use of membrane processes to treat groundwater; and (d) biota developed in the new surface water reservoirs. Results show that it is feasible to use this reclaimed water as drinking source.