Is Municipal Solid Waste Recycling Economically Efficient?

It has traditionally been argued that recycling municipal solid waste (MSW) is usually not economically viable and that only when externalities, long-term dynamic considerations, and/or the entire product life cycle are taken into account, recycling becomes worthwhile from a social point of view. This article explores the results of a wide study conducted in Israel in the years 2000–2004. Our results reveal that recycling is optimal more often than usually claimed, even when externality considerations are ignored. The study is unique in the tools it uses to explore the efficiency of recycling: a computer-based simulation applied to an extensive database. We developed a simulation for assessing the costs of handling and treating MSW under different waste-management systems and used this simulation to explore possible cost reductions obtained by designating some of the waste (otherwise sent to landfill) to recycling. We ran the simulation on data from 79 municipalities in Israel that produce over 60% of MSW in Israel. For each municipality, we were able to arrive at an optimal method of waste management and compare the costs associated with 100% landfilling to the costs born by the municipality when some of the waste is recycled. Our results indicate that for 51% of the municipalities, it would be efficient to adopt recycling, even without accounting for externality costs. We found that by adopting recycling, municipalities would be able to reduce direct costs by an average of 11%. Through interviews conducted with representatives of municipalities, we were also able to identify obstacles to the utilization of recycling, answering in part the question of why actual recycling levels in Israel are lower than our model predicts they should be.     

Reject management from a Mechanical Biological Treatment plant in Bangkok, Thailand

The potential reuse of rejects from upstream and downstream process of Mechanical-Biological-Treatment (MBT) plant for the production refuse derived fuel (RDF) was investigated in the present study. Since, the rejects were characterized with the high calorific values of approximately 21 kJ/kg for upstream process and 29.5 kJ/kg for downstream process, both can be considered for RDF production. Further, heavy metal contents were also not exceeding the European standards for using it as RDF is additional benefit. But, RDF production from upstream process rejects showed maximum energy supply of 3.20 × 10⁶ MJ/d with less ash (11.8%), chlorine (0.6%) and sulfur (0.2%) contents than the downstream process rejects. Among the three potential RDF users surveyed, the cement industries showed positive interest to burn RDF in their cement kiln with the energy supply cost of <2.1 USD/GJ. Few technical, economical and safety barriers were also identified with the RDF end users and potential suggestions were discussed for thriving RDF market in Thailand.     

Curbside collection of recyclables. II. Simulation and economic analysis

Curbside collection of recyclable material can be expensive because the inherent costs of curbside collection are high, but also because amounts collected per residence are small compared to the total waste stream, and extra activity may be required, such as sorting. In this paper a simulation model is used to investigate the effect of collection method and route characteristics on route time. The simulation models presented calculate set-out amount based on route characteristics, set-out rate (SOR), and participation rate (PR). Route times are estimated for various conditions: constant SOR, constant PR, and constant set-out amount. Furthermore, a method for using route time to estimate vehicle and labor needs is presented, and used to estimate economic costs for one and two-person crew collection methods for the three simulation conditions mentioned above. The two-person crew is found to cost less than the one-person crew, for most simulated conditions.     

Environmental and economic aspects of production and utilization of RDF as alternative fuel in cement plants: A case study of Metro Vancouver Waste Management

Municipal solid waste (MSW) disposal and management is one of the most significant challenges faced by urban communities around the world. Municipal solid waste management (MSWM) over the years has utilized many sophisticated technologies and smart strategies. Municipalities worldwide have pursued numerous initiatives to reduce the environmental burden of the MSW treatment strategies. One of the most beneficial MSWM strategies is the thermal treatment or energy recovery to obtain cleaner renewable energy from waste. Among many waste-to-energy strategies, refuse-derived fuel (RDF) is a solid recovered fuel that can be used as a substitute for conventional fossil fuel. The scope of this study is to investigate the feasibility of RDF production with MSW generated in Metro Vancouver, for co-processing in two cement kilns in the region. This study investigates environmental impacts and benefits and economic costs and profits of RDF production. In addition, RDF utilization as an alternative fuel in cement kilns has been assessed. Cement manufacturing has been selected as one of the most environmentally challenged industries and as a potential destination for RDF to replace a portion of conventional fossil fuels with less energy-intensive fuel. A comprehensive environmental assessment is conducted using a life cycle assessment (LCA) approach. In addition, cost–benefit analysis (CBA) has been carried out to study the economic factors. This research confirmed that RDF production and use in cement kilns can be environmentally and economically viable solution for Metro Vancouver.     

