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.     

Steel all over the world: Estimating in-use stocks of iron for 200 countries

Industrialization and urbanization in the developing world have boosted steel demand during the recent two decades. Reliable estimates on how much steel is required for high economic development are necessary to better understand the future challenges for employment, resource management, capacity planning, and climate change mitigation within the steel sector. During their use phase, steel-containing products provide service to people, and the size of the in-use stock of steel can serve as an indicator of the total service level. We apply dynamic material flow analysis to estimate in-use stocks of steel in about 200 countries and identify patterns of how stocks evolve over time. Three different models of the steel cycle are applied and a full uncertainty analysis is conducted to obtain reliable stock estimates for the period 1700–2008.Per capita in-use stocks in countries with a long industrial history, e.g., the U.S, the UK, or Germany, are between 11 and 16 tons, and stock accumulation is slowing down or has come to a halt. Stocks in countries that industrialized rather recently, such as South Korea or Portugal, are between 6 and 10 tons per capita and grow fast. In several countries, per capita in-use stocks of steel have saturated or are close to saturation. We identify the range of saturation to be 13 ± 2 tons for the total per capita stock, which includes 10 ± 2 tons for construction, 1.3 ± 0.5 tons for machinery, 1.5 ± 0.7 tons for transportation, and 0.6 ± 0.2 tons for appliances and containers. The time series for the stocks and the saturation levels can be used to estimate future steel production and scrap supply.     

Time-series analysis of global zinc demand associated with steel

This study aimed to analyze the global-scale substance flow of zinc associated with steel in order to discuss the sustainable use of zinc resources in the future. The relationship between the demand for steel and zinc was characterized in terms of zinc intensity for galvanized steel and the percentage of galvanized steel that accounts for the total steel demand. Zinc consumption for steel was divided into end uses according to the statistics on steel. Zinc demand in the future was forecasted with three scenarios for zinc intensity. Future steel demand was estimated using the stocks-drive-flows model, in which the demand is determined by the change in stock. The growth of in-use stock of galvanized steel in the future was estimated by considering economic growth on the basis of the transition of in-use stock of galvanized steel in the past. The cumulative zinc demand for galvanized steel up to the year 2050 was compared with the zinc reserves. It was found that the global average recovery rate of zinc was estimated at approximately 20% by the dynamic substance flow analysis for zinc. It is hoped that the recovery rate will increase. Even if zinc intensity is continuously reduced according to an experience curve based on technological development, a large portion of the current reserves will be consumed for galvanized steel. It was concluded that technological development in reducing zinc intensity will play a significant role in zinc resource conservation.     

Global anthropogenic tellurium cycles for 1940–2010

Tellurium is increasingly used in solar photovoltaics in the form of cadmium–telluride (CdTe) thin films. There are concerns regarding whether tellurium availability could be a constraint on large-scale deployment of CdTe photovoltaics. The present work brings a new perspective to the discussion of tellurium availability by providing the first extant global tellurium cycles constructed with material flow analysis principles. The tellurium cycles, for 1940–2010, present information on the production, fabrication and manufacturing, use, and resource management stages during this period. The results of the analysis show that during 1940–2010 approximately 11 Gg of refined tellurium was produced. This represents about 4.5% of the tellurium that was extracted from the ground during copper mining. Almost 80% of the refined tellurium, 8.5 Gg, was dissipated into end-uses such as metallurgical additives to iron, steel, and nonferrous metals, and thereby lost to potential reuse. As of 2010, the in-use tellurium stock is estimated at 1.1 Gg, which mainly accumulated after 1990s with the increasing tellurium use in electronics, specifically photovoltaic and thermoelectric devices. Because tellurium is a byproduct of copper ores, its supply can be enhanced by more attention to recovery during processing of the copper parent. Tellurium can also, in principle, be recovered from end-of-life electronics; the increasing in-use stock indicates the potential for significant end-of-life recycling in the coming decades.     

Quantification and spatial characterization of in-use copper stocks in Shanghai

Shanghai is the largest industrial and commercial city of China, where in-use stocks of metals are likely to be significant. The in-use stocks of copper in this city are thus established by an extensive “bottom-up” study. Spatial distribution of copper stocks within Shanghai has further been characterized for better understanding of copper utilization pattern of this city. For the year 2012, the results are a total stock of 914.6 Gg Cu, and 38.4–64.1 kg Cu per capita. Nearly 94% of copper stocks distribute in subcategories of electric power transmission and distribution, water transmission and distribution, buildings, and household durable. Features of spatial distribution show that three central districts of Jing An, Hong Kou and Huang Pu have the spatial density of more than 1 Gg/km². And Chong Ming county and Jin Shan District have the lowest spatial density of about 0.01 Gg/km². It has been found that the copper stock density within Shanghai is largely determined by population density and economic development level.     

