Disposal Options Research Articles

Reducing the environmental impact of the end-of-life of buildings depending on interrelated demolition strategies, transport distances and disposal scenarios

Construction and demolition waste (CDW) represents a high environmental impact. This is strongly related to the chosen alternatives for the disposal of these waste. In this paper, different strategies are analysed in order to achieve the most eco-friendly path for the treatment of the CDW, in order to promote both the reduction of environmental impact and the implementation of the circular economy in the construction sector. For each defined strategy and for each type of considered CDW, the environmental impact is determined, using the Life Cycle Assessment (LCA) approach to determine the indicators of climate change (GWP) and of abiotic depletion potential for fossil resources (ADP f.f.). Ten strategies are considered, which combine: two types of demolition (traditional and selective); the options for waste disposal and valorisation and; local or external treatment. Two case studies are herein considered. Due to the high influence of transport on the determination of the environmental impact, this is separately analysed. The obtained results demonstrate the high environmental benefit of maximizing valorisation and promoting selective demolition, as well as the influence of transport distance on those decisions.

A Comprehensive Review on Biochar

Biochar from the pyrolysis of organic biomass is a highly porous carbon with many useful applications. While providing practical options for disposal and disease control, it also contributes to carbon sequestration by trapping carbon in plant biomass. The composition and structure of biochar depends on factors such as temperature, heating rate and production time. It also leads to bio-oil and biogas, which can be used for biochar production, electricity generation and the production of various chemicals. Incorporating biochar into the soil improves pH, electrical conductivity, water holding capacity, cation exchange capacity and microbial activity.It reduces nutrient leakage and all necessary fertilizers reduce environmental pollution. Biochar also plays an important role in crop improvement. Besides improving the soil, biochar also has the advantage of reducing greenhouse gas emissions, reducing pesticide use and being used in the construction, cosmetics and treatment, wastewater and food industries. India is rich in biomass resources and has great potential for biochar production. This study explores various production technologies, their effects on biochar energy and the benefits of using biochar.

‘Out of the Penal System and into the Hospital Regime?’ Judicial Challenges in Sentencing Mentally Disordered Offenders and the Likely Impact of the 2020 Sentencing Council Guideline

Mentally disordered offenders may be vulnerable yet also pose particular risk to the public. Achieving appropriate sentencing poses complex challenges for judges in properly determining culpability and punishment, protecting the public, and meeting any identified treatment needs of the defendant. With respect to all three elements there is likely to be necessary reliance upon psychiatric expertise. Despite much previous statutory guidance, there has not – until very recently – been available specific sentencing guidelines from the Sentencing Council (SC) to assist the judiciary in what is a profoundly difficult exercise. This review describes and considers the guidance available to the judiciary in the Crown Courts of England and Wales regarding the various disposal options – including that which ‘hybridises’ penal and treatment disposal – in addition to facilitating and properly limiting the role of expert evidence. A specific focus is on contextualising, and commenting upon, the SC's recently published Guidance, Sentencing Offenders with Mental Disorders, Developmental Disorders or Neurological Impairments, which seeks to consolidate information, improve knowledge, reduce confusion, and assist the courts towards properly and consistently addressing the relevance of mental disorder to sentencing. In doing so, in the authors’ view, it privileges punishment over public safety, leaving judges to address public safety largely without the benefit of the explicit ‘routes to sentencing’ approach of the Guidance.

Reciclacentros: a sustainable municipal solid waste management initiative in a Mexican city

Due to the increase in the generation of municipal solid waste and its impact on the environment and health, governments have been overburdened by its impact. Therefore, they have developed initiatives for waste disposal options in which citizens are involved. For that reason, this article aims to identify the population sector that participates in the separation of municipal solid waste and goes to the collection centers, as well as to characterize waste in three points known as Reciclacentros in the city of Hermosillo, Sonora. For this purpose, surveys were applied, selecting the respondents in a non-probabilistic way. In the characterization, the amount of waste received at each point was weighed. The data obtained were analyzed through a non-parametric Kruskal - Wallis test with 95% confidence (p<0.05). It was found that the people going to the Reciclacentros have an average monthly income of more than 30 thousand Mexican pesos, mostly young adult women between 25 and 44 years old, with the highest participation. In addition, the collection center identified as R3 presented a significantly higher difference in waste received with respect to the other collection centers in the period evaluated (23 t). Cardboard and paper, plastic, and glass are the most recovered waste in the city.

