Browsing by Author "Wagland, Stuart"
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Item Open Access A decision support tool for enhanced landfill mining(Cranfield University, 2018-05-03 11:13) Coulon, Frederic; Wagland, Stuart; Griffiths, ZoeEnhanced Landfill Mining has great potential to reduce the negative effects of landfills on both the environment and human health, to reclaim valuable land and provide a new source of raw materials. However, uncertainties in economic feasibility and environmental and social outcomes act as a bottleneck to its widespread uptake. Here, we present a decision support tool which aims to reduce these uncertainties by assisting site operators in assessing the economic, environmental and social consequences of a proposed project, while also evaluating the best technology train to use and the amount of rare earth elements present. Such a tool is the first of its kind and we propose its use as an initial assessment aid prior to more complex modelling of project feasibility in order to increase the uptake of enhanced landfill mining practices in the field of sustainable waste management.Item Open Access Assessing metal recovery opportunities through bioleaching from past metallurgical sites and waste deposits: UK case study(CISA Publisher, 2022-12-31) Tezyapar Kara, Ipek; Marsay, Niall; Huntington, Victoria; Coulon, Frederic; Alamar, M. Carmen; Capstick, Michael; Higson, Stuart; Buchanan, Andrew; Wagland, StuartRecovery of metals from former industrial areas (also called brownfields) and closed landfill sites, are critical for future sustainable development and reducing the environmental risks they posed. In this study, the feasibility of using bioleaching for resource recovery of raw and secondary raw materials from a former metallurgical site and deposit (PMSD) located in the UK was investigated. Determination of the physicochemical parameters (conductivity, pH, moisture and ash content) that can affect bioleaching performance along with metal content analysis were carried out. Field measurement were also carried out using a portable X-ray fluorescence (pXRF) spectrometer as a rapid measurement tool and compared with the induced coupled mass spectrometry (ICP-MS) results. Fe (469,700 mg/kg), Ca (25,900 mg/kg) and Zn (14,600 mg/kg) were the most dominant elements present in the samples followed by Mn (8,600 mg/kg), Si (3,000 mg/kg) and Pb (2,400 mg/kg). The pXRF results demonstrated minimal variance (<10%) from the ICP-MS results. The preliminary assessment of bioleaching using Acidithiobacillus ferrooxidans at 5% pulp density with 22 g/L energy source and 10% (v/v) inoculum at pH 1.5 showed that 100% of Ti and Cu, 32% of Zn and 24% of Mn was recovered from the sample material, highlighting opportunities for the recovery of such metals through bioleaching processes.Item Open Access Assessing the opportunities of landfill mining as a source of critical raw materials in Europe(Eurowaste, 2017-10-16) Särkkä, H.; Kaartinen, T.; Hannus, E.; Hirvonen, S.; Valjus, Tuire; Lerssi, J.; Dino, G. A.; Piergiorgio, R.; Griffiths, Zoe; Wagland, Stuart; Coulon, FredericMany of the metals in landfill constitute valuable and scarce natural resources. It has already been recognised that the recovery of these elements is critical for the sustainability of a number of industries. Arsenic (which is an essential part of the production of transistors and LEDs) is predicted to run out sometime in the next five to 50 years if consumption continues at the present rate. Nickel used for anything involving stainless steel and platinum group metals (PGMs) used in catalytic converters, fertilisers and others are also identified as critical materials (CM) to the EU economy at risk of depletion However, despite the increasing demand, none of this supply is supported by recycling. This is due to the high cost of recovery from low concentrations when compared to conventional mining. As demonstrated by the two pilot case studies of this study, mining landfill sites only for their metals content is not expected to be financially viable. However, other opportunities such as Waste-derived fuels from excavated materials exist which if combined , form the concept of ‘enhanced landfill mining’. have the potential to be highly energetic. The energy potential is comparable to the levels of energy of Refuse-Derived Fuels (RDF) produced from non-landfilled wastes.Item Open Access The behaviour of metal(oid)s contaminants in woody biomass during advanced thermal conversion processes.