No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Landfill Mining: A review on Material recovery and its Utilization challenges
Abstract
Landfill mining (LFM) is excavating and processing legacy waste to recover secondary resources. This study reviews the technologies used for excavation and processing of the buried waste, fractions recovered from LFM, their characterization, and environmental and safety issues associated with LFM. The study first explains the process of literature selection by which publications were selected for inclusion in the manuscript. For waste excavation, the study compiles the technologies for excavation and material processing and the safety issues involved. The fractions obtained from LFM may be divided into four broad categories: (i) soil-like material, (ii) combustible fraction (including plastic, paper, wood, and textile), (iii) inert fraction (stone, glass, ceramic, and metal) and (iv) others consisting of the remaining fraction. For material recovery, the manuscript first summarizes the percentage of various fractions obtained, the cut-off diameter for soil-like fractions, and the effect of age on various fractions recovered. The lab analyses for determining the reusability of these fractions have been explained along with the instruments required. Afterwards, the environmental and safety issues associated with LFM have been discussed. Finally, the challenges and opportunities for reutilization of materials obtained from LFM have been elaborated upon.
In many developing countries, open dumping remains the primary method for disposing of municipal solid waste (MSW). However, this practice causes significant environmental problems. Leachate from these dumpsites pollutes surface water, while heavy metals from the waste contaminate groundwater over time. Additionally, the release of gases such as CO₂, CH₄, and other toxic emissions contributes to air pollution and exacerbates climate change. These dumpsites not only harm the environment but also become unsightly, emphasizing the urgent need for sustainable and eco-friendly waste disposal methods. Bio-mining offers a practical and effective solution for reclaiming large dumpsites. This process involves extracting, recycling, and reusing various materials from waste dumps in an organized manner, promoting resource recovery and economic benefits. Bio-mining is an innovative, cost-effective, fast, and environmentally sustainable method that remediates old dumpsites, eliminates landfill gases and leachate emissions, and restores land for reuse with minimal maintenance. A combined approach enhances this process, beginning with the stabilization of waste through bioreactor landfill treatment, followed by bio-mining techniques. A conceptual framework for implementing bio-mining at the MSW dumpsite has been developed. Additionally, a comprehensive plan for the future management of open dumpsites has been formulated, focusing on long-term sustainability and environmental protection
Dumpsite remediation has become a crucial aspect of sustainable waste management. This study reviews the current state of knowledge on dumpsite remediation, identifying key gaps in the literature. It explores site investigation, characterization of dumpsites, and remediation techniques, with a focus on dumpsite mining and rehabilitation measures. In the context of dumpsite mining, the study examines the potential recoverable fractions, challenges in recyclability and processing, and the economic aspects of mining operations. For rehabilitation, it discusses the importance of slope stabilization, leachate and gas management, and long-term monitoring strategies. Given the lack of specific criteria for selecting appropriate remediation methods based on site requirements, the study proposes criteria for choosing sustainable approaches. Additionally, case studies are reviewed to demonstrate the successful application of dumpsite remediation for environmental protection and containment, as well as the potential of mining to generate value-added products within a circular economy perspective. However, challenges observed in the case studies, such as heterogeneous waste composition, technological limitations, and economic viability, present significant barriers. The study suggests that overcoming these challenges requires legislative support, infrastructure development, and stakeholder collaboration. The paper concludes with recommendations for advancing circular economy solutions, emphasizing the need for integrated waste management, innovative technologies, and cooperative efforts to achieve sustainable waste management.
India faces a pressing issue with the ever-increasing amount of municipal solid waste (MSW) due to inadequate waste management practices. After decades of uncontrolled and continuous dumping, the existing dumpsites have transformed into mountains of legacy waste. Recognizing the urgency to address this concern, the National Green Tribunal (NGT) of India and the operational rules of the Swachh Bharat Mission 2.0 (SBM 2.0) made it necessary to dismantle legacy waste dumpsites through Landfill Biomining (LFBM). This book chapter provides an overview of the current status of legacy waste dumpsite management in India and the workflow process of LFBM operation and also points out multiple challenges that need to be overcome for sound implementation of LFBM. The study reveals that in the coming years, LFBM, as a reclamation approach to legacy waste dumpsites, will take off across the country with funding from SBM 2.0. However, a comprehensive policy direction for the utilization of reclaimed land and recovered fractions after LFBM is still lacking. There is an obvious need for cooperation between the government, industries and academia to create a circular economy–based economic model for legacy waste dumpsites management in India.
Landfill Mining (LFM) aims to recover resources by partially or completely excavating waste stored in landfills. Research on Enhanced Landfill Mining (ELFM) has been advanced to include the combined valuation of waste as both materials and energy carriers. In this article we present an overview of the literature on the global development of landfill mining based on domestic waste. Here we analyze the existing information on the chronological and geographic distribution in countries that publish in the area, and to describe the dynamics of the conceptual and scientific knowledge. The analyzed articles were retrieved from Scopus, using the “Landfill* Mining” search term. The LFM research on co-occurrence network (1990-2022) found 29 terms in the first decade, increasing to 52 terms in the second decade and, finally, 234 terms in the third decade, indicating the importance of the LFM research field in present days. Four prominent aspects of LFM research can be observed: a. LFM provides an efficient contribution to waste management strategy, b. the objectives of LFM are similar to those of Circular Economy, c. LFM uses advanced techniques for identifying metals and chemical elements; and d. there is a need for ecological and ecotoxicological assessment, and determination of microorganisms and microplastics in the mined material.
Legacy wastes are the wastes that are the result of events in the past. They include past industrial sites and radioactive waste disposal sites. Europe has around 150,000 to 500,000 landfill sites, with around 90% of them being “non-sanitary” landfills that tend to be filled with municipal solid waste (MSW) and often any environmental protection technology. To avoid future health and environmental problems, many of these landfills need remediation measures with an opportunity for a combined resource recovery and remediation strategy. About 60 abandoned uranium production sites throughout rural Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan pose a challenge for local and national governments that require technical expertise as well as resources for remediation. Over 190 Mt of legacy iron and steel slag are present in the UK. India added 31 Mt of waste to the legacy waste in 2016 to its 3,159 operational dumpsites and dumped 23.35 Mt of waste in existing dumpsites in 2019. More than 3200 contaminated sites have been identified in 2016 in 47 countries. Legacy waste has to be managed to get the land beneath it and protect environment. Remediation and reclamation are being done throughout the world wherever budget permits to do so. In other places, it continues to be accumulated which becomes responsibility for the next generation to manage it. This chapter discusses the key issues related to legacy waste and solutions, and their management.
Focusing on expanding and maturing the technology of excavated waste-to-energy pathways can promise a renewable energy production process in addition to reducing land occupation and greenhouse gas emissions. A very scarce comprehensive literature had covered the exergetic performance, life cycle analysis, and financial feasibility of hydrogen-from-excavated-waste technologies based on the plasma gasification process. This article aims to provide a comprehensive comparison under the exergy, techno-economic, and life cycle environmental analyses for two different hydrogen-from-excavated waste pathways. In this regard, two different configurations (under an innovative methodological and analytical approaches) have been proposed for conceptual design and comparative study of hydrogen fuel generation from excavated waste based on plasma gasification, sorption en-hanced/gas-water shift, and gas-water shift processes. The techno-economic and life cycle environmental analyses were compared at two levels (i.e., refuse derived fuel-to-hydrogen and excavated waste-to-hydrogen pathways), which had not been reported in most of the literature. From the outcomes, the proposed excavated waste-to-hydrogen process integrated with the carbon dioxide capture and storage process can provide superior environmental (especially in terms of impacts on human health) and thermodynamic performances compared to the standalone-plasma gasification process. Furthermore, the financial feasibility of the proposed project is completely affected by the selling price of hydrogen. The article's achievements can be competitive with similar pathways and provide attractive design and investment conditions to stakeholders and engineers.
