Economic and policy instrument analyses in support of the scrap tire recycling program in Taiwan

Understanding the cost-effectiveness and the role of economic and policy instruments, such as the combined product tax-recycling subsidy scheme or a tradable permit, for scrap tire recycling has been of crucial importance in a market-oriented environmental management system. Promoting product (tire) stewardship on one hand and improving incentive-based recycling policy on the other hand requires a comprehensive analysis of the interfaces and interactions in the nexus of economic impacts, environmental management, environmental valuation, and cost-benefit analysis. This paper presents an assessment of the interfaces and interactions between the implementation of policy instruments and its associated economic evaluation for sustaining a scrap tire recycling program in Taiwan during the era of the strong economic growth of the late 1990s. It begins with an introduction of the management of the co-evolution between technology metrics of scrap tire recycling and organizational changes for meeting the managerial goals island-wide during the 1990s. The database collected and used for such analysis covers 17 major tire recycling firms and 10 major tire manufacturers at that time. With estimates of scrap tire generation and possible scale of subsidy with respect to differing tire recycling technologies applied, economic analysis eventually leads to identify the associated levels of product tax with respect to various sizes of new tires. It particularly demonstrates a broad perspective of how an integrated econometric and engineering economic analysis can be conducted to assist in implementing policy instruments for scrap tire management. Research findings indicate that different subsidy settings for collection, processing, and end use of scrap tires should be configured to ameliorate the overall managerial effectiveness. Removing the existing boundaries between designated service districts could strengthen the competitiveness of scrap tires recycling industry, helping to reduce the required levels of product tax and subsidy. With such initial breakthroughs at hand to handle the complexity of scrap tire recycling technologies, there remains unique management and policy avenues left to explore if a multi-dimensional solution is to be successful in the long run.     

Scrap tires to crumb rubber: feasibility analysis for processing facilities

Crumb rubber can be produced from scrap tires in a wide range of particle sizes and quality levels. Ideally, the revenue stream includes tipping fees paid to receive the raw materials; sales of variously-sized crumb products to different end-user markets; and potential sales of scrap metal and fiber contained within the tires. General demand has been increasing, and submarkets for crumb products are growing in size and variety. However, the optimistic expectations of potential investors and government agencies contrast sharply with the experiences of many current and former producers. Production planning and operation is complex, real-dollar crumb prices have fallen, and many producers recount difficulties finding stable markets and competing against newer, state-subsidized competitors. This paper examines the engineering economics of crumb rubber facilities. Following a literature review and interviews with producers, a financial model of a nominal processing operation was created to aid the analysis of different market, crumb size, and production scenarios. The profitability of a crumb facility appears to be particularly sensitive to crumb rubber prices, operating costs, and raw material availability. Better analysis of market and production impacts on financial viability for proposed processing facilities would aid overall market efficiency.     

乌昌地区废旧轮胎回收利用现状调查及分析

选取新疆经济发展最快的乌昌地区为靶区,以现场调查资料为基础,根据国内外废旧轮胎回收利用发展变化特点,对该区域的废旧轮胎现状进行了统计分析,并对乌昌地区废旧轮胎的产生量进行了预测。通过对乌昌地区废旧轮胎回收市场特点的调查研究,指出了乌昌地区废旧轮胎回收市场目前存在的问题,提出了相应的建议和措施。     

Rubber tire life cycle assessment and the effect of reducing carbon footprint by replacing carbon black with graphene

