煤炭产业的环境保护问题及建议

从煤炭产业所面临的产能过剩、环境污染和开发布局不合理的困境出发,说明了煤炭行业环境污染产生的途径和污染源,从经济成本、健康损失和国际影响力、竞争力方面阐释了煤炭产业绿色发展的重要性和必要性。在此基础上,进一步提出并讨论了煤炭产业绿色发展转型的三点政策建议:研发绿色开采技术、推广煤炭清洁利用技术、优化煤炭产业结构。     

电动修复法对土壤中镉的去除及形态转化研究

面对镉污染土壤日益严峻的现象以及各种土壤修复技术存在的不足,采用快速、高效、对环境干扰较小的电动修复法对自制镉含量为200 mg/kg的污染土壤进行修复,在不同电压梯度下对土壤p H值、Cd去除效果进行研究,同时采用BCR法分步提取不同形态的镉,对不同形态镉的迁移转化情况进行分析。实验结果表明,随着电压的增加,土壤中不同形态的镉去除效果明显,在靠近阳极区域去除率达到90%以上,在阴极区域以弱酸提取态为主的镉出现了富集现象。另外,酸性条件有利于不同形态的镉向弱酸提取态转化,有利于提高镉的去除率。     

内源性稀土元素对土壤中氮素分布特征的影响

在离子型稀土开采过程中,由于部分防渗层渗漏、收集系统不完善等原因,有大量的氮化合物进入矿区周边土壤及地下水中,给当地居民生活环境带来了严重威胁。应用土柱实验,研究内源性稀土元素对矿区土壤氮化物吸附与解吸作用的影响。     

戴腰山铜矿采矿技改工程安全评价研究

为了提高戴腰山铜矿采矿技改工程本质安全程度,辨识技改工程中存在的主要危险、有害因素;结合技改项目资料和现场调查,将该项目划分为10个评价单元;针对不同评价单元特点,分别采用安全检查表(SCL)、预先危险性分析(PHA)、事故树分析(FTA)和作业条件危险性评价法(LEC)等对该技改工程中的危险、有害因素进行了定性、定量评价;针对安全评价中出现的问题提出了切实可行的安全措施建议。     

Analyzing the relationships between travel mode indicators and the number of passenger transport fatalities at the city level

Objective: A number of efforts have been conducted on travel behavior and transport fatalities at the neighborhood or street level, and they have identified different factors such as roadway characteristics, personal indicators, and design indicators related to transport safety. However, only a limited number of studies have considered the relationship between travel behavior indicators and the number of transport fatalities at the city level. Therefore, this study explores this relationship and how to fill the mentioned gap in current knowledge.

Method: A generalized linear model (GLM) estimates the relationships between different travel mode indicators (e.g., length of motorway per inhabitants, number of motorcycles per inhabitant, percentage of daily trips on foot and by bicycle, percentage of daily trips by public transport) and the number of passenger transport fatalities. Because this city-level model is developed using data sets from different cities all over the world, the impacts of gross domestic product (GDP) are also included in the model.

Conclusions: Overall, the results imply that the percentage of daily trips by public transport, the percentage of daily trips on foot and by bicycle, and the GDP per inhabitant have negative relationships with the number of passenger transport fatalities, whereas motorway length and the number of motorcycles have positive relationships with the number of passenger transport fatalities.     