The scarcity of natural resources, and energy demand/carbon footprints related to their processing and transportation, has led to the quest for alternate materials for road/pavement construction and other infrastructure development. On the other side, landfill mined soil like fraction (LMSF) forms significant proportion of mined legacy landfill waste that exists at different locations around the world; however, it has found limited applications. The present study explores the utilization of LMSF in development of novel asphalt road subbase layers for resilient road infrastructure. 30-60% of LMSF replacement has been studied, and findings based on gradation analysis, compaction tests and California bearing ratio (CBR) tests are quite encouraging. Most combinations of subbase layers studied exceed the design requirements for low volume roads in Indian scenario (rural and outer urban roads); while 30% LMSF in wet mix macadam satisfies requirements of Indian and other international codes. The cost-benefit analysis shows significant saving in material cost due to utilization of LMSF in road subbase layer. The potential utilization of low cost and sustainable LMSF in asphalt road subbase layer would allow design of superior roads with CBR exceeding design values, resulting in better life cycle performance of road infrastructure with high resilience to fatigue effects, water inundation and overloading.
Landfills pose global challenges, notably in terms of greenhouse gas (GHG) emissions, pollution release, and extensive land occupation. The transformative practice of landfill mining has redefined these sites as valuable resource reservoirs. The fine fraction (FF), often constituting the majority of excavated waste, is currently underutilized but holds the potential for biocover construction to mitigate methane emissions. This study comprehensively analyzes the FF from the Kuršenai landfill, collecting samples from various depths, reaching up to 10.5 m. The most suitable layers for biocover construction were determined based on basic physical and chemical parameters, along with the concentration of heavy metals and microplastics. The findings unveil significant parameter variations across different depths. Moderate–high correlations (ranging from 0.5 to 0.84) between several parameters were observed. The layer at a depth of 4.5–6 m emerged as the most suitable for biocover construction. However, this layer is characterized by elevated microplastic concentrations (30,208 ± 273 particles/kg), posing a challenge for its use in biocovers as microplastics can be released into the environment during FF extraction and biocover construction. Additionally, microplastics become finer with depth, increasing the associated risks. Therefore, a balanced approach considering material properties and pollution concentrations is vital for sustainable waste management practices.
The circular economy implementation demands following sustainability principles. Any degraded area, including brownfields and dumps, needs planning and assessment for primary reuse in future, whether it is green space, residential area or newly developed industrial center. Brownfields usually are associated with environmental pollution, surrounding contamination, and lost-to-economy abandoned resources. Responsible environmental and social governance principles include evaluation criteria of reclamation options. Ecosystem quality evaluation and land asset valuation are significant, either from the future use aspect, discount value or specific land use not always applicable for direct future benefit discern. The paper summarizes key novel aspects of brownfield recultivation as a tangible land asset integrating intangible ecosystem and cultural revitalization perspectives. The long-term recultivation strategies support reusing any resource, including landscape. The contemporary geographical approach reflects the landscape as a cluster of jointly interacting elements such as soil, biota, climate and human-made changes. In such an integrating framework, economic, social, environmental and cultural aspects are jointly included. Therefore, an estimation of regained land value, restored ecosystem services and recovered space for recreation, sports and culture can be performed. The authors have analyzed how to use set of tools such as land asset evaluation, discounted value and ecosystem services valuation for revitalized landfills that is novel approach.
Energy crisis has prompted the Indonesian government to achieve a renewable energy share of 23% in 2025 by recovering landfilled waste as an energy source. This research aims to characterize and evaluate the potential of landfill-mined materials in Jakarta Province for waste-to-energy source. A minimum of 100 kg d−1 mined material sample was collected from transport trucks for consecutive eight days during rainy and dry seasons in 2022, for composition analysis. Each sample was sifted into fine fraction (FF), medium fraction (MF), and coarse fraction (CF) of < 10 mm, 10–30 mm, and > 30 mm, respectively. Calorific value, moisture, volatile solids, ash, and fixed solids were determined using ASTM methods, while chlorine by APHA. Mined materials comprised FF 13.96–19.36%, MF 14.25–19.93%, and CF 66.11–66.39%. CF category most potential for refuse-derived fuel (RDF) with a calorific value 18.75–20.88 MJ kg−1, moisture 54.72–58.13%, volatile solids 82.37–83.80%, ash 13.54–14.97%, fixed solids 2.65–2.66%, and chlorine 0.21–0.42%. These results met RDF quality standards, except for moisture content, which required drying before use. Heavy metals and chlorine presence in CF require concern due to their potential impact on the cement kiln process, cement quality, and environment.
Landfill biomining (LFBM) has been proposed as a viable method for the reclamation of legacy waste dumpsites as well as the subsequent recovery of valuable resources and land value spaces. Despite these advantages, the potential of LFBM faces a significant challenge due to the composition, characteristics and end-use of the excavated materials. This paper assesses the composition of the excavated waste obtained during the LFBM operation of the four legacy waste heaps at the Boragaon dumpsite in North-East India and determines the physicochemical characteristics crucial for the material and energy recovery from the key reclaimed fractions. The compositional analysis revealed that the proportion of combustible and non-combustible fractions decreases from the youngest heap HP4 to the oldest heap HP1 due to variations in the consumption habits of the local community and the inadequate recycling of recyclable materials. However, the proportion of fine fraction (FF) shows an increasing trend from HP4 to HP1, suggesting enhanced biodegradation of easily degradable waste over the years. The proximate and energy content analysis suggest that refuse-derived fuel (RDF) preparation is the most suitable valorization option for the combustible fractions since surface defilements are too high for good quality material recovery. The elevated amount of organic matter and leachable heavy metals indicate that unrestricted reuse of FF as earth-fill material can cause long-term settlements and groundwater contamination, respectively. Even though every dumpsite is different in characteristics, the findings of this case study can assist in developing new strategies for recycling excavated waste.
(Enhanced) landfill mining (ELFM) is a sustainable waste management strategy which supports the circular economy and reduces the environmental risks related to landfills. To facilitate and encourage stakeholders to launch (E)LFM-projects, RAWFILL has developed (1) an Enhanced Landfill Inventory Framework (ELIF), (2) an innovative landfill characterization methodology combining geophysical imaging and guided sampling (HADESS) and (3) a two-step Decision Support Tool (DST) to allow smart (E)LFM-project planning and prioritization. Based on the Interreg Europe COCOON experiences, the (E)LFM-concept was broadened to Dynamic Landfill Management (DLM), a sustainable and active long-term management of former landfills. DSTs improve decision-making by increasing the efficiency and lowering the uncertainty. The two-step approach offers an efficient and cost-effective solution. The DST 1 (Cedalion) requires limited data and provides guidance to the next step. The result is a ranking score on 4 scenario’s: waste to materials, waste to energy, waste to land interim use. The DST 2 (Orion) provides an overview of relevant tools that can assist the user in the further project development, like estimations about the feasibility of a business case, simulating scenario’s or finding sustainable interim solutions. The latter, interim use, is the novelty in this dual DST and should be seen as a loop in the roadmap. To summarize, the innovative approach of RAWFILL is the broadening of the resource scope at landfills and their comprehensive management, spanning the whole project cycle: from first screening to final redevelopment, including sustainable management and interim uses.
The unavailability of clean drinking water is one of the significant health issues in modern times. Industrial dyes are one of the dominant chemicals that make water unfit for drinking. Among these dyes, methylene blue (MB) is toxic, carcinogenic, and non-biodegradable and can cause a severe threat to human health and environmental safety. It is usually released in natural water sources, which becomes a health threat to human beings and living organisms. Hence, there is a need to develop an environmentally friendly, efficient technology for removing MB from wastewater. Photodegradation is an advanced oxidation process widely used for MB removal. It has the advantages of complete mineralization of dye into simple and nontoxic species with the potential to decrease the processing cost. This review provides a tutorial basis for the readers working in the dye degradation research area. We not only covered the basic principles of the process but also provided a wide range of previously published work on advanced photocatalytic systems (single-component and multi-component photocatalysts). Our study has focused on critical parameters that can affect the photodegradation rate of MB, such as photocatalyst type and loading, irradiation reaction time, pH of reaction media, initial concentration of dye, radical scavengers and oxidising agents. The photodegradation mechanism, reaction pathways, intermediate products, and final products of MB are also summarized. An overview of the future perspectives to utilize MB at an industrial scale is also provided. This paper identifies strategies for the development of effective MB photodegradation systems.
