Control concept and countermeasures for shallow lakes’ eutrophication in China

Research on lake eutrophication in China began in the early 1970s, and many lakes in China are now known to be in meso-eutrophic status. Lake eutrophication has been showing a rapidly increasing trend since 2000. Investigations show that the main reasons for lake eutrophication include a fragile lake background environment, excessive nutrient loading into lakes, excessive human activities, ecological degeneration, weak environmental protection awareness, and lax lake management. Major mechanisms resulting from lake eutrophication include nutrient recycling imbalance, major changes in water chemistry (pH, oxygen, and carbon), lake ecosystem imbalance, and algal prevalence in lakes. Some concepts for controlling eutrophication should be persistently proposed, including lake catchment control, combination of pollutant source control with ecological restoration, protection of three important aspects (terrestrial ecology, lake coast zone, and submerged plant), and combination of lake management with regulation. Measures to control lake eutrophication should include pollution source control (i.e., optimize industrial structural adjustments in the lake catchment, reduce nitrogen and phosphorus emission amounts, and control endogenous pollution) and lake ecological restoration (i.e. establish a zone-lake buffer region and lakeside zone, protect regional vegetation, utilize hydrophytes in renovation technology); countermeasures for lake management should include implementing water quality management, identifying environmental and lake water goals, legislating and formulating laws and regulations to protect lakes, strengthening publicity and the education of people, increasing public awareness through participation in systems and mechanic innovations, establishing lake region management institutions, and ensuring implementation of governance and management measures.     

超声波局部放电检测在GIS自由颗粒缺陷检测中的应用

气体绝缘金属封闭开关(gas insulated switchgear, GIS)设备内部自由颗粒缺陷对GIS设备安全稳定运行构成较大危害,通过对GIS自由颗粒特性进行分析,提出采用超声波局部放电检测技术检测GIS中自由颗粒缺陷的方法。应用结果表明:超声波局部放电检测能有效检测出GIS设备内部自由颗粒缺陷,提前发现潜伏性缺陷,保障设备安全运行。     

铁氮共掺杂生物炭对二级水溶解性有机物的吸附特性与长效性评价

为经济高效地去除污水厂二级水中溶解性有机物(DOM),采用铁氮共掺杂生物炭材料(Fe-N-C)作为新型吸附剂,系统分析了该新型碳材料对于二级水DOM的吸附性能、动力学过程、选择性和作用机制.此外,通过固定床吸附装置深入考察了该吸附材料的长效性和重复利用性.结果表明,Fe-N-C对于二级水DOM具有突出的吸附性能,投加量...     

Scenario-based assessment and multi-objective optimization of urban development plan with carrying capacity of water system

• Impact of urban development on water system is assessed with carrying capacity. • Impacts on both water resource quantity and environmental quality are involved. • Multi-objective optimization revealing system trade-off facilitate the regulation. • Efficiency, scale and structure of urban development are regulated in two stages. • A roadmap approaching more sustainable development is provided for the case city. Environmental impact assessments and subsequent regulation measures of urban development plans are critical to human progress toward sustainability, since these plans set the scale and structure targets of future socioeconomic development. A three-step methodology for assessing and optimizing an urban development plan focusing on its impacts on the water system was developed. The methodology first predicted the pressure on the water system caused by implementation of the plan under distinct scenarios, then compared the pressure with the carrying capacity threshold to verify the system status; finally, a multi-objective optimization method was used to propose regulation solutions. The methodology enabled evaluation of the water system carrying state, taking socioeconomic development uncertainties into account, and multiple sets of improvement measures under different decisionmaker preferences were generated. The methodology was applied in the case of Zhoushan city in South-east China. The assessment results showed that overloading problems occurred in 11 out of the 13 zones in Zhoushan, with the potential pressure varying from 1.1 to 18.3 times the carrying capacity. As a basic regulation measure, an environmental efficiency upgrade could relieve the overloading in 4 zones and reduce 9%‒63% of the pressure. The optimization of industrial development showed that the pressure could be controlled under the carrying capacity threshold if the planned scale was reduced by 24% and the industrial structure was transformed. Various regulation schemes including a more suitable scale and structure with necessary efficiency standards are provided for decisionmakers that can help the case city approach a more sustainable development pattern.     

