Application of Image Processing for Modelling Pyrite Oxidation in a Coal Washing Waste Pile

In this paper, an image processing method was applied to model the pyrite oxidation in the wastes of the Alborz Sharghi coal washing plant waste pile, northeast Iran. Pictures of polished sections created from the powdered samples of coal wastes were used to determine the amount of pyrite that remained at different depths of the waste pile. The amount of pyrite in the same samples also measured applying a method presented by ASTM, and the results were in very good agreement with the values calculated by the image processing method.     

基于高分辨率影像的固体废物自动识别技术

随着经济快速发展,工业固废、非正规垃圾、未覆盖建筑渣土等固体废物急剧增加,对区域生态环境造成极大威胁。固废堆场具有面积小、分布散等特点,目前国内仍缺少针对各类固废堆场的遥感自动识别研究。为此,基于国产高分辨率卫星遥感数据,根据野外实地光谱采集结果,分别开展了未覆盖建筑渣土、工业固废及非正规垃圾的自动识别方法研究,提取研究区各类固废堆场。结果表明:未覆盖建筑渣土在蓝波段与绿波段分别存在"吸收谷"与"反射峰",基于该特征构建的比值指数模型,结合直方图双峰法阈值分割可以有效提取未覆盖建筑渣土区域;工业固废、非正规垃圾2种固废类型多样,光谱反射率没有明显规律,结合其纹理、色调等特征,采用面向对象多尺度分割、支持向量机监督分类方法能够较好地识别2种类型固废;基于自动化提取技术并结合人机交互判读方法,提取的研究区未覆盖建筑渣土、工业固废及非正规垃圾等3种固废堆场的精度分别达到96.83%、88.26%、85.71%,各类固体废物遥感识别精度较高,极大提高了固废监测效率。     

Comparison of static and mineralogical ARD prediction methods in the Nordic environment

Acid rock drainage (ARD) is a major problem related to the management of mining wastes, especially concerning deposits containing sulphide minerals. Commonly used tests for ARD prediction include acid–base accounting (ABA) tests and the net acid generation (NAG) test. Since drainage quality largely depends on the ratio and quality of acid-producing and neutralising minerals, mineralogical calculations could also be used for ARD prediction. In this study, several Finnish waste rock sites were investigated and the performance of different static ARD test methods was evaluated and compared. At the target mine sites, pyrrhotite was the main mineral contributing to acid production (AP). Silicate minerals were the main contributors to the neutralisation potential (NP) at 60% of the investigated mine sites. Since silicate minerals appear to have a significant role in ARD generation at Finnish mine waste sites, the behaviour of these minerals should be more thoroughly investigated, especially in relation to the acid produced by pyrrhotite oxidation. In general, the NP of silicate minerals appears to be underestimated by laboratory measurements. For example, in the NAG test, the slower-reacting NP-contributing minerals might require a longer time to react than is specified in the currently used method. The results suggest that ARD prediction based on SEM mineralogical calculations is at least as accurate as the commonly used static laboratory methods.     

Characterisation of sulphide-bearing waste-rock dumps using electrical resistivity imaging: the case study of the Rio Marina mining district (Elba Island, Italy)

Sulphide-bearing mine dumps are potential sources of pollution when acid mine drainage (AMD) occurs. Because the generation of AMD depends on the volume and composition of waste materials, their characterisation is crucial for the evaluation of geochemical hazards and for the design of remediation strategies to minimise their environmental impact. In this paper, a cost-effective strategy for the characterisation of an inactive mine dump in the Rio Marina mining district (Elba Island, Italy) using earth resistivity imaging (ERI) is presented. As no information regarding the nature of waste rocks is found in reports for the mine, five ERI profiles were acquired at the top of the waste pile. The results show that waste rocks are heterogeneous with a maximum thickness of 30 m. Due to the large amounts of dispersed sulphide minerals, the waste rocks are characterised by an electrically conductive geophysical signature in comparison to the surrounding resistive metamorphic bedrock. A geostatistical approach was adopted to estimate the elevation of the edges of the mine dump, and the net volume of the waste rocks was computed through a raster analysis of the elevations of the upper and lower boundaries of the mine dump. High-conductivity anomalies were detected within the core of the mine dump. The integration of the hydrogeological, geochemical and geological framework of the Rio Marina mining district suggests that these anomalies could be a geophysical signature of subsurface regions where AMD is currently generated or stored, thus representing sources of environmental pollution.     

