Assessment and characterization of solid and hazardous waste from inorganic chemical industry: Potential for energy recovery and environmental sustainability.

Rapid global urbanization and economic growth have significantly increased solid waste volumes, with hazardous waste posing substantial health and environmental risks. Co-processing strategies for industrial solid and hazardous waste as alternative fuels highlight the importance of integrated waste management for energy and material recovery. This study identifies and characterizes solid and hazardous industrial wastes with high calorific values from various industrial processes at Nirma Industries Limited. Nine types of combustible industrial wastes were analyzed: discarded containers (W1), plastic waste (W2), spent ion exchange resins from RO plants (W3), sludge from effluent treatment in soap plants (W4), glycerine foot from soap plants (W5), rock wool puff material (W6), fiber-reinforced plastic waste (W7), spent activated carbon (W8), and spent cartridges from reverse osmosis plants (W9). Physical characterization, proximate and ultimate analysis, heavy metal concentration evaluation, and thermogravimetric analysis were conducted to assess their properties, revealing high calorific values exceeding 2500 kcal/kg. Notably, W1 and W2 exhibited the highest calorific values (∼10,870 kcal/kg), followed by W6 and W8 (∼6000 kcal/kg) and W9 (∼8727 kcal/kg). Safe heavy metal levels are safe, and high calorific values support the prospects of energy recovery and economic and environmental benefits, reducing landfill reliance and enhancing sustainable waste management.

Improving landfill liner performance with bentonite-slag blend permeated with ammonia for a Municipal solid waste landfill.

Leachate emanating from landfills contains ammonia which may cause serious health effects on living things. An effectively designed clay barrier should not allow the contaminant to infiltrate the soil and groundwater systems. The utilization of certain industrial by-products in engineered landfill barriers, not only reduces the need for conventional liner materials but also helps in sustainable waste management. This study investigated the hydraulic conductivity, unconfined compressive strength, compaction, and adsorption characteristics of lithomargic clay blended with an optimum percentage of bentonite (10%) and granulated blast furnace slag (15%) permeated with ammonia. The results revealed that increasing the content of granulated blast furnace slag decreased the maximum dry density while increasing the optimum moisture content. In comparison to lithomargic clay, the hydraulic conductivity of the amended soil liner permeated with ammonia decreased from a value of 3 × 10-8 m/s to 5 × 10-10 m/s. The unconfined compressive strength of the amended soil specimens showed an increasing trend with curing times (i.e., 0, 14, 28, and 56 days). The batch adsorption results revealed that Freundlich and Langmuir's isotherm fits the equilibrium adsorption data and the adsorption of ammonia on clay liner follows non-linear behaviour. Overall, the experimental results implied that lithomargic clay blended with 10% bentonite and 15% granulated blast furnace slag can be used as an impermeable soil reactive barrier in engineered landfills.

Factors influencing willingness to pay for improved solid waste collection services among households in urban cities in Uganda: empirical evidence from Lira City.

Waste management in Lira City, Uganda faces significant challenges, particularly in the area of waste collection. Pollution and health risks from uncollected waste are rampant, posing serious threats to human health and the environment. This persistent problem demands urgent attention and effective solutions to improve waste collection and safeguard the well-being of the community and the natural surroundings. This study aimed to assess households' willingness to pay for improved waste collection services, examine their waste management practices, and identify influencing factors. We employed a multistage sampling technique to randomly select 585 household heads and conducted key informant interviews with city officials and private waste collectors. Data analysis was conducted with STATA 17 and results showed that 48.12% of households were willing to pay an average of UGX 3012 ($0.84) per month for better services. Factors including education level, occupation, distance to waste collection sites, and environmental awareness significantly influenced this willingness. The study highlights a significant gap in public awareness and understanding of efficient solid waste management practices and concludes that enhancing public awareness is crucial for improving environmental health and safety in Lira City.

Converting biomass waste into valuable biomaterials and bioactive compounds: an overview of antimicrobial activities in the pursuit of global sustainability and health.

The escalating global population poses formidable challenges to addressing pressing environmental concerns, hindering progress towards sustainable development goals. Unregulated human activities, particularly the excessive reliance on fossil fuels and unsustainable agricultural practices, contribute to pollution, climate change, and resource depletion. Inadequate waste management systems exacerbate environmental degradation and pose risks to public health. Leveraging biological resources and urban/industrial waste emerges as a promising solution. Various waste materials, such as food waste and agro-industrial by-products, have been efficiently repurposed into valuable bio-based products. This review explores the diverse applications of agricultural and food waste repurposing, including microbial production of biopolymers and biosurfactants, as well as the extraction of biologically active compounds for potential antimicrobial drugs.