The impact of landfill management approaches on methane emissions.

This article reports on how management approaches influence methane emissions from landfills. The project team created various landfill operational scenarios for different regions of the planet with respect to waste composition, organic waste reduction and landfill gas recovery timing. These scenarios were modelled by applying a basic gas generation model according to the United Nations Intergovernmental Panel on Climate Change (IPCC) recommendations. In general, the IPCC's recommended modelling parameters and default values were used. Based on the modelling undertaken, two options stand out as being the most effective methane mitigation measures in a wide range of conditions throughout the world: (a) early gas recovery and (b) reduction of the amount of biodegradable organic waste accepted in a landfill. It is noted that reduction of organic input to any given landfill can take many years to realize. Moreover, suitable alternative processing or disposal options for the organic waste can be unaffordable for a significant percentage of the planet's population. Although effective, organic waste reduction cannot therefore be the only landfill methane mitigation measure. Early landfill gas recovery can be very effective by applying basic technologies that can be deployed relatively quickly, and at modest cost. Policymakers and regulators from around the globe can significantly reduce adverse environmental impacts from landfill gas emissions by stimulating both the early capture and flaring and/or energy recovery of landfill gas and programmes to reduce the inflow of organic waste into landfills.

Residual waste management in London, England: a reality check

Residual waste is a key fraction of municipal solid waste generated, yet its management is poorly understood and has gained little attention over the past years. Using London as a case study, the present study analyses the amount of residual waste collected and managed to check on how well ahead the UK is in making progress on achieving the circular economy principles. The study found that 5 Mt of residual waste is reported to be managed in London, of which 3.5 Mt is managed via recovery operations and 1.59 Mt is managed via disposal operations. For the latter, landfills are the principal disposal option taking in 0.82 Mt of residual waste each year. Amongst the recovery options, incineration with energy recovery, is the most prevalent, accounting for the management of 1.44 Mt of residual waste. This highlights the presence of an important technological lock-in that could jeopardise UK’s ability to achieve its net zero carbon ambition. It is worth noting that the data collated and analysed depicts the movements of residual waste rather than its final treatment, pointing to blind spots in the final fate of residual waste as well as potential double counting; both of which prevent decision- and policy-making. Therefore, the need for transparency in data recording and monitoring and the creation of a level playing field for all stakeholders involved in residual waste management are of paramount importance in gradually breaking reliance on destructive treatment processes. This could empower improved segregation of waste at source, and in turn, enable the better management of residual waste. The study underlines that residual waste has a significant role to play in making the transition to a circular economy and therefore is imperative to pave the way for future policy direction on residual waste management.

Swelling Behavior of a Clay-Pellets Mixture Intended for the Isolation of Spent Nuclear Fuel

Deep geological repository is the most favorable option for the safe disposal of high-level nuclear waste (HLW) and spent nuclear fuel (SNF). The design of such a facility relies on the multi-barrier system, encompassing a cylindrical metallic container (encapsulating the HLW/SNF), an engineered barrier system (EBS, around the metallic container); and the host-rock (or natural barrier). The most preferred buffer material to construct the EBS is bentonite clays. They are being considered as potential buffer materials because of, amongst other reasons, their high swelling capacity provides mechanical stability to the metallic canister containing the HLW/SNF; their good thermal conductivity assists to dissipate the heat released by the HLW/SNF; their low permeability delays the flow of water and gas through the system [1].
 Bentonites are highly swelling smectites clays that exhibit significant volume increase when wetted under free-swelling conditions, and develop high swelling pressure upon soaking when the volume change is restricted. It is envisaged that the EBS will be built using blocks of compacted bentonites (Figure 1(a)), or a combination of high-density clay-pellets mixtures and blocks of compacted bentonites (i.e., where the metallic container sits, Figure 1(b)). Clay-pellets are also considered as possible seal materials to fill gaps that will be present in this type of system, e.g., the gap between the EBS and the surrounding host-rock [2]. Therefore, a better understanding of the swelling capacity and behavior of the bentonite in these two forms (i.e., compacted-clay and clay-pellets mixtures) is critical for a proper design and evaluation of the long-term performance of geological repositories for HLW/SNF.
 Most of the research conducted in this area has been mainly focused on compacted bentonites looking, e.g., at the influence of several factors on their swelling pressure capacity, namely, type of clay minerals, initial dry density, water content (or degree of liquid saturation), and type of water [3]. More recently, investigations have been conducted to study the behavior of high-density pelletized clay mixtures [4, 5], however, relatively less attention has been placed in this type of material. Clay-pellets presents a number of advantage, e.g., they are very suitable for filling (small) technological voids (Figure 1(a)), there is no need for additional in-situ compaction when they are used as a buffer/backfill material (Figure 1(b)), and it is relatively easy to manufacture them.
 The granular clay-pellets samples were manufactured, and the constant volume cells were developed at Texas A&M University to investigate the swelling behavior of expansive clays. It has been shown in figure 2 that both materials (compacted clay and pelletized clay) developed similar maximum values of swelling pressures. However, the patterns associated with the swelling pressures evolutions are different, owing to the different pore structures associated with these two materials, which impact on the kinetic of clay hydration and swelling pressure evolutions. The aim of this research is to gain a better understanding of the swelling pressure behavior of clayed materials intended as potential barriers materials for the safe isolation of the HLW/SNF.