A Time-Dependent System for Evaluating Groundwater Contamination Hazard Rating of Municipal Solid Waste Dumps

In developing countries, several old municipal solid waste dumps (unlined landfills) exist adjacent to large cities, releasing contaminants to the underlying aquifer, thus posing the hazard of groundwater contamination. These uncontrolled waste dumps need to be prioritized in terms of the groundwater contamination hazard posed by them, so that necessary control and remedial measures can be undertaken in a phased manner. This paper presents a time-dependent system for evaluating groundwater contamination hazard rating of municipal solid waste dumps. The system is based on source–pathway–receptor relationships and evaluates the relative value of hazard posed by a site over its entire leaching life, on a scale of 0–1,000. The system parameters have been selected based on literature and expert opinions. The Delphi technique is used to derive the relative importance weights of the system parameters. The proposed system is compared with six selected existing hazard rating systems. The comparison, made by way of score range analysis, shows that the proposed system exhibits a much wider range of hazard scores for various scenarios of site conditions, and hence the proposed system is more sensitive to varied site conditions. The application of different systems to six municipal solid waste dumps located in four cities of India shows that, whereas the existing systems individually produce clustered scores and return the same rank to more than one site, the proposed system produces significantly varying scores and return different ranks to different sites. This demonstrates that the proposed system improves decision making and makes a better basis for prioritization of municipal solid waste dumps for adopting control and remedial measures.     

Distribution and assessment of Pb in the supergene environment of the Huainan Coal Mining Area,Anhui, China

Coal mining area is highly subject to lead (Pb) pollution from coal mining activities. Several decades of coal mining and processing practices in dozens of coal mines in the Huainan Coal Mining Area (HCMA) have led to the accumulation of massive amounts of coal gangue, which piled in dumps. In order to investigate the impacts of coal gangue dumps on Pb level in the supergene media of the HCMA, a systematic sampling campaign comprising coal gangue, soil, wheat, and earthworm samples was conducted. The average Pb content in the coal mining area soil is 24 mg/kg, which is slightly higher than the associated coal gangues (23 mg/kg) and markedly higher than reference region soil (12.6 mg/kg). Soil in the HCMA present a slight to moderate Pb contamination, which might be related to the weathering and leaching of coal gangue dumps. Lateral distribution of Pb in HCMA soil differed among individual coal mines. The soil profile distribution of Pb depends on both natural and anthropogenic contributions. Average Pb content is higher in roots than in stems, leaves, and wheat husks, while the Pb level in seeds exceeded the maximum Pb allowance for foods (Maximum Levels of Contaminants in Foods of China, GB 2762–2012). Earthworms in the selected area are significantly enriched in Pb, suggesting higher bio-available Pb level in soil in the HCMA.     

Accounting embodied economic potential of healthcare waste recycling—a case study from Pakistan

Proper management of healthcare wastes is a key concern across resource-constrained countries in South Asia. Existing scientific research on this topic usually involves epidemiological and behavioral studies. Similarly, environmental impact assessment of healthcare wastes is mainly conducted from an end-user or anthropocentric point of view. In this study, we took a novel approach by analyzing healthcare wastes using an ecocentric position. Here, we utilize a case study of a general public hospital in a major city of Pakistan to analyze the embodied energy of its waste fractions by category. We used Emergy analysis to assess the true economic potential of recycling these waste items. While doing so, we compared the economic potential of current waste recycling practices with the scenario of 100% recycling of useful waste fractions. We discovered that the latent embodied energy of different recyclable waste fractions made them far more valuable than their existing market prices indicate. This value increased further if the useful waste fractions were completely recycled. In conclusion, this study used empirical evidence to argue in favor of source-segregation and recycling of healthcare wastes so that the higher costs associated with natural resource extraction and processing can be avoided. Future studies considering hazardous healthcare wastes can use the approach taken in this paper to analyze the impact of other practical waste treatment procedures.     