(Cranfield University, 2019-05) Al-Badri, Shurooq Badri; Wagland, Stuart; Jiang, YingA remarkable proportion (about 64%) of renewable biomass energy is produced from woody biomass (wood and its wastes). However, waste wood (WW) often exhibits a high level of chemical contaminants, likely due to the presence of metal(loid) elements in preservatives, paintings, coatings, and other related activities. By thermally treating WW, the metal(loid)s will end up in the bottom ash and/or be emitted into the atmosphere, causing severe environmental concerns and technical damages (e.g. slagging and corrosion). Thus, it is necessary to understand the behaviour of metal(loid)s during the woody biomass thermal conversion process, specifically gasification and pyrolysis. While a great deal of knowledge is available on this matter, there is still uncertainty surrounding the identification and characterisation of metal(loid) elements in relation to woody biomass utilisation, as well as the influences of reaction atmosphere composition in terms of interactions and interferences. In addition to that, knowledge is needed on partitioning profiles of the key metal(loid) elements during the gasification and pyrolysis of WW in order to evaluate the emission potential of these elements. This thesis firstly provides a highly informative dataset that contains comprehensive details about the characterisation and elemental composition of key metal(loid) elements (As, B, Co, Cr, Cu, Fe, Ni, Pb, Mn, Hg and Ti) that are regularly present in woody biomass. Moreover, chemical equilibrium calculations were performed to predict elemental phase transformation and speciation formation under given gasification and pyrolysis operation conditions. Among the results, it was found that Ni-As interactions form the dominant species As₂Ni₅ and As₈Ni₁₁, which increase the solid-gaseous phase transformation of As. In addition, the Ca-Cr interaction forms C₃Cr₇; meanwhile, the absence of Ca creates instability in the Cr phase transformation due to the generation of the species Cr₂Na₂O₄. Subsequently, a set of experiments were conducted using a TGA analyser with different heating rates to understand the thermal behaviour of woody biomass and define the operational conditions of the pyrolysis process. Tube furnace experiments were also conducted to investigate the distributions of Al, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Na, Mn, Mo, Ni, Pb, Si, Ti, V, and, Zn during the operation of pyrolysis. Experimental results indicated that Cd and Hg are exceedingly volatile elements, whereas Al, Co, Cr, Cu Fe, Mo, Ni, Si, Ti, and V are non-volatile elements. The elements As, Mn, Pb, and Zn exhibited differences in partitioning across all experiments. Importantly, this study provides unique insight into the behaviour of As in terms of As-Ni interaction. That is, the presence of Ni should be regarded in combination with its associated concentration profile. Finally, the experimental data and the calculation results are complementary rather than competitive. Overall, the experimental results are within acceptable validation limits.Item Open Access Bioleaching metal-bearing wastes and by-products for resource recovery: a review(Springer, 2023-05-22) Tezyapar Kara, Ipek; Kremser, k.; Wagland, Stuart; Coulon, FredericThe global transition to a circular economy calls for research and development on technologies facilitating sustainable resource recovery from wastes and by-products. Metal-bearing materials, including electronic wastes, tailings, and metallurgical by-products, are increasingly viewed as valuable resources, with some possessing comparable or superior quality to natural ores. Bioleaching, an eco-friendly and cost-effective alternative to conventional hydrometallurgical and pyrometallurgical methods, uses microorganisms and their metabolites to extract metals from unwanted metal-bearing materials. The performance of bioleaching is influenced by pH, solid concentration, energy source, agitation rate, irrigation rate, aeration rate, and inoculum concentration. Optimizing these parameters improves yields and encourages the wider application of bioleaching. Here, we review the microbial diversity and specific mechanisms of bioleaching for metal recovery. We describe the current operations and approaches of bioleaching at various scales and summarise the influence of a broad range of operational parameters. Finally, we address the primary challenges in scaling up bioleaching applications and propose an optimisation strategy for future bioleaching research.Item Open Access CORD_ASPEN Plus paper.xlsx(Cranfield University, 2020-03-19 11:39) Canopoli, Luisa; Coulon, Frederic; Wagland, StuartComplete dataset of ASPEN Plus modelling of pyrolysis of plastic wastes (polyethylene, PE, and polypropylene, PP) recovered from enhanced landfill mining. The ASPEN Plus simulation model was validated with published data and used for predicting possible outputs from the pyrolysis of excavated PE and PP. The model predicted oil yields within 