Microwave-assisted acid treatment for the mineral transformation of chrysotile as an alternative for asbestos waste management.

In this work, the effect of microwave-assisted acid treatments on the morphological and crystallochemical characteristics of chrysotile fibers is investigated. A low concentration of nitric acid (0.2 N) is used to remove Mg2+-species located in the octahedral sheet of its structure, thereby causing a crystallo-chemical change forming a skeleton of non-crystalline amorphous silica. This skeleton maintains an elongated morphology but characterized by rounded -not sharp-edges and porous surfaces whose physical resistance under stress is reduced when compared with the initial fibers of chrysotile, favoring a lower pathogenicity of the fibers. Thus, microwave-assisted acid treatment rise as a low-cost, fast and effective option in avoiding the dangerousness associated with asbestos waste management.

Management of methyl mercaptan contained in waste gases - an overview.

Methyl mercaptan is a typical volatile organosulfur pollutant contained in many gases emitted by urban waste treatment, various industries, natural gas handling, refining processes, and energy production. This work is a comprehensive overview of the scientific and practical aspects related to the management of methyl mercaptan pollution. The main techniques, including absorption, adsorption, oxidation, and biological treatments, are examined in detail. For each method, its capability as well as the technical advantages and drawbacks have been highlighted. The emerging methods developed for the removal of methyl mercaptan from natural gas are also reviewed. These methods are based on the catalytic conversion of CH3SH to hydrocarbons and H2S.

Circular economy life cycle cost for kerbside waste material looping process.

Rapid expansion in urban areas has engendered a superfluity of municipal solid waste (MSW) stemming from contemporary civilization, encompassing commercial sectors and human undertakings. Kerbside waste, a type of MSW, has the potential for recycling and reuse at the end of its first life cycle, but is often limited to a linear cycle. This study aimed to assess the life cycle costs of different separation and recycling methods for handling kerbside waste. A new life cycle cost model, drawing from the circular economy's value retention process (VRP) model, has been created and applied to assess the continuous recycling of kerbside glass. The study investigates two key separation techniques, kerbside recycling mixed bin recycling (KRMB) kerbside glass recycling separate bin (KGRSB) and analyses their impact on the life cycle cost of the recycling process. Additionally, the research explores two approaches of recycling and downcycling: closed-loop recycling, which pertains to the recycling of glass containers, and open-looped recycling, which involves the use of recycled glass in asphalt. The results showed when use annually collected waste as the functional unit, the KRMB model incurred lower costs compared to the KGRSB model due to its lower production output. However, when evaluated over a 1-ton production of glass container and asphalt, the KGRSB method demonstrated superior cost performance with a 40-50% reduction compared to the KRMB method. The open-loop recycling method (asphalt) incurred a higher cost compared to the closed-loop recycling method due to its larger production volume over a 21-year period.

Strategies to enhance the circularity of non-bottle PET packaging waste based on a detailed material characterisation.

The compositions of Dutch lightweight packaging waste (LWP) and sorted products named "PET (Polyethylene terephthalate) trays" have been determined on object level. Additionally, the PET trays from both waste types were sorted in 16 categories representing their packaging use and material build-up. The material composition of at least 10 representative trays from each category was determined with chemical and thermal analysis, based on which the average material composition per category was established. Based on this data the average material composition of sorted PET tray products was approximated. The recyclability of the various categories of PET trays was assessed based on their material build-up. The most ubiquitous PET trays in Dutch LWP and sorted products were only found to be suitable to produce opaque recycled PET with mechanical recycling processes. Whereas only some more uncommon PET trays can be used to produce transparent recycled PET with mechanical recycling processes. Depolymerisation is deemed to be a more appropriate recycling process that will allow the production of transparent food-grade recycled PET.

An in-depth study of the oxidative liquefaction process for polymeric waste reduction and chemical production from wind turbine blades and personal protective equipment used in the medical field.

