Economic analysis of the composition of household solid wastes

An analysis of economic and social factors affecting the quantity and composition of household solid wastes is reported in this paper. The weekly per capita and per household quantities of eleven selected household solid waste components are analyzed using regression equations. Household income, household size, and the age structure of the population are the major variables affecting the quantities of these components. The results indicate that if all glass, metals, plastics, newspaper, other paper, and textiles were recovered, then about 53% by weight of the summer household solid waste load would be usable resources.     

Impact of nickel mining and metallurgical activities on the distribution of heavy metals in sediments of Levisa, Cabonico and Nipe Bays, Cuba

At MayarÕ zone, northeast Cuba, important lateritic deposits have been exploited since 1943. The mineral is used as raw material in a nickel-processing plant which discharges its untreated solid and liquid wastes into Levisa Bay. Similarly to the adjacent Nipe and Cabonico bays, fluvial currents from the mining areas convey a significant mineral load into this bay. To assess the environmental impact caused by the mining and the metallurgical activities, the distribution of Ni, Co, Fe, Mn, Cu, Pb and Zn was investigated in surface and core sediment samples. Uni- and multivariate statistical methods as well as different indices and pollutant factors were used to interpret results. These revealed significant environmental impacts in some areas of the three bays with high concentrations of Ni, Co, Fe and Mn, whose values are up to two orders of magnitude greater than the zone baseline levels. The metal concentrations decreased with increasing distance from discharges. A comparison with other Cuban bays and coastal zones, confirmed that the main source of metal pollution in these three bays was not urban and industrial activities, but lateritic mining and metallurgy.     

The withdrawal of land from mining — A study of the implications for the future

As a result of several decades of growing environmental awareness, pressures to restrict mining activity in areas of high scenic and recreational value are great. The development of planning law, and legislation for National Parks, are outlined as a framework for current mineral policies in this country, which highlight the fact that at present, almost any area in Britain could theoretically be mined, i.e. few areas are actually banned from mineral working. This contrasts with the situation in the USA where considerable acreages, especially in the Western States, are either covered by absolute bans, or are heavily restricted from mining activity.Should some areas of Britain become similarly off-limits to mining, possible implications include increased deficits in the balance of payments, reduced reliability of mineral supplies to industry, adverse social effects on a local scale, and, on the advantageous side, more efficient use of recycled waste and other alternative sources of materials. Taking all these into account, it is concluded that a ban on mining in some areas would be a dangerously short-sighted, inflexible and irreversible step, and a more moderate approach is required, while the need to protect highly valued areas is recognised as being very important.     

Evaluation of recycling waste materials and by-products in highway construction

SUMMARY

The generation, handling, and safe disposal of waste materials has become a major concern in North America. Approval of facilities for waste processing and proper disposal is becoming more difficult to obtain. Furthermore, there is a growing public awareness of the importance of conserving and preserving our valuable natural resources. This expanding awareness has given rise to the trend towards recycling or reuse of awide variety of solid wastes. Experiences with using waste materials in highway construction can vary considerably, depending on material characteristics, construction processes, and climatic differences. A number of waste materials may be suitable for use in highway construction, but others may not. The objective of this paper is introduced in two tasks. The first is to include a survey of the waste materials and by-products that have been used successfully, or may be used, as materials for highway construction or maintenance work. This also includes determination of the state of practice concerning economic and technical factors for these wastes. The second is to rank these materials based on three criteria: number of uses by State agencies, economic uses and performance aspects.     

Prediction of particulate air pollution from a landfill site using CFD and LIDAR techniques

Landfill sites have been the most common way of eliminating solid urban waste, as well as that of public and mining wastes. Landfill sites are a constant source of environmental pollution and wind is the most important contributing factor to air pollution, due to the erosion which it produces over the landfill site surfaces, transporting dust away from the source point. This causes serious risks for human health and general dirt in the surrounding areas of the landfill site. The result of dust air pollution produced in a landfill site is analysed through CFD3D (Computational Fluid Dynamics) by joining the LIDAR (Light Detection and Ranging) technique and Ansys CFX 10.0 software. The CFD simulations determine the wind velocity distribution on the landfill site surface and the different particle threshold friction velocities which determine the dust emission in multiphase simulations (air-particles). These simulations are validated from field data obtained in three measurement programmes for each type of landfill site surface treatment which has been studied. It was determined that the superficial landfill site treatment with the lowest air pollution is tall grass and bushes. The methodology used can be applied to the dust emission calculation in the design or evaluation of other landfill sites.     

