岛屿硬化集水面雨水弃流方案与分质收集策略研究

通过研究海南岛文昌市水泥屋顶和水泥路面上的雨水径流特征,建立了岛屿地区不同硬化集水面的雨水弃流方案和分质收集策略.在降雨初期,水泥路面和水泥屋顶均发生明显的冲刷效应,水泥路面雨水径流污染物浓度远高于水泥屋顶,且不同硬化集水面上前30%雨水中的污染物浓度均高于后70%的雨水.通过与相关水质指标对比得出,水泥屋顶雨水径流可作为饮用水水源,水泥路面雨水径流经处理可作为城市杂用水使用.通过建立雨水径流污染物累积-冲刷经验模型,可计算不同硬化集水面的弃流雨量,并以此为依据制定了弃流方案.以两种典型硬质化集水面径流污染物传输特征、水质特征和弃流方案为基础,分别提出了屋顶雨水收集方案和多种生态方法协同作用的路面雨水收集方案,可为岛屿地区的雨水收集利用方案提供参考依据.     

Rehabilitating China's Largest Inland River

Abstract:  Wetlands are particularly important for conserving China's biodiversity but riparian wetlands in the Tarim River basin in western China have been reduced by 46% during the last 3 decades. The world's largest habitat for Populus euphratica , which is in the Tarim River basin, significantly shrank. To protect and restore the deteriorated ecosystems along the Tarim River and its associated wetlands, China's government initiated a multimillion dollar river restoration project to release water from upper dams to the dried-up lower reaches of the Tarim River starting in 2000. We monitored the responses of groundwater and vegetation to water recharge in the lower reaches of the river from 2000 to 2006 by establishing nine 1000-m-long transects perpendicular to the river at intervals of 20–45 km along the 320-km river course below the Daxihaizi Reservoir, the source of water conveyance, to Lake Taitema, the terminus of the Tarim River. Water recharges from the Daxihaizi Reservoir to the lower reaches of the Tarim River significantly increased groundwater levels and vegetation coverage at all monitoring sites along the river. The mean canopy size of the endangered plant species P. euphratica doubled after 6 years of water recharge. Some rare migrating birds returned to rest on the restored wetlands in summer along the lower reaches of the Tarim River. The biggest challenge facing decision makers, however, is to balance water allocation and water rights between agricultural and natural ecosystems in a sustainable way. A large number of inhabitants in the Tarim Basin depend on these limited water resources for a living. At the same time, the endangered ecosystems need to be protected. Given the ecological, socioeconomic, and sociopolitical realities in the Tarim Basin, adaptive water policies and strategies are needed for water allocation in these areas of limited water resources.     

基于Fluent的闭合环型缺氧反应器构造优化

为提高闭合环型缺氧反应器混合效果,选用基于Fluent软件的三维RNG k-ε紊流数学模型对闭合环型缺氧反应器进行流场模拟,以池底可能淤积面积比例作为混合效果的评价标准,分别从导流直墙长度、导流墙偏心距离及水下推进器偏置等3个方面对缺氧池的系统构造的最优设置进行研究。结果显示,在相同推进器功率下,导流直墙长度2.0 m为佳,导流墙偏心距离0.5 m为佳,推进器向内偏置0.5 m为佳。该研究方法及其结果可以作为闭合环型缺氧反应器的设计依据,具有较佳的技术参考价值。     

生态—水力学法在山区小型引水电站最小下泄流量计算中的应用

以川西某山区小型引水式电站为例,选择水深和流速为生境参数,以华鲮为生态保护目标,计算河道的最小生态需水量和对应的电站最小下泄流量,并与Tennant法、代表年法的计算结果对比。结果表明,生态水深0.12m对应的最小生态流量和Ten nant法的结果差异度为8.63%,较合理;生境参数标准值对计算结果影响显著;在选择合适的参数和参数标准值的前提下,生态—水力学法适用于山区小型河流。     

Recycling behaviour and attitude: the case of the Hong Kong people and commercial and household wastes

The increasing environmental awareness caused by the green movement has led to changes in attitude towards our traditionally wasteful society. Recent surveys in Hong Kong have shown that waste recycling has gained increasing verbal support among its citizens. This paper reports on recent findings which reveals that some discrepancies exist between people's attitude and behaviour towards waste recycling. The implication of this phenomenon on how and when a waste recycling policy should be carried out is considerable. Two major types of barriers to waste recycling and reduction were evident. Technical barriers to recycling included lack of appropriate information, lack of conveniently located bins and of temporary storage space, whilst the most critical barrier to paper waste recycling was the presence of non-recyclable materials in some paper items. Psychological barriers included the attitude of being troubled, and that too little waste was involved to be worth the effort. Technical barriers were found to dominate in commercial paper waste recycling, and can usually be overcome while psychological barriers were more significant in household waste recycling and are more difficult to solve. Thus, it might be concluded that, if a large scale household waste recycling programme were in place in Hong Kong, more effort should be devoted towards educating the public, to eliminate as many psychological barriers as possible. Findings from attitude surveys on recycling can provide valuable information for policy makers. However, a review of the literature indicates that findings from attitudinal and self-reported behavioural surveys may exaggerate the proportion of those who have a favourable attitude towards the surveyed subject matter. Thus, it is prudent for policy makers to consider the response rate of the surveys also.     

