复合生态滤床用于重金属污染地表水体修复

以蛭石为滤床基质,研究了复合生态滤床对受重金属污染地表水体的修复效能.结果表明,复合生态滤床对重金属污染水体有较好的处理效果,在水力负荷为2.0m.3m-.2d-1时,系统对Cu、Zn、Pb和Cd的平均去除率分别达到81.60%、80.55%、83.20%、62.21%;按照国家《地表水环境质量标准》(GB3838-2002),出水重金属浓度达到Ⅱ类水质标准;出水COD值为9.7～38.3mg·L-1,达到Ⅰ类水质标准;出水NH4+-N达到1mg·L-1以下,达到Ⅲ类水质标准.滤床基质中铜离子含量稳定在30mg·kg-1左右,表明植物根系可以有效地吸收蛭石吸附的重金属,从而有效提高蛭石的再吸附能力,延长滤床工作周期.     

山区小城镇生态化发展探析——以株洲市炎陵县下村乡为例

山区小城镇的生态化建设在中国山区的城镇建设中有着重要的指导性意义。株洲市炎陵县山区小城镇生态化建设是推进农村环境保护工作,长株潭城市群两型社会建设的重要举措。结合山区城镇特有的地形和生态特征,以株洲市炎陵县下村乡为例,尝试从生态城镇的三个结构构成部分：经济系统、社会系统和自然生态系统现状进行分析,明确山区城镇发展中存在的不足和有待进一步挖掘的发展优势,提出相应的山区城镇建设策略,来探讨山区小城镇生态化建设的途径。     

Measurements and predictions of harmful releases of the gathering station over the mountainous terrain

Having a risk analysis of harmful releases over mountainous terrains through wind tunnel experiment is a frontier problem in China. In this paper, a straight-flow wind tunnel is applied to simulate the atmospheric boundary layer and research the motion of high-sulfur gas released to atmosphere when accidental releases occur in a gathering station over the mountainous terrain. After an analysis of hourly concentration in the field accident for eight wind directions, experimental results reveal that nearby concentration fields are dominated by wind and far-field concentration distribution is dominated by topography, which leads to complete levels of consequence impact for the personnel risk inside and around the gathering station. Based on CFD techniques, a three-dimensional modelling was established in comparison with the wind tunnel experiment, which suggests that CFD prediction had underestimated the near-field gas concentration and the performance could not precisely match actual risks the gathering station causes to the mountainous terrain, which leads to a modified equation for numerical prediction. Instead of proposing a lower personnel risk evaluation obtained through the use of CFD techniques, the wind tunnel experiment offers a new choice for the consequence impact analysis for the petrochemical industry in China.     

重大危险源区域风险评价及监管对策

结合目前重大危险源事故频发的安全生产形势,分析了石油化学工业发展和城市化进程加快所带来的城市区域高风险,阐明了进行区域风险评价和重大危险源监管的必要性.现有区域风险定量评价方法主要有两个主流,分别为基于个人风险和社会风险的方法和基于风险补偿的方法.概要阐述了两种方法的基本原理、评价程序和最终得到的区域风险效果图,对比分析了两种区域风险定量评价方法的适用性.最后从区域规划阶段、运作阶段和应急阶段分别提出了强化重大危险源监管的对策,并阐述了重大危险源区域风险评价和监管的保障机制,以期能够对重大危险源集中区域的规划和监管提供相关的技术支持.     

一种修复Pb-Cd污染污泥的复合淋洗剂的研究

以某自来水厂污泥为背景泥样,人工添加重金属后泥样为研究对象,考察了葡萄糖酸、氯化钠、六偏磷酸钠复配溶液对污泥中重金属的洗脱效果.研究发现,复配淋洗剂对污泥中Pb和Cd有较好的萃取效果.形态分析表明,葡萄糖酸对污泥中的水溶态、离子交换态、碳酸盐结合态及部分弱有机结合态形式的重金属Pb、Cd有较好的萃取效果;六偏磷酸钠主要...     