In this study, Ailanthus altissima sawdust was chemically activated and characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), Energy Dispersive X rays (EDX), and surface area analyzer. The sawdust was used as an adsorbent for the removal of azo dye; Acid Yellow 29 (AY 29) from wastewater. Different kinetic and equilibrium models were used to calculate the adsorption parameters. Among the applied models, the more suitable model was Freundlich with maximum adsorption capacities of 9.464, 12.798, and 11.46 mg/g at 20 °C, 30 °C, and 40 °C respectively while R2 values close to 1. Moreover, the kinetic data was best fitted in pseudo second order kinetic model with high R2 values approaching to 1. Furthermore, adsorption thermodynamics parameters such as free energy, enthalpy, and entropy were calculated and the adsorption process was found to be exothermic with a value of ∆H° = −9.981 KJ mol−1, spontaneous that was concluded from ΔG° values which were negative (−0.275, −3.422, and −6.171 KJ mol−1 at 20, 30, and 40 °C respectively). A positive entropy change ∆S° with a value of 0.0363 KJ mol−1 indicated the increase disorder during adsorption process. It was concluded that the activated sawdust could be used as a suitable adsorbent for the removal of waste material, especially dyes from polluted waters.
Landfills are urban stocks and resource reservoirs for potential energy recovery. The purpose of this study is to evaluate the amount of energy that could be recovered from aged waste (around 5–20 yr old) recovered from landfills. Investigations were conducted on the physical and chemical properties of refuse-derived fuel (RDF) prepared from recovered landfill waste (RLW) in Andhra Pradesh, India. Waste characterization studies include determination of waste composition, proximity analysis, ultimate analysis, and energy content. The moisture content ranged between 25.7 to 31.3% and no trend was observed with age. In the ultimate analysis, the percentage of carbon increased from 42.9 to 71.7% with the age of the samples, this is due to an increase in the plastic content over time. The calorific value of the recovered landfill waste ranged from 10.4 to 21.8 MJ kg − 1 . From the findings, it can be summarized that the RDF can potentially be utilized as a feedstock for the recovery of energy from RLW. The results from this study will assist policy makers and local authorities in designing and developing strategies for resource and energy recovery from landfills in different urban cites across the globe.
In this study, activated carbon (AC) and magnetic activated carbon (MAC) were prepared from Dalbergia sissoo sawdust for the removal of antibiotic Azithromycin (AZM) from aqueous solution. The effect of initial concentration, contact time, pH, adsorbent dosage, and the temperature were investigated for both the adsorbents. The optimum AZM concentration, contact time, pH and adsorbents dosages were found to be 80 mg/L, 120 min, 6 and 7 (pH, respectively, for AC and MAC), and 0.1 g (for both AC and MAC), respectively. The isothermal data of both sets of experiments correlated well with the Langmuir isotherm model, while the kinetic data with the pseudo-second-order model. The adsorption of AZM on both adsorbents was found to be favorable, which is evident in the values of the thermodynamic parameters (ΔH = −26.506 and −24.149 KJ/mol, ΔS = 91.812 and 81.991 J/mol K, respectively, for AC and MAC). To evaluate the effect of AC and MAC on the membrane parameters, a continuous stirred reactor was connected with ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) membranes. High % retention and improved permeate flux (around 90%) were obtained for AC/UF, AC/NF AC/RO, MAC/UF, MAC/NF, and MAC/RO treatments. The percent retention of AZM observed for AC/UF, AC/NF AC/RO was higher than MAC/UF, MAC/NF, and for MAC/RO hybrid processes due to greater surface area of AC than MAC.
The catalytic activity of Pd/ZrO2 was studied in terms of the degradation of rhodamine-B dye in the presence of hydrogen peroxide. Pd/ZrO2 was prepared by impregnation method, calcined at 750 °C and characterized by XRD, SEM and EDX. The catalyst showed good catalytic activity for dye degradation at 333 K, using 0.05 g of the catalyst during 5 h. The reaction kinetics followed the pseudo-first order kinetics. The Freundlich, Langmuir and Temkin isotherms were applied to the data and the best fit was obtained with Freundlich isotherm. Thermodynamic parameters, like ΔH, ΔG and ΔS were also calculated. The negative values of ΔH (−291.406 KJ/mol) and Gibbs free energy (ΔG) showed the exothermic and spontaneous nature of the process. The positive ΔS (0.04832 KJ/mol K) value showed suitable affinity of catalyst for dye degradation. The catalyst was very stable, active and was easily separated from the reaction mixture by filtration. It can be concluded from the results that the prepared catalyst could be effectively used in dyes degradation/removal from water subjected to further validation and use for various dyes.
The main components of landfill gas are methane and carbon dioxide. Emissions of methane, a strong greenhouse gas, can be minimized by in situ oxidation in the bioactive cover layer. Typically, organic-rich porous materials such as compost are used for this process. In this study, the material for a biocover was obtained from the same landfill by landfill mining. The objective was to study the spatial distribution of gases and the efficiency of methane degradation in the biocover. The methane and carbon dioxide emissions were measured at 29 measuring points six times on the surface and once at a depth of 0.5 m. The highest values of both gases from the surface were recorded in July 2015: 1.0% for CO2 and 2.1% for CH4. Deeper in the cover layer, higher values of methane concentration were recorded. The results showed that (a) methane from the waste deposit was entering the biocover, (b) the migration of methane to the atmosphere was low, (c) fluctuations in the composition of gases are seasonal, and (d) the trend in the concentration of CH4 over time was an overall decrease. The described cover design reduces the CH4 emissions in landfills using elements of circular economy—instead of wasting natural soils and synthetic liners for the construction of the final cover layer, functional waste-derived materials can be used.
With the aim of examining the forcing factors in postmanagement landfills, in this study, excavation waste from nonhazardous municipal waste landfill in Tuscany was characterized for the first time. The specific objective was to estimate the feasibility of sampling and analyzing the excavated waste in order to define its properties and provide information about possible landfill mining projects. Based on the biochemical methane potential assays, it was shown that the excavated waste had not yet been stabilized (i.e., with a production of 52.2 ± 28.7 NlCH4/kgTS) in the landfill, probably due to the low excavated waste moisture content (36% ± 6% w/w). Furthermore, excavated waste has a high calorific value, i.e., 15.2 ± 4.1 MJ/kg; the quantity of combustibles in the industrial shredder waste (16 MJ/kg) was rather modest compared to that of municipal solid waste (20.8 MJ/Kg). In conclusion, during large scale excavation of the landfill, it was possible to evaluate how a dedicated treatment plant could be designed to treat and select waste which might appear in a different category. For excavated industrial waste, detailed mechanical sorting may be convenient for end-of-waste recovery to improve calorific value.
(Enhanced) landfill mining ((E)LFM) projects have been mainly driven by land reclamation, environmental pollution mitigation and remediation of old landfills and dumpsites, among others. However, previous studies have also shown that these sites may be a relevant source of secondary raw materials. In this respect and within the framework of the “EU Training Network for Resource Recovery through Enhanced Landfill Mining – NEW-MINE”, around 374 Mg of waste was excavated from a landfill site in the municipality of Mont-Saint-Guibert, Belgium, as part of a case study to evaluate the full implementation of ELFM. The excavated landfilled material was pre-processed with a ballistic separator onsite directly after excavation, with which the fine fractions (material <90 mm) were obtained. Subsequently, samples of the fine fractions were characterized in order to determine their main properties and material composition. According to these strategies a chain of mechanical processing steps was selected and tested in the processing of the fine fractions in the optimal water content (15 wt.% WC) and dry states. The mechanical processing in the dry state yielded total amounts of 41.9-43.9 wt.% DM fine fractions <4.5 mm, 35.9-39.0 wt.% DM inert materials, 7.4-10.0 wt.% DM combustible materials, 1.2-1.8 wt.% DM ferrous metals and 0.2-0.4 wt.% DM non-ferrous metals. These figures suggest that a significant share of the fine fractions could be recovered through the tested mechanical processing approach, which might contribute to the overall economic and environmental feasibility of the project in case of implementing full scale (E)LFM at the studied landfill site.