Assessing the impact on groundwater safety of inter-basin water transfer using a coupled modeling approach

Surface water and groundwater always behave in a coupled manner and are major components of hydrologic cycle. However, surface water simulation models and groundwater simulation models are run separately most of the time. Few models focus on the impact of hydraulic changes in the surface water flows on the groundwater, or specifically, the impact of a water transfer project to fill a seasonally dry channel. In this study, a linked surface water and groundwater simulation model was developed to assess the impact of a trans-basin water diversion project on the groundwater. A typical plain area east of Beijing was selected as a case study, representing Beijing’s main source of groundwater used for drinking water. A surface water quality model of the Chaobai River was developed based on the Water Quality Analysis Simulation Program (WASP), and a groundwater model was developed based on the Modular Finite-Difference Groundwater Flow Model (MODFLOW) and the Modular 3-D transport model (MT3D). The results of the surface water simulation were used as input for the groundwater simulation. Water levels and four contaminants (NH₃-N, COD_Mn, F, As) were simulated. With the same initial and boundary conditions, scenario analyses were performed to quantify the impact of different quantities of diversion water on the groundwater environment. The results showed the water quality of the groundwater sources was not significantly affected.     

地铁站台导流栏杆对人员疏散的影响研究

为研究地铁站台导流栏杆对人员疏散的影响,以某地铁车站为研究对象,采用数值模拟方法研究地铁站台导流栏杆的设置方式及长度对人员疏散的影响,为地铁车站导流栏杆的设置及优化提供参考。研究结果表明:随着固定导流栏杆长度的增加,人员疏散时间呈现增加趋势,固定导流栏杆长度为14 m时比不设导流栏杆时疏散效率降低了20.8%,人员在长度为14 m的固定导流栏杆内呈现通道型排队现象;随着可推拉导流栏杆长度的增加,人员疏散时间呈现减小趋势,可推拉导流栏杆长度为6 m时比固定导流栏杆长度为14 m时的疏散效率提高了9.7%。     

引汉济渭调水工程水资源配置研究

为解决关中地区水资源短缺问题,陕西省规划实施南水北调引汉济渭调水工程。在分析调水工程受水区用户、供水系统的基础上,构建了水资源配置网络图,并建立了该系统的水资源配置仿真模型,确定了配置原则。结合调水工程,设定了7种方案,通过长系列计算,得出了各方案的水资源利用情况。2020水平年,调水15.5×10⁸ m³后可增加供水10.69×10⁸ m³,占需水量的38.76%;调水15.5×10⁸ m³与调水10.0×10⁸ m³相比,工业供水保证率提高32.75%。计算结果表明,实施调水工程后可有效缓解受水区水资源短缺,调水量在保证城市用水、改善渭河河道生态环境方面发挥着主要作用。     

HSY算法在水质模型参数识别中的应用探讨

参数识别是水质模拟中的技术核心，数据稀缺是水质模型经常面临的问题。采用HSY算法可求得模型参数的分布，而不再是一个单一的最优参数，从而在一定程度上避免了由于“最优”参数失真带来的决策风险，本文以南水北调一期工为例，讨论了在稀疏数据条件下如何应用HSY算法识别CSTR水质模型的参数，并对识别的模型参数进行了检验。模型检验采取了2种方法：分别用动态和稳态计算方法得出的参数进行比较；用模拟结果分布于实测值进行比较。结果表明，HSY算法为稀疏数据条件下进行识别、建立数学模型提供了一条有效的途径。     

组合生物滤池对养殖废水的净化效率及影响因素分析

生物滤池作为一种有效的污水处理技术,已有广泛应用.但是关于组合生物滤池净化效能与影响因素系统分析仍然缺乏报道.为此,设计构建了曝气垂直流滤池+折流式水平流滤池的组合系统,通过设定不同的水力负荷(131、94、60mm·d-1)及分流比(8∶2、6∶4、4∶6)来探究运行工况的调整对组合系统净化效能的影响.结果表明,曝气垂直流滤池对有机物、氨氮及溶解性氮的平均去除率在80%以上,而折流式水平流滤池对氨氮、总氮及溶解性氮的平均去除率在40%以下.不同运行工况对生物滤池的净化效能存在显著影响,且两种不同类型滤池的净化效能也存在显著差异(P0.05).氧化分解是两种滤池中有机物去除的主要途径之一.两种滤池内都存在明显的硝化-反硝化,它们是滤池去除总氮的主要途径.垂直流滤池内的硝化-反硝化强度都高于水平流滤池.磷的去除主要受控于水力负荷、温度、溶解氧、有机物等,表明微生物吸收是滤池除磷的主要方式之一.相比于单一垂直流滤池,组合系统对总有机物和总磷的去除分别提高了4.4%和23.2%,对总氮的去除却降低了12.1%.降低分流比有助于提升水平流滤池反硝化强度,但是由于从原水中引入过多的氨氮,又水平流滤池的硝化能力有限,进而导致组合系统总氮去除率下降.因此,根据处理原水组成,控制适宜的分流比、停留时间及滤池内的氧化还原条件是提升该组合系统整体净化效果的关键.