Showing papers in "Haikibutsu Gakkaishi in 2022"
TL;DR: In this paper , the authors discussed the significance of black soldier fly larvae (BSFL) in the recycling of biowaste, and examined the present gaps and challenges on the direction to the efficient application of BSF for waste management and the commercialization of its by-products.
Abstract: The application of black soldier fly (BSF), Hermetia illucens based technology to process organic wastes presents a practical option for organic waste management by producing feed materials (protein, fat), biodiesel, chitin and biofertilizer. Therefore, BSF organic wastes recycling is a sustainable and cost-effective process that promotes resource recovery, and generates valuable products, thereby creating new economic opportunities for the industrial sector and entrepreneurs. Specifically, we discussed the significance of BSF larvae (BSFL) in the recycling of biowaste. Despite the fact that BSFL may consume a variety of wastes materials, whereas, certain lignocellulosic wastes, such as dairy manure, are deficient in nutrients, which might slow BSFL development. The nutritional value of larval feeding substrates may be improved by mixing in nutrient-rich substrates like chicken manure or soybean curd residue, for instance. Similarly, microbial fermentation may be used to digest lignocellulosic waste, releasing nutrients that are needed for the BSFL. In this mini-review, a thorough discussion has been conducted on the various waste biodegraded by the BSFL, their co-digestion and microbial fermentation of BSFL substrate, as well as the prospective applications and safety of the possible by-products that may be generated at the completion of the treatment process. Furthermore, this study examines the present gaps and challenges on the direction to the efficient application of BSF for waste management and the commercialization of its by-products.
10 citations
TL;DR: In this paper , the state-of-the-art of current research on LLMC management from leachate treatment plants towards a resource recovery approach is comprehensively reviewed, and a general recovery train based on the main LLMC characteristics is presented in this context.
Abstract: Membrane filtration processes have been used to treat landfill leachate. On the other hand, closing the leachate treatment loop and finding a final destination for landfill leachate membrane concentrate (LLMC) – residual stream of membrane systems – is challenging for landfill operators. The re-introduction of LLMC into the landfill is typical; however, this approach is critical as concentrate pollutants may accumulate in the leachate treatment facility. From that, leachate concentrate management based on resource recovery rather than conventional treatment and disposal is recommended. This work comprehensively reviews the state-of-the-art of current research on LLMC management from leachate treatment plants towards a resource recovery approach. A general recovery train based on the main LLMC characteristics for implementing the best recovery scheme is presented in this context. LLMCs could be handled by producing clean water and add-value materials. This paper offers critical insights into LLMC management and highlights future research trends.
10 citations
TL;DR: In 2018, a total of 6.083,000 end-of-life vehicles (EVLs) with a total weight of 6,732,000 tonnes (including waste parts) were generated in the European Union as discussed by the authors .
Abstract: In 2018, a total of 6,083,000 end-of-life vehicles (EVLs) with a total weight of 6,732,000 tonnes (including waste parts) were generated in the European Union. These vehicles are a subject of particular attention because of their bulky mass, the hazardous components they contain, and the valuable materials present. This article analyses the quantities of ELVs and parts of ELVs that have been recycled, energy recovered, disposed, and reused to assess the impact of the changes in these management options on the total quantities managed. The analysis covered the statistical data on EVLs in 31 European countries for the period 2006–2018, using a new extended version of the logarithmic mean divisia index (LMDI) analysis model, which allows analysts to compare and analyse different waste management options simultaneously. The results show that the changes in the waste intensities and household final consumption expenditure were the greatest drivers of changes in the total quantities managed, while changes in the quantities recycled, energy recovered, disposed of, and reused had the least impact. All countries met or were close to meeting the targets during the period analysed. Changes in the total quantities of waste managed depended on the economic activity, which influenced the quantities of ELVs generated and their subsequent management.
6 citations
TL;DR: This review focuses on the post-treatment and valorization of liquor which is produced by solid-liquid fractioning of digestate, which is used as fertiliser in the agriculture industry.
Abstract: Traditionally, digestate is considered a waste, which is used as fertiliser in the agriculture industry. Recent studies focus on increasing the profitability of digestate by extracting reusable nutrients to promote biogas plants cost-effectiveness, sustainable management and circular economy. This review focuses on the post-treatment and valorization of liquor which is produced by solid–liquid fractioning of digestate. Nutrient recovery and removal from liquor are possible through mechanical, physicochemical and biological procedures. The processes discussed involve complex procedures that differ in economic value, feasibility, legislative restrictions and performance. The parameters that should be considered to employ these techniques are influenced by liquor characteristics, topography, climate conditions and available resources. These are key parameters to keep in mind during designing and manufacturing a biogas plant. In the following chapters, a discussion on available liquor treatment methods takes place. The present study examines the critical aspects of the available liquor treatment methods.