An in-depth study of the oxidative liquefaction process has been provided to degrade the polymeric waste from personal protective equipment (PPEs) and wind turbine blades (WTBs). Thermogravimetric investigations demonstrate that WTBs have three prominent peaks throughout the degradation, whereas PPEs display solitary peak features. Experiments are carried out employing specific experimental design approaches, namely the Central Composite Face-Centered Plan (CCF) for WTBs and the Central Composition Design with Fractional Factorial Design for PPEs in a batch-type reactor at temperature ranges of 250-350 °C, pressures of 20-40 bar, residence times of 30-90 min, H2O2 concentrations of 15-45 %, and waste/liquid ratios of 5-25 % for WTBs. These values were 200-300 °C, 30 bar, 45 min, 30-60 % and 5-7 % for PPE. A detailed comparison has been provided in the context of total polymer degradation (TPD) for PPE and WTBs. Liquid products from both types of wastes after the oxidative liquefaction process are subjected to gas chromatography with flame ionization detection (GC-FID) to identify the existence of oxygenated chemical compounds (OCCs). For WTBs, TPD was 20-49 % and this value was 55-96 % for PPE while the OCC yield for WTBs (36.31 g/kg - 210.59 g/kg) and PPEs (39.93 g/kg - 212.66 g/kg) was also calculated. Detailed optimization of experimental plans was carried out by performing the analysis of variance (ANOVA) and optimization goals were maximum TPD and OCCs yields against the minimum energy consumption, though a considerable amount of complex polymer waste can be reduced and high concentrations of OCC can be achieved, which could be applied for commercial and environmental benefits.

Waste or resource? Investigating the interplay of structural d waste managers' household food waste interventions.

Globally, food waste is a significant environmental, economic and social issue. Food waste in landfill creates the potent greenhouse gas, methane, contributing to climate change, with its management predominantly falling to local governments. Despite efforts by many countries, and extensive infrastructure and market development funding, food waste continues to be landfilled, with apparently similar councils taking diverse approaches. Using a mixed methods study design, data was firstly collected from a National online survey of Australian council-based waste management staff (n = 183), with descriptive and factor analysis of the survey data revealing a strong sense of structural empowerment (PCA.75 to.90) and a preference for sourcing information from networks (48%). These results informed a series of semi-structured interviews (n = 43) which, after thematic analysis, provided rich insights into the attitudinal and situational interpretations council-based waste managers bring to decisions around household food waste management. Framed by four pillars of Structural Empowerment, the findings suggest that waste manager's attitude is equally as important as support, resources, and knowledge and that, despite mandates and targets, individual motivational factors and organisational paradigms determined decision-making. Identified barriers included perceived capacity constraints, inadequate focus on actionable interventions, and fragmented, uninspiring, planning. This article provides important insights around 1) leveraging networks for knowledge dissemination, 2) fostering capacity-building initiatives, and 3) advocating for sustained engagement with food waste diversion within councils. This underscores the need for additional research into evolving council typologies and effectively engaging key stakeholders to achieve food waste diversion targets and address climate change impacts.

Circular bioeconomy in action: Upscaling cutlassfish waste for eco-friendly recombinant protein production.

The fish processing industry generates a significant amount of waste, and the recycling of this waste is an issue of global concern. We sought to utilize the heads of cutlassfish (Trichiurus lepturus), which are typically discarded during processing, to produce peptone, which is an important source of amino acids for microbial growth and recombinant protein production. Cutlassfish head muscle (CHM) were isolated, and the optimal protease and reaction conditions for peptone production were determined. The resulting peptone contained 12.22 % total nitrogen and 3.19 % amino nitrogen, with an average molecular weight of 609 Da, indicating efficient hydrolysis of CHM. Growth assays using Escherichia coli have shown that cutlassfish head peptone (CP) supports similar or superior growth compared to other commercial peptones. In addition, when recombinant chitosanase from Bacillus subtilis and human superoxide dismutase were produced in E. coli, CP gave the highest expression levels among six commercial peptones tested. In addition, the expression levels of chitosanase and superoxide dismutase were 20 % and 32 % higher, respectively, in CP medium compared to the commonly used Luria-Bertani (LB) medium. This study demonstrates the potential of using cuttlassfish waste in the production of microbial media, thereby adding significant value to fish waste. The results contribute to sustainable waste management practices and open avenues for innovative uses of fish processing by-products in biotechnological applications.

An in-depth analysis of factors and forecasting techniques for emerging solid waste streams.