Monitoring quantity and characteristics of municipal solid waste in Dhaka City

A reliable estimate of the quantity of solid waste generation in the city is very important for proper solid waste planning and management. However, reported estimates of solid waste generation vary widely and lead to questionability. The reported values have been derived on the assumption of demography, standard rate of waste generation by households, density values, number of trucks engaged for waste transportation and monitoring of truck movement at dump sites, etc. This diverse nature of the available data and the question of accuracy necessitate a rigorous study that has tried to document the waste quantity in the recently formulated master plan of Dhaka City. The socio-economic parameters, behavioral characteristics, generation sources, seasonality, and per capita growth rate are considered in estimating the waste quantity along with its future projections. The findings from the estimation of waste quantities state that seasonal differences in the municipal solid waste stream are not substantial. The most seasonably variable material in the municipal solid waste stream is food waste. Residential waste is relatively homogeneous. Although there are some differences in waste generation depending on demographic and other local factors, most households dispose of essentially similar types of wastes. Variation occurs in waste composition dependent upon income levels and category of sources. Variation also occurs based upon the extent of source reduction and recycling opportunities. As opportunities exist to recycle wastes, the recycling facilities might have to grow at a similar pace to the generation of waste. Physical and chemical characteristics of solid waste are important to implement the waste disposal and management plan for the selection of resource and energy recovery potentials. A number of studies have been conducted to determine the composition of wastes including moisture content and calorific value. The data show that the moisture content in city waste is significantly higher and the calorific value is much lower, which determines the viability of composting or anaerobic digestions rather than waste combustion.     

Soil criteria to protect terrestrial wildlife and open-range livestock from metal toxicity at mining sites

Thousands of hard rock mines exist in the western USA and in other parts of the world as a result of historic and current gold, silver, lead, and mercury mining. Many of these sites in the USA are on public lands. Typical mine waste associated with these sites are tailings and waste rock dumps that may be used by wildlife and open-range livestock. This report provides wildlife screening criteria levels for metals in soil and mine waste to evaluate risk and to determine the need for site-specific risk assessment, remediation, or a change in management practices. The screening levels are calculated from toxicity reference values based on maximum tolerable levels of metals in feed, on soil and plant ingestion rates, and on soil to plant uptake factors for a variety of receptors. The metals chosen for this report are common toxic metals found at mining sites: arsenic, cadmium, copper, lead, mercury, and zinc. The resulting soil screening values are well above those developed by the US Environmental Protection Agency. The difference in values was mainly a result of using toxicity reference values that were more specific to the receptors addressed rather than the most sensitive receptor.     

The effects of socioeconomic parameters on household solid-waste generation and composition in developing countries (a case study: Ahvaz,Iran)

Environment problems associated with the generation of waste are part of societal changes where households play an important role. These societal changes influence the size, structure and characteristic of given households. For the effective planning of solid-waste handling infrastructure, it is essential to know the quantity of waste generation and its composition. This paper presents the findings of a study carried out in an urban municipal area in Iran to determine the household solid-waste generation rate and waste composition based on field surveys and to determine the related socioeconomic parameters. The dependent variables were waste generation and composition, and independent variables were family size, family employment, age, number of room and education. Over 400 sample households were selected for the study using a stratified random sampling methodology and from five different socioeconomic groups. Waste collected from all groups of households were segregated and weighted. Waste generation rate was 5.4 kg/household/day. Household solid waste comprised of ten categories of wastes and with the largest component (76.9%). The generation and composition of household solid waste were correlated with family size, education level and households income. This paper adequately suggests new insights concerning the role of socioeconomic parameters in affecting the generation of household waste.     