This research utilizes real operating data from a tire plant operating in Central Taiwan to investigate the carbon footprint emissions (CO₂e) involved in producing the electric bicycle. The simulation results are based on the PAS 2050 standard using the SimaPro 7.3 software tool. Our results show the total carbon footprint emissions of 1.2-kg tire for the electric bicycle weighing 4.53-kg CO₂e, composed of 2.63-kg CO₂e from raw tire materials stage, 1.295-kg CO₂e from tire manufacturing stage, and 0.605-kg CO₂e from tire transport stage. An international certified organization, British Standard Institute (BSI), verified the accuracy of our results as 98.7%. We found that carbon emissions at the raw materials stage were higher than that for the other two stages – manufacturing and transportation. Carbon black was determined as the maximum source of carbon emissions at the raw material stage. To reduce the tire plant carbon emissions, this paper recommends using graphene to replace carbon black. Graphene has been reported by many researches to improve the properties of rubber products. From our simulation results, the carbon footprint emissions of 4.56-kg CO₂e of the origin tire plant uses 0.456-kg carbon black to produce 1.2-kg electric bicycle tires. This can be reduced to 4.29 (5.92%), 4.03 (11.62%), 3.75 (11.76%), and 3.49-kg CO₂e (23.46%) by using graphene to replace carbon black 25, 50, 75, and 100 wt% respectively. If we focus only on 0.456-kg carbon black producing 1.08-kg CO₂e, the reduced carbon footprint will be 0.812 (24.81%), 0.547 (49.35%), 0.28 (74.07%), and 0.0128-kg CO₂e (98.81%) by using graphene to replace carbon black 25, 50, 75, and 100 wt% respectively. From our analysis, graphene replacing carbon black can reduce carbon footprint. This has not been published previously and provides a direction for the tire plant to save carbon emissions.     

Applying a mathematical approach to improve the tire retreading process

Problem of waste treatment is very important for environment and the share of tires in this scope is high. The aim of this paper is to analyse retreading as one very interesting way of tires’ treatment. In practice, firms involved with commercial vehicles exploitation have to decide whether to retread used tires or not, depending on the number of retreadings of used tires and travelled distances after each retreading. An approach based on Bayesian networks is proposed as a tool for decision making support in tire retreading process. Analysis is performed on database of tires’ exploitation from a company of public passenger transportation and the statistical results are used as inputs to the proposed model. The results obtained according to the proposed model provide a good basis when it comes to making a decision whether to retread or not a used tire.     

The contemporary European silver cycle

This paper examines the 1-year anthropogenic stocks and flows of silver as it progresses from extraction to final disposal on the European continent. The primary flows of silver include production, fabrication and manufacturing, use, and waste management. A substance flow analysis (SFA) was used to trace the flows and inventory data, and mass balance equations were used to determine the quantity of flows. The results reveal that Europe has a low level of silver mine production (1580 Mg Ag/year) and instead relies on silver imports and the recycling of scrap in production and fabrication. In the year 1997, Europe imported 1160 Mg Ag of ore concentrate and 2010 Mg Ag of refined silver, and recycled 2750 Mg Ag of new and old scrap. There is a net addition of 3320 Mg Ag/year into silver reservoirs at the use stage. This is the result of a greater amount of silver entering the system from manufacturing than is leaving the system into waste management. The waste flow with the highest content of silver is municipal solid waste, which contains 1180 Mg Ag/year. In total, 62% of all discarded silver is recycled and 38% is sent to landfills. The results of this study and other element and material flow analyses can help guide resource managers, environmental policy makers, and environmental scientists in their efforts to increase material recovery and recycling, address resource sustainability, and ameliorate environmental problems.     

Environmental consequences of recycling aluminum old scrap in a global market

Nowadays, aluminum scrap is traded globally. This has increased the need to analyze the flows of aluminum scrap, as well as to determine the environmental consequences from aluminum recycling. The objective of this work is to determine the greenhouse gases (GHG) emissions of the old scrap collected and sorted for recycling, considering the market interactions. The study focused on Spain as a representative country for Europe. We integrate material flow analysis (MFA) with consequential life cycle assessment (CLCA) in order to determine the most likely destination for the old scrap and the most likely corresponding process affected. Based on this analysis, it is possible to project some scenarios and to quantify the GHG emissions (generated and avoided) associated with old scrap recycling within a global market. From the MFA results, we projected that the Spanish demand for aluminum products will be met mainly with an increase in primary aluminum imports, and the excess of old scrap not used in Spain will be exported in future years, mainly to Asia. Depending on the scenario and on the marginal source of primary aluminum considered, the GHG emission estimates varied between −18,140 kg of CO₂ eq. t⁻¹ and −8427 of CO₂ eq. t⁻¹ of old scrap collected. More GHG emissions are avoided with an increase in export flows, but the export of old scrap should be considered as the loss of a key resource, and in the long term, it will also affect the semifinished products industry. Mapping the flows of raw materials and waste, as well as quantifying the GHG impacts derived from recycling, has become an essential prerequisite to consistent development from a linear toward a circular economy (CE).     

