首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
Solid waste disposal poses a significant problem, as it leads to land pollution if openly dumped, water pollution if dumped in low lands and air pollution if burnt. Moreover, the scarcity of land and increase in land prices especially in Dhaka, the capital city of Bangladesh create the problems of developing new landfill sites. Realising the existing and future impacts of waste disposal issues, the analytic hierarchy process model was applied to select an appropriate Waste-to-Energy (WTE) conversion technology for household waste of Dhaka-Mirpur Cantonment area. Three alternatives, namely, anaerobic digestion, pyrolysis and plasma gasification (PG) technologies and nine criteria under three aspects (technological, environmental and financial) were chosen for comparison. The analysis revealed that PG is the most appropriate WTE conversion technology in the study area. The selected PG technology has a relatively small footprint; it can treat unsorted waste and can produce good-quality synthetic gas without generating extremely toxic by-products.  相似文献   

2.
In many developing countries, including India, governments have implemented programs for improvement of environment and health in rural settlements through the provision of a subsidized household toilet with specifications selected and benchmarked from the experts’ perspective with only partial consideration of users’ perception. Provision of household toilets with specifications or service quality as perceived by users is a requirement for the sustainability and sustained use of toilet infrastructure. Users do not judge only the overall quality of a service but also base their judgment on a few attributes which are either perceived to be relatively more important or where there is a wider gap between expectation and perception . This paper presents a review of the service quality attributes of the household toilet as found in the relevant literature and provides a step-by-step approach for identifying appropriate attributes based on users’ perspective. While an initial list of attributes was developed based on literature review, initial selection and modifications of the attributes’ definition and units were carried out as per our judgment. This list was further modified through focus groups discussions and incorporating expert opinions. The final list of attributes is selected based on the stated importance level of attributes as perceived by users. The study finds that the attributes prioritized by the users are different from the experts. While government policies emphasize on the construction of toilet, maintenance of toilet is found an important issue for the users.  相似文献   

3.
Viability of solar photovoltaics as an electricity generation source for Jordan was assessed utilising a proposed 5 MW grid‐connected solar photovoltaic power plant. Long‐term (1994–2003) monthly average daily global solar radiation and sunshine duration data for 24 locations – distributed all over the country – were studied and analysed to assess the distribution of radiation and sunshine duration over Jordan, and formed an input to the RetScreen Software for evaluation and analysis of the proposed plant's electricity production and economic feasibility. It was found that depending on the geographical location, the global solar radiation on horizontal surface varied between 1.51 and 2.46 MWh/m2/year with an overall mean value of 2.01 MWh/m2/year for Jordan. The sunshine duration was found to vary, according to the location, between 8.47 and 9.68 hours/day, with a mean value of 9.07 hours/day and about 3311 sunshine hours annually for Jordan. The annual electricity production of the proposed plant varied depending on the location between 6.886 and 11.919 GWh/year, with a mean value of 9.46 GWh/year. The specific yield varied between 340.9 and 196.9 kWh/m2, while the mean value was 270.59 kWh/m2. Analysis of the annual electricity production of the plant, the specific yield, besides the economic indicators, i.e. internal rate of return, simple payback period, years to positive cash flow, net present value, annual life cycle saving, benefit/cost ratio, and cost of energy – for all sites – showed that Tafila and Karak are the most suitable sites for the solar photovoltaic power plant's development and Wadi Yabis is the worst. The results also showed that an average of 7414.9 tons of greenhouse gases can be avoided annually utilising the proposed plant for electricity generation at any part of Jordan.  相似文献   

4.
The recent development of infrastructure all around the world has resulted in an increasing trend of online examination in universities. The paper is an approach in theory and practical aimed at analyzing the feasibility of sustainable examination in four universities and its environmental impact reducing the paper use terming it as green examination. The paper studied the integration of sustainability through the use of computers and technology in the examination of the universities viz. King Khalid University (KKU), Saudi Arabia, Integral University (IU), India, Aligarh Muslim University (AMU), India, and The Hague University (HU), The Netherlands. The study has analyzed the trend of paper requirement, paper utilized and paper wasted in all the four universities. The environmental impact resulting from reduced paper use has been also analyzed. The feasibility of e-examination, its implementation and the implications has been undertaken in the study. The study concludes that the e-examination can almost make the examinations paperless and feasible in the four universities.  相似文献   

