Minimization of environmental risk of landfill site using fuzzy logic, analytical hierarchy process, and weighted linear combination methodology in a geographic information system environment

This paper presents a GIS-based multi-criteria site selection for municipal solid waste landfilling in Ariana Region, Tunisia. Based on the regional characteristics, literature related to disposal sites and waste management, local expert, data availability and assessments via questionnaires, 15 constraints, and 5 factors were built in the hierarchical structure for landfill suitability by multi-criteria evaluation. The factors are divided into environmental and socio-economic groups. The methodology is used for preliminary assessment of the 20-year most useful lifetime suitable landfilling sites by combining fuzzy set theory, weighted linear combination (WLC) and analytic hierarchy process (AHP) in a GIS environment. The criteria standardization is undertaken by application of different fuzzy membership functions. The fuzzy membership functions shape and their control points are chosen through assessment of expert opinion. The weightings of each selection criterion are assigned depending on the relative importance using the AHP methodology. The WLC approach is applied for alternative landfill sites prioritization. The results of this study showed five potential candidate sites, which are generated when the environmental factors are valued higher than socio-economic factors. These sites are ranked in descending order using the ELECTRE III method. However, the final decision will require further detailed geotechnical and hydrogeological analyses toward the protection of groundwater as well as surface water.     

Urban Waste Disposal and Its Impact on Groundwater Pollution in China

Waste production in cities is increasing with growing urbanization in China. As the incorrect disposal of waste can lead to environmental problems and pollution of groundwater, it is important to asses the suitability of sites for waste disposal. In this paper, 831 waste disposal sites in 295 cities in China were investigated, and suitability assessments of 508 sites were made. The results showed that the number of “suitable”, “moderately suitable”, “barely suitable” and “unsuitable” waste disposal sites accounted for 17.7%, 29.5%, 14.2% and 38.6% of the sites investigated, respectively. The pollution condition of 465 sites was examined, and the results indicated that groundwater in 282 sites was contaminated. Groundwater samples from two polluted sites were collected and analyzed to inform a proposal on urban waste disposal.     

Assessing flood risk associated with waste disposals: methodology,application and uncertainties

Waste disposal sites are mostly located in lowland areas close to residential areas inducing a long-term risk of potential environmental contamination due to flooding. During recent flood events, these areas were reportedly exposed to inundations. This paper aims to develop a qualitative approach to assess flood risk associated with flood-prone waste disposals at the basis of Austrian case studies. Risk is investigated as a function of the probability of an event and the consequences of that event. The presented assessment approach is characterized as qualitative as consequences are expressed in risk categories but not in expected (monetary) losses. The probability of inundation, the hydrodynamic impacts on considered waste disposal sites and the expected consequences to the environment (potential emissions of hazardous substances) were linked. Derived risk categories from “minor risk” to “serious risk” were used to express flood risk to environmental goods like groundwater bodies, nature reserves and recreation areas. A screening of 1,064 waste disposals yielded roughly 30% of sites located within or close to flood risk zones. Three representative case study areas were selected and investigated in detail by applying 2D hydrodynamic models to calculate flow depths and shear stress and by developing emission scenarios. The hydrodynamic modelling covered three hydrologic scenarios with statistical recurrence intervals of 30, 100 and 300 years. Derived leaching scenarios ranged from minor emissions up to total erosion of the waste disposal site. Based on four parameters representing flood characteristics, the susceptibility to erosion (flow velocity and shear stress) and the estimated leaching behaviour, a flood risk evaluation matrix (FREM) was elaborated. The study outlines that in case of flooding the hazardous emissions could lead to partly tremendous impacts on environmental goods. Identified uncertainties associated with considered processes were considerably high. However, the developed qualitative approach provides a decision support aid to identify waste disposals with imminent risk for humans and the environment.     

Locating hazardous waste treatment facilities and disposal sites in the State of Yucatan,Mexico

In this work, geographic information systems (GIS) and multi-criteria decision analysis (MCDA) were used in order to identify the appropriate location for hazardous waste (HW) treatment facilities and final disposal sites in the State of Yucatan, Mexico. For HW-treatment facilities, in addition to the distance to generators and treatment facilities, geographic conditions of the site, such as vegetation, soil type, accessibility, distance to urban or rural communities, and all the boundary elements as agricultural or livestock areas, were considered in GIS and MCDA. Final disposal was taken into account only for those HW that could not be avoided or treated. In order to find the most suitable areas, the Mexican Official Norm NOM-055-SEMARNAT-2003 criteria were observed too. It was found that the most suitable zones for HW-treatment facilities were at the centre of the State, whereas the most recommended areas for HW final disposal sites were at the south.     