Gaseous contaminant emissions as affected by burning scrap tires in cement manufacturing

We studied the environmental impact (gaseous emissions) of using scrap tires as a fuel substitute at a cement plant that produces one million tons of cement per year. Using a combination of tires and coal as opposed to only coal caused variations in the pollutant emission rate. The study recorded a 37% increase in the rate of emission for CO, a 24% increase for SO2, an 11% decrease for NOx, and a 48% increase for HCl when tires were included. The rate of emission for metals increased 61% for Fe, 33% for Al, 487% for Zn, 127% for Pb, 339% for Cr, 100% for Mn, and 74% for Cu, and decreased 22% for Hg. On the other hand, the emission rate of organic compounds dropped by 14% for polycyclic aromatic hydrocarbons, 8% in naphthalene, 37% in chlorobenzene, and 45% in dioxins and furans. We used a Gaussian model of atmospheric dispersion to calculate the average pollutant concentration (1-h, 24-h, and annual concentrations) in the ambient air at ground level with the help of the ISC-ST2 software program developed by the USEPA. When tires were used, we observed (i) a 12 to 24% increase in particulate matter, this range considering the concentration variation depending on the average used (1-h, 24-h, and annual basis), 31 to 52% in CO, 22 to 34% in SO2, 39 to 52% in HCl, 12 to 27% in Fe, -3 to 8% in Al, 30 to 37% in Zn, and 270 to 885% in Pb; (ii) a decrease of 8 to 13% in NOx, 9 to 13% in polycyclic aromatic hydrocarbons, 6 to 7% in naphthalene, 32 to 39% in chlorobenzene, and 32 to 45% in dioxins and furans. The results obtained showed that the maximum ground-level concentrations were well within the environmental standards (for operation with only coal as well as for operation with a combination of coal and tires).     

Historical evolution of anthropogenic aluminum stocks and flows in Italy

Dynamic stocks and flows analysis was applied to the anthropogenic aluminum cycle in Italy in order to detect and quantify metal flows and in-use stocks over the years 1947–2009. The model utilized a top-down approach, including data for production, consumption, loss, and trade flows of aluminum. Seven end-use markets were considered, namely buildings and construction, transportation, consumer durables, machinery and equipment, electrical engineering, containers and packaging, and miscellaneous appliance types. The results of this dynamic stocks and flows analysis model quantified the contemporary anthropogenic reservoirs (or in-use stocks) of aluminum at about 320 kg per capita, mainly embedded within the transportation and building and construction sectors. Cumulative in-use stock represents approximately 11 years of supply at current usage rates (about 20 Mt versus 1.7 Mt/year), implying significant potential for recycling in the future as this stock comes out of use. Flow analysis revealed that Italy imports mainly unwrought aluminum and exports final products, while the main material losses occur during alumina refining and collection of old scrap: specifically, containers and packaging have the highest old scrap generation rate, but for the lowest recovery rate (50%). Increasing support to collection of scrap and initiatives oriented to aluminum recovery specifically would allow Italy to increase its reliance on domestic material, and may also allow a decline of the country import-dependence on primary sources. The dynamic stocks and flows model created here provides a quantitative historical record of the aluminum required by Italian society during important periods of development and provides guidance for future decision-making around the use of domestic secondary resources.     

In-depth analysis of aluminum flows in Austria as a basis to increase resource efficiency