城市垃圾填埋场渗滤液处理工艺综述

城市垃圾对环境的影响越来越严重,垃圾填埋导致垃圾渗滤液的大量产生,渗滤液中含有大量的有机物、大量的病菌、病毒、寄生虫等以及一些有毒有害的物质,若渗滤液不加以妥善处理、肆意排放,必将对地下水、地表水构成严重威胁,因此垃圾渗滤液的有效处理就成为一个亟待解决的问题。本文对城市垃圾填埋场渗滤液的处理工艺进行了分析和探讨,介绍了国内外垃圾渗滤液处理的主要技术,包括土地处理法、生物法和物化法,并对电解法处理垃圾渗滤液进行了详细的介绍。     

塑料和橡胶类废弃物的热物理特性及焚烧特性的研究

塑料和橡胶类的废弃物是城市垃圾的重要组成。本文在新式焚烧炉中对它们的焚烧特性、污染特性进行了研究。这将有助于进一步优化新型转式焚烧炉，完善低染、低腐蚀、低粘结的废弃物的焚烧工艺。     

动态发酵工艺参数的研究

本文定量地研究了城市生活垃圾滚筒式好氧堆肥处理技术的工艺参数。确定了动态发酵的适宜有机物含量为５０ ％ ～６０ ％ 、含水率为３０ ％ ～５０ ％ ,一次发酵时间为１ ～３ 天,二次发酵时间为１０ 天;一次发酵最佳温度为５５ ℃～６５ ℃。     

我国城市生活垃圾处理的市场化对策探讨

本文通过对城市生活垃圾的产生、处理现状的分析,看到垃圾处理的严峻性和刻不容缓的态势,提出我国城市垃圾处理必须走市场化道路的对策。领先全民参与、人人动手解决垃圾污染问题,促进城市垃圾蛄量化、无害化、资源化进程。尽快稳步提高我国城市垃圾处理水平,实现我国城市处理的市场化、产业化。     

A model recycling program for Alabama

Solid waste disposal is becoming a difficult problem for many states. Since 1960, the amount of municipal solid waste (MSW) has been increasing at a rate of 1% per year. More than 75% of the waste is comprised of recyclable materials. Several states have mandated recycling to decrease the volume of waste intended for disposal. Those mandated programs are very popular, but depend on many political, social, and economic factors for success. While Alabama has the manufacturing infrastructure to support a mandated recycling program, no recycling legislation has been promulgated. At this time recycling is only being done on a voluntary basis. A mandatory program with the proper support, education and funding could allow Alabama to recycle much of the 5.2 million tons of waste that are generated within its borders each year.     

2010年上海世博会垃圾组分的预测

为了便于2010年上海世博会期间生活垃圾的处理与处置,选择了和世博园区垃圾性质相近似的南京路步行街为参照区,进行垃圾组分的调研,预测模拟世博园区垃圾的组成与性质。研究结果表明：南京路步行街垃圾中食物垃圾占50％左右,塑料和纸张占45％左右,而一般的城市生活垃圾中塑料和纸张只占20％～30％左右,可见对于类似的垃圾资源化程度非常高。因此对于世博园垃圾进行分选,实现各组分垃圾的分流,可以更好地实现垃圾的资源化、减量化。     

一种城市生活垃圾产量预测的改进方法

将灰色系统理论与多元线性回归分析方法相结合，是研究城市生活垃圾产量预测的一种改进方法。以成都市为例。运用灰色关联度分析确定影响城市生活垃圾产量的4个主要因子：城市非农业人口、气化率、城市人均消费性支出、清扫面积。利用GM(1，1)模型预测上述4个因子的变化情况。建立一个包含这些因子的垃圾产量的多元线性回归分析预测模型，并对2004～2010年的垃圾产量进行预测。该模型预测精度高，实用性强，可为垃圾产量预测提供一种可靠的方法。     

南京市生活垃圾现状及综合处理对策研究

根据采样结果与统计分析,文章总结了南京市生活垃圾的现状,以及其产量和组成特性的变化趋势。城市生活垃圾处理是一个复杂的系统工程,任何单一的处置措施都无法满足。针对现实处理,过程中存在的问题,作者提出了生活垃圾的综合方案,即以设施为依托,以技术为核心,以市场为动力的设施－技术－市场三位一体综合方案。     

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。     

WILLINGNESS TO PAY FOR FLOOD RISK REDUCTION AND ITS DETERMINANTS IN JAPAN1

ABSTRACT: This study aimed to clarify public preferences for flood control measures in Japan, willingness to pay (WTP), and the main factors involved in WTP by applying the contingent valuation method. Findings showed that most residents surveyed expected some flood control measures, and revealed a diversity of interest in river management. WTP levels for different measures ranged from a mean of ¥2,887 to ¥4,861 and from a median of ¥1,000 to ¥2,000. However, WTP for additional flood risk reduction beyond initial levels was found to be zero. This was considered to be because WTP for flood risk reduction must be determined within a multi‐risk context. WTP for flood control measures may increase with per capita income, individual preparedness, and/or experience with flooding, but may decrease with distance from a river, acceptability of flood risk, and provision of environmental information. Furthermore, perception of flood risk may increase WTP, while perception of other risks may decrease it. Methods of dealing with environmental risk that were proposed in the survey may have affected WTP levels.     