Size-dependent characterisation of historical gold mine wastes to examine human pathways of exposure to arsenic and other potentially toxic elements

Abandoned historical gold mining wastes often exist as geographically extensive, unremediated, and poorly contained deposits that contain elevated levels of As and other potentially toxic elements (PTEs). One of the key variables governing human exposure to PTEs in mine waste is particle size. By applying a size-resolved approach to mine waste characterisation, this study reports on the proportions of mine waste relevant to human exposure and mobility, as well as their corresponding PTE concentrations, in four distinct historical mine wastes from the gold province in Central Victoria, Australia. To the best of our knowledge, such a detailed investigation and comparison of historical mining wastes has not been conducted in this mining-affected region. Mass distribution analysis revealed notable proportions of waste material in the readily ingestible size fraction (≤250 µm; 36.1–75.6 %) and the dust size fraction (≤100 µm; 5.9–45.6 %), suggesting a high potential for human exposure and dust mobilisation. Common to all mine waste types were statistically significant inverse trends between particle size and levels of As and Zn. Enrichment of As in the finest investigated size fraction (≤53 µm) is of particular concern as these particles are highly susceptible to long-distance atmospheric transport. Human populations that reside in the prevailing wind direction from a mine waste deposit may be at risk of As exposure via inhalation and/or ingestion pathways. Enrichment of PTEs in the finer size fractions indicates that human health risk assessments based on bulk contaminant concentrations may underestimate potential exposure intensities.     

An environmental assessment of enhanced oil recovery

The objective of this assessment is to quantify some of the environmental effects of a significant increase in United States oil production by tertiary or enhanced oil recovery (EOR) methods. The problems associated with each EOR technology are discussed and controls and regulations are briefly summarised. A tertiary oil production scenario for the United States was developed focussing only on mainland fields in the lower 48 states. It included all of the EOR methods expected to be in use during the next two decades. The environmental impacts, including water requirements, air emissions and generation of solid wastes, are then scaled to this scenario. The effects of control technologies and state regulations are considered. A comparison is also made between the impacts of EOR as an energy source and impacts associated with coal and synthetic fuels which concludes that EOR is preferable in many respects. There are environmental risks associated with EOR technologies, specific projects and specific fields in the production scenario; however, most problems are solvable by responsible regulation, enforcement of regulations and application of the best professional engineering by project operators.     

Hazardous waste management in educational and research centers: a case study

The hazardous waste management (HWM) practice at Tehran University of Medical Sciences Central Campus, Iran, was investigated in this study. Four schools were selected and the required information such as type and amount of wastes, temporary storage methods, waste discharge frequency, and final waste disposal methods using sampling, questionnaires, interviews with laboratory staff, and reference to available documents were gathered. The quantity of hazardous waste generation per year excluding the uncontrolled wastewater was found to be 2.072 tons per year. The obtained results show that wastes having features of being infectious, toxic, ignitable, carcinogenic, corrosive, and reactive were present at 32%, 28%, 16%, 14%, 8%, and 2%, respectively. In the central campus, hazardous solid wastes managed with household solid wastes and hazardous liquid waste were discharged into the sinks without any kind of control; improper HWM practices are evident from the point of waste production to final disposal.     

Evaluation of acid production potential of mining waste materials

The formation of acidic effluents from mining waste materials is discussed and the chemisry involved explained. The bacteriumThiobacillus ferrooxidans plays an important role in acid production due to its ability to rapidly oxidize reduced forms of iron and sulphur which can result in the generation of H₂SO₄. The sulphide mineral pyrite (FeS₂), often present in waste materials, is generally recognized as the chief source of acid mine drainage.A small-scale test procedure has been developed which rapidly evaluates a waste material's capability to produce an acidic effluent. If the material is assessed as a potential acid producer, then scale-up testing procedures are available which can be used to simulate the characteristics of the effluents produced from a commercial-size waste dump.During periods of little rainfall, localized biological activity may occur in wet areas of a waste dump, resulting in possible accumulation of soluble pollutants. The length of these dry periods greatly affects effluent characteristics during subsequent rainfalls.     