4% error.Item Open Access CORD_Data paper_Pyrola.xlsx(Cranfield University, 2020-03-19 14:42) Canopoli, Luisa; Coulon, Frederic; Wagland, StuartComplete dataset of Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS), which was used to analyse the pyrolysis decomposition products of 10 plastic samples made up of fresh and excavated samples of different ages from 4 MSW landfill sites. The samples included a single polymer for fresh and excavated polyethylene (PE) and polypropylene (PP), and two types of mixed excavated plastic materials, sample A (PE, PP, polystyrene (PS)) and sample B (PE, PP, PS, polyethylene terephthalate (PET), polyvinyl chloride (PVC)).Item Open Access Data for the paper "Degradation of excavated polyethylene and polypropylene waste from landfill"(Cranfield University, 2019-09-09 08:48) Wagland, Stuart; Coulon, Frederic; Canopoli, LuisaDegradation of excavated polyethylene and polypropylene waste from landfill, including composition and chemical characterisation.Item Open Access Deep learning in material recovery: Development of method to create training database(Elsevier, 2019-02-05) Vrancken, Carlos; Longhurst, Phil; Wagland, StuartIncreasing the rate of material identification, separation and recovery is a priority in resource management and recovery, and rapid, low cost imaging and interpretation is key. This study uses different combinations of cameras, illuminations and data augmentation techniques to create databases of images to train deep neural networks for the recognition of fibre materials. Using a limited set of 24 material samples sized 1200 cm2, it compares the outcome of reducing them to 30 cm2. The best classification accuracies obtained range from 76.6% to 77.5% indicating it is possible to overcome problems such as limited available materials, time, or storage capabilities, by using a setup with 5 cameras, 5 lights and applying simple software image manipulation techniques. The same method can be used to create deep neural network training databases to recognise a wider range of materials typically found in solid waste streams, in real-time. Furthermore, it offers flexibility as the classification cameras could be deployed at different stages within solid waste processing plants, providing feedback for process control, with the potential of increasing plant efficiency and reducing costs.Item Open Access Deoxygenation in anisole decomposition over bimetallic catalysts supported on HZSM-5(Elsevier, 2018-10-29) Zhang, Jiajun; Fidalgo, Beatriz; Wagland, Stuart; Shen, Dekui; Zhang, Xiaolei; Gu, SaiThis work investigated the deoxygenation reaction in anisole decomposition over HZSM-5 (HZ(25)) zeolite supported bimetallic catalysts to produce benzene, toluene and xylene (BTX). Experiments were performed in order to evaluate the synergistic effect between the two active metals with the focus on the effect of temperature, metal type, and metal loading ratio. Experimental results showed that 1%Ni-1%Mo/HZ(25) led to both the highest BTX yield (i.e. 30.0 wt%) and selectivity (i.e. 83.7%). On the contrary, bimetallic catalysts containing Fe were less effective in promoting the BTX production. It was identified that the optimum temperature for BTX production over 1%Ni-1%Mo/HZ(25) catalysts was 500 °C. Characterization of fresh and spent catalysts showed microcrystal particles of bi-metal loadings highly dispersed on the zeolite surface, and some agglomeration of metallic particles were also observed. Large amount of carbonaceous deposit was observed on the spent catalysts mainly in the form of amorphous. Density Functional Theory (DFT) modelling was carried out in order to study the adsorption energy of anisole and phenol molecules onto Ni-Mo, Ni-Fe and Mo-Fe surfaces; and the interactions between phenol molecule and bimetal surfaces were further analysed. All the analysed bimetal surfaces exhibited strong interactions with the adsorbed molecule. Ni-Mo surface declined electrons energy levels mainly around 1.5 eV in the adsorbate molecule and released the highest adsorption energy; while Ni-Fe and Mo-Fe surface led to more electrons exchange with the adsorbate during the adsorption. The modelling results agreed well with experiments by revealing that the strong binding between phenolic compounds (Phs) and the Ni-Mo based catalysts bimetal surface would lead to a higher BTX production in the deoxygenation reaction in the decomposition of anisole.Item Open Access Design and commissioning of a multi-mode prototype for thermochemical conversion of human faeces(Elsevier, 2018-03-23) Jurado Pontes, Nelia; Somorin, Tosin; Kolios, Athanasios J.; Wagland, Stuart; Patchigolla, Kumar; Fidalgo, Beatriz; Parker, Alison; McAdam, Ewan; Williams, Leon; Tyrrel, SeanThis article describes the design and commissioning