Based on the method of material flow analysis (MFA), a static model of Austrian aluminum (Al) flows in 2010 was developed. Extensive data research on Al production, consumption, trade and waste management was conducted and resulted in a detailed model of national Al resources. Data uncertainty was considered in the model based on the application of a rigorous concept for data quality assessment. The model results indicated that the growth of the Austrian “in-use” Al stock amounts to 11 ± 3.1 kg yr⁻¹ cap⁻¹. The total “in-use” Al stock was determined using a bottom-up approach, which produced an estimate of 260 kg Al cap⁻¹. Approximately 7 ± 1 kg of Al yr⁻¹ cap⁻¹ of old scrap was generated in 2010, of which 20% was not recovered because of losses in waste management processes. Quantitatively, approximately 40% of the total scrap input to secondary Al production originated from net imports, highlighting the import dependency of Austrian Al refiners and remelters. Uncertainties in the calculation of recycling indicators for the Austrian Al system with high shares of foreign scrap trade were exemplarily illustrated for the old scrap ratio (OSR) in secondary Al production, resulting in a possible range of OSRs between 0 and 66%. Overall, the detailed MFA in this study provides a basis to identify resource potentials as well as resource losses in the national Al system, and it will serve as a starting point for a dynamic Al model to be developed in the future.     

The economics of tire remanufacturing

The world market for tires is described to identify the current material flow from raw materials to tires and the used tire disposal problem. Then, I describe the value-adding operations in the tire production process and in the tire retreading process. Once retreading is identified as the only recovery alternative that maximizes tire utilization, I explain why heat generation is the only recovery alternative, when retreading is not technically feasible. The economic values of heat generation in electric plants and in cement kilns are discussed. The paper culminates with the case of retreading, the tire remanufacturing process and the recommendation of a simple decision rule for selecting the number of times a tire should be retreaded to maximize its utilization.     

Road traffic and nearby grassland bird patterns in a suburbanizing landscape

An extensive road system with rapidly increasing traffic produces diverse ecological effects that cover a large land area. Our objective was to evaluate the effect of roads with different traffic volumes on surrounding avian distributions, and its importance relative to other variables. Grassland bird data (5 years) for 84 open patches in an outer suburban/rural landscape near Boston were analyzed relative to: distance from roads with 3000–8000 to >30,000 vehicles/day; open-habitat patch size; area of quality microhabitat within a patch; adjacent land use; and distance to other open patches. Grassland bird presence and regular breeding correlated significantly with both distance from road and habitat patch size. Distance to nearest other open patch, irrespective of size, was not significant. Similarly, except for one species, adjacent land use, in this case built area, was not significant. A light traffic volume of 3000–8000 vehicles/day (local collector street here) had no significant effect on grassland bird distribution. For moderate traffic of 8000–15,000 (through street), there was no effect on bird presence although regular breeding was reduced for 400 m from a road. For heavier traffic of 15,000–30,000 (two-lane highway), both bird presence and breeding were decreased for 700 m. For a heavy traffic volume of ≥30,000 vehicles/day (multilane highway), bird presence and breeding were reduced for 1200 m from a road. The results suggest that avian studies and long-term surveys near busy roads may be strongly affected by traffic volume or changes in volume. We conclude that road ecology, especially the effects extending outward >100 m from roads with traffic, is a sine qua non for effective land-use and transportation policy.     

轮胎低温耐久性能试验台架研究

针对轮胎冬季耐久试验中低温开裂现象和耐久试验的环境限制,设计开发一套模拟整车状态下轮胎低温运行状态的试验台架。该台架系统包括低温环境仓,低温控制系统,执行机构和控制机构四部分。根据冬季黑河实际道路试验确定台架试验的试验车速、环境温度、运行载荷、定位角度、运行周期以及运行里程。通过对比试验和验证试验结果显示:当失效率为10%时(即轮胎B10寿命),试验台误差在10%以内,验证了新开发试验台的有效性,为考核同类型轮胎低温性能提供了有效途径。     

An overview of waste materials recycling in the Sultanate of Oman

Various wastes and by-product materials are generated in the Sultanate of Oman including reclaimed asphalt pavement (RAP) aggregate, demolition concrete, cement by-pass dust (CBPD), copper slag, petroleum-contaminated soils (PCS), discarded tires, incinerator ash, and others. Recycling of such materials in construction is not practiced. Research data are also minimal into the potential use of selected materials in construction applications. This paper will present the results of several laboratory studies conducted into the use of PCS in asphalt concrete mixtures; on the use of CBPD in soil stabilization and flowable fill mixtures; on the utilization of copper slag and CBPD as cementitious materials; on the use of incinerator ash in cement mortars; and on the use of RAP aggregate in road bases and sub-bases. Laboratory data generally indicate that it is feasible to partially reuse some of these materials in construction provided that economic incentives and environmental concerns are taken into consideration.     