6 citations
TL;DR: In this paper , the potential risks posed by eight approaches to recovering value during the resource recovery phase from post-consumer plastic packaging waste collected and separated with the purported intention of recycling.
Abstract: Over the coming decades, a large additional mass of plastic waste will become available for recycling, as efforts increase to reduce plastic pollution and facilitate a circular economy. New infrastructure will need to be developed, yet the processes and systems chosen should not result in adverse effects on human health and the environment. Here, we present a rapid review and critical semi-quantitative assessment of the potential risks posed by eight approaches to recovering value during the resource recovery phase from post-consumer plastic packaging waste collected and separated with the purported intention of recycling. The focus is on the Global South, where there are more chances that high risk processes could be run below standards of safe operation. Results indicate that under non-idealised operational conditions, mechanical reprocessing is the least impactful on the environment and therefore most appropriate for implementation in developing countries. Processes known as ‘chemical recycling’ are hard to assess due to lack of real-world process data. Given their lack of maturity and potential for risk to human health and the environment (handling of potentially hazardous substances under pressure and heat), it is unlikely they will make a useful addition to the circular economy in the Global South in the near future. Inevitably, increasing circular economy activity will require expansion towards targeting flexible, multi-material and multilayer products, for which mechanical recycling has well-established limitations. Our comparative risk overview indicates major barriers to changing resource recovery mode from the already dominant mechanical recycling mode towards other nascent or energetic recovery approaches.
6 citations
TL;DR: In this article , polypropylene (PP) was recycled in a non-stirred batch reactor by slow pyrolysis at low temperature, and the highest yields of liquid product were obtained at 350°C and 400°C (82.0 and 82.3 w/w%, respectively).
Abstract: In this study, polypropylene (PP) was recycled in a non-stirred batch reactor by slow pyrolysis at low temperature. Virgin PP and waste PP as well as mixed material of equal amounts of virgin PP plus virgin PP pyrolysis oil (ratio 1:1 w/w) were used as raw material. The highest yields of liquid product were obtained at 350°C and 400°C (82.0 and 82.3 w/w%, respectively). The density, viscosity and calorific value of the gasoline and diesel fractions of the obtained pyrolysis oils comply with EN228 and EN590 standards, respectively. The flash point corresponded to the standard only for some of the oils, but the cold filter clogging point, the pour point and especially the oxidation stability were far above the stated reference values of the standards. The pyrolysis oils as products of thermal decomposition were determined by the methods of 1H and 13C and two-dimensional-heteronuclear single quantum coherence nuclear magnetic resonance (2D-HSQC NMR) spectra. Spectral analysis showed that only very little aromatic compounds were present in the oils, but they contained many unsaturated compounds, which is presumably consistent with the measured oxidation stability and limits their use in the production of alternative fuels. The research octane number (RON) calculated from the NMR analyses corresponds to the lower limit of gasoline.
5 citations
TL;DR: In this article , a pre-treatment of groundnut shells was investigated using particle size reduction of mechanical pretreatment methods, and 30 samples were digested in a batch digester at mesophilic temperature.
Abstract: Optimising biogas yields from anaerobic digestion of organic wastes is significant to maximum energy recovery in the biodigestion process and has become an important topic of interest. Substrate particle size is an important process parameter in biogas production, and it precedes other pretreatments methods for the majority of the lignocellulose materials. Optimisation of biogas yield using Response Surface Methodology (RSM) was done, and temperature, hydraulic retention time and particle size were considered variables to develop the predictive models. Pretreatment of groundnut shells was investigated using particle size reduction of mechanical pretreatment methods. After pretreatment, 30 samples were digested in a batch digester at mesophilic temperature. The experimental results showed that the temperature, hydraulic retention time and particle size had significant effects of interaction (p < 0.05). The optimum experimental and predicted yields are: 44.70 and 42.92 (lNkgoDM) organic dry matter biogas yield, 20.80 and 19.09 (lN/kgFM) fresh mass biogas yield, 24.00 and 22.68 (lNCH4oDM) organic dry methane yield and 12.30 and 15.59 (lNCH4FM) fresh mass methane yield, respectively. The R2 recorded for the four yield components were 0.6268, 0.5875, 0.6109 and 0.5547. These values seem to be lower and a sign of the average fit of the model. Biogas production from groundnut shells was significantly improved with statistical optimisation and the pretreatment method.