纳米二氧化钛光催化转化甲基砷的研究

二甲基胂酸(DMA)和一甲基胂酸(MMA)是环境中甲基砷的主要种类.由于农药滥用及含砷废水的释放等,严重危害人类健康.本文应用实验室人工合成纳米TiO2研究了甲基砷(DMA和MMA)光催化转化过程,考察了光照和pH对光催化转化过程的影响,通过测定液相及固相中的不同化学形态,解析光催化转化产物.结果表明:UV光照下,相比自然光时,纳米TiO2对DMA和MMA的去除率在不同pH条件下均有提高.pH值的影响为:在低pH条件(pH为3、5)下去除率高,而在高pH条件(pH为7、9)下去除率低,这主要是取决于纳米TiO2的等电点(pHpzc=5.8).转化产物解析结果表明:无光条件下,DMA和MMA均不发生转化;在自然光条件下,纳米TiO2催化少量DMA和MMA发生一步转化,分别形成MMA和As(V);在紫外光条件下,纳米TiO2能够催化几乎全部的DMA和MMA彻底转化,形成As(V).因此,在UV光下,纳米TiO2能够催化DMA和MMA转化为As(V),同时此纳米TiO2对As(V)有较强的吸附能力,所以,UV光照能够显著提高纳米TiO2对DMA和MMA的去除率.     

煤中汞在燃煤电站中的形态转化

论述了汞在煤中的存在形态以及在电站燃煤过程中汞的形态转化过程和汞在大气中的传播。     

OPTIMIZATION IN MUNICIPAL WATER SUPPLY SYSTEM DESIGN1

ABSTRACT. The design of a municipal water supply system may involve utilizing singly or in combination a conventional water supply, a desalted water supply, and a supply from a recharged aquifer reservoir. Optimization of the design requires a model formulated in a way that modern methods of systems analysis can be used. This study concerns the formulation, solution, and evaluation of a mathematical model of a municipal water supply system that includes a supply from a variable quality output desalting plant. The combined system is operated in conjunction with an artificially recharged aquifer reservoir. Also considered are short periods of water shortages. The model is set up in an approximate linear programming format, and the optimum solution (minimum cost) is found. The model is tested by applying it to the design of a supply system to meet the 1985 estimated water demand of the city of Lincoln, Nebraska. Results of this test indicate that the artificial reservoir and the existing conventional supply system are capable of supplying that demand during all but the peak period. An electrodialysis desalting system is used in this analysis. It is competitive only when the length of transmission pipeline for a conventional supply system approaches 90 miles. The model is formulated in a general way so that it can be applied to almost all situations encountered in municipal water supply design, as well as to the specific system designated for this study.     

GENERATED MONTHLY STREAMFLOWS FOR THE MIDWESTERN AND SOUTHWESTERN UNITED STATES1

ABSTRACT A critical examination of single gage site, monthly streamflow statistical characteristics for two southern Illinois rivers, an Oklahoma river and a Texas river was made using a digital computer at Northwestern University. High flow variability for the rivers was evident in that, for the rivers tested, 8 to 11 months had coefficients of variation in excess of unity. The gamma distribution was not as efficient as the normal distribution for fitting power or logarithmic transforms of the historical monthly flow data (i.e., F^1-0, F^0-5, F^0-25, Fa¹²⁵, F^0.085, and log F). No single transform to a normal distribution was adequate for all twelve monthly flows, since definite seasonal grouping patterns were found for the four rivers examined. The highly variable flow in the low-flow season(s) indicated much more skewness than was typical of the remainder of the year. For the low-flow seasons, the higher-root (smaller exponent) transforms were particularly useful. Flows were generated from a linear regression model of lag one utilizing two or more transforms for the twelve periods. The definite seasonal patterns found historically were reproduced quite well in the generated streamflows. The effect of a change in data transform from one season to the next was insignificant after one month. Thus the use of different transforms within the year did not bias the results from the linear regression model appreciably, but did help in reproducing the seasonal distribution pattern. The technique seems especially well suited for rivers with highly variable flows.     

华北油田岔南联合站污水处理技术改造及效益分析

采油污水必须经过处理达到油田注水水质控制指标才能回注。华北石油管理局第二采油厂岔南联合站建成投产后，采取了选用合适的化学药剂，改善加药方法等措施，使岔南联合站污水水质得到较大改善，达到了油田注水水质控制指标，并同时收到了减少电耗和化学药剂使用量，节约成本的效果。环境效益和经济效益都十分显著。本文介绍了该站污水处理系统技术改造的试验过程及效果。