Towards the estimation of demand for recycling in Chile: The case of Santiago

In developing countries, the recycling of municipal solid waste (MSW) as an alternative to the traditional MSW management requires an economic sustainability valuation. From this perspective, the estimation of demand for recycling is crucial. In this paper, we study the case of recycling MSW in Santiago, Chile. We estimate the relation between the monthly amount of MSW separated voluntarily from apartments located in Santiago and the monthly price required to participate in a municipal recycling program. We consider the transference of the municipal cost savings to the owners of the apartments due to the amount of MSW separated for recycling, which is not collected and deposited in the current MSW system. For the estimation, we use concepts from environmental economics and psychology, analyzing the operation and municipal costs incurred by current MSW management and designing and applying a survey based on a contingent valuation method (CVM) approach. The results indicate that the percentage of MSW separated for recycling varies between a 27.98% and 33.18%, that only four MSW types are affected by a variation of the monthly price, and that a reduction of monthly collection trips in the current MSW system from 24 to 18 can be obtained. Additionally, we discuss a number of methodological aspects to be considered in a similar study of valuation of recycling in developing countries. Our conclusion is that Santiago has favorable conditions for the implementation of a recycling program as an alternative to the current MSW system.     

烟气回流工艺在垃圾焚烧系统NOX减排中的工程应用分析

为有效抑制生活垃圾在机械炉排炉焚烧过程中NO_X的产生,有研究者提出采用烟气回流技术可以有效抑制NO_X的生成和排放。目前关于烟气回流技术的理论研究和数值模拟较多,而基于实际工程应用的研究较少。选择了烟气回流工艺在山东省某生活垃圾焚烧项目上的应用情况进行研究,从烟气回流工艺的技术原理、排放指标、运营数据和经济性等方面进行了分析,同时也总结了本工艺在应用过程中需注意的事项。研究表明,采用烟气回流工艺的#3炉引风机出口NOX平均排放和氨水平均用量比未采用烟气回流工艺的#1炉,分别降低了25.8%和43.7%,且NO_X浓度波动与烟气含氧量密切相关。总体上,烟气回流工艺的使用能够有效抑制NOX_的产生,并且同时减少了氨水等物料的消耗,降低了运营的成本。但是当进入焚烧炉的垃圾品质出现急剧恶化的情况下,会影响焚烧炉的燃烧工况而使烟气回流量降低,导致NOX减排效果下降。     

垃圾焚烧飞灰中重金属的固化/稳定化处理实验研究

研究了城市生活垃圾焚烧-电灰的特性及飞灰中重金属的特性,对利用水泥作粘结剂进行飞灰固化/稳定化处理效果开展了系统的实验研究,分析了水泥固化/稳定化飞灰的工艺特点和最佳工艺参数,并讨论了粘结剂固化飞灰机理以及重金属浸出毒性,为进一步研究城市生活垃圾焚烧飞灰的无害化处理与利用提供了有重要价值的参考依据.     

Effects of planned expansion of waste incineration in the Swedish district heating systems

Recent targets for reduced amounts of waste to landfills in Sweden will result in a large increase in waste incineration with recovery of energy, used primarily for district heating. The aim of this study is to investigate what changes in the usage of other fuels and technologies for district heat production would be caused by this increase. A questionnaire was sent out to the largest district heating companies, and simulations in an energy systems model were carried out. The analysis shows that increased waste incineration reduces the demand for other fuels, especially biomass, for district heat production. The effects include reductions in operating hours as well as the avoidance or postponement of investments in new plants for district heat production. Increased waste incineration will also lead to a greater use of district heating in Sweden.     

城市生活垃圾源减量化技术与对策

解决垃圾问题最好的方式是避免其产生,这样就无需收集、运输或处置。此外,源减量化在能源利用、温室气体排放和其他环境影响方面,要远优于其他诸如焚烧和填埋等处理方式。生活垃圾源减量化具有环境和经济的双重效益。本文阐述了生活垃圾源减量化的概念和特征,并通过借鉴美国在生活垃圾源减量化问题上的成功经验和成熟技术,探讨了适合上海的生活垃圾源减量化对策。