Global anthropogenic selenium cycles for 1940–2010

Selenium plays an important role in emerging thin film solar energy technologies. As solar energy is expected to have a larger share in the world's future energy portfolio, the long-term availability of selenium becomes a potential concern, yet no global cycles have ever been generated. In this work, the global cycles, stocks, and flows of selenium are characterized for the entire time period 1940–2010 by using principles of material flow analysis (MFA). The cycles present information on the production, fabrication and manufacturing, use, and resource management stages during that period. The results of the analysis show that during 1940–2010 approximately 90 Gg of refined selenium was produced and entered into fabrication and manufacturing worldwide. 60 Gg of this amount (two-thirds!) was dissipated into the environment through end-uses such as chemicals, pigments, glass manufacturing, metallurgical additives, and fertilizer and feed additives. The in-use stock of selenium is estimated at 2.7 Gg as of 2010. Because of data limitations such as proprietary and withheld information, these figures represent informed estimates rather than exact values. Selenium can be recovered from end-of-life electrical and electronic equipment, while for other end-uses recycling is difficult or impossible. One of the ways to buttress supplies of selenium for future technologies would be to deploy recycling schemes for photovoltaics as well as other electronics applications.     

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.     

Cement and concrete flow analysis in a rapidly expanding economy: Ireland as a case study

A national material flow model for concrete, the most popular construction material in Ireland, was developed based on the framework of material flow analysis. Using this model the Irish concrete cycle for the year 2007 was constructed by analysing the material life cycle of concrete which consists of the three phases of: production (including extraction of raw materials and manufacture of cement), usage (ready-mix and other products) and waste management (disposal or recovery). In this year, approximately 35 million metric tonnes of raw materials were consumed to produce 5 million metric tonnes of cement and 33 million metric tonnes of concrete. Concrete production was approximately 8 metric tonnes per capita. By comparison, the concrete waste produced in that year was minimal at only 0.3 million metric tonnes. Irish building stock is young and there was little demolition of structures in the year of study. However this build up of construction stock will have implications for the future waste flows when the majority of stock built in the last decade (43% of residential stock was constructed in the last 15 years) reaches its end of life.     

Dynamic material flow analysis of steel resources in Korea

Material flow analysis (MFA) is an evaluation technique that systematically identifies the flows and stocks of materials within predefined spatial and temporal boundaries. In this paper, the steel resources in Korea are investigated using dynamic MFA. Iron ore and steel scrap are added as raw material components during the production processes of steel, which is then used in a variety of product groups such as construction products, transportation equipment, machinery/metal products, electrical/electronic devices, and other products through fabrication and manufacturing processes. When such product groups are discarded, they are either recycled or landfilled. With consideration for the lifetimes of various product groups in conjunction with steel resource flows in Korea, dynamic MFA is conducted on the flows of steel stock change and annual scrap generation. By 2020, these two flows are expected to increase by as much as 40% and 30%, respectively, compared to 2008, with transportation equipment, in particular, envisaged to experience high growth. At the current recycling rate, however, it will be hard to meet future scrap demand. According to the scenario analysis, 100% of this future scrap demand can be supplied domestically if the recycling rate is increased to over 70% for all product groups, except construction products and transportation equipment, which already have high recycling rates. By 2020, the reduction in scrap importation costs is projected to offer a financial gain of 2.3 billion dollars.     

基于VMAS四川省在用点燃式轻型车尾气污染削减预测

针对四川省在用车辆尾气污染情况开展了详细的调查研究,结果表明四川省机动车尾气污染中约71.3%的CO、68.6%的HC、95.3%的NOx和99.2%的PM均来自于汽车尾气。同时分析得出简易瞬态工况法是在用车辆尾气排放控制的有效控制方法,有利于四川省大气环境质量的改善,经预测采用简易瞬态工况法以及简易瞬态工况法排放标准后可使四川省在用点燃式轻型车尾气排放的CO削减约28.76%~50.48%,HC+NOx削减约1.53%~23.24%。     

Use of system dynamics for proper conservation and recycling of aggregates for sustainable road construction

A significant amount of mineral aggregates are used in constructing, rehabilitating and maintaining roads. As local (nearby) quarries get exhausted, aggregates need to be hauled from sources that are at ever-greater distances. Hence, over time the cost of trucking as well as the amount of emissions generated by trucking increases with a decrease of local natural aggregate stocks. The objectives of this study are to construct and utilize a system dynamics model of the depletion of a stock of natural aggregates due to pavement construction and maintenance, and determine the effect of using local and nonlocal aggregates, recycling and project cancellation (slowing growth) on the paving of roads. Long-term simulations are carried out with available aggregate stock, trucking distance and cost data. The quality of roads and a sustainability score, based on engineering, economic and environmental factors (emissions) are evaluated for different scenarios. An optimal combination of the use of local and nonlocal recycled aggregates, recycling and project cancellation is recommended. The proposed system dynamics model could be utilized by agencies to plan for the proper utilization of aggregate resources for road development and maintenance/rehabilitation projects.     