of a micro-combustor for energy recovery from human faeces, which can operate both in updraft and downdraft modes. Energy recovery from faecal matter via thermochemical conversion has recently been identified as a feasible solution for sanitation problems in low income countries and locations of high income countries where access to sewage infrastructures is difficult or not possible. This technology can be applied to waterless toilets with the additional outcome of generating heat and power that can be used to pre-treat the faeces before their combustion and to ensure that the entire system is self-sustaining. The work presented here is framed within the Nano Membrane Toilet (NMT) project that is being carried out at Cranfield University, as part of the Reinvent the Toilet Challenge of the Bill and Melinda Gates Foundation. For this study, preliminary trials using simulant faeces pellets were first carried out to find out the optimum values for the main operating variables at the scale required by the process, i.e. a fuel flowrate between 0.4 and 1.2 g/min of dry faeces. Parameters such as ignition temperature, residence time, and maximum temperature reached, were determined and used for the final design of the bench-scale combustor prototype. The prototype was successfully commissioned and the first experimental results, using real human faeces, are discussed in the paper.Item Open Access Exploiting secondary raw materials from extractive waste facilities: A case study(Unknown, 2018-02-06) Dino, Giovanna Antonella; Rossetti, Piergiorgio; Lorenzi, Alessio; Mister, Ivan; Cazzaniga, Alberto; Coulon, Frederic; Griffiths, Zoe; Wagland, StuartIn recent years, resource scarcity has emphasised a need to transition from a linear to a circular flow of resources. Securing supplies of critical and secondary raw materials (CRM/SRM) for the manufacturing industry is at the forefront of industrial challenges, especially in Europe, USA and Asia. A key step towards achieving resource efficiency, is to recover these materials from anthropogenic waste deposits, such as urban landfill sites and extractive waste facilities. This means breaking away from the traditional linear use of resources to a closed-loop approach that allows maximum recovery of resources from waste. The management of extractive waste deposits and resource recovery is closely linked to the concept of urban mining. In this paper, we present a case study illustrating the feasibility of recovering SRM from EW facilities and discuss the pros and cons of undertaking such activities.Item Open Access The influence of humic acid on metal(loid)s leaching in landfill leachate for enhancing landfill mining(Elsevier, 2023-07-06) Lee, Hyeyeon; Coulon, Frederic; Wagland, StuartThe aim of this study was to investigate the effect of different concentrations of humic acid on the recovery rate of metal(loid)s in landfill leachate. The study focused on the release of 12 selected metal(loid)s, including critical raw materials (CRM) in landfills that were less than five years old and those that were more than ten years old. The experimental setup involved using different concentrations of humic acid (w/v) (0 %, 0.1 %, and 0.5 %) at pH 4 and 6. The results of the study showed that humic acid was effective in releasing Al, Cr, Co, Ni, Cu, Zn, As, Cd, and Pb. On the other hand, an increase in humic acid concentration led to a decrease in the release of Li, Mn, and Hg. The immobilization of Li, Mn, and Hg was due to the coordination and adsorption of humic acid. The presence of humic acid accelerated the release of metal(loid)s by carboxylic acidity compared to the recovery rate of metal(loid)s in landfill leachate without humic acid. However, a higher concentration of humic acid did not always result in a stronger recovery rate. The recovery rate of metal(loid)s was related to the solubility and concentration of humic acid. These findings can inform the development of more efficient and environmentally-friendly methods of recovering metal(loid)s using humic acid as a leaching agent.Item Open Access Influence of pH, depth and humic acid on metal and metalloids recovery from municipal solid waste landfills(Elsevier, 2021-09-15) Lee, Hyeyeon; Coulon, Frederic; Wagland, StuartThe recovery of metal(loid)s from municipal solid waste (MSW) samples <10 years old and >10 years old was investigated using a series of pH-dependence leaching batch tests ranging between pH 2 and 10. Further to this, the influences of various parameters, including depth, and humic acid (HA) concentrations on the recovery of metal(loid)s including Li, Al, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Pb, and Hg were investigated. The Visual MINTEQ geochemical software was then used to model the metal(loid)s release in