An inexact two-stage mixed integer linear programming method for solid waste management in the City of Regina

In this study, an interval-parameter two-stage mixed integer linear programming (ITMILP) model is developed for supporting long-term planning of waste management activities in the City of Regina. In the ITMILP, both two-stage stochastic programming and interval linear programming are introduced into a general mixed integer linear programming framework. Uncertainties expressed as not only probability density functions but also discrete intervals can be reflected. The model can help tackle the dynamic, interactive and uncertain characteristics of the solid waste management system in the City, and can address issues concerning plans for cost-effective waste diversion and landfill prolongation. Three scenarios are considered based on different waste management policies. The results indicate that reasonable solutions have been generated. They are valuable for supporting the adjustment or justification of the existing waste flow allocation patterns, the long-term capacity planning of the City's waste management system, and the formulation of local policies and regulations regarding waste generation and management.     

垃圾焚烧炉预处理系统设计与优化

论述了垃圾预处理系统的一些关键设备和技术要点,分析了垃圾焚烧炉预处理系统的流程设计和不同的设备组合方式,并介绍了一种用于循环流化床焚烧炉的预处理系统流程和试验结果。     

Landfill space consumption dynamics in the Lower Rio Grande Valley by grey integer programming-based games

The Lower Rio Grande Valley (LRGV) region in South Texas emerges as a warehouse and transportation center between Central America and the US with positive growth impacts due to the North American Free Trade Agreement (NAFTA). In 10 years time, a 39.8% population increase has resulted in a 25% boost in solid waste per capita disposal rate in the region. A landfill space shortage drives a need for landfill operators to understand their optimal management strategies in this highly-competitive market. Initially, a strategic plan for optimal solid waste pattern distribution minimizes net costs for cities. This is accomplished through a grey integer programming algorithm that encapsulates all uncertainty present in the solid waste system. Secondly, a series of grey integer submodels construct payoff matrices for a zero-sum two-person game. The ensuing game theoretic analysis is critical for evaluating optimal pricing strategies for tipping fees available to the most significant regional landfills (e.g. Browning-Ferris Industries (BFI) and City of Edinburg) as they compete over disposal contracts. The BFI landfill intrinsically benefits from its competitive pricing policy and central location to solid waste generators. The City of Edinburg landfill, on the other hand, wishes to secure its lucrative solid waste management revenue. It desires a gaming strategy backed by optimality that integrates ambiguity in solid waste generation, design capacity boundaries, and unitary shipping costs. Results show that a two-tiered analysis via grey integer programming-based games may pave the way for 'grey Nash equilibria' pricing tactics that will help the Edinburg landfill maintain its waste contracts.     

Solid Waste Management in Nigeria: Problems and Issues

/ This paper is a presentation of the problems of solid waste management in Nigeria and certain important issues that must be addressed in order to achieve success. At the core of the problems of solid waste management are the absence of adequate policies, enabling legislation, and an environmentally stimulated and enlightened public. Government policies on the environment are piecemeal where they exist and are poorly implemented. Public enlightenment programs lacked the needed coverage, intensity, and continuity to correct the apathetic public attitude towards the environment. Up to now the activities of the state environmental agencies have been hampered by poor funding, inadequate facilities and human resources, inappropriate technology, and an inequitable taxation system. Successful solid waste management in Nigeria will require a holistic program that will integrate all the technical, economic, social, cultural, and psychological factors that are often ignored in solid waste programs.KEY WORDS: Solid waste; Management; Problems; Solutions; Nigeria     

对固体废物中挥发性有机物浸出方法的几点实验探讨

采用零顶空提取器,对陈旧油墨渣和蒽琨渣样品中的挥发性有机物进行了浸出实验和分析测定,浸出液采用静态顶空分流进样、GC/MS法分析。对影响挥发性有机物浸出效率的因素进行了研究,结果表明,浸提剂加入方式、浸出时间和浸出液收集方法等对分析结果准确度有较大影响。     

顶空固相微萃取-气相色谱质谱法测定水体中的苯甲醚

建立了顶空固相微萃取-气相色谱质谱法定性定量检测水中苯甲醚的分析方法。对影响检测结果的因素如萃取头的选择、萃取时间等进行了优化。经过条件优化，方法在1～1 000 μg/L 范围内线性良好，线性相关系数＞0.999，实际水样加标质量浓度分别为10，60，300 μg/L时，加标回收率为85%～120%，相对标准偏差（RSD）为3.95%～6.72%。全扫描模式下，苯甲醚的检出限为0.3 μg/L。实验结果表明，该方法快速、简便、灵敏度高，方法精密度和准确度均能满足水中微量及痕量苯甲醚检测的要求。     