加强城市固体废物污染防治促进循环经济的发展

为加强城市固体废物污染防治，促进循环经济的发展，文章论述了国内外城市固体废物污染防治现状，天津市固体废弃污染防治对策，“十五”期间天津市固体废物污染防治的十大工程项目。     

Effect of poultry,cattle, sheep manures and sewage sludge on N mineralisation

The effects of various organic wastes on nitrogen mineralisation in soil were investigated. For this purpose, poultry (pl), cattle (ct), sheep (sh) manures and sewage sludge were used as organic wastes. This study was conducted as a laboratory incubation experiment with a calcareous soil. Organic wastes (3%) were added to pots of soil and incubated at 28°C for 16 weeks under non-leaching conditions. The cumulative mineralised N was then fitted to a single exponential model. Maximum nitrogen mineralisation was determined in the second week of incubation in soil treated with poultry manure. Overall, the results showed that the amount of mineral nitrogen in soil treated with different organic wastes was controlled by the type of manure. The results indicated that among the organic wastes, sewage sludge induced the highest quantities of net N mineralisation. Generally, organic wastes increased the amount of N mineralisation in the studied soil and the values of N₀ and k in treated soil varied depending on the type of organic waste. The highest N₀ and k values were found in poultry-treated soil.     

Copepod communities in the middle Adriatic as affected by different levels of pollution

The paper describes some results on copepod studies from two different areas in the middle Adriatic. The Maloston Bay is a naturally eutrophicated area, and the Kastela Bay is under a variety of influences of industrial wastes, agricultural wastes, food processing industry, shipyard, etc.

Although these two shallow areas are under the similar impact of sea‐water dynamics, as to the different levels of pollution, different consequences have been found to the copepod communities.     

城市固体废弃物堆肥化处理的影响因素

城市固体废弃物的堆肥化处理已经成为各国越来越重视的方法。堆肥化处理是通过控制堆腐过程条件,使废弃物在短时间内最有效地达到稳定,杀灭病原菌,使产品可以安全地使用。本文对堆肥的原理及基本机理进行了介绍,同时对堆肥过程的重要参数（ 水分含量、有机质含量、 Ｃ／ Ｎ 比、ｐ Ｈ 值、通气量等） 进行了综述。     

Arsenic partitioning among particle-size fractions of mine wastes and stream sediments from cinnabar mining districts

Tailings from abandoned mercury mines represent an important pollution source by metals and metalloids. Mercury mining in Asturias (north-western Spain) has been carried out since Roman times until the 1970s. Specific and non-specific arsenic minerals are present in the paragenesis of the Hg ore deposit. As a result of intensive mining operations, waste materials contain high concentrations of As, which can be geochemically dispersed throughout surrounding areas. Arsenic accumulation, mobility and availability in soils and sediments are strongly affected by the association of As with solid phases and granular size composition. The objective of this study was to examine phase associations of As in the fine grain size subsamples of mine wastes (La Soterraña mine site) and stream sediments heavily affected by acid mine drainage (Los Rueldos mine site). An arsenic-selective sequential procedure, which categorizes As content into seven phase associations, was applied. In spite of a higher As accumulation in the finest particle-size subsamples, As fractionation did not seem to depend on grain size since similar distribution profiles were obtained for the studied granulometric fractions. The presence of As was relatively low in the most mobile forms in both sites. As was predominantly linked to short-range ordered Fe oxyhydroxides, coprecipitated with Fe and partially with Al oxyhydroxides and associated with structural material in mine waste samples. As incorporated into short-range ordered Fe oxyhydroxides was the predominant fraction at sediment samples, representing more than 80 % of total As.     

