Waste plastics recycling process using coke ovens

The Japan Iron and Steel Federation (JISF), as its voluntary energy-saving action plan, proposed a 10% energy reduction by 2010 with 1990 as the basis. Further, it has suggested an additional 1.5% energy saving by the use of waste plastics as a metallurgical raw material. The amount of processing of waste plastics which corresponds to this amount of energy conversion is about 1 million t scale during 1 year. Conventional known methods for recycle-processing of waste plastics include, for example, the method of injection into a blast furnace to use waste plastics as an iron-ore reducing agent instead of coal. On the other hand, the coking process is considered to be suitable as a waste plastic recycling facility because the process involves coal carbonization in a high-temperature and reducing atmosphere. Carbonization tests with mixed waste plastics were conducted with laboratory equipment and in actual coke ovens. As a result, it was confirmed that the waste plastics recycling process using coke ovens is feasible. Therefore, a waste plastics recycling process using coke ovens was started as a chemical recycling technology at Nippon Steel.     

中国的污水处理与水环境管理政策

中国已建有420座污水处理厂,城市污水处理率达30％以上。但污水处理任务仍很艰巨,必须采取加强工业污染防治,建设大批新的污水处理厂和控制面源污染等对策。     

Korea's policy instruments for waste minimization

This paper considers the current status of waste generation and waste treatment trends, and introduces a wide variety of policy instruments for waste minimization at every stage of economic activity in Korea, i.e., production, distribution, and consumption. At each stage, the Korean government has imposed a policy mix of direct regulations and economic incentives. These policy instruments have made definite contributions to a reduction of waste generation and an increase in the recycling rate. Despite these fruitful outcomes, there are still some shortcomings with respect to efficiency and equity. Among other aspects, this paper examines three representative economic incentives – the charge system, the volume-based-collection fee system, and the deposit–refund system – and identifies shortcomings in each. Some suggestions are made for the creation of better systems of economic incentives. However, many experts insist that this kind of piecemeal change in each policy instrument is not enough to achieve the ultimate goal of resource circulation and an environmentally friendly society, especially in Korea, which is a country with little land, a high population density, and a high economic growth rate. Among experts, special emphasis is placed on the activation of recycling industries to achieve these goals. Received: April 2, 2001 / Accepted: September 10, 2001     

The city of San José's integrated waste management program: a case study for reaching high levels of diversion

The city of San José, California, USA, has a widely recognized integrated waste management program and is currently diverting close to 50% of its waste stream from landfill disposal. This paper describes the residential and commercial components of the city's waste management program. Information is presented on performance (e.g., types and quantities of materials that are collected, processed, and disposed of), customer service, and costs associated with the program. Received: October 4, 2000 / Accepted: February 15, 2001     

城市生活垃圾堆肥厂中的除臭技术

本文分析了垃圾堆肥厂臭气的来源，臭气的成份，介绍了脱臭技术及其设计参数，提出了在垃圾堆肥厂的设计建设中应重视臭气污染，除臭设施应同步建设的观点。     

Engineering properties of asphalt concrete made with recycled glass

Taiwan is an island nation with high population density: 23 million people living in a total land area of 30 000 sq. km. The island has transformed from an agricultural society to an industrial one in the past three decades. Coming with the transformation is a cumulated waste problem. Taiwan produces nearly 5 million tons of waste each year, of which 10% is of glass materials. Bureau of Highway Department funded a research program to investigate ways of recycling the glass waste. This report presents information on the program and laboratory/field test data. Materials used in the test program included 85/100 asphalt, Type II modified asphalt, and treated glass waste. Four glass contents: 0, 5, 10, and 15%, in terms of the total aggregate weight, were used in the mixture designs for casting series of 10 cm diameter by 6.35 cm disk specimens. Tests including Marshall stability value, dry/wet moisture damage, skid resistance, light reflection, water permeability, and compaction were carried out in accordance with the ASTM and AASHTO procedures. The test results reveal that glass waste is a viable material for asphalt concrete that has been widely used in pavement that offers profound engineering and economic advantages.     

Mixed signals: market incentives, recycling, and the price spike of 1995

Environmental economics assumes that reliance on price signals, adjusted for externalities, normally leads to efficient solutions to environmental problems. We explore a limiting case, when market volatility created ‘mixed signals’: prices of waste paper and other recycled materials were suddenly extremely high in 1994–1995, then plummeted back to traditional low levels in 1996. These rapid reversals resulted in substantial economic and political costs. A review of academic and business literature suggests six possible explanations for abrupt price spikes. An econometric analysis of the prices of wood pulp and waste paper shows that factor which explained price changes in 1983–1993 contribute very little to understanding the subsequent price spike. From the econometric analysis and from other sources, we conclude that speculation must have played a major role in the price spike, perhaps in combination with modest effects from changes in government policy and in export demand. If speculatively driven price spikes can disrupt an environmentally important industry such as recycling, what is the appropriate role for public policy? When price volatility is sufficiently disruptive, then measures to control or stabilize prices, rather than interfering with the market, might help to make it more efficient.     

造纸工业废水资源化途径的新探讨

本文从造纸工业废水治理技术现状分析入手,讨论了目前用于处理造纸黑液和白水的主要处理工艺及其特点。在此基础上,提出了造纸工业废水尤其是造纸黑液综合利用的新途径。着重对造纸工业废水污灌作了重点的分析,对用造纸黑液作为型煤粘合剂和水煤浆生产工艺用水作了探讨性分析,为造纸工业废水尤其是造纸黑液资源化途径的探讨提出了新思路。     

黄磷厂废渣作水泥混合材的研究

本文较系统地研究了影响黄磷渣作水泥混合材的因素；推荐了提高黄磷渣作水泥混合材的掺量必须控制的条件；按推荐的控制条件，黄磷渣作水泥混合材的掺量可高达４０％以上。     

Environmental assessment of packaging: Sense and sensibility

The functions of packaging are derived from product requirements, thus for insight into the environmental effects of packaging the actual combination of product and package has to be evaluated along the production and distribution system. This extension to all related environmental aspects adds realism to the environmental analysis and provides guidance for design while preventing a too detailed investigation of parts of the production system. This approach is contrary to current environmental studies where packaging is always treated as an independent object, neglecting the more important environmental effects of the product that are influenced by packaging. The general analysis and quantification stages for this approach are described, and the currently available methods for the assessment of environmental effects are reviewed. To limit the workload involved in an environmental assessment, a step-by-step analysis and the use of feedback is recommended. First the dominant environmental effects of a particular product and its production and distribution are estimated. Then, on the basis of these preliminary results, the appropriate system boundaries are chosen and the need for further or more detailed environmental analysis is determined. For typical food and drink applications, the effect of different system boundaries on the outcome of environmental assessments and the advantage of the step-by-step analysis of the food supply system is shown. It appears that, depending on the consumer group, different advice for reduction of environmental effects has to be given. Furthermore, because of interrelated environmental effects of the food supply system, the continuing quest for more detailed and accurate analysis of the package components is not necessary for improved management of the environmental effects of packaging.