5 citations
5 citations
TL;DR: In this paper , a catalogue of solutions for food, packaging and other ‘non-food’ waste that foodservice establishments can implement is presented. But the authors focus on management systems to establish waste management standards for hospitality, food and beverage (F&B) services, restaurants, and non-commercial catering.
Abstract: Foodservice businesses influence the sustainability of their natural environment by producing significant amounts of waste. Yet, research has, thus far, been dominated by studies that limit their scope to food waste alone. Few studies have taken a broader look at sustainable waste initiatives, including innovative waste processing techniques, with a view to constructing management indicators for foodservices. This study combines management innovation practices related to resource management, waste prevention, processing and disposal techniques, and stakeholder involvement to offer sustainable standards. It primarily adopts the Delphi technique to propose specific solutions pertaining to waste management. Experts from government, industry, and academia reveal that potential waste management initiatives comprise three facets – service, process (operational), and organisational practices and innovations, 15 sub-facets and 41 indicators. This study thus establishes a catalogue of solutions for food, packaging and other ‘non-food’ waste that foodservice establishments can implement. In addition to its practical implications, an important contribution is its focus on management systems to establish waste management standards for hospitality, food and beverage (F&B) services, restaurants, and non-commercial catering.
5 citations
TL;DR: Li et al. as mentioned in this paper compared the impact of two battery replacement methods (buying a new vehicle or replacing the battery) on future EOL EV production, and predicted the difference in the amount of EOL EVs battery production under two probability functions (normal and Weibull's distributions).
Abstract: With the development of the electric vehicle (EV), vehicle end-of-life (EOL) management has become a significant challenge. This study sets two EV sales scenarios (low and high), compares the impact of two battery replacement methods (buying a new vehicle or replacing the battery) on future EOL EV production, and predicts the difference in the amount of EOL EV battery production under two probability functions (normal and Weibull’s distributions). The results show that when the EV power battery is retired and the vehicle owner chooses to buy a new vehicle, the predicted scrap quantity under low sales and high sales (HS) scenarios in 2030 is 4.3 and 5.3 million, respectively. Replacing the battery and continuing to use the vehicle will mean fewer EOL vehicles are generated. Considering the construction of an EOL EV battery recycling management system in China is still in the exploratory period, it is necessary to encourage vehicle owners to replace the battery and continue to use the vehicle. Under a HS scenario, the predicted number of EOL EV batteries in 2030 is 3.8–7.4 million. In the next 10 years, the issue of EV recycling should be raised to the same level as the issue of EV popularisation.
5 citations
TL;DR: In this article , the authors evaluated the impact of management practices and environmental risks at two landfill sites using a floristic survey of identified plant species and found that significant differences existed between the two landfill locations, with neophytes, invasive and expansive species dominating on one of the landfill sites, which may be attributed to climatic and geomorphological differences between two sites, but also to variations in landfill management.
Abstract: Proper management of municipal solid waste (MSW) is crucial to avoid pollution, environmental impacts and threat to public health. The problem of MSW is mainly arising from inadequate landfill site management. The objective of this study was to evaluate the impact of management practices and environmental risks at two landfill sites. The landfills were subject to long-term (10 years) vegetation monitoring. The vegetation was assessed using a floristic survey of identified plant species. The vegetation analysis showed that significant differences existed between the two landfill locations, with neophytes, invasive and expansive species dominating on one of the landfill sites, which may be attributed to climatic and geomorphological differences between the two sites, but also to variations in landfill management. These environmentally problematic species can potentially spread from the landfill into adjacent ecosystems, displace native plants and degrade adjacent farmland areas. The study of vegetation monitoring data suggests that, in addition to other types of monitoring, landfills should be subjected to regular vegetation biomonitoring, too. Landfill management practices should target the regulation of unwanted species, create conditions that are favourable to native plant species and provide as early as possible the restoration of filled cells.
TL;DR: In this paper , a review article provides an insight on findings from various articles on disposal of obsolete mobile phones by users/consumers, such as reasons for replacement, disposal methods adopted by users and consumers, impact due to the adoption of improper disposal methods such as handing them over to the informal recycling sector and storage/hibernation after its in-use lifespan.