For decades, ballistic separators have been used in Europe as a means of sorting waste to separate mixed waste material streams at material recovery facilities and municipal solid waste treatment plants. Currently, with the growing need to remediate landfill sites, ballistic separators can be employed to recover calorific fractions from excavated landfill material within the framework of enhanced landfill mining. Ballistic separators provide multiple separation steps in one machine: they sort flat two-dimensional materials from rigid three-dimensional materials, while the material is screened to a selected particle size at the same time. The present study shows the results obtained during an investigation performed at the landfill in Mont-Saint-Guibert, Belgium. The main objectives were to acquire first-hand information regarding the efficiency of the ballistic separator in relation to processing old and untreated landfilled material and to study the potential of the landfill as a reservoir of secondary resources. The excavated material was processed through a pre-treatment chain of steps, including material classification and separation, as well as particle size reduction. As a first step, the material was processed with a ballistic separator using two different mesh sizes, 200 mm and 90 mm. Subsequently, the performance of the separator in question was evaluated, especially regarding its effectiveness in the production of refuse derived fuel. The two-dimensional flow was characterized by combustible materials from municipal solid waste and the three-dimensional by construction and demolition waste. As a result, 46% (dry basis) of the input material were fines particles <20 mm, 3% had a calorific value of 22.4 MJ kg-1, 1% 16.0 MJ kg-1 and approximately 1% were magnetic metals that could be recovered by mechanical processes. The results of processing and valorising the potential resources disposed in landfills are essential for the implementation of enhanced landfill mining since revenues from material and energy recovery could contribute to the economic feasibility of the project.
There is no proper intermediate treatment for municipal solid waste in Indonesia before dumped in a landfill. Most of the Indonesian dumpsite already over capacity and need intensive treatment. This study examines Jatibarang Dumpsite in Semarang City, Indonesia to assess the material recovery potential for solid fuel. After excavation obtained material consist of 46% of the combustible material (organic and plastic), 52% of the fine particle, and 2% of the incombustible material (metal and glass). A simulation of incineration with the steam turbine is used to predict the electricity generation. The simulation results show that the amount of electricity produced could reach 461.67 kW with CO2 emission up to 0.18 kg/sec.
Reclamation of the dumps/landfills having huge quantities of decades-old garbage (aged waste or legacy waste) in an environmentally sound manner is one of the major challenges faced by the developing nations in general and in particular by urban local bodies in India. The article presents the feasibility of landfill mining operation specifically to recover soil-like material at old dumpsites of India for re-use in geotechnical applications. Aged municipal solid waste was collected from three dumpsites of India and initial tests were conducted on the soil-like material of the municipal solid waste. Initial tests results of grain size distribution, compositional analysis, organic content, total dissolved solids, elemental analysis, heavy metal analysis and colour of the leached water from finer fraction of aged municipal solid waste are presented. From the preliminary investigation, it was found that organic content in 15–20-year-old dumpsites varies between 5%–12%. The total dissolved solids ranges between 1.2%–1.5%. The dark coloured water leaching out from aged waste, with reference to local soil, is one of the objectionable parameters and depends on the organic content. The concentration of heavy metals of the finer fraction were compared with the standards. It was found that copper, chromium and cadmium are present at elevated levels in all the three dumpsites. The study concluded that the bulk of the soil-like material from aged municipal solid waste landfills can be used as cover material for landfills at the same site. However, some treatment in terms of washing, thermal treatment, blending with local soil, biological treatment, etc., is required before it can be re-used in other geotechnical applications.
A review of available literature of landfill mining and potential challenges, opportunities and work scope.
Landfill mining is an alternative technology that merges the ideas of material recycling and sustainable waste management. This paper reports a case study to estimate the value of landfilled materials and their respective market opportunities, based on a full-scale landfill mining project in Estonia. During the project, a dump site (Kudjape, Estonia) was excavated with the main objectives of extracting soil-like final cover material with the function of methane degradation. In total, about 57,777 m³ of waste was processed, particularly the uppermost 10-year layer of waste. Manual sorting was performed in four test pits to determine the detailed composition of wastes. 11,610 kg of waste was screened on site, resulting in fine (<40 mm) and coarse (>40 mm) fractions with the share of 54% and 46%, respectively. Some portion of the fine fraction was sieved further to obtain a very fine grained fraction of <10 mm and analyzed for its potential for metals recovery. The average chemical composition of the <10 mm soil-like fraction suggests that it offers opportunities for metal (Cr, Cu, Ni, Pb, and Zn) extraction and recovery. The findings from this study highlight the importance of implementing best available site-specific technologies for on-site separation up to 10 mm grain size, and the importance of developing and implementing innovative extraction methods for materials recovery from soil-like fractions.
Leachate emission from uncontrolled municipal solid waste landfills (referred to as waste sites in the present study) is a major threat to the environment and living beings in its vicinity. Surface water contamination potential resulting from leachate may be used as one of the criteria for prioritization of sites for remediation purposes. The existing hazard rating systems that prioritize waste sites considering surface water contamination potential as one of the criteria are mainly suited for the developed countries where these were developed initially. In developing countries like India, the set of conditions differ from those in developed countries, and therefore the existing systems may not be suitable for developing countries. Thus in the present study, an improved system is proposed to assess surface water contamination potential from MSW sites. The system is based on the concept of Source, Pathway and Receptor. The proposed system employs parameters derived from the review of existing rating systems and selects their best and worst values based on literature review, design standards and field conditions. The importance weights of the system parameters have been decided based on expert judgment using Delphi technique. Sensitivity analysis of the system shows that the improved system is more sensitive than the existing systems for the site conditions encountered in developing countries. Monte Carlo analysis of the proposed system confirms the spread of the scores obtained from the system over the full scale of 0–1000. The improved system is compared with existing systems by applying it to waste sites from metropolitan cities of India and performing clustering analysis on the rating scores. The clustering analysis shows that the rating scores from the improved system are less clustered as compared to the scores from the existing systems. This demonstrates that the improved system makes a better tool to distinctly prioritize the waste sites for remediation purpose.
Since the need for raw materials in countries undergoing industrialisation (like China) is rising, the availability of metal and fossil fuel energy resources (like ores or coal) has changed in recent years. Landfill sites can contain considerable amounts of recyclables and energy-recoverable materials, therefore, landfill mining is an option for exploiting dumped secondary raw materials, saving primary sources. For the purposes of this article, two sanitary landfill sites have been chosen for obtaining actual data to determine the resource potential of Austrian landfills. To evaluate how pretreating waste before disposal affects the resource potential of landfills, the first landfill site has been selected because it has received untreated waste, whereas mechanically-biologically treated waste was dumped in the second. The scope of this investigation comprised: (1) waste characterisation by sorting analyses of recovered waste; and (2) chemical analyses of specific waste fractions for quality assessment regarding potential energy recovery by using it as solid recovered fuels. The content of eight heavy metals and the net calorific values were determined for the chemical characterisation tests.
Landfill mining applied in reclamation at the territories of old dump sites and landfills is a
known approach tended to global economic and environmental benefits as recovery of metals
and energy is an important challenge. The aim of this study was to analyse the concentration
of several metallic elements (Ca, Cu, Cr, Fe, K, Mn, Pb, Zn) in the fine fraction of waste
derived in the landfill and to compare the results of measurements obtained by field-portable
equipment with the data gained by advanced analytical tools. Atomic absorption spectrometry
(AAS) and inductively coupled plasma mass spectrometry (ICP-MS) were used for the
quantitative detection of metallic elements at the laboratory; whereas field-portable X-ray
fluorescence spectrometry (FPXRF) was applied for rapid sample characterisation in the field
(on-site). Wet digestion of samples (fine fraction of waste at landfill) was done prior
analytical procedures at the laboratory conditions, but FPXRF analysis was performed
using raw solid samples of waste fine fraction derived in the Kudjape Landfill in Estonia.