A plasma display window?-The shifting baseline problem in a technologically mediated natural world

Humans will continue to adapt to an increasingly technological world. But are there costs to such adaptations in terms of human well being? Toward broaching this question, we investigated physiological effects of experiencing a HDTV quality real-time view of nature through a plasma display “window.” In an office setting, 90 participants (30 per group) were exposed either to (a) a glass window that afforded a view of a nature scene, (b) a plasma window that afforded a real-time HDTV view of essentially the same scene, or (c) a blank wall. Results showed that in terms of heart rate recovery from low-level stress the glass window was more restorative than a blank wall; in turn, a plasma window was no more restorative than a blank wall. Moreover, when participants spent more time looking at the glass window, their heart rate tended to decrease more rapidly; that was not the case with the plasma window. Discussion focuses on how the purported benefits of viewing nature may be attenuated by a digital medium.     

Why recycle? A comparison of recycling motivations in four communities

Four Illinois communities with different sociode-mographic compositions and at various stages of planning for solid waste management were surveyed to determine the influence of sociodemographic variables and planning stages on the factors that motivate recycling behavior. A factor analysis of importance ratings of reasons for recycling and for not recycling yielded five factors interpreted as altruism, personal inconvenience, social influences, economic incentives, and household storage. The four communities were shown to be significantly different in multivariate analyses of the five motivational factors. However, attempts to explain these community differences with regression analyses, which predicted the motivational factors with dummy codes for planning stages, a measure of self-reported recycling behavior, and sociodemographic measures were unsatisfactory. Contrary to expectation, the solid waste management planning stages of the cities (curbside pickup, recycling dropoff center, and planning in progress) contributed only very slightly to the prediction of motivational factors for recycling. Community differences were better explained by different underlying motivational structures among the four communities. Altruistic reasons for recycling (e.g., conserving resources) composed the only factor which was similar across the four communities. This factor was also perceived to be the most important reason for recycling by respondents from all four communities. The results of the study supported the notion that convenient, voluntary recycling programs that rely on environmental concern and conscience for motivation are useful approaches to reducing waste.     

The Tribal Environment: Solid Waste in Indian Country

The issue of solid waste management in Indian country is multidimensional in scope because it affects more than just regulatory concerns. There are more than 550 federally recognized Alaska Native and American Indian Tribes in the United States. Tribes are sovereign nations that have a special relationship to the federal government and a unique legal status. The environmental problems faced by tribes are many, and it is only fair that tribes, as sovereigns, specify the levels of protection on their lands. The one-size-fits-all regulatory approach to environmental problems and solid waste management in particular does not work and often leads to conflict between tribes and the federal and state governments. Inherent tensions also exist between tribes and various levels of government concerning jurisdiction of lands and managing solid waste. These intergovernmental relationships are often complex and present unique challenges to all. More research needs to be done on targeting resources to meet the capacity-building needs of tribes, as well as the overall environmental management needs of Indian country under the federal trust obligation. Successful intergovernmental relationships can be fostered through partnership arrangements between tribes and federal, state, and local governments. In the area of solid waste such partnerships have worked. It requires that all levels of government deal with tribes with careful consideration of their cultural, historic, and socioeconomic aspects, which are often intertwined.     

Market imperfections in recycling markets: conceptual issues and empirical study of price volatility in plastics

The effectiveness of recycling depends upon efficient functioning of secondary material markets. This paper focus on the role that price volatility can play in slowing investment and market development. However, a statistical analysis of the relative volatility of secondary and primary material prices does not confirm the widely-held belief that relative price volatility is higher in secondary than in primary materials, at least at national levels.An econometric estimation of the determinants of plastic recovery volumes in Seattle contributes to the literature in four ways: the use of monthly (as opposed to annual) data; the use of local (as opposed to national) data; the use of an explanatory variable to reflect price volatility; and, the focus on plastics, which have not been examined previously. Some tentative conclusions can be made: the results generally support the principal hypothesis that price volatility has a negative effect on recovery of secondary materials; in addition, and consistent with previous studies, price elasticities are low and insignificant; and finally, policy factors are clearly important. The concluding section treats the economic and policy implications of market inefficiency in secondary material markets.