Abstract: Usage/consumption of mobile phones has increased rapidly around the world. As of April 2021, there were 5.27 billion mobile phone users. Meanwhile, the generation of obsolete mobile phones/mobile phone wastes is also increased mainly due to the replacement of mobile phones. The in-use lifespan of mobile phones is correspondingly getting decreased. The inappropriate disposal of obsolete mobile phones leads to adverse consequences on the environment, human health and on metal recovery. This review article provides an insight on findings from various articles on disposal of obsolete mobile phones by users/consumers. The various aspects, such as reasons for replacement, disposal methods adopted by users/consumers, impact due to the adoption of improper disposal methods such as handing them over to the informal recycling sector and storage/hibernation after its in-use lifespan, were covered. Along with this, the study even focuses on reduce, reuse and recycle (3Rs) of sustainability. Reduce means reduction of mobile phone replacement frequency. Storage of mobile phones post-in-use lifespan is the most opted disposal method, and it is one of the significant barriers to reuse, recycling and metal recovery. When it comes to recycling, the research undertaken on the recycling of obsolete mobile phones is not as in-depth when compared to the research done on recycling of e-waste in general. This article identifies future directions for sustainable end-of-life management of obsolete mobile phones.
TL;DR: In this article , a suite of novel simulations investigated the influence of key parameters on bed-cooling time and found that cooling time decreased nearly linearly with decreases of volume-averaged bed temperature and bed bulk density.
Abstract: STARx (Self-sustaining Treatment for Active Remediation ex situ) is a thermal treatment strategy for contaminated soils and organic wastes. Key to this technology is that organics are embedded in porous matrix beds (e.g. sand). STARx induces a self-sustaining smouldering combustion front that traverses the bed, burning away the embedded contaminants/wastes. The time and cost effectiveness of this technology is largely dictated by the time required for cooling of the hot, clean, porous matrix bed that remains after treatment. This study is the first to explore the cooling of these beds. A suite of novel simulations investigated the influence of key parameters on bed-cooling time. The results reveal that cooling time decreased nearly linearly with decreases of volume-averaged bed temperature and bed bulk density. Increased injection air fluxes led to the non-linear decrease of cooling time. Also, cooling time was negatively impacted by bed temperature inhomogeneity, which influenced preferential air flow through cooler regions of the bed, bypassing hotter regions. From these results, using lower bulk density bed materials, increased air fluxes and enhancing wall insulation to improve bed temperature homogeneity were identified as system optimisations to reduce cooling times. While the aim of this research is to improve the STARx cooling process, the results are also highly applicable to many similar engineering systems that involve hot porous bed cooling.
TL;DR: In this article , the authors describe how industrial symbiosis is reposed in studies dealing with the Brazilian context, based on a systematic literature review in the Scopus and Web of Science databases, relying on the Prisma method and a research protocol.
Abstract: This study describes how industrial symbiosis is reposed in studies dealing with the Brazilian context. This study was based on a systematic literature review in the Scopus and Web of Science databases, relying on the Prisma method and a research protocol. The results embrace quantitative and qualitative aspects such as the number of publications, the territorial scope of the studies, authors and keywords networks. The sample was also segregated into three categories, theoretical works, opportunities and formed networks, reporting the presence of industrial symbiosis in Brazil in the extant literature. The main contribution of this research is to aggregate the studies already published in the international literature, demonstrate how the IS is reported and how they can be expanded in territories or business cases not yet portrayed.
TL;DR: In this paper , the process and functionalities of livestock waste generated from the piggery farm and their combinations with other by-products such as biochar and ash in comparison with mineral fertilization as sources of nitrogen applied in agricultural soil were assessed.
Abstract: The race is on to achieve an important level of efficiency in the attainment of a circular economy in agriculture especially with the aim of sustainable nitrogen management. This cycle in the agricultural sector cuts across livestock farming, agriculture-induced waste generation, recycling and utilization, energy generation, crop production, ecosystem protection and environmental management through the mitigation of climate changes. In this work, we assess the process and functionalities of livestock waste generated from the piggery farm and their combinations with other by-products such as biochar and ash in comparison with mineral fertilization as sources of nitrogen applied in agricultural soil. The experiment was performed in a controlled environment with wheat (Triticum aestivum L.) grown in a neutral and an acidic soil. Pig manure was used as the primary feedstock, fed and processed to biogas and nutrient-rich digestate by the anaerobic digestion process. The results revealed that the co-amendments of pig manure digestate with biochar and ash had complimentary positive effect on measured indices such as mobile potassium, phosphorus, biomass yield and nitrogen use efficiency. The mineral nitrogen fertilizer significantly induced carbon dioxide emissions from day 35 when compared to emissions from the organic amendments. In contrast, the organic amendments influenced nitrous oxide emissions from the onset till day 30 before flattening out. The individual combination of pig manure digestate with biochar and ash had a negative influence on enzymatic activity (dehydrogenase). Soil microbial biomass carbon was induced across all treatments in both soil types. Pig manure digestate + ash and pig manure digestate had 32.1 and 48.8% soil microbial biomass increase in neutral soil and acidic soil, respectively. Overall, the processing and application of single-use amendment or in combination with biochar and ash holds huge potential in the optimization of nitrogen and carbon efficiency towards sustainable soil management via improving soil quality, carbon sequestration and climate change.