5.
6.
The Stockholm Convention on Persistent Organic Pollutants includes in its aims the minimisation of unintentional releases of polychlorinated dibenzo-dioxins and dibenzofurans (PCDD/PCDF) and dioxin like PCB (dl-PCB) to the environment. Development and implementation of policies to achieve this aim require accurate national inventories of releases of PCDD/PCDF/dl-PCB. To support this objective, the Conference of Parties established a process to review and update the UNEP Standardized Toolkit for Identification and Quantification of Dioxin and Furan Releases. An assessment of all emission inventories was that for many countries open burning of biomass and waste was identified as the major source of PCDD/PCDF releases. However, the experimental data underpinning the release estimates used were limited in number and, consequently, confidence in the accuracy of the emissions predictions was low. There has been significant progress in measurement technology since the last edition of the Toolkit in 2005. In this paper we reassess published emission factors for release of PCDD/PCDF and dl-PCB to land and air.In total, four types of biomass and 111 emission factors were assessed. It was found that there are no systematic differences in emission factors apparent between biomass types or fire classes. The data set is best described by a lognormal distribution. The geometric mean emission factors (EFs) for releases of PCDD/PCDF to air for the four biomass classes used in the Toolkit (sugarcane, cereal crops, forest and savannah/grass) are 1.6 μg TEQ (t fuel)−1, 0.49 μg TEQ (t fuel)−1, 1.0 μg TEQ (t fuel)−1 and 0.4 μg TEQ (t fuel)−1, respectively. Corresponding EFs for release of PCDD/PCDF to land are 3.0 ng TEQ (kg ash)−1, 1.1 ng TEQ (kg ash)−1, 1.1 ng TEQ (kg ash)−1 and 0.67 ng TEQ (kg ash)−1. There are now also sufficient published data available to evaluate EFs for dl-PCB release to air for sugarcane, forest and grass/savannah; these are 0.03 μg TEQ (t fuel)−1, 0.09 μg TEQ (t fuel)−1 and 0.01 μg TEQ (t fuel)−1, respectively. The average EF for dl-PCB release to land is 0.19 ng TEQ (kg ash)−1. Application of these EFs to national emissions of PCDD/PCDF for global estimates from open burning will lower previous estimates of PCDD/PCDF releases to air and to land by 85% and 90%, respectively. For some countries, the ranking of their major sources will be changed and open burning of biomass will become less significant than previously concluded.  相似文献   

7.
Concentrations of persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and organochlorine pesticides were measured in human breast milk collected from mothers residing near an open dumping site and a reference site in Kolkata, India during 2004–2005. POPs were detected in all the human milk samples analyzed, suggesting that residents of Kolkata are widely exposed to these contaminants. Concentrations of dioxin-like PCBs in the samples from the dumping site were significantly higher than in the reference site samples, whereas no such difference was found for PCDDs and PCDFs. In addition, significantly higher concentrations of total PCBs were also observed in the samples from the dumping site than the reference site. Interestingly, concentrations of total and dioxin-like PCBs in the breast milk of mothers from the dumping site significantly increased with the number of years of residence near the dumping site. These results indicate that significant pollution sources of PCBs are present in the dumping site of Kolkata and the residents living around are exposed to relatively higher levels of PCBs. When the residue levels of dioxins and related compounds in fish collected from ponds near the Kolkata dumping site and the reference site were measured, it was found that dioxin-like PCB and TEQ levels in fish from the dumping site were notably higher than those from the reference site. This result indicates that fish is a potential source of PCBs for residents living near the Kolkata dumping site.  相似文献   