Soil carbon stocks and changes in the Republic of Ireland

The soil carbon (C) stock of the Republic of Ireland is estimated to have been 2048 Mt in 1990 and 2021 Mt in 2000. Peat holds around 53% of the soil C stock, but on 17% of the land area. The C density of soils (tCha(-1)) is mapped at 2 km x 2 km resolution. The greatest soil C densities occur where deep raised bogs are the dominant soil; in these grid squares C density can reach 3000 tCha(-1). Most of the loss of soil C between 1990 and 2000-up to 23 MtC (1% of 1990 soil C stock)-was through industrial peat extraction. The average annual change in soil C stocks from 1990 to 2000 due to land use change was estimated at around 0.02% of the 1990 stock. Considering uncertainties in the data used to calculate soil C stocks and changes, the small average annual 'loss' could be regarded as 'no change'.     

Using nighttime light data to estimate water evaporation inside buildings in China's urban areas

Urbanization has a great impact on urban evapotranspiration. Water evaporation inside buildings is an important part of urban water vapor resources and a crucial core of urban hydrological processes. The systematic studies on building water evaporation (BWE) are mostly the method of experimental monitoring. This study proposed a new method to simulate and estimate water evaporation flux inside buildings in urban areas. Based on the nighttime light data and urban per capita gross domestic product (GDP), a new modeling system was built to simulate the total BWE. Building area was calculated using the nighttime light data. And the BWE coefficient D_f was estimated according to the important indicator of economic development per capita GDP value. Then the water evaporation inside urban buildings and the spatial distribution of water evaporation inside buildings in typical cities could be obtained. The results showed that the total amount of water evaporation inside buildings in China's urban areas was 24.5 billion m³. Among the 31 provincial capitals in China, Shanghai had the largest BWE of 1.08 billion m³. The minimum water evaporation of buildings in Lhasa was 20.0 million m³. Studies of BWE can assess urban water budgets, support on-demand allocation of water resources, and provide a fundamental understanding of the relationship between water resources and energy heat island effects in urban areas.     

Trends and development of steel demand in China: A bottom–up analysis

With economic development, the Chinese steel industry has rapidly expanded over the past three decades. However, this expansion has resulted in many problems, such as increasing energy consumption and excessive environmental pollution. Therefore, it is important to analyze the future steel demand in China. This study presents changes in steel production and apparent steel consumption in the years 1998–2010. Steel is mainly consumed by construction, machinery, automobiles, shipbuilding, railways, petroleum, household appliances and containers, and these nine industries are analyzed separately using stock based models. The study suggests steel demand in China will rise from 600 million t in 2010 to a peak of 753 million t in 2025, and then gradually decrease to 510 million t in 2050. The construction industry is the largest steel consumer, although its share of total steel demand will decrease in the future. Steel demand in automobile manufacturing, by contrast, will increase rapidly before 2035, and its share will increase from 6.0% in 2010 to 19.0% in 2050. Sensitivity analysis on the four major impact factors such as saturation levels, lifetime distributions, GDP and urbanization rate shows that saturation levels of different products greatly affect long-term and short-term steel demands, while GDP and lifetime distributions, especially the lifetime distribution of buildings, mainly affect the short-term and long-term steel demands, respectively.     

Improving National-Scale Carbon Stock Inventories Using Knowledge on Land Use History

National-scale inventories of soil organic carbon (SOC) and forest floor carbon (FFC) stocks have a high uncertainty. Inventories are often based on the interpolation of sampled information, often using a number of covariables to help such interpolation. The rationale for the choice of these covariables is not always documented, despite the fact that many local-scale studies have identified the factors explaining spatial variability of SOC and FFC stocks. These studies indicate, among others the importance of long-term land use history. Despite this, information on the effects of land use history has never been used to explain variability of carbon stocks in national-scale inventories. We designed an alternative method to improve national-scale inventories of SOC and FCC for the Dutch sand area that takes stock of the findings of detailed case studies. Determinants for SOC and FFC stocks derived from landscape-scale case studies were used to map national-scale spatial variability and to calculate national totals. The resulting national-scale spatial distribution was compared with the SOC stock map from the current Dutch greenhouse gas inventory. Using land use history to explain SOC variability decreased the error of the SOC stock estimate in 60 % of the area. The error in FFC stocks decreased in half of the forest area after including soil fertility, tree species, and forest age as explanatory factors. Estimates with reduced uncertainty will make land use and land management a more attractive and acceptable mitigation option to reduce emissions of greenhouse gases for the LULUCF sector.     