Although the use of AAS and ICP-MS for the measurements of metals achieves more precise
results, it was concluded that precision and accuracy of the measurements obtained by
FPXRF is acceptable for fast approximate evaluation of quantities of metallic elements in
fine fraction samples excavated from the waste at landfills. Precision and accuracy of the
results provided by express method is acceptable for quick analysis or screening of the
concentration of major and trace metallic elements in field projects; however, data correction
can be applied by calculating moisture and organic matter content dependent on sample
matrix as well as special attention must be paid on sample selection and homogenisation and
number of analysed samples.
Landfill mining is an environmentally-friendly technology that combines the concepts of material recycling and sustainable waste management, and it has received a great deal of worldwide attention because of its significant environmental and economic potential in material recycling, energy recovery, land reclamation and pollution prevention. This work applied a cost-benefit analysis model for assessing the economic feasibility, which is important for promoting landfill mining. The model includes eight indicators of costs and nine indicators of benefits. Four landfill mining scenarios were designed and analyzed based on field data. The economic feasibility of landfill mining was then evaluated by the indicator of net present value (NPV). According to our case study of a typical old landfill mining project in China (Yingchun landfill), rental of excavation and hauling equipment, waste processing and material transportation were the top three costs of landfill mining, accounting for 88.2% of the total cost, and the average cost per unit of stored waste was 12.7USDton(-1). The top three benefits of landfill mining were electricity generation by incineration, land reclamation and recycling soil-like materials. The NPV analysis of the four different scenarios indicated that the Yingchun landfill mining project could obtain a net positive benefit varying from 1.92 million USD to 16.63 million USD. However, the NPV was sensitive to the mode of land reuse, the availability of energy recovery facilities and the possibility of obtaining financial support by avoiding post-closure care.
Copyright © 2014 Elsevier Ltd. All rights reserved.
EXECUTIVE SUMMARY When the prices for raw materials increase further or some resources are no longer available from primary sources, the reuse of landfilled wastes as source of secondary raw material might become relevant. This paper analyses the amounts and types of resources stored in Tyrolean landfills. Information published by the Tyrolean Regional Government, the Austrian Government and the Environment Agency Austrian was evaluated and in addition operators of Tyrolean landfills have been interviewed to identify the amounts and types of waste landfilled in Tyrol. The collected information can be summarized as follow: Since 1.1.2009 it is forbidden to landfill untreated waste in Tyrol, and the last four landfills for residual waste in Tyrol closed with the 31.12.2008. Within the last 60 years 19 larger landfills for residual waste, with a landfill volume ranging from 14.000 m³ to 3.4 million m³ have been operated in Tyrol. The oldest one started its operation in 1942. It can be estimated that around 12.6 million m³ of waste have been disposed of in these landfills. The types of landfilled waste are mainly municipal and similar commercial waste, followed by bulky waste and construction waste. Industrial waste, sewage sludge, excavated soil and hazardous wastes are included to a smaller extent.
Thousands of old landfills and dumpsites exist throughout the developing countries representing a threat for human health for the next decades, unless appropriate measures are taken. Landfill mining, involving the excavation, screening and separation of material from landfills into various components including soil, recyclable materials and residues is central to the sustainable approach to prolong the landfill life and to remediate contamination from unlined open dumps. The focus of this paper is on the concept and utility of landfill mining as a key part of sustainable landfill management especially for the rehabilitation of the municipal solid waste dumpsites in developing countries. The paper would discuss the findings of the studies on mining of decomposed materials from the dumpsites at Kodungaiyur and Perungudi, near Chennai and compare with the results of similar studies in Deonar, near Mumbai in India, Europe and USA.
The condition of Maung Pathum dumpsite in Pathumthani province, Thailand was investigated for potential rehabilitation and material recovery. Analysis of solid wastes and leachate samples from the dumpsite showed that the waste is stabilized, mainly consisting of soil fraction (69-75%). The result of toxicity characteristics leaching procedure (TCLP) revealed that the soil fraction was not hazardous and potential to be reused as landfill cover material. Moreover, soil fractions of particle size
This article describes landfill-mining tests, including excavation, screening, and fraction characterization, carried out in the Msalycke and Gladsax landfills for municipal solid waste (MSW) in Sweden. The excavated waste in these two sites was 17–22 and 23–25 years old, respectively. The main part of Msalycke was unaffected by degradation, and during excavations no substantial amount of biogas was detected. After screening, three size fractions were obtained: <18mm, 18–50mm, and >50mm. Soil amendment and anaerobic digestion with energy extraction are suggested for the first and second fraction, respectively. Incineration with energy recovery is possible with the third fraction after any coarse (inert) material is removed, and construction/demolition waste can easily be recycled provided that it is not contaminated by hazardous material. Excavated waste taken from different depths was also analysed and compared in relation to composition, calorific value, and leachate constituents.
In the last decade landfill mining (LFM) has gained particular attention due to the possibility of resource recovery from landfills. However, landfills consist mainly of soil-like material (SLM) which is of little or no economic value. The aim of the present study is to provide a global overview of SLM in terms of heavy metal concentrations and its resource potential. As references for the resource assessment served metal concentrations in ores, thresholds for compost and earthworks, and abundance in Earth's crust. The preparation of a meta-analysis included 573 chemical analyses from 59 landfills in 12 countries. Average concentrations of arsenic, zinc and nickel turned out to be quite similar worldwide, whereas those of lead, copper and mercury showed remarkable differences between the landfills. Chromium, nickel, lead and zinc concentrations proved to exceed most likely compost, while arsenic and mercury concentrations remained usually below thresholds. With regard to a reuse of SLM in earthworks, elevated zinc concentrations were most of concern, followed by lead, copper, chromium and cadmium. However, chromium and nickel concentrations were found to be most similar to abundances in Earth's crust. Heavy metal concentrations in SLM were worldwide not comparable to those found in ores. Moreover, we observed that the option of multiple metal recovery did not improve significantly the resource potential.
Lowered air supply and organic carbon need are the key factors to reduce wastewater treatment costs and thereby, avoid eutrophication. Denitrifying PO4³⁻- removal (DPR) process using nitrate instead of oxygen for PO4³⁻ uptake was started up in the sequencing batch reactor (SBR) at a nitrate dosing rate of 20–25 mg N L⁻¹ d⁻¹. Operation with a real municipal wastewater supplied with CH3COONa, K2HPO4 and KNO3 succeeded in the cultivation of biomass containing denitrifying polyphosphate accumulating organisms (DPAOs). The durations of SBR process anaerobic/anoxic/oxic cycles were 1.5 h, 3.5 h and 1 h, respectively. SBR operation resulted in a maximum PO4³⁻-P uptake of 17 mg PO4³⁻-P g⁻¹ MLSS. The highest TN and PO4³⁻ removal efficiencies were observed during the first half of reactor operation at 77 (±10) % and 71 (±5) %, respectively. An average COD removal rate of 172 (±98) mg g⁻¹ MLSS and a high average removal efficiency of 89 (±4) % were achieved.
Nitrite effect with/without nitrate as DPR electron acceptor was investigated in batch-scale to show possibilities to use high nitrite and nitrate contents simultaneously as electron acceptors for the anoxic phosphate uptake. Nitrate attenuation against nitrite toxicity can be economically justified in full-scale treatment applications in which wastewater has a high nitrogen content. Nitrate attenuated nitrite toxicity (caused by nitrite content at 5–100 mg NO2⁻-N L⁻¹) when using supplemental additions of nitrate (at concentrations of 45–200 mg NO3⁻-N L⁻¹) in batch tests. Illumina sequencing emphasized that during biomass adaption microbial community changed by lowered aerobic cycle length and by lowered nitrate dosing towards representation of key DPAO/PAO- organisms, such as Candidatus Accumulibacter, Xanthomonadaceae, Comomonadaceae, Saprospiraceae and Rhodocyclaceae. This study showed that DPAO biomass adaption to nitrate maintained an efficient COD, nitrogen and phosphorus removal and the biomass can be applied for treatment of wastewater containing high nitrite and nitrate content.