A solid waste disposal site selection procedure based on groundwater vulnerability mapping

In this study, a new, GIS-based solid waste site selection tool (DUPIT) is introduced to obtain a systematic and unbiased methodology during the evaluation phases of alternative solid waste disposal areas with regards to vulnerability to groundwater pollution. The proposed tool is an index technique based on the linear combination of five different hydrogeological parameters including Depth to groundwater table, Upper layer lithology, Permeability of the unsaturated zone, Impermeable layer thickness and Topographic slope. Five different categories are developed to classify each alternative based on the suitability of the site for a solid waste disposal area. As a result, each site is ranked according to the contamination risks for groundwater resources. The proposed technique is applied to the District of Torbali near Izmir, Turkey to determine the most appropriate solid waste disposal site location. The Torbali application is implemented by using a GIS database developed for the area. Based on the results of this application, the best alternative solid waste disposal site for Torbali is selected to be located in the northern portions of the city where the groundwater table is deep, the permeability is low and the topographic slope is mild.     

高放废物深地质处置地下水数值模拟应用综述

开展地下水数值模拟研究是高放废物处置场地安全评价的重要组成部分,然而深地质处置介质类型的复杂性、基岩深部资料的相对匮乏性导致模拟结果存在不确定性,如何刻画深部地下水动力场并评估可能引起的风险已成为高放废物处置安全评价中重点关注的问题。在大量文献调研的基础上,综述了世界典型国家高放废物深地质处置场地的地下水数值模拟与不确定性分析应用,并归纳总结该领域研究经验,得到以下认识:（1）深地质处置场深部构造、裂隙的发育与展布决定了地下水循环条件,探究适用于基岩裂隙地区新的水文地质试验方法是提高地下水数值模型仿真性的基础;（2）不同尺度模型融合是解决深地质处置地下水模拟的有效技术方法,区域尺度多采用等效连续介质法,场地尺度使用等效连续多孔介质和离散裂隙网络耦合模型,处置库尺度使用离散裂隙网络方法,其次需重点关注未来大时间尺度下放射性核素在地质体中的迁移转化规律,模拟预测场址区域地下水环境长期循环演变对核素迁移的潜在影响;（3）考虑到不同的处置层主岩岩性以及在多介质中发生的THMC（温度场—渗流场—应力场—化学场）过程,目前国内外常用的地下水模拟软件有:Porflow、Modflow、GMS及MT3DMS等用于模拟孔隙或等效连续介质,Connectflow、Feflow及FracMan等用于模拟地下水和核素在结晶岩、花岗岩等裂隙中的迁移,TOUGH系列软件主要应用于双重介质的水流、溶质及热运移模拟;（4）指导开展有针对性的模型和参数的不确定性分析工作,减少投入工作量,提高模型精度,并可针对处置库长期演变、废物罐失效、极端降雨等多情景预测模拟,为处置库安全评价及设计提供基础数据支撑;（5）针对我国深地质处置地下水数值模拟研究现状,下一步应加强区域地质、水文地质、裂隙测量以及现场试验等相关的调查及监测工作,多介质耦合、多场耦合模拟及不确定性分析研究将会是未来的研究重点。     

Evaluation of waste disposal site using the DRASTIC system in Southern Korea

As a systematic approach to waste disposal site screening for groundwater pollution protection, the DRASTIC system developed by the US Environmental Protection Agency (USEPA), was introduced at Younggwang County in Korea. Hydrogeological spatial databases for the system include information on depth to water, net recharge, aquifer media, soil media, topographic slope, hydraulic conductivity and lineament. Using the databases, the DRASTIC system and a GIS, the regional groundwater pollution vulnerability of the study area was assessed. The fracture density extracted from lineament maps was added to the DRASTIC system to take into account the preferential migration of contaminants through fractures. From the results of the study, a degree of groundwater pollution vulnerability through the study area was easily interpreted, and waste disposal sites could be screened for groundwater protection.     