电子废物现状评述与资源化初探

电子垃圾是目前增长速度最快的固体废物之一,对其不合理处置和利用已引起了日趋严峻的环境污染。文章从电子废物的危害及回收利用的角度,概述了当前国内外数量巨大的电子废物的污染现状及其回收利用处理技术,并结合国内实际,从电子废物的回收系统和资源化处理利用技术方面提出了具有可行性的建议和设想。     

Changes in surface water quality from small-scale gold mining operations in the Surinamean rainforest

Abstract

Small-scale miners often engage in environmentally damaging activities, are subject to poor safety conditions, and utilize inefficient mineral extraction technologies. Here, we explore environmental impacts to surface waters from regional artisanal small-scale gold placer mining operations conducted in iron and aluminum-rich saprolites found within the lateritic, interior Amazon rainforest of Suriname. Heavy equipment was utilized to release gold from its host material followed by amalgamation and gravity separation. In contrast with background tributary recordings, streams adjacent to these gold mining operations consistently contained turbidity measurements that exceeded United States’ EPA guidelines for aquatic species of 50 nephelometric turbidity units and were typically in the hundreds to thousands of units. Turbidity was further heightened in association with precipitation events. Mercury played a prominent role in whole ore amalgam concentration practices. Freshwater fish from the region were found to harbor mercury that encroached upon public health criteria. Dissolved phase metals present further ecotoxicological challenges to the region, but their association with mining activities was less clear. These findings collectively reveal that small-scale placer gold mining practices in the Surinamese rainforest result in an increase of suspended sediments and release of mercury into waterways that could impact communities that depend upon local fisheries.     

粉煤灰综合利用于生产复合肥的探索

随环保事业的迅速发展,固体废物的综合利用越来越被人们重视。本文主要介绍利用粉煤灰生产硅钙镁复合肥的新工艺,从而既可减少固体废物污染,又可使废物综合利用。     

北京市非正规垃圾填埋场垃圾成分特性

通过北京市3处典型非正规垃圾填埋场与1处正规垃圾卫生填埋场对比研究,结果表明,非正规垃圾填埋场与正规垃圾填埋场陈腐垃圾物理组成相近,但非正规垃圾填埋场有机物含量更低,同时垃圾分布不均匀;以建筑渣土为主的区域有机质含量一般低于5%;以生活垃圾为主的区域有机质含量与正规垃圾场相近,一般高于10%,内部最高温度可达42℃左右。     

区域资源环境与社会经济系统的非连续运动分析——以吉林省为例

针对区域资源环境与社会经济系统的非连续运动特征,基于尖点突变理论构建数学模型对区域资源环境与社会经济系统的突变过程及其响应机制进行定量描述与分析。吉林省社会经济进入快速发展时期,以吉林省作为研究区域进行实例分析,能够为区域社会经济与资源环境协调发展战略的制定与筛选提供技术手段和决策依据。研究结果表明,吉林省经济进入快速增长阶段;矿业的衰退将成为影响吉林省经济持续稳定发展的重要因素;吉林省资源消耗总量与万元产值消耗量的突变,标志着吉林省对钢铁和水泥等大宗固体矿产的消费进入快速增长阶段;受生态省建设战略影响,固体废物、SO2、粉尘的排放总量与万元产值SO2及固体废弃物排放量发生根本性转变,吉林省生态环境进入新的发展时期。     

Disposal of Mine Wastes Containing Pb and Zn Near the Ocean: An Assessment of Associated Environmental Implications in the Arctic

The past two decades have witnessed an increase in the exploration for, and development of, mineral resources at Arctic latitudes. Such effort has resulted in the commencement of production at a number of different localities in close proximity to the ocean. Since proximity to a source of transportation for the conveyance of concentrates to the market is a primary requirement governing the economic decisions for the mine to proceed, it is logical that ore deposits near a coastline are primary targets for development.

Closely tied to coastal mining developments is the need to dispose of tailings and waste rock in the most economical manner. Prior to the advent of heightened public awareness and environmental concern, and the enactment of pollution legislation, disposal practices were largely based upon convenience. Currently, however, proposed disposal and operating practices receive closer scrutiny, with a view to providing adequate protection for aquatic resources and habitat. This paper summarizes some of the features of three Arctic mines, wastes from which enter the marine environment, and compares the disposal practices used at each to measures of environmental change as indicated by metal concentrations in various media.