8.
技术是应对气候变化的重要手段,关键技术创新差异的扩大将不利于各国应对气候变化的协同发展。以技术产出的专利为数据源,运用大数据挖掘工具、泰尔熵指数及空间计量学的方法和理论,分析了"一带一路"沿线国家应对气候变化关键技术创新差异的时空格局演变情况。研究结果表明:(1)沿线国家应对气候变化关键技术创新差异整体上呈现下降态势,并以初期震荡向后期平稳有升过度。(2)按地理位置划分的区域技术创新差异呈现高的空间集聚效应,且强强集聚与弱弱集聚具有一定时期内的稳定性,部分地区面临陷入技术贫困陷阱风险。(3)沿线各国应对气候变化技术创新差异存在趋同俱乐部现象,个别国家随时间推移可能经历不同俱乐部过度。针对这种趋同特征及各国技术需求特点可划分为4种类别:技术转出区、技术转入区、技术扩散区和技术承接区。技术转出区多集中在东欧某些经济发达、能源依存度高的国家。为此,本文提出如下建议:(1)各国根据自身情况制定减排政策的同时,需要国际社会制定与其相适应的差异化且有侧重的援助方案。(2)技术创新强国在涉及应对气候变化技术转移知识产权等事项上应该给予技术需求国让步。同时,技术转移应考虑区域协同及地理邻近的扩散。(3)中国应发挥好南南合作援助基金的作用,加强特定区域内共性技术的帮扶力度,建立与适宜国家间关键技术联合研发与示范机制,树立大国形象。(4)中国应加快沿线战略布局,根据不同区域各国应对气候变化的现状及其技术能力制定差异化的产业和技术转移的政策,加强与沿线国家的技术合作与贸易往来,形成优势互补的产业链。  相似文献   

9.
Here we review some of the main processes and key parameters affecting the mobility of radiocesium in soils of semi-natural areas. We further illustrate them in a collection of soil surface horizons which largely differ in their organic matter contents. In soils, specific retention of radiocesium occurs in a very small number of sorbing sites, which are the frayed edge sites (FES) born out of weathered micaceous minerals. The FES abundance directly governs the mobility of trace Cs in the rhizosphere and thus its transfer from soil to plant. Here, we show that the accumulation of organic matter in topsoils can exert a dilution of FES-bearing minerals in the thick humus of some forest soils. Consequently, such accumulation significantly contributes to increasing 137Cs soil-to-plant transfer. Potassium depletion and extensive exploration of the organic horizons by plant roots can further enhance the contamination hazard. As humus thickness depends on both ecological conditions and forest management. our observations support the following ideas: (1) forest ecosystems can be classified according to their sensitivity to radiocesium bio-recycling, (2) specific forest management could be searched to decrease such bio-recycling.  相似文献   

10.
Sustainability science requires the development of a theoretical framework to understand, analyze, and design innovation to solve social, economic, and environmental issues. This paper extends the framework of multi-level perspectives (MLP) by introducing a technology readiness level (TRL), and analyzes the innovation of the advanced turboprop (ATP) engine in the aviation industry, also known as a propfan or an open rotor engine, which is one of the most promising engine innovations expected to mitigate climate change. The concept of TRL was introduced to explain the mechanisms of ATP failure in the late 1980s as well as the transition of the geared turbofan (GTF). In this paper, we discuss why ATP and GTF faced different fates although both were developed under the same landscape in the aviation industry. We also discuss the different roles of the socio-technical regime, such as uneven and dynamic opportunity windows, technological readiness, niche stock, institutional support of export products, and the risk of a ‘launch’ customer, at different TRLs. As illustrated in this paper, MLP with TRL is expected to facilitate future interdisciplinary collaboration between social scientists and engineers, and also transdisciplinary expertise between academia and practitioners by supporting analysis and design of the industry’s transition toward a more environmentally friendly regime as well as its effective management.  相似文献   