Road Traffic and Nearby Grassland Bird Patterns in a Suburbanizing Landscape

An extensive road system with rapidly increasing traffic produces diverse ecological effects that cover a large land area. Our objective was to evaluate the effect of roads with different traffic volumes on surrounding avian distributions, and its importance relative to other variables. Grassland bird data (5 years) for 84 open patches in an outer suburban/rural landscape near Boston were analyzed relative to: distance from roads with 3000–8000 to >30,000 vehicles/day; open-habitat patch size; area of quality microhabitat within a patch; adjacent land use; and distance to other open patches. Grassland bird presence and regular breeding correlated significantly with both distance from road and habitat patch size. Distance to nearest other open patch, irrespective of size, was not significant. Similarly, except for one species, adjacent land use, in this case built area, was not significant. A light traffic volume of 3000–8000 vehicles/day (local collector street here) had no significant effect on grassland bird distribution. For moderate traffic of 8000–15,000 (through street), there was no effect on bird presence although regular breeding was reduced for 400 m from a road. For heavier traffic of 15,000–30,000 (two-lane highway), both bird presence and breeding were decreased for 700 m. For a heavy traffic volume of ≥30,000 vehicles/day (multilane highway), bird presence and breeding were reduced for 1200 m from a road. The results suggest that avian studies and long-term surveys near busy roads may be strongly affected by traffic volume or changes in volume. We conclude that road ecology, especially the effects extending outward >100 m from roads with traffic, is a sine qua non for effective land-use and transportation policy.     

Energy and CO2 from high performance recycled aggregate production

The use of recycled concrete aggregates (RCA) in applications other than road sub-layers is limited by two factors: the high porosity of RCA in comparison with natural aggregates, and the restrictions set forth in standards and building codes. Research efforts aimed at alleviating these restrictions are focused on improving the quality of coarse RCAs by reducing the amount of adhered cement pastes, which is the weakest element in this system and influences the rheological behaviour.This paper presents an analysis of the environmental impacts of the recent mechanical and thermo-mechanical processing techniques which produce high performance RCA by reducing the volume of adhered cement paste. Based on published data, processing scenarios were established. These scenarios permit making rough estimates of energy consumption, CO₂ emissions, fines generation and product quality. Using these data and the available emission factors from several countries, an objective comparison was made between these innovating processes and conventional recycling.The production of fines increases from 40% up to as much as 70% as the volume of adhered cement paste on the RCA is reduced. Fuel fed thermo-mechanical process energy consumption, per tonne of recycled aggregate, varies between 36 and 62 times higher than conventional recycling processes. Mechanical processing, combined with microwave heating, increases energy consumption from 3 to a little more than 4 times conventional recycling. Consequently, CO₂ emissions released by conventional coarse aggregate production go from 1.5 to 4.5 kgCO₂/t, to around 200 kgCO₂/t, for that of fossil fuel fed thermo-mechanical treatments.Mechanical and mechanical/microwave treatments appear to have the greatest environmental potential. Notwithstanding, the further development of markets for fines is crucial for reducing environmental loads.     

Comparing Environmental Conditions Using Indicators of Pollution Hazard

/ Land use/land cover classifications for 1973 and 1991, derived from the interpretation of satellite imagery, are quantified on the basis of biophysical land units in a study area in southeastern Australia. Nutrient export potentials are estimated for each land unit based on their composition of land use/land cover classes. Spatial and temporal comparisons are made of the land units based on the calculated pollution hazard indicators to provide an insight into changes in the state of the environment and the regional significance of land use changes. For example, one ecosystem, unique to the study, showed a large increase in pollution hazard over the study period as a manifestation of an 11-fold rise in cleared area and an expansion of cropping activities. The benefits to environmental management in general are discussed.KEY WORDS: Land cover change; Nutrient export; Environmental condition; Pollution hazard; Agricultural pollution; Nonpoint source pollution; Diffuse pollution; Environmental degradation     

Training carbon management engineers: Removing a major hurdle for geologic CO2 storage by increasing educational capacity