UiO-66(Zr)@多孔陶瓷复合材料的制备及对络合态重金属EDTA-Cu(Ⅱ)的去除

本文采用多孔陶瓷作为基体制备了锆基金属有机骨架UiO-66@多孔陶瓷复合材料.通过扫描电子显微镜(SEM)、粉末X射线衍射(PXRD)、氮气吸附和傅里叶变换红外光谱(FTIR)等表征手段对比了氢氧化钠脱硅和乙二胺表面改性等基体活化方式对UiO-66(Zr)在多孔陶瓷表面负载情况的影响.结果表明,经过乙二胺表面改性的多孔陶瓷对UiO-66(Zr)的负载更均匀,负载效果更好.以EDTA-Cu(Ⅱ)为考察对象,研究了UiO-66(Zr)@乙二胺表面改性多孔陶瓷复合材料对络合态重金属的净化效能.结果表明,UiO-66(Zr)@多孔陶瓷复合材料在较宽的酸碱条件下(pH=3—9)对络合态重金属EDTA-Cu(Ⅱ)均表现出良好的吸附性能,饱和吸附量为1.17 mg·g~(-1),并可通过NaOH解吸再生,从而实现材料的重复利用.     

HCFCs和HFCs对流层寿命的预测

利用Ｃ－Ｈ键的Ｍｕｌｌｉｋｏｎ键重叠布局数，对甲烷的不完全氟氯取代物的对流层寿命用公式作了计算。对传统的人工神经网络法－反向传递算法作了改进。在电荷这一量化参数基础上，用ＡＮＮ法对一碳和二碳的ＨＣＦＣｓ和ＨＦＣｓ的对流层寿命作了预测。     

Occurrence and distribution of organochlorine pesticides - lindane, p,p'-DDT, and heptachlor epoxide - in surface water of China

Persistent organochlorine pesticides pollutants (OCPs) have been reported to occur at relatively high concentrations in some Chinese waters. In order to map the distribution of organochlorine pesticides in the surface water throughout China, samples were collected from over 600 sites in seven major river basins and three main internal rivers drainage areas during 2003 and 2004. The surface water samples were analyzed for the representative organochlorine pesticides contaminants including lindane (gamma-HCH), p,p'-DDT and heptachlor epoxide. In general, the most frequently detected compound was lindane, being detected in 83.9% of samples (mean=31.3 ng/l; range <0.17-860 ng/l), and the highest concentration was present in the Yellow River basin. p,p'-DDT was detected in 63.1% of the samples collected (mean=14.6 ng/l; range <0.14-368 ng/l) with the highest concentration present in the Huaihe River basin. Heptachlor epoxide was detected in only 9.3% of water samples (range <0.11-10 ng/l). Measured concentrations for the three compounds were low and rarely exceed the environment quality standard for surface water of China. Lindane was more frequently detected at much higher concentrations in the rivers of northern China compared with those of southern China. The sites with higher concentration of lindane and p,p'-DDT mainly occurred in the Yellow River and Huaihe River basins, so the results of this investigation indicate that the organochlorine pesticide contamination of Yellow River and Huaihe River basins should be of particular concern relative to the other basins. When compared with other regions of the world, it appears that the Chinese surface water is moderately polluted by lindane and p,p'-DDT.     

太湖沉积物中无机硫的化学特性

选取太湖富营养化相对较严重的梅梁湾北部(ML)与西五里湖(WL)为研究对象,对沉积物及其间隙水中的无机硫形态进行了分析.结果表明,WL 和ML 间隙水中Fe²⁺的平均含量分别为72.1~162.7µmol/L 和63.0~182.7µmol/L,是∑S^2-的18 倍和6 倍,分析认为,太湖沉积物中的还原环境是以Fe³⁺为主导而并非SO4^2-.沉积物中酸性可挥发性硫化物(AVS)的含量为1.0~11.7µmol/g,在未受污染湖泊范围之内.黄铁矿态硫(Pyrite-S)/AVS>3,表明AVS 能够高效地转化为黄铁矿,也说明黄铁矿是SO4^2-还原的主要产物.沉积物中黄铁矿化程度(DOP)<10%、硫化程度(DOS)<14%,说明黄铁矿的形成主要受SO4^2-的控制.     

上海北郊大气挥发性有机物(VOCs)变化特征及来源解析

2019年1月1日到10月31日期间在上海北部郊区,采用在线气相色谱仪对58种VOCs定量检测,分析了大气VOCs组成、季节变化特征和日变化规律,并利用最大增量反应活性(MIR)估算了VOCs的臭氧生成潜势(OFP),应用因子分析法对VOCs来源进行了解析。结果表明,上海大气总VOCs体积浓度为25.79×10-9,其中烷烃占比63.2%,烯烃占比11.6%,芳香烃占比19.8%,炔烃占比5.4%。总VOCs体积浓度呈现夏季高,秋季低的季节变化特征。大气臭氧生成潜势为76.99×10-9,烷烃贡献率为22.1%,烯烃为37.5%,芳香烃为38.7%,炔烃为1.7%。VOCs特征物比值(V(TVOC)/V(NO_x)和T/B比值)法表明观测点为VOCs控制区,受周边工业区源和交通源影响。大气VOCs主要来源为机动车排放、工厂生产、燃料燃烧、工业溶剂挥发及天然源。