中国固体废物的环境管理与环境监测技术现状

为加强中国固体废物的环境管理和环境监测技术,回顾了中国自１９８５年以来制定的固体放心物环境管理法规制度以及１９８４年至１９９８年颁布的２０多年家或行业的固体废物处置标准体系等固体废物的环境管理状况,着重论述了中国固体废物环境监测技术的发展历史与现状。指出经过２０多年的努力,在固体废物环境监测技术与方法上初步形成了该领域框架体系,有固体废物的采样与制样技术;危险废物的有害特性试验鉴别方法,固体废物具     

The use of Landsat to monitor Deep Water Dumpsite 106

Since the early 1970's, remote sensing has been used to study ocean dumping at some of the hearshore ocean dump sites off the coast of the United States, but little remote sensing had been done over the deep water ocean disposal sites. This report summarizes what has been learned from the remote sensing of ocean dumping by the Landsat satellites at Deep Water Dumpsite 106. Of the three major types of waste material discharged at Deep Water Dumpsite 106, only the titanium pigment process acid waste has been sighted. From early in 1977 to May 1979, 11 acid dumps were observed by Landsat. All five of the dumps sighted in 1977 occurred within warm core Gulf Stream eddies and the plumes moved clockwise within the eddies. Four of those dumps were seen to be located northeast of the original dump location while the fifth one was sighted south of the original dump location. The six remaining observed dumps, discharged in the absence of an eddy, were seen to be located generally south of the original dumping locations. The average speed of the dump movement was 0.68 kt with a range from 0.17 to 1.17 kts. Plume dispersion showed a tendency toward greater dispersion as the plume got older with the widest plume cross section measured on the order of 2100 m.     

长江经济带工业来源危险废物污染与处理特征分析及监管对策建议

依据2017年环境统计数据, 分析了长江经济带工业危险废物的污染及处理特征:长江经济带危废产生 量较大的省份是江苏、浙江、云南、湖南和四川;危废种类主要是来源于化工、钢铁、有色和造纸行业的废酸、有色金属冶炼废物、废碱和焚烧处置残渣;各地对危废的处理情况各有优劣。根据以上特征,提出加强对重点 区域的监管和调度,针对特定行业和危废种类,建议出台最佳可行的处理技术,建立区域之间危废管理大平台,促进区域危废处理优势互补和均衡发展,挖掘企业自行处理能力,减轻危废集中处理压力。     

Management of hospitals solid waste in Khartoum State

This research had been conducted during year 2012 to review existing data on hospital waste management for some of Khartoum town hospitals and to try to produce appropriate proposals acceptable for waste management and final treatment methods. The overall status of hospital waste management in Khartoum has been assessed through direct visits and designated questionnaires. Eight main hospitals were covered in the study with an overall bed capacity of 2,978. The current waste management practice observed at all studied hospitals was that most of waste, office, general, food, construction debris, and hazardous chemical materials were all mixed together as they are generated, collected, and finally disposed of. Only a small portion of waste in some hospitals (part of potentially infectious, body parts, and sharps) are collected separately and treated in a central incinerator. The estimated value of per bed generation rate in the studied hospitals was found to be 0.87 kg/day, which lies within the range for the low-income countries. In all studied hospitals, it was found that workers were working under very poor unsafe conditions with very low salaries ($35 to $45 per month on average). About 90 % were completely illiterate or had very low education levels. At the national level, no laws considering hospital waste, or even hazardous waste, were found; only some federal general environmental regulations and some procedures from town and city localities for controlling general municipal waste exist. At the hospital level, no policies or rules were found, except in the radiotherapy center, where they manage radioactive wastes under the laws of the Sudanese Atomic Agency. Urgent actions are needed for the remediation and prevention of hazards associated with this type of waste.     

