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531.
Wastewater collection and treatment is quite important for sustainable management. It would be uneconomical and impractical to provide sewer systems and separate wastewater treatment plants (WWTP) for small communities. The decision process in wastewater planning is rather important in terms of comparing the alternatives considered. The two important points in the management of wastewater at rural areas not connected to a sewer system are to develop an optimized operation strategy and to make sure that the complete system is environmentally and economically sustainable. In some regions, package treatment could be an alternative solution. However, in cases where there is an existing large WWTP, a cluster system, where sewage generated by small communities could be transported via conveyors to a centralized WWTP, could be employed. In this study, the wastewater treatment and disposal problems in small communities were addressed and an alternative wastewater handling scenario was proposed. Additionally, three wastewater handling scenarios were compared. As a case study, Gebze villages were selected. 相似文献
532.
吹吸式酸雾捕集经常用于蓄电池和较短的酸洗槽的酸雾捕集方面。在长酸洗槽(一般长度>10m)上运用吹吸式捕集酸雾。在此对目前常用酸洗槽设计方法进行了分析比较,并对一长酸洗槽(长14m)做了设计实例,经过实践检验,证明设计采用方法是恰当的,各设计参数是合理正确的。 相似文献
533.
We employed the contingent valuation method to estimate the willingness to pay of the respondents to improve the waste collection system in Dhaka city, Bangladesh. Our objective was to estimate how WTP differs between respondents who received or did not receive door to door waste collection. The methodology consisted of asking people directly about their willingness to pay an additional waste collection service charge to cover the costs of a new waste management project. The mean value of WTP for areas that received waste collection service areas was higher than for residents of areas that did not but the difference was not statistically significant. The aggregate value of WTP of the respondents in Dhaka city was 7.6 million Taka (USD0.1 million). 相似文献
534.
Managing diffuse water pollution from agricultural land continues to be one of the more intractable challenges for environmental policy. The advent of the Water Framework Directive places the onus on EU member states to identify reasons why water bodies fail or are at risk of failure to meet good ecological status. In such cases, programmes of measures are to be enacted to mitigate the causes at least cost. Failing this, users may ultimately be faced with the full costs of pollution. This paper considers the scope for measures that address nitrogen and phosphorus pollution at source. Specifically the paper relates the diffuse pollution problem to the extent of over application of nitrogen and phosphorus. Data envelopment analysis applied to English cereal and dairy farmers, provides an indication of resource use and evidence of over application. This inefficiency provides a potential basis for either a least cost abatement approach using effective information and advice, or alternatively a pollution charge. 相似文献
535.
The importance of riparian vegetation to support stream function and provide riparian bird habitat in semiarid landscapes
suggests that standardized assessment tools that include vegetation criteria to evaluate stream health could also be used
to assess habitat conditions for riparian-dependent birds. We first evaluated the ability of two visual assessments of woody
vegetation in the riparian zone (corridor width and height) to describe variation in the obligate riparian bird ensemble along
19 streams in eastern Oregon. Overall species richness and the abundances of three species all correlated significantly with
both, but width was more important than height. We then examined the utility of the riparian zone criteria in three standardized
and commonly used rapid visual riparian assessment protocols—the USDI BLM Proper Functioning Condition (PFC) assessment, the
USDA NRCS Stream Visual Assessment Protocol (SVAP), and the U.S. EPA Habitat Assessment Field Data Sheet (HAFDS)—to assess
potential riparian bird habitat. Based on the degree of correlation of bird species richness with assessment ratings, we found
that PFC does not assess obligate riparian bird habitat condition, SVAP provides a coarse estimate, and HAFDS provides the
best assessment. We recommend quantitative measures of woody vegetation for all assessments and that all protocols incorporate
woody vegetation height. Given that rapid assessments may be the only source of information for thousands of kilometers of
streams in the western United States, incorporating simple vegetation measurements is a critical step in evaluating the status
of riparian bird habitat and provides a tool for tracking changes in vegetation condition resulting from management decisions. 相似文献
536.
冯展杭 《安全.健康和环境》2011,11(1):37-39
介绍了储运各个过程中的油气排放情况,及吸收法、吸附法、冷凝法、膜分离法和氧化燃烧法这5种油气回收方法的基本原理。重点介绍了近几年吸收法、吸附法、冷凝法、膜分离法这4种油气回收装置在油库和加油站应用的国内外新成果,以及新兴的车载油气回收系统(ORVR)。 相似文献
537.
雨滴对气溶胶粒子的清除系数与捕集效率密切相关,并依赖于雨滴附近的气流型式.考虑到实际大气背景均为湍流状态,分别对层流和湍流状态下大尺寸雨滴表面上惯性粒子的捕集过程进行了数值模拟,讨论了湍流脉动对不同粒子轨迹的畸变和扰动.结果表明,层流条件下的模拟结果与已有的实验结果具有很好的一致性.若对雨滴的绕流附加一个湍流强度,则雨滴附近流动速度的随机变化将对粒子的运动轨迹产生明显的影响,导致惯性粒子在湍流状态下被雨滴捕获的效率大于层流捕集效率,湍流脉动效应对粒子捕集效率的提高幅度随粒子尺度的增大而减弱. 相似文献
538.
539.
采用随机问卷方式,调查了宁波市居民对现行垃圾分类方法的态度、可能的分类方法、实行垃圾分类后的行为方式等。结合我国生活垃圾分类行业标准及居民在实际垃圾分类过程中的行为方式,提出了适合宁波市的生活垃圾分类收集方案。其特点是,居民只需区分食物垃圾与非食物垃圾,而非食物垃圾集中运往分拣中心按行业标准进行分类或按回收企业要求进行进一步细分类。 相似文献
540.