复杂地形下的福建省龙眼冻害风险评估

为减小福建省龙眼冻害损失,提高在复杂地形下的防御冻害风险能力,利用福建省67个气象站1950/1951-2009/2010年60年的极端最低气温资料,融合经纬度、海拔高度、坡度和坡向等地理因子,构建复杂地形条件下的龙眼冻害分布模型,基于GIS技术分别得出龙眼冻害危险性、暴露性和防灾减灾能力等因子空间分布状态,进而确定龙眼冻害的风险区划并进行风险评估和分析。结果表明:龙眼冻害无(轻)风险区域主要分布在莆田及其以南的沿海县(市);低风险区域分布比较广泛且零散,总面积较小;中风险区域面积大、分布广,主要是分布在海拔较高的丘陵山地;高风险区域主要在南平北部的武夷山脉、宁德西北部的鹫峰山脉、龙岩的玳瑁山脉及其它高海拔地区和部分较高海拔的北坡区域。     

复杂电磁环境下机载电子设备的电磁兼容仿真研究

分析了机栽电子设备所处的复杂电磁环境,介绍了机载系统内部干扰和典型外界干扰,并据此建立了机载设备电磁兼容仿真模型;最后,给出了仿真算法并介绍了仿真软件。对复杂电磁环境下的航空电子装备的保障进行了有益的探索。     

流域水资源丰富度评价的MFP模型及应用

水资源系统与许多因素有关,如各种水资源量、人口、社会经济发展指标等,它们共同组成了一个典型的复杂非线性系统。以最大流原理为基础,导出了描述水资源系统的信息动力学演化方程,建立了水资源评价的信息动力学模型,运用信息动力学模型建立了评价标准。该模型无需人为给定参数,客观性强,操作简便。最后运用理论模型对辽西沿海诸河流域水资源丰富度进行评价分析,得到各流域的丰富度状况,并与其它模型评定结果做出了比较,结果表明该方法具有较好的合理性和可操作性。由于该模型从一定程度上体现了水资源丰富度系统的演化动力学机理和水资源系统时空演变特性。因此,不仅在评价上有较大的优越性,在水资源丰富度发展变化状态的预测上也具有潜力。     

Fate of microplastics in a coastal wastewater treatment plant: Microfibers could partially break through the integrated membrane system

• Fate of microplastics in integrated membrane system for water reuse was investigated. • Integrated membrane system has high removal efficiency (>98%) for microplastics. • Microplastics (>93%) were mainly removed through membrane bioreactor treatment. • Small scale fiber plastics (<200 μm) could break through reverse osmosis (RO) system. • The flux of microplastics maintained at 2.7 × 10¹¹ MPs/d after the RO treatment. Rare information on the fate of microplastics in the integrated membrane system (IMS) system in full-scale wastewater treatment plant was available. The fate of microplastics in IMS in a coastal reclaimed water plant was investigated. The removal rate of microplastics in the IMS system reached 93.2% after membrane bioreactor (MBR) treatment while that further increased to 98.0% after the reverse osmosis (RO) membrane process. The flux of microplastics in MBR effluent was reduced from 1.5 × 10¹³ MPs/d to 10.2 × 10¹¹ MPs/d while that of the RO treatment decreased to 2.7 × 10¹¹ MPs/d. Small scale fiber plastics (<200 μm) could break through RO system according to the size distribution analysis. The application of the IMS system in the reclaimed water plant could prevent most of the microplastics from being discharged in the coastal water. These findings suggested that the IMS system was more efficient than conventional activated sludge system (CAS) for the removal of microplastics, while the discharge of small scale fiber plastics through the IMS system should also not be neglected because small scale fiber plastics (<200 μm) could break through IMS system equipped with the RO system.     

Sulfur mediated heavy metal biogeochemical cycles in coastal wetlands: From sediments,rhizosphere to vegetation

• In sediments, the transformation of sulfides may lead to the release of heavy metals. • In the rhizosphere, sulfur regulates the uptake of heavy metals by plants. • In plants, sulfur mediates a series of heavy metal tolerance mechanisms. • Explore interactions between sulfur and heavy metals on different scales is needed. The interactions and mechanisms between sulfur and heavy metals are a growing focus of biogeochemical studies in coastal wetlands. These issues underline the fate of heavy metals bound in sediments or released into the system through sediments. Despite the fact that numerous published studies have suggested sulfur has a significant impact on the bioavailability of heavy metals accumulated in coastal wetlands, to date, no review article has systematically summarized those studies, particularly from the perspective of the three major components of wetland ecosystems (sediments, rhizosphere, and vegetation). The present review summarizes the studies published in the past four decades and highlights the major achievements in this field. Research and studies available thus far indicate that under anaerobic conditions, most of the potentially bioavailable heavy metals in coastal wetland sediments are fixed as precipitates, such as metal sulfides. However, fluctuations in physicochemical conditions may affect sulfur cycling, and hence, directly or indirectly lead to the conversion and migration of heavy metals. In the rhizosphere, root activities and microbes together affect the speciation and transformation of sulfur which in turn mediate the migration of heavy metals. As for plant tissues, tolerance to heavy metals is enhanced by sulfur-containing compounds via promoting a series of chelation and detoxification processes. Finally, to further understand the interactions between sulfur and heavy metals in coastal wetlands, some major future research directions are proposed.