环境矿物材料在土壤、水体、大气污染治理中的利用

本文在简要阐明了环境矿物材料对污染物的净化机理与净化功能的基础上,明确了环境矿物材料的应用领域,重点展望了在土壤重金属污染防治、地表水和地下水水质改善及燃煤固硫除尘等三类状态污染控制与环境保护领域中应用的前景。认为经济、简便、有效地用于污染治理与环境修复的无机界矿物学方法类似于有机界生物学方法,均是自然界地球系统中天然自净化作用的反映。     

Behavior of a municipal landfill from field measurement data during a waste-disposal period

The behavior of a municipal waste landfill on marine clay was analyzed from field measurement data. Instruments, e.g., a groundwater level sensor, piezometer, earth pressure gauge, settlement plates, inclinometer, etc., were installed and operated during the disposal period from October 1992 to November 2000. A database system was developed to manage the data from this landfill using Access (Microsoft) with Delphi programs. From the analyses, it was determined that the settlement of the landfill during the initial period of waste disposal was small because of the high leachate level in the landfill. As the level of waste became higher than the leachate level, the settlement of the landfill increased significantly due to the increasing effective pressure within the landfill. From a stability point of view, the critical time for the landfill in this study was the initial period of landfill disposal, which was caused by either the impact load of waste disposal or the time schedule of waste disposal, which was faster than the consolidation of foundation clay caused by the waste load.     

Municipal solid waste landfill siting by using GIS and analytical hierarchy process (AHP): a case study in Qom city,Iran

Qom is the eighth most populated city in center of Iran, and its population growth rate is among the highest in this country. Th presence of a Great Salt Lake, petroleum potential and tourism attractions in this city sheds light on the importance of how solid waste landfill locations should be disposed, located and managed as an environmental issue. Considering the key parameters in landfill site selection, in this study a series of location analysis have been conducted to locate optimum regions for municipal solid waste disposal, using analytical hierarchy process (AHP) and geographical information system (GIS). The main factors in selecting the suitable location for waste disposal include geomorphology–hydrography, environmental–social factors and design criteria, each of which are subdivided into several categories. Criteria are selected according to the regional condition; therefore, important factors such as distance from sea and forested areas were not considered. In the next step, digital layers are weighted and classified according to the available standards and expert judgment. Then, analytical multi-criteria decision-making algorithms as AHP and weighted linear combination are applied upon existing layers in GIS. The results show that by implementing the AHP method in this region only 7% of the study area has a very good and appropriate condition for landfill location and the field observation confirms them. Finally, considering the environmental effects of landfill, appropriate locations are suggested.     

北京地区垃圾填埋对地下水的污染及垃圾填埋场选址分区

本文介绍了北京市生活垃圾处理现状及由于垃圾填埋而引起的地下水污染问题。以北京西郊南部北天堂垃圾填埋场的污染状况为例进行研究,通过建立数学模型来模拟污染物在地下水中的运移及补救效果,对污染控制进行了模拟,分析及提出相关建议;并对北京市生活垃级填埋场遗址进行了分区。     

Landfill site selection by using geographic information systems

One of the serious and growing potential problems in most large urban areas is the shortage of land for waste disposal. Although there are some efforts to reduce and recover the waste, disposal in landfills is still the most common method for waste destination. An inappropriate landfill site may have negative environmental, economic and ecological impacts. Therefore, it should be selected carefully by considering both regulations and constraints on other sources. In this study, candidate sites for an appropriate landfill area in the vicinity of Ankara are determined by using the integration of geographic information systems and multicriteria decision analysis (MCDA). For this purpose, 16 input map layers including topography, settlements (urban centers and villages), roads (Highway E90 and village roads), railways, airport, wetlands, infrastructures (pipelines and power lines), slope, geology, land use, floodplains, aquifers and surface water are prepared and two different MCDA methods (simple additive weighting and analytic hierarchy process) are implemented to a geographical information system. Comparison of the maps produced by these two different methods shows that both methods yield conformable results. Field checks also confirm that the candidate sites agree well with the selected criteria.     