Technological advances have led to the generation of novel streams of solid wastes, comprising materials previously excluded from traditional waste considerations. The absence of proper handling and management policies for these Emerging Solid Waste Streams (ESWSs) poses a great cause of concern. Proper estimation of current and future quantities is necessary for efficient policy making. This study, through a systematic literature review, analyses forecasting models for four major ESWSs: PV waste, e-waste, battery waste, and biomedical waste. A total of 40 modelling methodologies which successfully forecast the quantities of these ESWSs are identified and analyzed in this review. These highly heterogeneous models are classified into several crucial categories based on the modelling method, independent variable, geographical scale and data type involved. This categorization proves to be pivotal in the selection of an appropriate forecasting model. Around 40 modelling methods and 100+ independent variables, crucial for a successful forecast are identified and categorized. This study also focuses on the uncertainty involved in input data, a factor contributing to inaccurate predictions. It further entails identifying and analysing potential data sources, examining the rationale behind their selection, and providing recommendations for choosing suitable data sources. Beyond analysis, potential future areas of research and gaps involved in the field of forecasting ESWSs have also been highlighted. Serving as a valuable guide for beginners, the research also proposes a methodology to navigate the intricacies of forecasting ESWSs, contributing to both our understanding of forecasting models and the development of robust waste management policies in the evolving technological landscape.

From riverbank to the sea: An initial assessment of plastic pollution along the Ciliwung River, Indonesia.

This study presents the first comprehensive analysis of anthropogenic debris on the riverbanks of the Ciliwung River, covering upstream to downstream areas. The mean of debris found in each measurement was 32.79 ± 15.38 items/m2 with a weight of 106.00 ± 50.23 g/m2. Plastic debris accounted for over 50 % of all litter items identified and represents 55 % by weight, signifying a significantly high prevalence compared to global studies examining litter along riverbanks. The majority of the plastics found originated from Single-use applications and were predominantly made from Styrofoam. This investigation demonstrated the importance of actions to reduce single use applications and to improve waste management strategies. This can be achieved through proactive initiatives coupled with adaptable approaches, such as implementing effective urban planning and enhancing waste collection capacity.

Waste management in the operating theatre.

INTRODUCTION: Poor clinical waste management and its effect on the environment is an increasingly recognised concern for global healthcare systems. Approximately two thirds of waste produced in healthcare is from the operating theatre. In the Republic of Ireland, an estimated 580,977 tonnes of hazardous waste was produced in 2019. The cost of incineration of this hazardous waste is approximately €2,125 per tonne and €935 per tonne for sterilisation. Pollution from incineration is substantial and harmful. METHODS: A literature review was performed on the topic of hospital waste management, specifically looking at the Republic of Ireland. A comparison could then be drawn between Ireland, Europe and the United States of America. Observation of our current operating theatre environment and practices were carried out. DISCUSSION: An increased focus towards sustainability and reusable equipment means that there is potentially a decreased amount of waste for disposal, but an increase in the process of sterilisation. Approximately 66% of healthcare related waste is inappropriately contaminated, meaning that significant savings are possible if correct segregation and recycling were to occur. An increase in the amount of bins, identification labels above bins and education of staff results in an increased likelihood of successful segregation of waste. Clear and concise hospital guidelines of what is considered hazardous versus non-hazardous waste will decrease the amount of inappropriately disposed items.

New powder reuse schema in laser-based powder bed fusion of polymers.

The laser-based powder bed fusion of polymers (PBF-LB/P) process often utilizes a blend of powders with varying degrees of degradation. Specifically, for polyamide 12, the traditional reuse schema involves mixing post-processed powder with virgin powder at a predetermined ratio before reintroducing it to the process. Given that only about 15% of the powder is utilized in part production, and powders are refreshed in equal proportions, there arises a challenge with the incremental accumulation of material across build cycles. To mitigate the consumption of fresh powder relative to the actual material usage, this study introduces the incorporation of recycled material into the PBF-LB/P process. This new powder reuse schema is presented for the first time, focusing on the laser sintering process. The characteristics of the recycled powder were evaluated through scanning electron microscopy, differential scanning calorimetry, X-ray diffraction, particle size distribution, and dynamic powder flowability assessments. The findings reveal that waste powders can be effectively reused in PBF-LB/P to produce components with satisfactory mechanical properties, porosity levels, dimensional accuracy, and surface quality.

Conversion and fate of waste Li-ion battery electrolyte in a two-stage thermal treatment process.