This paper assesses the effect of ageing on physicochemical characteristics of excavated municipal solid waste from Mulund dumpsite in Mumbai, India. Based on disposal year, waste was excavated from different zones in the dumpsite. The excavated waste was screened into five different size categories and further sorted into different streams. Physicochemical characteristics, i.e., pH, bulk density, ultimate and proximate analysis, calorific value and heavy metal concentration of excavated waste were also determined. The results indicate a change in the characteristics and composition of waste with age. The particle size distribution of waste revealed that waste above 80 mm was mostly plastic and textile, whereas <4 mm (fine fraction) composed of soil-like material. Above 80 mm fraction shows a decreasing trend with age and depth, suggesting particle size reduction with time. Parameters like volatile matter, total and organic carbon and calorific value of excavated waste also reduced with the age. A significant portion of waste was fine fraction (∼45%) emphasising on its valorisation for success of landfill mining. Furthermore, metal content in the dumpsite was <1%. The findings from this study can be used to reclaim dumpsites and suggest possible valorisation routes for excavated waste in developing countries like India.
Landfill mining is a prospective tool for the recycling of valuable materials (waste-to-material) and secondary fuel (waste-to-energy) from old, therefore more or less stabilised municipal solid waste landfills. The main target of Horizon 2020 ‘SMARTGROUND’ R&D was improving the availability and accessibility of data and information from both urban landfills and mining dumps through a set of activities to integrate all the data – from existing sources and new information retrieved with time progress – in a single EU database. Concerning urban landfills, a new sampling protocol was designed on the basis of the current Hungarian national municipal solid waste analysis standards, optimised for landfill mining. This protocol was then applied in a sampling campaign on a municipal solid waste landfill in Debrecen, Hungary. The composition and parameters of the landfilled materials were measured as a 12-year timescale. The total wet and dry mass of the valuable components possible for utilisation was estimated.
Conventionally, the concept of mining has been understood from the perspective of recovering metals from mineral ores and other valuable products from the earth. The mining concept is now being applied to old dumpsites and landfills for recovering materials out of municipal solid waste (MSW). Materials recovered from MSW can be turned
into useful raw material for other purposes and allied industries. Plastics recovered from the dumpsites can be utilised as fuel in thermal power plants, cement and brick industries. Reclaimed earth could be utilised as fill or as a raw material in the construction industry. However, a detailed study is needed before mining an MSW dumpsite or a landfill, particularly to decide if the project would be economically sustainable. This paper describes a study conducted on a dumpsite situated in Nagpur, India, wherein the motivation was to rehabilitate the site after the removal of different constituents of MSW. Two scenarios were considered as the potential removal strategies:
(a) mining for recovery and (b) transferring MSW from the dump to a new sanitary landfill. The study revealed that MSW mining for recovery is more economical and sustainable compared with putting MSW in a new sanitary landfill.
Groundwater hazard rating systems are generally based on source-pathway-receptor approach. This study determines the response of rating system to the variations in subsurface conditions (generally designated as pathway component). Besides, the study also investigates the ability of the rating systems to respond to the changes in other components too (i.e., source and receptor components). For the purpose, three groups of sites with various combinations of site conditions, that may be encountered in the field, are employed, e.g., a smaller site located in sandy soil with receptors all around it using groundwater or a larger site having a thick clay layer underneath it and the receptors in vicinity using groundwater for drinking. For the analysis, four sets of corresponding rating scores are determined in this study from the selected eleven rating systems (ten earlier rating systems and mGW-HARS, a recently developed system). The investigation shows that mGW-HARAS performs the best for the three sets; for the remaining one set, the performance of mGW-HARAS is marginally lower than its predecessor, GW-HARAS. The sensitivity analysis of the selected rating systems with respect to four critical pathway parameters depicts that mGW-HARAS is sensitive to all the four parameters and has the highest sensitivity to soil permeability, i.e., 83% amongst all the selected rating systems. When these rating systems are applied to ten waste dumps from Indian cities, only one system, i.e., mGW-HARAS, is able to categorize these waste dumps in four hazard categories and responds suitably to the subsurface conditions encountered at these waste dumps.
One of the possible solutions to reduce or eliminate landfill gas emissions is to cover the landfill with bioactive cover layer, where methane is oxidized in-situ. The main innovation of the closure project at Kudjape landfill, Estonia, was to extract the < 40 mm fine fraction from the same landfill cell by using landfill mining technology in order to construct a methane degradation cover and to restore the previous landfill area for the benefit of the community. European larch (Larix decidua) and Norway spruce (Picea abies) were planted into the cover layer to create community forest. Along with vegetation the multi-purpose sporting trails were designed on the remediated landfill to return it into public service.
The aim of the research was to investigate whether anthropogenic cover material is suitable as growing media for trees and to study which characteristics have influence on their growth. Vegetation has been monitored during three years. Soon after planting it was noticed that some of the trees were not adapting to the environment. Two years later, 60 % of larches and 40 % of spruces had died off. The annual increment of survived trees was 6-7 times less than in regular conditions, referring on variety of stress factors.
According to the results, the methane degradation layer which is made from excavated fine fraction serves very well for degradation of methane but is challenging as growing media. The research continues to monitor the processes within the methane degradation cover layer in order to study if vegetation improves methane degradation. Corrective measures, undertaken to replace die-off trees, refer on better possibilities for vegetation if smaller trees are planted, particularly with better root: soot ratio. Tree species should be selected on different bases compared to regular forestation. As the organic-rich cover layer mineralises in time, growing conditions are expected to improve in coming years.
ABSTRACT: For decades, ballistic separators have been used in Europe as a waste sorting technique to separate mixed waste material streams at material recovery facilities and municipal solid waste treatment plants. Nowadays, with the growing need to remediate landfill sites, ballistic separators can also be employed to recover calorific fractions from excavated landfill material along the line of Enhanced Landfill Mining (ELFM). Ballistic separators provide multiple separation steps in one machine: They sort flat 2-dimensional materials from rigid 3-dimensional materials, while the material is screened to a selected particle size at the same time. The EU Project “New-Mine”, funded by the Programme HORIZON 2020, carries out ELFM studies at different landfills in Europe. The present study shows some of the results obtained during an investigation performed at the landfill site of Mont Saint Guibert, Belgium. The excavated material was processed through a treatment chain including different steps, such as classifying, shredding and separation. As a first step, the material was processed with a ballistic separator using two different mesh sizes, 200 mm and 90 mm, and its performance, regarding its effectiveness to produce RDF, was evaluated. The main objectives of this investigation were to obtain firsthand information about the efficiency of the ballistic separator in relation to processing untreated old landfilled material and to study the potential of the landfill as a reservoir of secondary resources. To separate and valorize the potential resources disposed in landfills is essential, since resource recovery is one of the possible revenues that may help to make ELFM projects economically feasible.
Keywords: enhanced landfill mining, material recovery, RDF, mechanical processing, ballistic separator, recycling, waste-to-energy, waste-to-material
The study focuses on developing an improved rating system to assess the hazard for subsurface migration of landfill gas leading to explosion. From literature review, the study first identifies eight parameters important for the hazard: waste quantity, waste depth below ground, biodegradable fraction, annual rainfall, number of rainy days, soil permeability, distance to nearest receptor and land use. Consequently, assessment of the only existing rating system i.e. RASCL applicable to MSW sites for the hazard, indicates that it gives equal ratings to sites with distinct characteristics as it employs only five out of the total eight parameters identified and that too, with improper ranges for four of the parameters. RASCL was improved into ExpRASCL by modifying ratings for existing parameters, introducing ratings in the system for the three parameters and provision to account for uncertainty in the input data using fuzzy logic. When compared to RASCL, ExpRASCL performs better when applied to MSW sites with continuously varying characteristics and in sensitivity analysis. When applied to waste dumps from Indian cities, ExpRASCL is able to categorize these waste dumps in distinct hazard categories and helps deciding a closure alternative between cover system with active gas collection system and cover system only.