Evaluation of an abandoned aggregate quarry used for uncontrolled waste disposal using remote sensing technologies (Atabey,Isparta-Turkey)

Today, waste is an important environmental problem that needs to be solved. The way it is collected and managed should be considered with respect to the negative impact on the environment. Although the Atabey aggregate quarry was operated with natural sand-gravel until 2 years ago, it was closed due to technological renovation in the crushing-screening unit and uneconomic production. This area was later used by the Atabey Municipality as a waste storage area. Thus, uncontrolled storage occurred at the quarry site. As a result, new, more intensive environmental problems have emerged in the area, such as visual pollution and the pollution of groundwater. This paper evaluates the impact of municipal solid waste disposal in an abandoned quarry site on groundwater, land surface temperature, land surface moisture, and vegetation cover using GIS (Geographic Information Systems) and remote sensing technologies. According to the obtained results, the solid wastes stored in the area caused groundwater pollution, increased surface temperature, and reduced soil moisture.     

Case studies in organic contaminant hydrogeology

The effective management of domestic solid waste and hazardous, toxic, and radioactive waste is a major problem in the area of environmental geology and water sciences over the world. This series of case studies of organic contaminants from both solid and hazardous waste disposal facilities provides examples of these problems. The facilities were investigated to determine risks and liabilities before acquisition, to determine the site hydrogeologic conditions for design of appropriate groundwater monitoring plans, and/or to determine the potential for groundwater contamination. The results of these studies and investigations by Waste Management Inc. (WMI) and its consultants have shown certain relationships in the distribution of organic pollutants to the different geologic and hydrogeologic charac teristics of each facility. In each of the case studies, all 129 priority pollutants were analyzed in private wells and/or monitoring wells at the request of regulatory agencies. The 31 volatile organic compounds (VOCs) of the priority pollutant list were the majority of the organic compounds detected and these data are evaluated in each case study. The case studies are on disposal facilities located in glacial tills, carbonaceous weathered clay soils, weathered shale, limestone bedrock, dolomite bedrock, and alluvial and sedimentary deposits. A brief discussion of groundwater quality impacts and remedial measures also is included.Presented at the Second Annual Canadian/American Conference on Hydrogeology: Hazardous Wastes in Ground Water—A Soluble Dilemma. Banff, Alberta, Canada, June 26, 1985.     

放射性废物处置研究进展

放射性废物的处置是制约核能可持续发展的关键因素,目前已成为国际社会关注的热点问题之一.针对处置场地核素运移污染的风险问题,对放射性废物的处置及其选址、核素运移试验和核素运移模型进行了回顾和论述.指出采用多重屏障系统进行放射性废物的处置,其安全性是可以得到保障的;处置场的选址应遵循就近原则,并应从环境水文地质的角度来构建...     

An environmental geomorphologic approach to site selection for hazardous wastes

Geomorphological features are essential parts of the environment and they represent an important conditioning factor for the development and distribution of certain biological assemblages, as well as for a variety of human activities. However, environmental geomorphology usually receives very limited or no attention at all in the process of environmental impact assessment (EIA). Nevertheless, the site selection process for hazardous wastes in environmental impact studies for individual projects plays an essential role. In order to determine the most suitable site in a region for municipal/hazardous wastes, several criteria are used, including geology, groundwater condition, climate, and land use. The present work describes a methodology taking advantage of environmental geomorphological features, and reducing these criteria in the site selection procedure in land disposal of waste; in addition, a case study is presented to demonstrate the applicability of the proposed methodology. The validity of the adopted site screening method is explained. This methodology comprises the use of a single geomorphological map to locate suitable landfilling sites for hazardous waste, instead of using separate maps for geological features, climatic features (temperature, precipitation, and speed and direction of the prevailing wind), slope and erosion. Furthermore, the present study is compared with a previous study performed in the GAP region, where the use of land resources is crucial for agricultural and water management purposes. The application of the described selection process and the verified method in this region shows that the adopted method and detailed criteria are valid.     

Hydrogeochemical Evaluation of Heavy Metal Loadings to Waters and Sediments by Leachate: A Case Study from the Golbasi Waste Disposal Site,Ankara, Turkey