Comparative life cycle assessment of single-use cardiopulmonary bypass devices

The purpose of this study is to evaluate the impacts of the common cardiopulmonary bypass device over its life cycle. This represents the first such assessment of a complex medical device, to the best of the authors’ knowledge. This study was motivated by practitioners’ concerns over cardiopulmonary bypass devices constructed mainly of single-use plastics, such as polyvinyl chloride and polycarbonate. The open-source software OpenLCA was used to perform each life cycle assessment with respect to ten common impact categories: global warming, eutrophication, acidification, smog, human health cancer, human health non-cancer, water intake, human health air pollutants, ecotoxicity, and natural resource depletion. The environmental impact was evaluated using the Building for Environmental and Economic Sustainability impact assessment method. To quantify the uncertainty in the results, Monte Carlo simulation was used using 5000 runs. A comparative assessment was conducted to determine the potential trade-offs in each impact category of using alternative construction materials. Incineration as a common disposal option could contribute up to 33 % of total CO2 equivalent emissions over the life cycle of the device. Another 33% of total CO2 equivalent emissions are attributed to polycarbonate used in the construction of devices. Polycarbonate was also implicated as the top contributor to the other impact categories considered, except for human health cancer, which is almost entirely affected by the use of polyvinyl chloride in the device, primarily in the tubes. The accuracy of these results is corroborated by the uncertainty analysis. Lastly, the results show that replacing polycarbonate with polyethylene terephthalate, polypropylene, or polyethylene would be no worse than polycarbonate and provide a significant decrease in almost every impact category. Cardiopulmonary bypass devices are constructed primarily of single-use plastics that have relatively significant impacts in the 10 common categories considered. Alternative disposal methods and replacement of polycarbonate with alternative plastics could dramatically reduce the effects in most impact categories.

Panel: “novel” nuclear reactors as an alternative disposal option

Abstract. States and private industries are researching and developing reactor concepts that are not based on the current light- or heavy-water-cooled reactor technology. One important aspect of these so called novel or advanced nuclear reactor designs, both large gigawatt types and small modular reactors, is their potential for radioactive waste management. The prospects for their development and industrial use also largely depend on possible improvements to reactor safety, on the proliferation resistance of the fuel cycle and on the economics of those reactor concepts. The panelists will discuss opportunities and impediments to the implementation and use of advanced reactor concepts and their fuel cycles, as well as their use as an alternative disposal option. The discussion will be open for the audience to participate. Regarding the method, a moderated panel discussion with four panelists is planned. First, after a short introduction by the moderator, the panelists will be given the opportunity to briefly present their view on important advantages and disadvantages of new reactors as a waste disposal option for about 20 min total. The focus should be on the involved fuel cycle (partitioning and transmutation); the state of science and technology of reactors for waste management, reprocessing and fuel fabrication; the impact of reactors on the quantity and composition of nuclear waste; and the possible deployment scenarios focusing on nuclear waste management. The need to use reactors for this alternative disposal option is a controversial issue in light of differing views on the use of nuclear energy nationally and internationally. We plan to invite a heterogeneous panel with expertise in reactor-based nuclear waste management, nuclear safety and security; the state of science and technology of advanced nuclear reactors (technology readiness level); and nuclear power economics. Ideally this panel will express differing views on the use of nuclear power as the panel's goal is explicitly to engage in an interactive discussion with the audience.