TL;DR: In this article , a systematic review and content analysis to categorise all types of waste management (WM) during the COVID-19 pandemic was conducted to accomplish a well understanding of the relation between the CoVID-2019 pandemic and its impacts on WM within the literature.
Abstract: The COVID-19 pandemic has a negative impact on the environment. Waste generation and improper management during the COVID-19 pandemic posed a major threat to human health and the environment. Irregular and improper waste collection, handling, suspension of waste recycling and unsanitary disposal were all important issues in the processing and management of generated waste. This study emphasised a systematic review and content analysis to categorise all types of waste management (WM) during the COVID-19 pandemic to accomplish a well understanding of the relation between the COVID-19 pandemic and its impacts on WM within the literature. In this systematic review, a number of published papers on different aspects of WM during March 2020 to February 2021 were considered in order to identify major challenges in handling WM during the pandemic time and highlight multi-strategic approaches suggested. A content analysis of the 58 relevant papers was carried out by incorporating different types of WM at local as well as global scales. The present review results revealed that the COVID-19 has impacted the quantity and composition of waste, and the crisis caused by the pandemic has also altered the nature of global WM system. A comprehensive analysis on how the systems of WM were affected through the advancement of COVID-19 and what would be the healthier solutions was also highlighted in this systematic review. The results of this systematic review would be beneficial for better policymakers to holistically address potential future pandemics, if any.
TL;DR: The transboundary movement of all waste, not just hazardous waste, remains a societal challenge globally, frequently surfacing as an ethical question on the one hand and a story of resource management/trade on the other as mentioned in this paper .
Abstract: Multiple cases of toxic waste dumping from the Organisation for Economic Co-operation and Development (OECD) countries to non-OECD countries in the 1980s led to scholarly attention to transboundary waste movements. The Basel Convention was established to provide an international legal framework to tackle such problems in the early 1990s, focusing on hazardous waste. However, the transboundary movement of all waste, not just hazardous waste, remains a societal challenge globally, frequently surfacing as an ethical question on the one hand and a story of resource management/trade on the other. This phenomenon has been studied across disciplines resulting in diverse, scattered and often contested understandings. Despite previous and ongoing efforts, waste production, management and transboundary movements are increasing and are predicted to grow significantly with global social, environmental and economic implications. This literature review uses a research synthesis and problematisation approach to critically analyse the transboundary waste literature since 1985. The findings highlight research trends, the need for data reliability and policy coherence, and the sustainability implications of the phenomenon. One recurring theme in the literature is the reduction of the complex phenomenon involving multiple countries, policies, actors and waste streams into simple opposite narratives, which we called transboundary waste binaries. We have identified and then challenged assumptions behind transboundary waste binaries and discussed the implications of such assumptions on the broader discourse. We have concluded with future research recommendations to look past the transboundary waste binaries towards a nuanced and contextual understanding of transboundary waste flows.
TL;DR: The approach of physical recycling methods described in this mini-review helps to maintain the value of polymer materials in the value chain allowing the reuse in the original or similar application as mentioned in this paper .
Abstract: Although the use of plastic components is increasing in the automotive industry, yet the recovery rates of these materials in end-of-life vehicle (ELV) is lower compared to metals. One of the main problems of ELV plastic waste is poor separation and sorting. Large car plastic parts consist of fibre-reinforced plastics, whereas other components end up in the automotive shredder residue (ASR), featuring a very heterogeneous mix of light materials that contains mostly non-metallic materials such as textiles, plastics, cartridges and wood. Generally, ASR was disposed in landfill or diverted to thermal treatments, such as pyrolysis or gasification, for energy recovery. Currently, the recovery of raw materials from various waste streams plays a key role in new European strategy for plastics in a circular economy. The approach of physical recycling methods described in this mini-review helps to maintain the value of polymer materials in the value chain allowing the reuse in the original or similar application.