At sites of groundwater contamination, predictions of contaminant behavior and evaluation of remedial strategies depend on identification and characterization of the geochemical processes affecting contaminant migration. Heavy-metal loadings to waters and sediments by leachate from the Golbasi waste disposal site in Ankara, Turkey, have been evaluated quantitatively using hydrogeochemical modeling. The groundwater of the waste disposal area, characterized by high concentrations of Ca, K, Cl, Cd, Pb, Zn, Cu, B, Ni, SO₄, and NO₃, contaminates the waters and sediments in the down-gradient area, Eymir Lake and a swamp along the flow path. An advective mass transport duration is ～15 years for unretarded contaminants to move from the waste disposal well area to the southern shoreline of Eymir Lake. Mixing calculations suggest that the down-gradient groundwater is formed by mixing of 40 to 72% upgradient groundwater and 28 to 60% waste-disposal-area groundwater, as well as Eymir Lake surface-water ion concentrations formed by mixing of down-gradient groundwater (3%-25%) and swamp-water ion concentrations (75-97%) along the flow path. An evaluation of the changes in concentration of trace ion-related precipitation/dissolution and exchange reactions between water and sediments for the formation of both Eymir Lake surface-water composition and the down-gradient groundwater composition indicate considerable trace-ion content of the clays (exchangers) and related reactions in the system. These results suggest that the amounts of contaminants removed from or added both to the down-gradient groundwater and to surface waters through mixing, dilution, and evaporation processes are rather small. The amounts of ions in the waters at the present stage of the contamination process are predominantly governed by exchange and dissolution/precipitation reactions.     

Problems of soil and groundwater pollution in the disposal of “marble” slurries in NW Sicily

This work deals with disposal of slurries generated during the cutting and polishing processes of slabs of decorative sedimentary carbonate rocks in the north western Sicily. At present, they are used as fillers of dismantled quarries near the sawmills and, as a final step of reclamation, are covered with earth layers. In spite of such inexpensive solution, there is lack of knowledge about the composition of the waste. In order to assess if there is any threat for the environment and to suggest indications for alternative solutions, such as recycling or inactivation processes, the slurries were analysed by XR diffraction, simultaneous thermal analysis, ICP/MS, ionic chromatography, FTIR, UV-Vis, COD and TOC measurements, grain size analysis. Results indicate that the slurries can threaten the groundwater, because of the high chemical oxygen demand; furthermore they can modify the mechanism of groundwater recharge, because of their grain size distribution. Some laboratory tests show that, even in very aggressive conditions, the solid pollutants persist in the waste and slowly release into water the products of their degradation. The slurry therefore should be subjected to inactivation treatment before disposal or, alternatively, recycled as secondary raw material for a suitable process.     

Landfill site selection based on reliability concepts using the DRASTIC method and AHP integrated with GIS – a case study of Bengaluru city,India

The selection of landfill sites for municipal solid waste (MSW) disposal involves consideration of geological, hydrological and environmental parameters which exhibit large spatial variability. Therefore, it is necessary to define, to what extent the chosen sites are reliable such that the probability of environmental pollution and health risks to population is minimal. In the present study, groundwater vulnerability to contamination has been assessed using the standard DRASTIC method. The results showed that the study region has 9.45% of very less, 32.94% of less, 25.47% of moderate, 22.79% of high and 9.35% of very high vulnerable zones. The study also revealed that none of the landfills are located in safe zones. This suggests that it requires proper remedial measures to avoid environmental pollution. A landfill site selection process has been carried out using the Analytical Hierarchy Process integrated with Geographical Information System tools. The obtained results showed that only 3.59?km² (0.08%) of the total area is suitable for landfills. The reliability analysis of the site suitability revealed that landfills are located at unreliable locations where the probability of risk to environmental pollution is high. The presented approach assists decision-makers in selecting reliable locations for the safe disposal of MSW.     

Regional hydrogeological screening characteristics used for siting near-surface waste-disposal facilities in Oklahoma,U.S.A.

The Oklahoma Geological Survey has developed several maps and reports for preliminary screening of the state of Oklahoma to identify areas that are generally acceptable or unacceptable for disposal of a wide variety of waste materials. These maps and reports focus on the geologic and hydrogeologic parameters that must be evaluated in the screening process. One map (and report) shows the outcrop distribution of 35 thick shale or clay units that are generally suitable for use as host rocks for surface disposal of wastes. A second map shows the distribution of unconsolidated alluvial and terrace-deposit aquifers, and a third map shows the distribution and hydrologic character of bedrock aquifers and their recharge areas. These latter two maps show the areas in the state where special attention must be exercised in permitting storage or disposal of waste materials that could degrade the quality of groundwater. State regulatory agencies and industry are using these maps and reports in preliminary screening of the state to identify potential disposal sites. These maps in no way replace the need for site-specific investigations to prove (or disprove) the adequacy of a site to safely contain waste materials.