Proliferation aspects of partitioning and transmutation (P&T) fuel cycles

Abstract. Nuclear fuel is usually irradiated once but sometimes twice (MOX fuel). This procedure leaves a huge amount of spent fuel. Spent fuel is highly radioactive for a long time. Deep geological repositories are considered the best option for final disposal of this high-level radioactive waste. However, no such repository has been put into operation yet. Several countries consider partitioning and transmutation (P&T) a possible alternative. In P&T nuclear fuel cycles, the spent nuclear fuel is chopped into pieces and separated into different material streams such as plutonium, uranium and minor actinides. This process is called partitioning. From plutonium and minor actinides, new fuel elements are fabricated and used in nuclear reactors. If the overall physical conditions there are favorable, most prominently the presence of a fast neutron spectrum, at least a part of the minor actinides is fissioned and thus transmuted into other, hopefully easier-to-handle, nuclides. Especially when looking at the ingestion-based radiotoxicity index, reduction in minor actinides in nuclear waste is beneficial and might ease the requirements for a final repository. There are several drawbacks when looking at the concept of P&T: among others, several irradiation cycles are needed because the transmutation efficiency is so low. The technology for the processing of the spent fuel, the fuel fabrication and the irradiation is far from commercially available, and it is not clear whether this level can be met at all. This presentation focuses on the proliferation risk posed by possible P&T fuel cycles. The nexus between civil and military use of nuclear technology is widely known. If new fuel cycles are implemented, they should be more proliferation-resistant and not less. This would not be true for P&T fuel cycles: they require a closed nuclear fuel cycle with far more advanced reprocessing than today. Fissile material contained in spent nuclear fuel is not sent to final disposal but is separated into its components, which must be made available separately before they can be recombined into new fuel elements. Besides plutonium, this also includes other transuranic elements of small critical mass. The radiation barrier, an essential protection against unauthorized access to fissile material that could be used for nuclear weapons, is no longer present. The handling of those materials requires special facilities to cope with the immense amount of heat and radiation of the fuel containing high fractions of minor actinides. In those facilities, fissile material fitting for military purposes could be handled as well. Even if thorough safeguards are in place, detailed accountancy of all materials is not possible. The quantities needed to build a nuclear weapon are small compared to the quantities that need to be handled in a commercial-sized P&T fuel cycle. P&T technology is a civil application which clearly strengthens military capabilities. It would be hard to argue why it should only be available to a trustworthy partner (whoever that might be). The implementation of P&T fuel cycles would thus increase the risk of unauthorized diversion of nuclear material, technology and knowledge.

The role of international collaboration in the United States geologic disposal research program

Abstract. More than a decade ago, the United States disposal program discontinued all research activities focused on the unsaturated fractured tuff formation at Yucca Mountain as the geologic disposal site for spent fuel and high-level radioactive waste. A new research and development (R&D) program was initiated to provide a sound technical basis for alternative disposal options across clay, crystalline, and salt rocks. The goals of this broad program were (and still are) to (1) increase confidence in the robustness of generic disposal concepts, (2) develop the science and engineering tools needed to support disposal concept implementation, and (3) conduct R&D on the direct disposal of existing dual-purpose (storage and transportation) canisters. Recognizing the benefits of international collaboration toward the common goal of safely and efficiently managing the back end of the nuclear fuel cycle, the program emphasized international cooperation as an effective strategy for sharing information and knowledge. In a multi-laboratory effort coordinated by Lawrence Berkeley National Laboratory, the United States Department of Energy (DOE) program established formal and informal cooperation partnerships with several international initiatives and institutions and developed a number of collaborative R&D activities in important research areas, such as engineered barrier integrity, near-field perturbations, radionuclide transport, performance assessment, and methods for characterization and monitoring of engineered and natural barriers. This presentation gives an overview of these R&D activities, with a specific focus on activities that improve our current understanding of the coupled thermal–hydrological–mechanical–chemical (THMC) processes occurring in engineered and natural barriers. We start with a brief review of selected international collaboration initiatives and then describe a few specific collaboration projects. We focus specifically on such studies that use experimental data sets provided by international research cooperation for joint modeling work to increase confidence in performance-relevant predictions of coupled processes. Overall, the focus on international collaboration has allowed deep engagement of US researchers with the international waste management R&D community in terms of best practices, new scientific advances, state-of-the-art simulation tools, new monitoring and performance confirmation approaches, and lessons learned. The joint R&D with international researchers, worldwide sharing of knowledge and experience, and access to relevant data and experiments from a variety of host rocks have helped our researchers to significantly improve their understanding of the current technical basis for disposal in a range of potential host rock environments. International collaboration also provides ample opportunity for training and educating junior staff that are well suited to move the United States disposal research program forward into the next decades, a promising avenue for developing a next-generation workforce of disposal scientists.