Close vicinity of uncontrolled municipal waste sites (or ‘waste dumps’) to well-populated communities makes the air contamination a prominent hazard from the waste dumps. The hazard rating systems, considered useful in prioritizing these sites for remediation, are investigated for their suitability to assess air contamination of municipal waste dumps. Out of the eight systems employed in the study, six rating systems respond well to changes in site conditions when applied to hazardous waste sites. However for MSW sites, all eight rating systems give scores in a narrow range and do not perform well. One system is selected for improvement by modifying the indicators for waste quantity and rainfall and, introducing the indicators for waste composition and fresh waste quantity using expert judgment. The modified system performs well for MSW dumps, produces air contamination hazard ratings in a wider range and responds to higher number of scenarios in sensitivity analysis, thus making it an appropriate tool fo...
Recycling of minerals from waste deposits could potentially double the recycling flows while offering an opportunity to address the many problematic landfills. However, this type of activity, i.e., landfill mining, brings many advantages, risks and uncertainties and lacks economic feasibility. Therefore, we investigate the capacity of the Swedish authorities to navigate the environmental, resource, and economic conditions of landfill mining and their attitude to support such radical recycling alternatives towards a resource transition.
By analyzing three governmental commissions on landfill mining, we show how the authorities seem unable to embrace the complexity of the concept. When landfill mining is framed as a remediation activity the authorities are positive in support, but when it is framed as a mining activity the authorities are negative. Landfill mining is evaluated based on how conventional practices work, with one and only one purpose: to extract resources or remediation. That traditional mining was a starting point in the evaluation becomes particularly obvious when the resource potential shall be evaluated. The resource potential of landfills is assessed based on metals with a high occurrence in the bedrock. If the potential instead had been based on metals with low incidence in the Swedish bedrock, the potential would have been found in the human built environment.
Secondary resources in landfills seem to lack an institutional affiliation, since the institutional arrangements that are responsible for landfills primarily perceive them as pollution, while the institutions responsible for resources, on the other hand, assume them to be found in the bedrock. Finally, we suggest how the institutional capacity for a resource transition can increase by the introduction of a broader approach when evaluating emerging alternatives and a new institutional order.
In opencast mining operation, the stability of waste materials stands at high priority from the safety and economic perspective. Poor management of overburden (OB) dump results the instability of slope in an opencast mine. The present paper deals with the stability analysis of dump material of an opencast coal mine at Talcher coal field, Angul district, Odisha, by means of different geotechnical parameters and mineralogical composition affecting the dump slope. The prolonged rainfall in the mining area causes dump failure and loss of valuable life and property. A recent dump failure that occurred in 2013 at Basundhara mines of Mahanadi Coalfields Limited (MCL), Odisha, took 14 lives, and created problems for the mining industry. Most of the dump failure that occurs in the study area are mainly due to increase in pore water pressure as a result of rainfall infiltration. The stability of the waste dump was investigated using the limit equilibrium analysis to suggest an economical, sustainable and safe disposal of the dump in the study area.
This paper presents a summary of the sizes and site characteristics of 30 operational MSW dumps of cities of India with population in excess of 1 million. The impact of these dumps (which have no liners and inadequate covers) on the environment is discussed. The study presents seven options for rehabilitation of old dumps and demonstrates the use of hazard rating systems to select the suitable option. Six alternatives for enhancing the capacities of existing MSW dumps are also highlighted.
This study assesses the recycling potential of municipal solid waste from a closed irregular landfill in Beijing. The assessment comprises an analysis protocol, including waste composition, chemical characteristics, and environmental bioassays. The waste samples were screened at 10 mm and 5 mm, which proved to be effective in reducing the heavy metal content. Chemical analyses of the waste soil showed that the concentrations of nutrients were much higher than the relevant standard. The possible phytotoxicity of the waste soil was explored by conducting germination tests on rice seeds (Oryza sativa L.). The results indicated that the waste soil could have adverse effects on the growth of the plants. The newly developed pot experiment with Poa pratensis Linn. showed that a significant improvement in the compatibility of waste soil with plants was induced by the application of coal cinders. Assessment by the toxicity characteristic leaching procedure showed that heavy metal concentrations in the mixed substrates were all below the allowable US standard. In conclusion, the experimental activities conducted demonstrate that recycling waste soil (size < 5 mm) is potentially safe and suitable for remediation activities.
Landfilling has been the major method for municipal solid waste (MSW) disposal during recent decades. Recently utilization of deposited materials, commonly referred to as landfill mining, has been increasingly considered due to increasing raw material costs and environmental reasons. When mining municipal solid waste (MSW) landfills, finding suitable treatment and utilization routes for different types of materials is essential because of the economic aspects and to minimize the re-landfilled fraction of the waste. This paper describes a case study to sample, characterize and process wastes of a potential landfill mining site. The study combines manual sorting with full-scale mechanical treatment to better assess the treatability of the landfilled wastes. The approach also aimed at complying with the challenges of the heterogenous nature of the landfilled MSW. An approximately 30 m high and 10-year-old Finnish landfill was sampled in connection with the drilling of three gas collections wells, producing samples from two layers of waste of slightly different ages (ca. 5-10 years). Manual sieving and sorting into seven waste fractions as well as full-scale mechanical processing was performed. Further characterization included the fuel properties of the calorific fractions and the leaching properties of the fine materials. Manual sorting of the materials yielded 40-45% (w/w) of the possible fuel fraction in the land filled waste with a net calorific value of approximately 20 MJ/kg dry matter. The metal fractions recovered in the manual sorting amounted to 3-4% (w/w). The landfilled waste was also processable by full-scale mechanical processes, including shredding, magnetic separation, screens and a wind sieve, despite the moisture and impurities in the landfilled waste. Results from the mechanical process showed that approximately 30% (w/w) of the material could be recovered as solid recovered fuel with similar calorific values to the fuel fraction from the manual sorting. Approximately 1% (w/w) could be recovered as magnetic metals in the mechanical process. The yields of fuel and metal fractions are site-specific but could likely be improved by optimizing the mechanical process for landfill mining purposes, as is indicated by the results from the manual sorting of the materials. The amount of fine materials (<20 mm in the manual sorting and <30 mm in the mechanical process) was found to be ca. 50% (w/w) which supports previous reports of the amount of the fines. The fine materials require attention to minimize the waste remaining from landfill mining. The Fe and Al contents of the fine fraction, at approximately 5% (w/w) both in the manually sorted and mechanically treated waste, are interesting for recovery purposes. The findings from this study highlight the importance of proper exploration stage in a landfill mining project in order to plan the best applicable full-scale processes for material recovery. (c) 2013 Elsevier Ltd. All rights reserved.
Collier County, Florida began mining one of their closed landfill cells in 1986. There were several motiva tions: recovery of recyclable materials, recovery of the landfi ll space for reuse and production of a humic mate rial both for daily cover and possible use as soil augmen tation off-site. Markets for recycled materials led to further consideration of processing the mined material to recover salable components that had not degraded. The development of a process train for mined material became an independent research effort. Various types of screening, ferrous and nonferrous metals recovery, and density separation were considered to various de grees. Some were rejected due to shortcomings immedi ately obvious from waste characteristics, and some were actually tried. Included have been: shaker screens, trommels, tail-rotor magnets, belt magnets, eddy current separators, air classifiers, and air knives. As equipment was tried, its perfOImance was assessed through material characterizations involving hand sorting and screening. This paper presents a discussion of goals and the process of equipment evaluation. Data on material characteristics after various steps are pre sented and analyzed. Experience with equipment is dis cussed. Recommendations are formulated for pro cessing of material mined from degraded fills, as well as for industry enhancement of this type of development.
Recent research and policy directives have emerged with a focus on sustainable management of waste materials, and the mining of old landfills represents an opportunity to meet sustainability goals by reducing the release of liquid- and gas-phase contaminants into the environment, recovering land for more productive use, and recovering energy from the landfilled materials. The emissions associated with landfill mining process (waste excavation, screening, and on-site transportation) were inventoried based on diesel fuel consumption data from two full-scale mining projects (1.3 to 1.5 L per in-place m3 of landfill space mined) and default unit emissions (mass per L diesel consumption) from heavy equipment typically deployed for mining landfills. An analytical framework was developed and used in an assessment of the life-cycle environmental impacts of a few end-use management options for materials deposited and mined from an unlined landfill. The results showed that substantial greenhouse gas emission reductions can be realized in both the waste relocation and materials and energy recovery scenarios compared to a "do nothing" case. The recovery of metal components from landfilled waste was found to have the greatest benefit across nearly all impact categories evaluated, while emissions associated with heavy equipment to mine the waste itself were found to be negligible compared to the benefits that mining provided.