11.
重点生态功能区对维护国家和区域生态安全至关重要,农户作为该区最主要的经济活动主体和最基本的生态环境保护单元,其对生计压力的适应性直接关系到重点生态功能区主体功能的发挥。本文以地处青藏高原东缘的甘南黄河水源补给区为例,基于入户调查数据,分析了农户的生计压力、适应能力及适应策略,并利用多元logistic回归模型探明了影响适应策略选择的关键因素。结果表明:①甘南黄河水源补给区有近90%的农户遭受多重生计压力的冲击,其中,“自然+社会+经济”型压力是该区农户面临最多的生计压力组合。②经济示范区农户的适应能力最高,恢复治理区次之,重点保护区最低;遭受“自然+社会”型压力冲击的农户适应能力最高,遭受“自然+社会+经济+政策”型压力冲击的农户适应能力最低。③甘南黄河水源补给区有87.45%的农户采取多种适应策略来应对生计压力,其中,选择“扩张+援助+收缩”型适应策略的农户占比最大。④自然资本、人力资本、社会资本、自然压力的严重程度和生计压力的多样化程度是影响适应策略的关键因素。鉴于此,政府应加大生态环境保护力度,拓宽农户增收渠道,建立多元化信贷机制,加强偏远地区基础设施建设,完善社会保障体系,提高农户在面临生计压力时的适应能力,促进生计可持续发展。  相似文献   

12.
Situated within the Jordan Rift Valley, along the shores of Lake Kinneret (Sea of Galilee) which serves as the national water reservoir of Israel, are saline hot springs that are notable for their enrichment in radon and radium. Though the anomalous radioactivity has been known for almost half a century, the source of the radioactive anomalies has been a subject of conjecture. Radiometric analysis of a rock core drilled through Mt. Arbel, situated to the west of the lake, reveals that the oil shale sequence of the Senonian En Zetim and Ghareb formations is strikingly deficient in radium. Mt. Arbel has been cut by Rift Valley related faults that serve as conduits for ascending brines. The organic matter enriched sequence is encountered in the subsurface at elevations lower than the water level of the nearby radioactive enriched hot springs. It is thus concluded that hot ascending brines underlying the lake flush through the organic matter enriched sequence and remove a substantial percentage of 226Ra from the uranium enriched organic material, before draining to the outlets of the springs. Saline springs that are in contact with organic matter enriched sequence show excess of radium and radon, while fresh water springs in the same stratigraphic position show only excess of radon.  相似文献   

13.
This paper describes a new model of sustainable development planning based on a case study of a successful planning process for the Great Bear Rainforest on Canada’s west coast. The planning region is an area of international ecological significance that contains one-quarter of the world’s remaining ancient coastal temperate rainforest. An innovative collaborative planning process was initiated in 1996 to develop a plan for the region that balances social, economic, and environmental values. The plan, which was accepted by consensus agreement of all stakeholders in 2006, uses a new model for sustainable regional development that is based on collaborative planning, collaborative implementation, informal conflict resolution, contextual adaptation incorporating comanagement with indigenous peoples (First Nations), joint fact finding, ecosystem-based management, and integration of social, economic, and environmental objectives.  相似文献   

14.
The results of paleoecological analysis of chironomid remains in bottom sediments of a mountain lake exposed to atmospheric pollution with acidifying compounds and heavy metals are described. With consideration of the reconstructed chironomid assemblages, it is demonstrated that the course of natural lake ontogeny has been tending to change since the beginning of industrial development in the region. Chironomid taxa promising as indicators for biological monitoring are discussed.  相似文献   

15.
Activities of radionuclides in the 238U (230Th, 226Ra, 210Pb) and 232Th (232Th, 228Th, 228Ra) decay series were determined in sediments from an east Texas watershed and examined with isotope ratios and compared to particulate organic carbon (POC), % fines (<63 microm) and total concentrations of Al, Fe and Mn. The objective was to elucidate the presence or absence of relationships affecting the effectiveness of these radionuclides in modeling sediment transport. Strong positive correlations were observed between radionuclides and Mn (Th) and % fines (Ra and Th). Isotope ratios effectively reduce these influences, supporting the contention that isotope ratios offset extrinsic variability in terrestrial sediments. Strong associations of 210Pbxs (excess 210Pb) and 226Ra/230Th with POC agree with data from marine and terrestrial settings, indicating that the role of POC in isotope fractionation, transport and sequestration merits further investigation.  相似文献   