TL;DR: In this article , the suitability of different chemical recycling processes for plastics recycling is assessed by means of examples from running installations and their suitability for polyethylene polymers is assessed.
Abstract: Increased media coverage of plastic pollution in the environment and import bans on plastic waste in several countries have resulted in plastic waste becoming one of the most discussed waste streams in recent years. In the European Union (EU), only about one-third of the post-consumer plastic waste is recycled; the rest goes to energy recovery and landfilling in equal parts. In connection to the necessary increase in efforts to achieve the ambitious EU recycling targets, chemical recycling is currently receiving more and more attention. The assumption is that chemical recycling processes could open up new waste streams for recycling and generate valuable raw materials for the chemical industry. Although there exists no legal definition for chemical recycling, there is more or less agreement that it covers the conversion of plastic polymers into their monomers or chemical building blocks. Techniques such as gasification, pyrolysis and liquefaction as well as solvolysis can be used for chemical recycling. So far, only few large-scale plants for chemical recycling exist worldwide. This article presents the different processes by means of examples from (formerly) running installations and their suitability for plastics recycling is assessed. However, to date, only few chemical recycling plants are in continuous operation, and further scientific evidence for the ecological and economic benefits is still necessary for final evaluation.
TL;DR: In this paper , the applicability of ground penetrating radar (GPR) technology to estimate waste depth and volume of a construction waste landfill was investigated, and the results revealed the following: the GPR technology effectively delineated boundaries between underground waste and the surrounding strata; the topographic structure obtained from the analysis of the associated images was consistent with the actual topography.
Abstract: Underground landfill, the primary disposal method of construction waste in several areas, negatively affects the surrounding environments. Suitably locating and estimating waste volume in an underground landfill are vital for adequate disposal and recycling of construction wastes. In this study, we investigated the applicability of ground penetrating radar (GPR) technology to estimate waste depth and volume of a construction waste landfill. The results revealed the following. (1) The GPR technology effectively delineated boundaries between underground waste and the surrounding strata; the topographic structure obtained from the analysis of the associated images was consistent with the actual topography. (2) Layer information from GPR images and electromagnetic wave velocity calculated using the complex refractive index model for construction waste burial depth inversion produced highly accurate results. Waste depth in the landfill was estimated using the GPR inversion results and spatial interpolation. Kriging interpolation exhibited the highest accuracy. (3) The trapezoid, Simpson and Simpson 3/8 rules were suitable for estimating construction waste volume. A three-dimensional model created using the spatial interpolation grid precisely depicted the structure of the buried landfill. Our study provides references for the management, recycling and environmental impact assessment of construction waste.
TL;DR: In this paper , the authors measured tree stem and soil greenhouse gas (GHG) emissions (CH4 and CO2) from a closed UK landfill and comparable natural site, using an off-axis integrated cavity output spectroscopy analyser and flux chambers.
Abstract: Trees have morphological adaptations that allow methane (CH4) generated below ground to bypass oxidation in aerobic surface soils. This natural phenomenon however has not been measured in a landfill context where planted trees may alter the composition and magnitude of CH4 fluxes from the surface. To address this research gap, we measured tree stem and soil greenhouse gas (GHG) emissions (CH4 and CO2) from a closed UK landfill and comparable natural site, using an off-axis integrated cavity output spectroscopy analyser and flux chambers. Analyses showed average CH4 stem fluxes from the landfill and non-landfill sites were 31.8 ± 24.4 µg m–2 h–1 and –0.3 ± 0.2 µg m–2 h–1, respectively. The landfill site showed seasonal patterns in CH4 and CO2 stem emissions, but no significant patterns were observed in CH4 and CO2 fluxes at different stem heights or between tree species. Tree stem emissions accounted for 39% of the total CH4 surface flux (7% of the CO2); a previously unknown contribution that should be included in future carbon assessments. Graphical Abstract
TL;DR: ROI for active and passive GCS is estimated with numerical modelling (two-dimensional) for all definitions of ROI at different suction pressures for Bagalur landfill, suggesting the usability of the model for future investigations.