the presence of different HA concentrations ranging from 28 mg/L to 100 mg/L, which can be found in landfill sites and pH ranging from 2 to 10. The results showed that the release amount of Li, Al, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Pb, and Hg are in the range of 0.03–0.14 mg/L, 0.65–83.33 mg/L, 0.01–0.19 mg/L, 0.18–18.17 mg/L, 0.01–0.09 mg/L, 0.06–0.38 mg/L, 0.12–5.2 mg/L, 0.14–11.57 mg/L, 0.02–0.10 mg/L, 0.00–26.17 mg/L, 0.03–25.17 mg/L, and 0.00–0.01 mg/L with deionised water as leachant at different pH. The release amount of HA was relatively increased from 0 to 2% in 48–55 m compared to 3–9 m in the MSW landfill. HA can promote the leaching rate of metals with an appropriate amount. Base on the study results, the optimal condition of leaching metals was pH 2, and HA 28 mg/L at less than 10 m depth. The high concentration of metals in landfill leachate may be enhanced to effectively recover metals as the critical challenge of recovering metals from leachate is the low concentration of metals. Thus, the information can be useful for economically feasible in the recovery of metals.Item Open Access Landfill mining from extractive waste facilities: The importance of a correct site characterisation and evaluation of the potentialities. A case study from Italy(Elsevier, 2018-05-01) Dino, Giovanna Antonella; Rossetti, Piergiorgio; Perotti, Luigi; Alberto, Walter; Sarkka, Heikki; Coulon, Frederic; Wagland, Stuart; Griffiths, Zoe; Rodeghiero, FrancoRaw materials (RM) and critical raw materials (CRM; EC, 2017) supply is essential to both the maintenance and development of the EU economy as its industries rely on a steady RM supply. Thus, securing a sustainable RM and CRM supply and their circular use in the economy is of importance at EU level and beyond (Blengini et al., 2017, Coulomb et al., 2015, Vidal-Legaz et al., 2016). Furthermore, the developments of clean technologies coupled with economic growth exacerbate the short and long-term demand and needs (Blagoeva et al., 2016, Pavel and Tzimas, 2016). For example, Habib and Wenzel (2014) reported that the necessary supply Nd and Dy will grow from 10.0 Gg to 54.5 Gg and 0.5 Gg to 4.95 Gg respectively from 2010 to 2050.Item Open Access Landfill mining report_2016.pdf(Cranfield University, 2017-04-21 11:46) Canopoli, Luisa; Wagland, Stuart; Coulon, FredericAn era of rising consumption has led to resource scarcity across major industries. One way to overcome this challenge and ascertain future supply of resources is recovery of landfilled material. This so-called landfilled mining may valorise previously discarded material streams for a number of purposes and contribute to a circular economy. Across England and Wales, there are more than 20,000 landfill sites of which 90% have been closed before 1996. Besides the general belief that valuable resources can be found within landfills, mining the waste has a number of additional benefits. One stems from the fact that they often lack modern environmental protection technology, which may lead to negative environmental and health impacts. The combination of these facts poses an interesting opportunity for combined resource-recovery and remediation strategies. The report at hand is in place to assess viability and feasibility of landfill mining processes across England and Wales in a step-wise approachItem Open Access Metal(loid)s concentration with humic acid in <1 and >10 year old landfills(Cranfield University, 2023-03-21 08:43) Wagland, Stuart; Lee, Hyeyeon; Coulon, FredericMetal(loid)s mobilised from landfill samples at differing pH and humic acid concentrations. The datasets provide metal(loid) concentrations for samples 10 years old.Item Open Access Occurrence and distribution of organic compounds in landfill leachate and their influence on metal mobility and recovery.(Cranfield University, 2021-09) Lee, Hyeyeon; Wagland, Stuart; Coulon, FredericResource security has attracted increasing attention globally due to the growing demand for use in a wide range of products. Municipal solid waste landfills and leachate are significant untapped resources that can contribute to a sustainable and secure supply of raw materials. Recent studies reported heavy metals (HM) and rare earth elements within the waste mass buried in landfills that can theoretically be recovered and reintroduced within the material loop of the circular economy framework. However, metal recovery only cannot be visible economically due to its low concentration. Therefore, research is required to understand how metals can be effectively mobilised. This research is carried out to develop a methodology to demonstrate the metals in landfill leachate as a potential secondary source. The batch and column percolation tests are performed to establish the