16.
Traditional research into sustainable design has typically focused on reducing the environmental impact of products during the manufacture and disposal stages of a products' lifecycle. The last decade, however, has seen an explosion of research into understanding and moderating user behaviour during the use phase of a products' lifecycle; often the most resource-intensive phase. One of the biggest factors that affects behaviour is a users cultural context; however, the effect of cultural context on design for sustainable behaviour has had little exploration in this relatively new research field.  相似文献   

17.
This paper examines the relevance to groundwater management of Ostrom’s design principles for managing common property resources. Experience in four case studies of groundwater management in the Murray Darling Basin in Australia and the Upper Guadiana Basin in Spain suggests that while Ostrom’s design principles are relevant, sustainable groundwater management depends on the effective collaboration between government authorities and water users. A flexible and adaptive management approach is required, with collaboration between scientists, policy makers, water suppliers, and water users. Key management challenges include agreeing on a sustainable level of extraction, and establishing effective coordination and collaboration, and monitoring and control systems. Further case studies of groundwater management and their synthesis could make a useful contribution to the transition towards sustainable groundwater management regimes.  相似文献   

18.
Dilution of indoor air contaminants with less contaminated outdoor air is the most common strategy for control of indoor air quality. Unfortunately this strategy frequently imposes a substantial energy burden. If the contaminants are associated with occupants and their activities, a ventilation control system based on the carbon dioxide level in the controlled space is shown to relieve this energy burden. A test was carried out in the Fridley, MN, Junior High School Music Department to obtain air quality, energy, and subjective response data on an Automatic Variable Ventilation System. A control system with both CO2 and temperature inputs was devised to control the use of outdoor air. Infiltration measurements lead to a quantitative measure of ventil3tion efficiency. This in turn led to recommendations for air circulation patterns in rooms. The measured ventilation efficiency enabled energy and CO2 models to fit measured data. Energy savings of approximately 20% were found for this application. Subjective response of the occupants also was measured. A special questionnaire, subjected to statistical analysis, showed that the subjects felt warmer with increased CO2 in the room air.  相似文献   

19.
We constructed a survey system of radon/methane/nitrate/salinity to find sites of submarine groundwater discharge (SGD) and groundwater nitrate input. We deployed the system in Waquoit Bay and Boston Harbor, MA where we derived SGD rates using a mass balance of radon with methane serving as a fine resolution qualitative indicator of groundwater. In Waquoit Bay we identified several locations of enhanced groundwater discharge, out of which two (Childs and Quashnet Rivers) were studied in more detail. The Childs River was characterized by high nitrate input via groundwater discharge, while the Quashnet River SGD was notable but not a significant source of nitrate. Our radon survey of Boston Harbor revealed several sites with significant SGD, out of these Inner Harbor and parts of Dorchester Bay and Quincy Bay had groundwater fluxes accompanied by significant water column nitrogen concentrations. The survey system has proven effective in revealing areas of SGD and non-point source pollution.  相似文献   

20.
A multi-objective goal programming model was developed for water distribution from multiple sources to multiple users. The model was applied in Riyadh, Saudi Arabia, for the period of 2015–2050. In Riyadh, water sources are groundwater (GW), desalinated water (DW) and treated wastewater (TWW), while the users are domestic, agricultural and industrial sectors. The model was applied to: (1) satisfy water demands and quality; (2) maximize TWW reuse and GW conservation; and (3) minimize overproduction of DW and overall cost. In 2015, the required allocations of GW, DW and TWW are 3286, 662 and 609 MCM, respectively, which are projected to be 4345, 1554 and 1305 MCM in 2050, respectively. GW source is likely to satisfy the predicted withdrawal of GW till 2035, while probabilities of non-satisfaction of full demands of GW in 2040, 2045 and 2050 were 0.04, 0.23 and 0.51, respectively. Supply of DW and reuse of TWW are needed to be increased to satisfy the predicted quantities during 2015–2050.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号