Abstract: The design of a gas collection system (GCS) for a landfill involves estimating several critical parameters, such as the radius of influence (ROI), suction pressures, number of wells and their spacing. One of the biggest challenges lies in the estimation of ROI for a particular landfill. In this study, the ROI for a Bagalur landfill is estimated for various possible gas generation rates. ROI for active and passive GCS is estimated with numerical modelling (two-dimensional) for all definitions of ROI at different suction pressures. An inverse correlation was observed between the values of various definitions of ROI at different gas generation rates. Justification for this behaviour is brought out by addressing the conceptual difference between these definitions. The number of wells along with their spacing was then calculated, and the efficiency of the design was assessed with three-dimensional modelling. Passive and active systems had average methane recovery rates of 84% and 88%, respectively, with an atmospheric methane flux ranging from 10−9 to 10−10 kg m−2 s−1. The high recovery rate and low methane flux indicate the effectiveness of the design. The values of the methane flow rate from the extraction well were validated with a theoretical method, suggesting the usability of the model for future investigations.
TL;DR: In this article , the authors discuss the evolution of waste to energy incineration and highlight the currently used and advanced incineration technologies, including combined incineration with other energy, for instance, hydrogen production, coal and solar energy.
Abstract: With the huge generation of municipal solid waste (MSW), proper management and disposal of MSW is a worldwide challenge for sustainable development of cities and high quality of citizens life. Although different disposal ways are available, incineration is a leading harmless approach to effectively recover energy among the applied technologies. The purpose of the present review paper is to detail the discussion of evolution of waste to energy incineration and specifically to highlight the currently used and advanced incineration technologies, including combined incineration with other energy, for instance, hydrogen production, coal and solar energy. In addition, the environmental performance is discussed, including the zero waste emission, leachate and fly ash treatment, climate change contribution and public behaviour. Finally, challenges, opportunities and business model are addressed. Trends and perspectives on policies and techno-economic aspects are also discussed in this review. Different simulation tools, which can be used for the thermodynamic assessment of incineration plants, are debated; life-cycle inventory emissions and most critical environmental impacts of such plants are evaluated by life-cycle analysis. This review shows that waste incineration with energy yield is advantageous to handle waste problems and it affects climate change positively.
TL;DR: In this article , the authors identify the validity of this domain both in the global and native research community by conducting a detailed review using bibliometric analysis and content analysis, and provide the struts for a circular and sustainable supply chain for processed seafood in developing economies.
Abstract: Food loss and waste have become an issue of global significance, considering their concurrent effects on the socioeconomic and environmental facet of society. Despite this domain gaining prolific attention recently, issues hampering the effective utilization of residues from fish processing usually go unidentified in developing economies such as India. This occurs mainly owing to fragmented supply chains, inappropriate handling, discontinuous cold chains, inadequate temperature monitoring and so on, affecting quality and causing underuse. Any researcher trying to understand the prospects of utilizing these fish processing co-streams in a developing economy with the vision of improving consumption, economic sustainability, reducing discards and promoting circularity faces a lacuna. The authors address this demand in research by identifying the validity of this domain both in the global and native research community by conducting a detailed review using bibliometric analysis and content analysis. Data from Scopus with 717 documents, comprising 612 research articles from 78 countries, 1597 organizations and 2587 authors, are analysed. Results signify (i) developing a focus on hydroxyapatite production, bio-methane generation, transesterification processes, biomass and the rest raw material generated from fish processing, and (ii) reduced research on supply chain-related aspects despite their considerable importance. To comprehend this deficiency, especially in the Indian stance, barriers hindering the utilization of generated by-products are identified, and recommendations for improvements are proposed. The results will provide the struts for a circular and sustainable supply chain for processed seafood in developing economies.
TL;DR: This is the first study conducted in Portugal; the results showed that the delivery to pharmacies was used by the majority of the respondents, indicating a good awareness of pharmaceutical waste management issues, when compared to the reviewed studies.
Abstract: The end of life of pharmaceutical products through environmentally unsafe routes is a growing concern in our society. However, the studies reported so far, apart from being limited in number, do not reflect the current management practices for the end-of-life management of pharmaceuticals. Published work lacks an in-depth analysis in focusing on the pharmaceutical waste in households. The present work focused on (1) performing a state-of-the art overview to compare worldwide studies and the results and (2) implementing a comprehensive survey in Portugal (n = 454 respondents). The results showed that the delivery to pharmacies was used by the majority of the respondents (72%), indicating a good awareness of pharmaceutical waste management issues, when compared to the reviewed studies. Statistically significant variables for the destination of end-of-use pharmaceuticals include gender, age and distance from the residence to the pharmacy (p < 0.05). Most participants believe that educating the population on existing structures of medication and packaging management is of the utmost importance to improve the national managing system. This is the first study conducted in Portugal; it includes statistical analysis of the data and reflects on the practices that should be adopted to reduce incorrect pharmaceutical waste disposal. These findings call upon the strategies to strengthen the pharmaceutical waste management programme.