Policies and regulations for solar photovoltaic end-of-life waste management: Insights from China and the USA

The solar photovoltaic (PV) industry has experienced rapid growth in recent years, resulting in a substantial increase in the amount of end-of-life (EOL) waste generated by these panels. Proper waste management is crucial to minimize environmental and health risks. The purpose of this study is to examine the EOL solar PV waste management policies and regulations in China and the United States, identifying challenges and recommending policy implications for enhancing sustainable waste management practices. China has promulgated policies and regulations for managing PV EOL waste, including the National Solid Waste Law and GB or GB/T standards. In the US, federal regulations and guidelines such as the Resource Conservation and Recovery Act (RCRA) and state-specific hazardous waste programs, universal waste rules, and waste recycling programs are enacted. The findings of this study indicate that China and the US face distinct challenges in solar PV end-of-life waste management. China lacks comprehensive local government-level regulations, while the USA exhibits variations in coverage and specific management requirements across states. In light of these observations, as policy implications, it is recommended. Firstly, there is a need for greater harmonization between federal and local/state-level policies and regulations. Secondly, continued research and development efforts are crucial to explore cost-effective and environmentally responsible recycling and disposal options for PV panels. Furthermore, promoting collaboration among policymakers, industry stakeholders, and researchers can facilitate knowledge sharing and the exchange of best practices. Such measures will contribute to the effective and sustainable management of solar PV EOL waste in China and the USA.

Unveiling the Hidden Value of Cotton Gin Waste: Natural Synthesis and Hosting of Silver Nanoparticles.

Cotton gin waste presents a significant challenge in the cotton ginning industry due to its abundant generation and limited disposal options. In this study, we explored the potential of cotton gin waste as a naturally occurring source material that can synthesize and host silver nanoparticles. The noncellulosic constituents of cotton gin waste served as effective reducing agents, facilitating the conversion of silver ions into silver atoms, while its porous structure acted as a microreactor, enabling controlled particle growth. A simple heat treatment of cotton gin waste powder in an aqueous silver precursor solution actualized the in situ synthesis of silver nanoparticles, without the need for additional chemical agents. Remarkably, a high concentration of silver nanoparticles (14.7%) with an average diameter of approximately 27 nm was produced throughout the entire volume of cotton gin waste. Electron microscopic images of cross-sectioned cotton gin waste confirm the internal formation of nanoparticles. Rietveld refinement analysis of X-ray diffraction patterns showed that the majority of the nanoparticles possess a cubic silver crystal structure. By leveraging the well-known biocidal properties of silver nanoparticles, the resulting silver nanoparticle-filled cotton gin waste holds promise for novel antimicrobial and antifungal material applications.

Exploring the characteristics of microbial community and enzyme activity in the aged refuse landfill environment of Taiyuan, China