Implementing geologic storage of CO₂ at a material scale (ca. 1 Gt C/year) will require an industry comparable in size to the current oil and gas industry and a workforce trained in subsurface engineering. Since the same technologies that apply to hydrocarbon production apply to the subsurface storage of CO₂, petroleum engineering (PE) graduates will be valuable candidates to work in the carbon storage industry. We expect however that the demand for PEs from the oil and gas industry will increase, and that already strained educational capacity will not be sufficient to supply both industries. Thus we advocate building new targeted educational infrastructure. We present a model curriculum based on an existing accredited multidisciplinary degree program. This program combines the fundamentals of petroleum engineering with the subsurface architecture emphasis of geology and the environmental perspective of hydrogeology. We indicate key elements of this program that could be integrated with other, more traditional undergraduate engineering majors that also deal with the subsurface.     

Variability in environmental impacts of Brazilian soybean according to crop production and transport scenarios

Soybean production and its supply chain are highly dependent on inputs such as land, fertilizer, fuel, machines, pesticides and electricity. The expansion of this crop in Brazil in recent decades has generated concerns about its environmental impacts. To assess these impacts, two representative chains supplying soybeans to Europe were identified: Center West (CW) and Southern (SO) Brazil. Each supply chain was analyzed using Life Cycle Assessment methodology. We considered different levels of use of chemical and organic fertilizers, pesticides and machinery, different distances for transportation of inputs and different yield levels. Because transportation contributed strongly to environmental impacts, a detailed study was performed to identify the routes used to transport soybeans to seaports. Additionally, we considered different levels of land occupation and land transformation to represent the impact of deforestation in the CW region. Environmental impacts were calculated for 1000 kg of soybean up to and including the delivery to Europe at the seaport in Rotterdam, at 13% humidity. Overall results showed that the impacts are greater for CW than for SO for all impact categories studied, including acidification (7.7 and 5.3 kg SO₂ eq., respectively), climate change (959 and 510 kg CO₂ eq.), cumulative energy demand (12,634 and 6,999 MJ) and terrestrial ecotoxicity (4.9 and 3.1 kg 1,4-DCB eq.), except eutrophication and land occupation. The same trend was observed for the crop-production stage. Efforts to reduce chemical fertilizers and diesel consumption can reduce CO₂ emissions. Although deforestation for crop production has decreased in recent years, the contribution of deforestation to climate change and cumulative energy demand remains significant. In the CW scenario deforestation contributed 29% to climate change and 20% to cumulative energy demand. Results also showed that although there are different transportation options in Brazil, the current predominance of road transport causes severe environmental impacts. In CW, road transport contributed 19% to climate change and 24% to cumulative energy demand, while in SO it contributed 12% and 15% to these impacts, respectively. Improvements in the logistics of transportation, giving priority to rail and river transports over road transport, can contribute significantly to reducing greenhouse gas emissions and decreasing energy use. Future studies involving Brazilian soybeans should take into account the region of origin as different levels of environmental impact are predicted.     

Light rail use is more likely on “walkable” blocks: Further support for using micro-level environmental audit measures

The primary purpose of the study was to address the claim that people are more likely to walk to a transit stop if they live on a “walkable” block. An additional purpose was to evaluate the Irvine Minnesota Inventory (IMI) as an environmental audit tool. The IMI was used to measure walkability features of 19 blocks in a revitalizing neighborhood. We hypothesized that residents who walked to a light rail TRAX stop (n = 22) would live on blocks with higher walkability ratings compared to residents who did not walk to TRAX (nonriders, n = 15), or who walked only after a closer TRAX stop was built (new users, n = 11). A MANCOVA indicated the IMI scales differentiated the blocks; the strongest differences were obtained in subscales that measured the block's diversity, safety from crime and density (marginally significant). Participants' perceptions of their complete walk to the transit stop were consistent with the home block IMI scores, with the continuing riders having more positive views than the other two groups. The results show the ability of the IMI to distinguish among blocks in walkability, and support further use of this audit tool in environmental analyses and active living research. We end with a discussion of conceptual and methodological issues in the use of audit tools and provide recommendations for using these measures for local, immediate interests, as well as for building a broader science of environmental measurement.