Prediction of AMD generation potential in mining waste piles, in the sarcheshmeh porphyry copper deposit, Iran

This study investigates the possibility of acid mine drainage (AMD) generation in active and derelict mine waste piles in Sarcheshmeh Copper Mine produced in several decades, using static tests including acid–base accounting (ABA) and net acid-generating pH (NAGpH). In this study, 51 composite samples were taken from 11 waste heaps, and static ABA and NAGpH tests were carried out on samples. While some piles are acid producing at present and AMD is discharging from the piles, most of them do not show any indication on their AMD potential, and they were investigated to define their acid-producing potential. The analysis of data indicates that eight waste piles are potentially acid generating with net neutralization potentials (NNPs) of ?56.18 to ?199.3, net acid generating of 2.19–3.31, and NPRs from 0.18 to 0.44. Other waste piles exhibited either a very low sulfur, high carbonate content or excess carbonate over sulfur; hence, they are not capable of acid production or they can be considered as weak acid producers. Consistency between results of ABA and NAGpH tests using a variety of classification criteria validates these tests as powerful means for preliminary evaluation of AMD/ARD possibilities in any mining district. It is also concluded that some of the piles with very negative NNPs are capable to produce AMD naturally, and they can be used in heap leaching process for economic recovery of trace amounts of metals without applying any biostimulation methods.     

Bacteria Associated with Degradation of Wastes from Rubber Processing Industry

An investigation of bacteria found in rubber processing wastes was carried out. Rubber wastes which include effluents from washing tanks and natural rubber waste serum (NRWS) were obtained from Greenpark Rubber Industries Limited, Umutu, Delta State, Nigeria. Five bacterial species were isolated from the wastes. These include Arthrobacter sp., Bacillus sp., Lactobacillus sp., Psuedomonas sp. and Streptococcus sp. Apart from these a number of coliforms were also encountered. Arthrobacter sp. was found to be the dominant species and its potential to utilize rubber hydrocarbon was determined. It was found that the growth of Arthrobacter in both effluent and NRWS was related to pH with the highest growths recorded at pH of 8.5 and 7.5 for effluent and NRWS respectively. It was also found that at controlled pH of 7.5 in NRWS, the growth of Arthrobacter was consistent and was accompanied by a reduction in biological oxygen demand (BOD) which was the the main index for measuring pollution strength of the wastes. It is therefore being recommended that rubber wastes be treated with Arthrobacter under controlled pH to reduce their pollution potentials before disposal. It is however suggested that a combined biological treatment using both Arthrobacter and Mucor as was earlier suggested be used. It is also recommended that chemical flocculants should be used to remove suspended solids in the effluent. A combination of these two cheap methods will go a long way in alleviating the problems of pollution caused by rubber effluents from some tropical rubber processing factories.     

Greenhouse gas emissions from Australian open-cut coal mines: contribution from spontaneous combustion and low-temperature oxidation

Spontaneous combustion and low-temperature oxidation of waste coal and other carbonaceous material at open-cut coal mines are potentially significant sources of greenhouse gas emissions. However, the magnitude of these emissions is largely unknown. In this study, emissions from spontaneous combustion and low-temperature oxidation were estimated for six Australian open-cut coal mines with annual coal production ranging from 1.7 to more than 16 Mt. Greenhouse emissions from all other sources at these mines were also estimated and compared to those from spontaneous combustion and low-temperature oxidation. In all cases, fugitive emission of methane was the largest source of greenhouse gas; however, in some mines, spontaneous combustion accounted for almost a third of all emissions. For one mine, it was estimated that emissions from spontaneous combustion were around 250,000 t CO₂-e per annum. The contribution from low-temperature oxidation was generally less than about 1% of the total for all six mines. Estimating areas of spoil affected by spontaneous combustion by ground-based surveys was prone to under-report the area. Airborne infrared imaging appears to be a more reliable method.     