Municipal solid waste landfill is the main disposal option for domestic garbage, in which microbial activities play an important role. However, despite the widespread practice of landfilling, the metagenomic microbial profiles of landfill sites remain poorly characterized. In this study, we used a combination of physicochemical analysis, ultraviolet-visible spectrophotometry, and high-throughput Illumina shotgun sequencing to systematically investigate the changes in soil enzyme activities, microbial community structure, and functional attributes in aged refuse collected from the Xingou Municipal Solid Waste Landfill in Taiyuan, China, with ordinary topsoil from an area within 5 km of the landfill as control soil. Except for neutral phosphatase (P = 0.065), the activities of urease, laccase, dehydrogenase, sucrase, neutral protease, and β-glucosidase were all significantly reduced (P < 0.05) in the aged refuse compared with the control soil. Contrastingly, catalase activity was found to be significantly elevated in the aged refuse. Compared with the control soil, aged refuse was characterized by higher richness and diversity of microbial communities, as reflected by the higher values of community richness estimators (Chao 1 and ACE) and diversity indices (Shannon and Simpson). In total, 186 phyla, 4 354 genera, and 34 459 species were identified, with 132 phyla, 1 914 genera, and 7 369 species showing significantly different abundances between the aged refuse and the control soil. Actinobacteria and Acidobacteria were identified as the dominant phyla in the control soil, whereas Proteobacteria, Euryarchaeota (archaea), and Firmicutes were found to predominate in the aged refuse. Notably, Euryarchaeota and Methanoculleus were the major taxa detected in the aged refuse, but were almost completely absent in the control soil. Xenobiotic biodegradation and bacterial chemotaxis were the main functions of the microflora in the aged refuse, whereas the carbohydrate, amino acid, energy, and lipid metabolism pathways were significantly enriched in the control soil. Moreover, the aged refuse contained a high abundance of genes involved in quorum sensing. Our findings in this study revealed close associations between enzyme activities and variations in the microbial community structure and genes that were actively involved in biodegradation activities at landfill sites. It was found that the landfill environment was characterized by a more complex spectrum of microbial activities than expected. Further investigations are needed to gain a more comprehensive understanding of the microbial community structure and functional attributes as well as their potential influencing factors in the landfill environment.

The Impact of Organic, Inorganic Fertilizers, and Biochar on Phytochemicals Content of Three Brassicaceae Vegetables

The need for soil fumigants of natural origin such as glucosinolates (GSLs) has increased due to the general prevention of manmade soil fumigants. GSLs and other phytochemicals (vitamin C and phenols) present in Brassica vegetables such as turnips, arugula, and mustard have antioxidant properties, and hence have important health attributes. The study examined how different soil amendments (chicken manure CM, vermicompost Vermi, horse manure HM, sewage sludge SS, elemental inorganic fertilizer Inorg, organic fertilizer Org, and biochar) impact the concentrations of glucosinolates (GSLs), vitamin C, phenols, and reducing sugars in three varieties of turnips (Purple Top White Globe PTWG, Scarlet Queen Red SQR, and Tokyo Cross TC), arugula, and mustard greens grown under field conditions. The results showed that mustard greens contained higher concentrations of GSLs (974 µg g−1 fresh shoots) than arugula (651 µg g−1 fresh shoots), and the TC variety of turnip had the highest concentrations of GSLs, vitamin C, and sugars. Additionally, amending the soil with SS, CM, and HM significantly increased the vitamin C content in mustard shoots by 82%, 90%, and 31%, respectively, and the total phenols by 77%, 70%, and 36%, respectively, compared to the control treatment. The increased inorganic fertilizers cost, and availability of large amounts of animal manure made animal manure application to cropland an attractive disposal option.

Life cycle assessment of e-waste management system in Australia: Case of waste printed circuit board (PCB)

Electronic waste (e-waste) is one of the fastest-growing waste streams globally. Recycling is one of the environment-friendly waste management strategies that creates a net environmental gain in recovering valuable materials. In some countries, downstream recycling (high-value material recovery) is done overseas, and Australia is one of them. Waste printed circuit board (PCB) is a critical component of various electronic equipment, and it contains metals such as copper, tin, gold, aluminium, iron, silver, and others. Waste PCB, as apart of e-waste is mainly recycled overseas in Australia. However, the overall environmental impacts of recycling the waste stream overseas have yet to be investigated. The benefits of recovering the material in Australia have yet to be extensively understood from a supply chain perspective. This study aims to develop multiple scenarios using lifecycle assessment (LCA) methodology to identify the best possible solution for waste PCB disposal (final sink) derived from e-waste. Using SimaPro and Ecoinvent databases, four scenarios have been developed, along with a baseline scenario where waste PCB is recycled overseas. Receipe 2016 impact assessment methodology was utilized for the analysis, and results of the study showed that Scenario 2 (integrated material and energy recovery) is the best approach for waste PCB recycling in Australia, while landfill and direct incineration were the identified two worst scenarios in terms of final disposal option. When choosing local recycling over overseas recycling of waste PCB (material recovery only), it was found that impact categories such as global warming (human health) and fossil resource scarcity were reduced by 53% and 98%, respectively. In addition, the net positive environmental gain could be achieved for human non-carcinogenic toxicity by 7.16% when the waste stream is recycled in Australia. Uncertainty analysis of the study showed that in almost all major impact categories, material and energy recovery together scored high compared to scenarios when only material recovery was considered. This study is the first systematic attempt to characterize system-level lifecycle environmental impact assessment for waste PCB recycling. Future policies and regulations should focus on data transparency and availability across the value chain, local infrastructure development, and resource circularity. This study will add value to decision-making, policy on investment and future policy planning. It will also help industry and researchers develop optimized recycling-focused low-emission resource recovery supply chains.