面向城市管理的城市建筑存量研究综述

城市建筑存量研究是为适应当前城市管理的需要而出现的理论研究,与国家制定的城市可持续发展战略具有内在一致性。本文对城市建筑存量的概念进行解析,全面阐述了城市建筑存量研究的意义,概述了城市建筑存量研究的系统边界、内涵和研究方法等,总结了城市建筑存量研究的三大领域：城市建筑存量时空演变及影响因素研究、城市建筑废弃物资源化开发潜力分析研究和城市可持续管理决策支持系统开发的研究现状。目前城市建筑存量理论体系尚不够完善、定量工具和基础数据库严重缺乏,对于城市决策支持不足,未来应在城市建筑存量时空演变及环境影响分析、开发融合多学科交叉及新技术应用的分析方法和辅助城市可持续管理决策三个领域加强和深化研究。     

Towards environmentally sustainable industrialization: a case study of some mini iron and steel industries in India

Summary Iron and steel have been used in India since ancient times (possibly as early as 5000 BC). There are several references to the use of iron and steel in the Vedic literatures. The rust and corrosionfree iron pillar of Qutub Minar in Delhi, built 1500 years ago and the steel girders used in the temples of Orissa around AD 700–1200 still bear the testimony of these early industries. Steels are in great demand today but the large steel plants provide a limited range of steel mostly consumed in building and construction activities. In India, heavy machine tools, locomotives, automobiles, aviation, ship building and engineering tools require super grade steels with various specifications and these are met by mini iron and steel industrial plants. There are approximately 160 such plants mostly situated in big cities and towns. There are several economic and ecological advantages of these mini steel plants. They mostly use iron and steel scrap and other kinds of iron wastes from large industries as their raw material, contrary to the large plants which use iron ores as primary raw materials, the extraction processing and utilization of which involves severe environmental damage by way of deforestation and air and water pollution. Mini steel plants consume much less water and energy. The government of India has given a number of incentives to the mini steel industries by way of exemption from income tax, custom and excise duties, depreciation and investment allowances and rebates on charges for consumption of water and electricity.Dr Rajiv K. Sinha is an assistant professor in human ecology at the University of Rajasthan. Mr V.N. Bhargava is an engineer employed at the Research and Development Division of National Engineering Industries, Khatipura Road, Jaipur 302006, India.     

贵阳城市污水处理厂污泥生产轻质陶粒的研究

贵阳市小河污水处理厂以机械脱水污泥为原料,配以页岩、少量锯末及玻璃粉,摸拟贵州坤泰建材工贸有限公司粘土陶粒厂生产工艺,经练泥搅拌、挤压成球、预热焙烧（焙烧温度1050℃并保温30min）等各生产工序,成功生产出不同密度等级的普通轻质陶粒。     

Using growth curves to forecast long-term trends for processed raw materials

The methods of using growth curves in the economic field to forecast consumption and market developments have been based on the ‘black box’ principle in most of the published cases and have therefore failed to produce reliable results in the medium and long term. This paper introduces an engineering approach for forecasting long-term trends pertaining to the use of processed raw materials. The forecasting is performed by means of a newly developed growth model. To prove the usefulness and validity of the model presented, long-term trends have been calculated for various processed raw materials, such as nickel, platinum and steel.     

Nitrogen in the Baltic Sea--policy implications of stock effects

We develop an optimal control model for cost-effective management of pollution, including two state variables, pollution stock and ecosystem quality. We apply it to Baltic Sea pollution by nitrogen leachates from agriculture. We present a sophisticated, non-linear model of leaching abatement costs, and a simple model of nitrogen stocks. We find that significant abatement is achievable at reasonable cost, despite the countervailing effects of existing agricultural policies such as price supports. Successful abatement should lead to lower nitrogen stocks in the sea in 5 years or less. However, the rate of ecosystem recovery is less certain. The results are highly dependent on the rate of self-cleaning of the Baltic Sea, and less so on the discount rate. Choice of target has a radical effect on the abatement path chosen. Cost-effectiveness demands such a choice, and should therefore be used with care when stock effects are present.