Disposal of electrolytes from waste lithium-ion batteries (LIBs) has gained much more attention with the growing application of LIBs, yet handling spent electrolyte is challengeable due to its high toxicity and the lack of established methods. In this study, a novel two-stage thermal process was developed for treating residual electrolytes resulted from spent lithium-ion batteries. The conversion of fluorophosphate and organic matter in oily electrolyte during low-temperature rotation distillation was investigated. The distribution and migration of the concentrated electrolytes were studied and the corresponding reaction mechanisms were elucidated. Additionally, the influence of alkali on the fixation of fluorine and phosphate was further examined. The results indicated that hydrolyzed carbonate esters and lithium in the electrolyte could combine to form Li2CO3 and the hydrolysable hexafluorophosphate was proven to be stable in the concentrated electrolyte (45 rpm/85 °C, 30 min). It was found that CO2, CO, CH4, and H2 were the primary pyrolysis gases, while the pyrolysis oil consisted of extremely flammable substances formed by the dissociation and recombination of chemical bonds in the electrolyte solvent. After pyrolysis at 300 °C, fluorine and phosphate were present in the form of sodium fluoride and sodium phosphate. The stability of the residue was enhanced, and the environmental risk was reduced. By adding alkali (KOH/Ca(OH)2, 20 %), hexafluorophosphate in the electrolyte was transformed into fluoride and phosphate in the residue, thereby reducing the device's corrosion from fluorine-containing gas. This study provides a viable approach for managing the residual electrolyte in the waste lithium battery recovery process.

Facing the solid waste of cotton straw and plastic mulch film mixture in China: Centralized or decentralized pyrolysis facility?

The widespread use of plastic mulch film (PMF) has led to significant environmental pollution, with PMF residues dispersed and mixed with straw and soil, posing challenges for recycling. Here, we proposed the mobile pyrolysis facility for the cotton straw and mulch film mixture (CMM) to mitigate the collection, storage, and transportation costs, while the application of co-pyrolysis technology for CMM conversion could improve the added value of products. Additionally, centralized combustion power generation and centralized pyrolysis systems were also established to evaluate and compare their sustainability from economic and environmental perspectives. Results showed that mobile pyrolysis has better economic performance than the centralized scenarios, due to its high internal rate of return (31 %) and significant net present value (29.21 M USD). Meanwhile, the mobile pyrolysis facility achieved a GWP of -1.298 kgCO2-eq/kg, reducing emissions by 70.79 % and 38.82 % compared to the two centralized scenarios. In conclusion, mobile pyrolysis technology provides a promising solution for PMF residue recycling because of its economically competitive approach with a lower carbon footprint.

Improved recycling of a gasification fly ash: An integrated waste management approach within the framework of a Circular Economy.

A Circular Waste Management alternative is considered in this paper in which a complete ash valorization process is proposed for an Integrated Gasification with Combined Cycle fly ash, trying to extract maximum value from this waste before it is discarded. In the paper, germanium, a scarce resource vital in our modern society, is first extracted from fly ash using water, with an extraction yield of 85%, and subsequently, the leached fly ash is used in the manufacture of fire-resistant boards containing 60% ash, thereby avoiding its disposal in a landfill. The potential environmental impact caused by the two stages of the process was analyzed, and the final effluent was considered to achieve a zero-discharge objective. This paper contributes to the development of a more sustainable management alternative for an industrial waste produced in increased amounts and provides the basis for a symbiotic coupling relationship among various industrial sectors.

Elemental characterization of electronic waste: a review of research methodologies and applicability to the practice of e-waste recycling.

Economic and environmental considerations have elucidated research interests on the best approach to managing electronic waste (e-waste), which has increasing social, environmental, and economic impacts. Proper e-waste managementis essential for resource recovery, environmental sustainability, and public health protection, and effective management of e-waste necessitates analytical techniques to assess and characterize their elemental composition. Despite expansive literature published on the topic of e-waste, there is scarce coverage of the various analytical techniques employed to characterize the inorganic contents of e-waste. This review discusses the various e-waste characterization techniques used in studies published between 2013 and 2023. Specifically, this review covers the analytical approaches employed to characterize the inorganic content of e-waste, the electronic devices or their components analyzed, the elements identified, the sample preparation methods adopted, and the merits and demerits of the analytical procedures. This review highlights the disparate approaches to e-waste characterization and the need for reliable and repeatable e-waste analysis and sample preparation methods.