Developing a Decision-Support System for Waste Management in Aluminum Production

Industrial enterprises constitute a major portion of the world’s economy, as well as a large proportion of a country’s businesses and total employment. In Turkey, industrial enterprises are underdeveloped in terms of knowledge, skill, capital, and particularly accessing and benefiting from the advantages provided by modern information and communication technologies. Aluminum manufacturing has been reported to be the largest industry in Turkey with respect to production volumes and application fields. However, aluminum production is known to be an important contributor to environmental pollution, and the relative contribution of other related enterprises to the total industrial environmental impact is unknown. Environmental pollution sources can typically be classified into three categories: gaseous emissions, solid wastes, and wastewaters. The types of wastes produced by aluminum production vary based on the process line used, the variety of target products produced, and the production capacity of a given plant. As the capacities of facilities grow, the type and amount of waste become more variable. Therefore, the primary objective of this study is to determine the priority of each waste type in aluminum manufacturing industries. This study was conducted in the Industrial Zone of Kayseri in Turkey. Three different facilities that range in size from large to small based on their production volume, plant capacity, and variety of production are selected for this study. The priority of waste types was determined by combining the AHP and PROMETHEE II multicriteria decision methods. While wastewater was categorized as having the highest priority in large facilities, solid waste was determined to be the highest priority in medium and small facilities.     

Groundwater contamination and its effect on health in Turkey

The sources of groundwater pollution in Turkey are identified, and pathways of contaminants to groundwater are first described. Then, the effects of groundwater quality on health in Turkey are evaluated. In general, sources of groundwater contamination fall into two main categories: natural and anthropogenic sources. Important sources of natural groundwater pollution in Turkey include geological formations, seawater intrusion, and geothermal fluid(s). The major sources of anthropogenic groundwater contamination are agricultural activities, mining waste, industrial waste, on-site septic tank systems, and pollution from imperfect well constructions. The analysis results revealed that natural contamination due to salt and gypsum are mostly found in Central and Mediterranean regions and arsenic in Aegean region. Geothermal fluids which contain fluoride poses a danger for skeleton, dental, and bone problems, especially in the areas of Denizli, Isparta, and Ayd?n. Discharges from surface water bodies contaminate groundwater by infiltration. Evidence of such contamination is found in Upper K?z?l?rmak basin, Gediz basin, and Büyük Melen river basin and some drinking water reservoirs in ?stanbul. Additionally, seawater intrusion causes groundwater quality problems in coastal regions, especially in the Aegean coast. Industrial wastes are also polluting surface and groundwater in industrialized regions of Turkey. Deterioration of water quality as a result of fertilizers and pesticides is another major problem especially in the regions of Mediterranean, Aegean, Central Anatolia, and Marmara. Abandoned mercury mines in the western regions of Turkey, especially in ?anakkale, ?zmir, Mu?la, Kütahya, and Bal?kesir, cause serious groundwater quality problems.     

Fuzzy Possibilistic Modeling for Closed Loop Recycling Collection Networks

Nowadays, in the competitive market, commercial companies due to their economic problems and also restrictions imposed by international organizations to comply with environmental regulations are making noticeable efforts to reduce the level of their wastes in their manufacturing systems and consequently the level of waste in consumers’ products. In harmony with this issue, one of the most effective ways which has successfully been used and proven to be economically profitable is to take products lifecycles into consideration. Consideration of products lifecycle has made supply chain practitioners to investigate the reverse logistics activities in addition to forward logistics activities. Hence, corporations, in order to reduce their cost on the one hand and boosting their efficiency on the other hand, were obligated to employ closed loop supply chain models to concurrently benefit from its economical and environmental advantages. Therefore, in this paper, a mixed nonlinear facility location–allocation model is proposed for recycling collection centers. The considered closed loop logistics model consists of multiple echelons, multiple suppliers, multiple collection centers, multiple time period and also multiple facilities. In real-life problems parameters like demand, cost, capacity, distances, and quantities of returned products are always uncertain. Therefore, in order to solve a realistic problem, foregoing parameters are considered as fuzzy in our proposed model. Subsequently, to solve fuzzy mixed nonlinear programming model, one of the most effective technique in the literature is used. Additionally, in order to demonstrate the behavior of the parameters employed in the model, a comprehensive sensitivity analysis is conducted. Computational results demonstrate that the proposed model can show favorable efficiency in solving supply chain problems.