A review on the recent advances in electrochemical treatment technologies for sludge dewatering and alternative uses

Municipal wastewater treatment plants generate enormous quantities of sludge as a byproduct, which not only contains a significant amount of water and harmful pathogens but also serves as a repository for a variety of essential materials and nutrients. The recovery of water and other valuable substances is highly dependent on the employed treatment methods. In recent years, electrochemical processes have attracted a great deal of interest as an efficient technique for sludge dewatering and resource recovery. By separating free and bound water from the sludge matrix, electro-dewatering can substantially reduce the volume of sludge, making it a more cost effective and sustainable method of sludge management. Furthermore, the resulting sludge cake is more manageable and transportable, making it a viable option for further disposal or resource recovery. By considering the beneficial aspects of sludge electro-dewatering, this paper aims to critically review the mechanism underlying electrochemical methods of sludge dewatering as well as modified development strategies for scal-up potentials.

Poultry waste management in Nigeria: a neglected sector

The recent surge in poultry production has led to an increase in poultry waste production. Waste from poultry production often includes hatchery waste, dead birds, condemned carcasses, and manure. Manure is normally applied to agricultural soils as a source of fertilizer. Excessive production of waste from poultry farms and its improper disposal has led to air pollution and contamination of agricultural farmlands and eventually surface and water groundwater pollution and this has become a major public health concern to the society. Improper disposal of poultry waste affects poultry farmers, individuals residing close to the farms, and the environment. Published articles on poultry production and poultry waste management were retrieved from the search engine Google Scholar and were used to summarize the impact of poultry waste as a source of contamination and/or pollution to the environment with associated public health implications on animals and humans. Options for proper disposal and utilization of waste from poultry production are further discussed.

Integrating food waste management into urban wastewater treatment: Economic and environmental impacts

Food waste is the main component of municipal solid waste (MSW) and its sustainable management is a global challenge. Co-treatment of food waste and urban wastewater in wastewater treatment plants (WWTPs) could be a plausible management strategy to reduce the MSW amount that is disposed in landfills, while converting its organic fraction into biogas in the WWTP. However, the increased organic load in the wastewater influent would impact the capital and operating costs of the WWTP, mainly due to the increase in sludge production. In this work, different scenarios for co-treatment of food waste and wastewater were studied from both economic and environmental perspectives. These scenarios were designed based on different sludge disposal and management options. The results showed that the co-treatment of food waste and wastewater would be more environmentally friendly than their separate treatment, but its economic feasibility strongly depends on the ratio between the management costs of MSW and sewage sludge.

Impact of compacted bentonite microbial community on the clay mineralogy and copper canister corrosion: a multidisciplinary approach in view of a safe Deep Geological Repository of nuclear wastes

Deep Geological Repository (DGR) is the preferred option for the final disposal of high-level radioactive waste. Microorganisms could affect the safety of the DGR by altering the mineralogical properties of the compacted bentonite or inducing the corrosion of the metal canisters. In this work, the impact of physicochemical parameters (bentonite dry density, heat shock, electron donors/acceptors) on the microbial activity, stability of compacted bentonite and corrosion of copper (Cu) discs was investigated after one-year anoxic incubation at 30 ºC. No-illitization in the bentonite was detected confirming its structural stability over 1 year under the experimental conditions. The microbial diversity analysis based on 16 S rRNA gene Next Generation Sequencing showed slight changes between the treatments with an increase of aerobic bacteria belonging to Micrococcaceae and Nocardioides in heat-shock tyndallized bentonites. The survival of sulfate-reducing bacteria (the main source of Cu anoxic corrosion) was demonstrated by the most probable number method. The detection of CuxS precipitates on the surface of Cu metal in the bentonite/Cu metal samples amended with acetate/lactate and sulfate, indicated an early stage of Cu corrosion. Overall, the outputs of this study help to better understand the predominant biogeochemical processes at the bentonite/Cu canister interface upon DGR closure.