PLANNING OF URBAN BEST MANAGEMENT PRACTICES1

ABSTRACT: A “user-friendly” computer program has been developed for application in personal computers for preliminary design, evaluation, and cost effectiveness analysis of various best management practice (BMP) measures to control stormwater quantity and quality. The algorithms utilize the SCS TR-55 method for calculating runoff hydrographs for a single storm event and a first order pollutant washoff equation to generate pollutographs. Sensitivity analyses based on different policy scenarios is performed on a hypothetical watershed for the purpose of illustration. Three types of BMP measures, namely detention ponds (dry, wet, and extended wet ponds), infiltration trenches, and porous pavements are considered. It is found that the extended wet ponds have the best cost effective performance of the measures evaluated.     

Estimating the Relative Efficiency of Brazilian Publicly and Privately Owned Water Utilities: A Stochastic Cost Frontier Approach1

Abstract: This paper assesses cost efficiencies of Brazilian public and private companies of water supply. To measure the efficiency, we used a stochastic frontier model derived from the translog family – a specification similar to a Cobb‐Douglas including a quadratic term in log output. The model parameters are estimated by maximum likelihood using Brazilian data for the year 2002. Statistical inference leads to the conclusion that there is no evidence that private firms and public firms are significantly different in terms of efficiency measurements.     

煤矿安全投入和安全成本的界定

安全投入不足是煤矿安全事故频发的主要原因之一。目前,安全投入与安全成本的概念存在着严重的模糊性。为此,笔者重新给出了安全成本的定义:在基准的安全标准下,发生的与安全有关的费用总和,包括安全投入和事故损失两部分。为了进一步明确安全成本与生产成本间的界限,还提出了从采矿方法、地质采矿技术条件、生产工艺环节等3个方面对安全成本与生产成本间的界限进行界定,以及对事故损失按照可列的直接经济损失、隐含的直接经济损失、可列的间接经济损失和隐含的间接经济损失等4个层次分别进行计量的建议。最后提出了发展煤炭科技、严格煤矿设计审查制度、制定煤矿安全成本统计标准、变革煤矿税费体系等应对措施。     

Benefit–Cost Analysis of StormwaterQuality Improvements

The major purpose of this paper is to explore the potential value of benefit–cost evaluation for stormwater quality management decisions at a local level. A preliminary benefit–cost analysis (BCA) screening method is used for maximum extent practicable (MEP) analysis, identifying promising management practices, and identifying societal and economic tradeoffs for local stormwater problems. Ballona Creek, a major urban storm drain in Los Angeles, California, USA, is used to illustrate the practicality of the benefit–cost evaluation. The Ballona Creek example demonstrates the economic limits of stormwater management in an urban region and attests to the value of coordinated basinwide management compared to uncoordinated management by individual landowners. Evaluation results suggest that in urban areas, the benefit of stormwater quality improvements might be far greater if accompanied by comprehensive redesign of drainage networks and neighboring land uses. In this case, benefit–cost analysis is found to be useful for evaluating and understanding stormwater management alternatives despite the uncertainties in characterizing stormwater quality and the effects of stormwater management on improving receiving water quality.     

城市公园建设项目综合费-效分析的灰色评价

城市公益性建设项目是国家投资,不以盈利为目的基本建设,因此此类工程项目的经济评价一直不被重视,而且缺乏适当的评价指标和方法。文章综合考虑费用-效益、费用-效果评价、城市竞争力效果评价和社会效果评价的因素,运用定性指标和定量指标相结合的分析方法,建立综合评价指标体系,并用灰色聚类决策方法进行评价和探讨。用灰色评价和层次分析相耦合的方法对益阳市梓山湖生态公园建设项目进行具体评价。     

燃煤电厂运行中环境成本分析与计算

以经济学为理论基础,结合环境经济学方法,提出燃煤电厂环境成本的定量计算模型,并以某电厂为例进行计算说明。研究成果为燃煤电厂节能减排的效益计算提供了理论依据,同时有助于燃煤电厂正确计算发电成本,制定合理的上网电价。     

两种土地处理污水方法比较

文章对我局建设并投入运行管理的人工湿地工程和人工快渗工程进行统计分析,对这两种土地污水处理法从工艺特点、建设的主要经济指标、运行成本和投入产出比、实际运行效果等方面进行对比,总结出各自的优缺点,以期能对今后建设同类型的项目有所启示。     

高效无囊过滤器在热电厂水处理中的应用

结合吉林油田热电厂YN-高效过滤器存在的问题,将YN-高效过滤器改造成Gxw-高效无囊过滤器,解决了原系统存在的生水处理能力小、出水浊度大、过滤设备反洗自用水量大的问题,保证了生水系统及后续水处理设备的正常运行,且节水、节能,效益显著。     

莫桑比克东部滨海砂矿矿物组成及特征

滨海砂矿是目前全球最大的潜在矿产资源之一。以莫桑比克的滨海砂矿作为研究对象,利用光学显微镜、X射线衍射、扫描电镜、等离子体质谱(ICP-MS)等手段对莫桑比克东部滨海砂矿的矿物组成及特征进行了研究。并用数理统计方法讨论了重砂矿的元素赋存状态及其载体矿物。研究结果表明:(1)砂矿的矿石矿物主要为钛铁矿、金红石和锆石,脉石矿物主要为石英和长石。(2)重砂矿的主要化学组分为Ti和Zr;Hf及REE为次要组分;而主要有害元素组分Th和U,其总体含量低,故重砂矿对采选加工和产品利用均无明显环境危害。(3)重砂矿中元素含量与粒度之间呈一定相关性,显示Zr、Hf、U、Cr、Ta的载体矿物的粒度相对较细;Ti、Fe、V、Nb的载体矿物的粒度相对较粗。     

常用曝气系统在城市给水工程中的应用对比

生物接触氧化法作为城市给水工程生物预处理工艺,近年来得到了日益广泛的实际应用。本文对给水生物接触氧化法预处理工艺中常用的两种曝气系统(微孔曝气器曝气和穿孔管曝气)作了简单介绍,并结合中试试验和工程实践对这两种不同曝气系统作了充氧性能、系统造价、运行成本及运行管理等方面的比较分析。研究表明,在实际污水处理厂生物池曝气系统应用中,采用微孔曝气器的曝气系统优于采用穿孔管的曝气系统。