TL;DR: In this paper , landfill leachate (LL) was used as an aqueous medium during hydrothermal carbonisation (HTC) of food waste to produce hydrochar (FWH-LL-C).
Abstract: This study aims to use landfill leachate (LL) as an aqueous medium during hydrothermal carbonisation (HTC) of food waste to produce hydrochar (FWH-LL-C), which could be used as an electrode material in energy storage devices. The structural properties and electrochemical performance of the hydrochar were compared to that obtained using distilled water as a reaction medium (FWH-DW-C). The results showed that there is a difference in Brunauer–Emmett–Teller (BET) surface area of FWH-LL-C (220 m2 gm−1) and FWH-DW-C (319 m2 gm−1). The electrochemical properties were comparable, with FWH-LL-C having 227 F g−1 specific capacitance at 1 A g−1 current density and FWH-DW-C having 235 F g−1 specific capacitance at 1 A g−1 current density. Furthermore, at a power density of 634 W kg−1, FWH-DW-C achieved the highest energy density of 14.4 Wh kg−1. The energy retention capacity of the electrode was 98% which indicate that the material has an excellent energy storage capacity. The findings suggested that LL could be used as an alternative source of aqueous media during the HTC of food waste to produce hydrochar which could be used as an effective electrode material in supercapacitors.
TL;DR: In this article , the authors employed regression analysis and material flow analysis approaches to ensure a cross-comparability of waste generation data and found that almost one third of the total waste generated is not collected, and most of what is collected is not treated accordingly to current ideas of sound management.
Abstract: This study contributes to estimate the total waste generated at global level. A few studies have provided an efficient and comprehensive global estimate. However, data reporting is globally inconsistent due to varying interpretation of terminology, lacking standardised categories and varying methodologies used to observe and measure waste amounts. This study employs regression analysis and material flow analysis approaches to ensure a cross-comparability of waste generation data. The result implies that total global waste arisings are around 20 billion tonnes in 2017. This corresponds to 2.63 tonnes of total waste per capita (cap) per year. The total global waste generated is expected to grow to 46 billion tonnes by 2050 under a business-as-usual scenario. Municipal solid waste (MSW) is a much smaller amount, ranging from 2.3 to 3.1 billion tonnes (average of 2.7 billion tonnes) in 2019. This figure reflects an increase of between 30% and 50% in MSW generated during the last 15 years (2004–2019). MSW generated is expected to grow to 2.89–4.54 billion tonnes by 2050, depending on which assumptions are used. This represents a 26%–45% increase compared to 2019. The overall assessment in this study reveals that almost one-third of the total MSW generated is not collected, and most of what is collected is not treated accordingly to current ideas of sound management. Moreover, almost 42% of MSW goes to open dumping or uncontrolled burning. The finding provides valuable insight for policymakers to design and assess circular economy policy instruments towards achieving sustainable development goals.
TL;DR: In this article , the ability of different optical spectroscopy technologies to detect two different plastic additives, fire retardants ammonium polyphosphate and aluminium trihydrate, inside polypropylene plastic matrix was compared.
Abstract: The use of plastics is rapidly rising around the world causing a major challenge for recycling. Lately, a lot of emphasis has been put on recycling of packaging plastics, but, in addition, there are high volume domains with low recycling rate such as automotive, building and construction, and electric and electronic equipment. Waste plastics from these domains often contain additives that restrict their recycling due to the hazardousness and challenges they bring to chemical and mechanical recycling. As such, the first step for enabling the reuse of these fractions is the identification of these additives in the waste plastics. This study compares the ability of different optical spectroscopy technologies to detect two different plastic additives, fire retardants ammonium polyphosphate and aluminium trihydrate, inside polypropylene plastic matrix. The detection techniques near-infrared (NIR), Fourier-transform infrared (FTIR) and Raman spectroscopy as well as hyperspectral imaging (HSI) in the short-wavelength infrared (SWIR) and mid-wavelength infrared (MWIR) range were evaluated. The results indicate that Raman, NIR and SWIR HSI have the potential to detect these additives inside the plastic matrix even at relatively low concentrations. As such, utilising these methods has the possibility to facilitate sorting and recycling of as of yet unused plastic waste streams, although more research is needed in applying them in actual waste sorting facilities.