relationship between metals recovery rate and other parameters. This PhD project investigates the influence of factors to increase metal mobility. Firstly, pH value and depth effect on metal release were analysed. The pH value plays a critical role to increase metal recovery rate; however, no significant correlation between depth and metal release was observed. As the analysis shows that metal release is highly increased in acidic conditions, column percolation was conducted at the optimise pH values with leachate recirculation. Leachate recirculation accelerates the degradation of organic waste, consequently enhancing the hydrolysis rate that may reduce the pH value. Lastly, different humic concentration on the metal(loid)s release from landfill leachate was investigated. This thesis presents a high potential to help evaluate the environmental impact to control the pollution and recover metal(loid)s.Item Open Access Recovering metal(loids) and rare earth elements from closed landfill sites without excavation: leachate recirculation opportunities and challenges(Elsevier, 2021-12-27) Lee, Hyeyeon; Coulon, Frederic; Beriro, D. J.; Wagland, StuartMetal (loids) and Rare Earth Elements (REE) (‘metals’) are used in a wide range of products, and therefore, the improvement of expectations for everyday comforts with demand continues to grow. Metal-bearing wastes are a secondary source of raw material that can meet this demand by providing a previously unconsidered low impact supply source. Total annual leachate production is 1,056,716 m3. Therefore, landfill leachate emerges as a significant potential resource as it contains high concentrations of metals. However, realising a profitable return on investment for leachate processing is a challenge due to relatively low recovery rates of approximately 0.02% of total heavy metals in a landfill being leached out in 30 years. Variation within the multi-element value and the effect of other chemicals in these complex mixtures. There is a need to better understand the mechanisms and potential applicability of extraction methods for optimising metals recovery from leachate. This paper addresses this need by providing a systematic review of the critical factors and environmental conditions that influence the behaviour of metals within the landfilled waste. The paper provides a synthesis of how the factors and conditions may affect leachate recirculation efficiency for recovery in the context of a range of opportunities and challenges facing circular economy practitioners. To approach feasibility metal recovery economically from landfill leachate without energy-intensive and environmentally destructive, future research actions need to be initiated in lab-based and later on semi-pilot to pilot studies, which the review can help achieve the challenges.Item Open Access Reduce toxic emissions of As, Cr, and Cu phases during woody biomass gasification: A thermodynamic equilibrium study(Unknown, 2018-05-19) Al-Badri, Shurooq; Jiang, Ying; Wagland, StuartGasification of blended waste wood samples resulting from different activities and operations would be beneficial for reducing toxic emissions of metal(loid) elements while producing energy. This paper deals with willow wood (40%) and demolition waste wood (60%) gasification specifically focusing on the phase transformation temperature and speciation formation of As, Cr, and Cu which are regularly present in woody biomass. The gasification of mixed fuel was modelled under atmospheric pressure as typical reaction zones; partial combustion reaction (PCR) and boudouard reaction (BR). The PCR performed at temperature range of 0-1800 (°C) and both equivalence and steam/air ratios were 0.28 and 1:2, respectively. On the other hand, the BR model was operated from 0 to 1300 (°C) along with typical CO2 to biomass ratio of 1:3. The samples were selected from ETI-UK database (83 willow wood) and ECN PHYLLIS2 database (9 demolition waste wood). Further, @Risk analysis simulation package was exploited to estimate the best composition data of each element in these samples. Refinement of the obtained results by PCR reveals that the phase transformation temperature of both As and Cr increased about 150 (°C) and 100 (°C), respectively, comparing to those obtained by gasification of willow wood. On the other hand, solid –gas phase transition of Cr was decreased about 100(°C) comparing to that when only demolition wood was gasified. In regards to BR, the phase transformation temperature of As, Cr, and Cu was similar (-1100(°C)) for all gasified woods. However, only concentration shifts were observed in gaseous phase of these elements. Eventually, the results from this study could be useful to reduce emissions and to disposal contamination waste wood via gasification process.