The present study addresses the theme of recycling potential of old open dumpsites by using landfill mining. Attention is focused on the possible reuse of the residual finer fraction (<4 mm), which constitutes more than 60% of the total mined material, sampled in the old open dumpsite of Lavello (Southern Italy). We propose a protocol of analysis of the landfill material that links chemical analyses and environmental bioassays. This protocol is used to evaluate the compatibility of the residual matrix for the disposal in temporary storages and the formation of “bio-soils” to be used in geo-environmental applications, such as the construction of barrier layers of landfills, or in environmental remediation activities. Attention is mainly focused on the presence of heavy metals and on the possible interaction with test organisms. Chemical analyses of the residual matrix and leaching tests showed that the concentration of heavy metals is always below the legislation limits. Biological acute tests (with Lepidum sativum, Vicia faba and Lactuca sativa) do not emphasize adverse effects to the growth of the plant species, except the bioassay with V. faba, which showed a dose–response effect. The new developed chronic bioassay test with Spartium junceum showed a good adaptation to stress conditions induced by the presence of the mined landfill material. In conclusion, the conducted experimental activities demonstrated the suitability of the material to be used for different purposes.
Concentrated leachate from membrane treatment processes is a potential pollution source for the surroundings. In this study, with comparison of the landfill leachate, chemical and microbial characteristics of concentrated leachate including biodegradability, amount of nitrogenous compounds and heavy metals, dissolved organic matter composition, and microbial community were investigated in three landfill leachate treatment plants. The results showed that hydrophilic (HyI) fraction was the major dissolved organic carbon in the landfill leachates, accounting for 54.6-60.7%, while humic substances including humic acid (HA) and fulvic acid (FA) were relatively higher in the concentrated leachates, ranging from 61.7% to 69.2%. Conjugated nitrogen existed mainly in FA and HyI in the concentrated leachates. The analysis of excitation emission matrix fluorescence spectroscopy, specific ultraviolet absorbance at 254nm (SUVA254) and GC/MS showed that aromatic compounds, long-chain hydrocarbons and halohydrocarbons were abundant in the concentrated leachates. During landfill leachate treatment processes, Cl(-), SO4(2-) and heavy metals were commonly accumulated in the concentrated leachates. NO3(-)N and/or NH4(+)N were the major nitrogenous compounds in the concentrated leachates. All the leachates from three landfill sites contained toluene in the range of 44.5-728.4μgL(-1). Ethylbenzene, chlorobenzene, and the phthalic acid esters including dibutyl phthalate, dimethyl phthalate and di-n-octyl phthalate were also detected in the concentrated leachates. Higher microbial diversity was observed in the concentrated leachate in comparison with landfill leachate.
The report describes the landfill mining process as demonstrated under the U.S. EPA, Risk Reduction Engineering Laboratory's Municipal Waste Innovative Technology Evaluation (MITE) Program by the Collier County (Florida) Solid Waste Management Department. Landfill mining is the recovery of useful resources (e.g., cover soil) from previously landfilled solid wastes. During the two week demonstration 265 MT (292 tons) of excavated material was mechanically processed. The characteristics of the recovered soil fraction were similar to a low-grade MSW compost. State regulators have approved the use of the soil fraction as landfill cover. Based on the demonstration period, the unit cost was 115/ton) of material mined.
A landfill reclamation project was considered to recover landfill airspace and soil, reduce future groundwater impacts by removing the waste buried in the unlined area, and optimize airspace use at the site. A phased approach was utilized to evaluate the technical and economic feasibility of the reclamation project; based on the results of these evaluations, approximately 6.8ha of the unlined cells were reclaimed. Approximately 371,000 in-place cubic meters of waste was mined from 6.8ha in this project. Approximately 230,600 cubic meters of net airspace was recovered due to beneficial use of the recovered final cover soil and reclaimed soil as intermediate and daily cover soil, respectively, for the current landfill operations. This paper presents the researchers' landfill reclamation project experience, including a summary of activities pertaining to reclamation operations, an estimation of reclamation rates achieved during the project, project costs and benefits, and estimated composition of the reclaimed materials.
A side by side comparison of two 8,000 metric ton test cells was performed to evaluate the effects of leachate recirculation on refuse decomposition at Yolo County, CA. After about 3 years of operation, refuse was excavated in three borings from the enhanced cell E1, E2, and E3 and two borings from the control cell C1 and C2. Refuse moisture content data show that leachate recirculation resulted in an increase in refuse moisture content, but also show that the refuse in the enhanced cell was not uniformly wet. The average moisture content in E1, E2, and E3 was 38.8, 31.7, and 34.8%, respectively, while the average moisture content in C1 and C2 was 14.6 and 19.2%, respectively. Leachate recirculation resulted in both higher methane yields, 63.1 versus 27.9 L CH 4 /wet-kg over 1231 days and increased settlement 15.5% versus 3% of the waste thickness. The extent of decomposition of excavated refuse samples was determined by the biochemical methane potential BMP and the ratio of cellulose plus hemicellulose to lignin CH/Li. Solids analyses showed the average BMP in the enhanced and control cells to be 24.0 and 30.9 mL CH 4 /dry-g, respectively. The corresponding CH/Li ratios were 1.09 and 1.44, respectively. These data correlate well with the increased methane production in the enhanced cell. Thus laboratory and field data show more decomposition in the enhanced cell relative to the control cell. The refuse sampling program conducted for the Yolo County test cells, in concert with data on settlement, methane production, and the volume of liquid actually recycled, represents perhaps the most complete set of data available to date on a field-scale leachate recirculation landfill.
The composition of material excavated from the Burlington County landfill in New Jersey was determined, and the major reclaimed fractions characterized. Based on a waste age map, 98 samples 80 kg each collected from 13 gas extraction well borings were handsorted into 14 fractions and fines 2.54 cm that fell through the screen were collected. At least 50%, by weight, of the material was fines. The most abundant oversize materials overs fractions, by weight, were miscellaneous items, wood, other plastics not polyethylene terephthalate or high density polyethylene containers, and paper. Less paper was found in the oldest 7.5– 11.5 years section of the landfill P 0.10, most likely due to microbial degradation. Several of the characteristics of the materials excavated from the landfill, such as temperature, particle size, bulk density, volatile solids, and contamination were correlated with the age of the deposits made. High levels of adherent soil will likely prove to be an insurmountable obstacle to recycling most excavated waste fractions other than fines unless further processing is pursued.
A study on recycling potential was performed on the stabilized municipal solid waste from Nonthaburi dumpsite in Thailand. The waste was excavated and subjected to separation process using trommel screen with screen openings of 25 mm and 50 mm. The screened wastes were classified into three fractions based on the sizes such as fine fraction (<25 mm), medium fraction (25–50 mm) and large fraction (>50 mm). The waste composition, physical and chemical characteristics of each waste fraction were determined to evaluate suitability of waste for recycling. The possible phytotoxicity of waste to be used as compost was explored by conducting seed germination and root elongation test of rice plant (Oryza sativa L.). The dumpsite was observed to be heterogeneous and mainly composed of plastics and soil.The trommel screen, proved to be effective in separating the waste fractions that can be used as feedstock for alternative applications of solid waste, particularly where the metal content of the product is a critical parameter. By screening, approximately 69% of soil was removed from waste and the remaining 31% was found in the waste fractions >50 mm size. The quality of waste fraction >50 mm composed mainly of plastics showed high potential for recycling as refuse derived fuel (RDF) and waste fraction <25 mm with soil as compost. The remaining waste fractions between 25 mm and 50 mm composed of non-combustible waste, which needs to be landfilled.