Landfill Disposal Research Articles

In-situ halloysite coupled with ex-situ nano-aluminosilicate on heavy metals fate during pyrolysis of solid wastes in a rotary kiln and potential application of pyrolysis residue

During the pyrolysis of heavy metal-containing solid waste, the immobilization and stabilization of heavy metals (HM) is of great significance for its safe disposal and resource utilization of pyrolysis products. This study aims to enhance the enrichment and stability of HMs in pyrolysis residues from HM-containing solid waste in a rotary kiln by combining in-situ halloysite (Hal) with ex-situ nano-aluminosilicate (NC2.6). With 13 % Hal and 10 % NC2.6, the relative retention rate of Cd, Pb, Zn, Cu, and Cr increased by 4.82 %, 29.45 %, 20.98 %, 1.71 %, and 2.61 %, respectively, at 700 ℃. Bureau Communautaire de Référence (F4 > 85 %) and Toxicity Characteristic Leaching Procedure (7.536 mg/L at 10 % addition ratio) extraction results showed that NC2.6 adsorption products exhibit low toxicity, suitable for landfill disposal. The mobility of HMs in pyrolysis residues significantly decreased with increasing temperature and Hal addition. At 13 % Hal addition, low-risk pyrolysis residue (RI = 22.23) was obtained at 700 ℃. Dynamic adsorption experiments evaluated the feasibility of using this pyrolysis residue for methylene blue (MB) adsorption. Under the conditions of a 6 cm adsorption column height and a solution flow rate of 2.5 mL/min, the HM concentration in the effluent met relevant standards, and the adsorption capacity reached 22.733 mg/g. Furthermore, DFT simulations explored the effect of HMs in biochar on MB adsorption, revealing that the adsorption energy between Zn and N reached −281.03 kJ/mol, significantly lower than that of common oxygen-containing functional groups (COC, CO, HOCO, and OH), indicating more stable adsorption. The findings of this research offer novel insights into the immobilization of HMs during the pyrolysis of HM-containing solid waste and resource utilization of HM-containing pyrolysis residue.

Ecotoxicological assessment of waste foundry sands and the application of different classification systems.

The application of a battery of bioassays is widely recognized as a useful tool for assessing environmental hazard samples. However, the integration of different toxicity data is a key aspect of this assessment and remains a challenge. The evaluation of industrial waste leachates did not initially undergo any of the proposed integration procedures. This research addressed this knowledge gap. Twenty-five samples of waste foundry sands were subjected to a leaching test (UNI EN 12457-2) to evaluate waste recovery and landfill disposal. The leachates were evaluated using a battery of standardized toxicity bioassays composed of Aliivibrio fischeri (EN ISO 11348-3), Daphnia magna (UNI EN ISO 6341), and Pseudokirchneriella subcapitata (UNI EN ISO 8692), both undiluted and diluted. Daphnia magna and P. subcapitata were the most affected organisms, with significant effects caused by 68% and 64% of undiluted samples, respectively. The dilution of samples facilitates the calculation of EC50 values, which ranged from greater than the highest concentration tested to 2.5 g/L for P. subcapitata. The data on single-organism toxicity were integrated using three methods: the Toxicity Classification System, the toxicity test battery integrated index, and the EcoScore system. The three classifications were strongly similar. According to all applied systems, three samples were clearly nontoxic (from iron casting plants) and two were highly toxic (from steel casting plants). Moreover, the similar ranking between undiluted and diluted leachates suggests the possibility of using only undiluted leachates for a more cost-effective and time-efficient screening of waste materials. The findings of this study highlight the usefulness of integrating ecotoxicological waste assessment. Integr Environ Assess Manag 2024;00:1-18. © 2024 The Author(s). Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Evaluation of high-volume fly-ash cementitious binders incorporating nanosilica as eco-friendly sustainable concrete repair materials

Nowadays, the use of environmentally friendly, long-lasting building materials with minimal energy and carbon dioxide emissions are highly recommended. Some of these materials can be made from industrial and agricultural wastes. By replacing ordinary Portland cement (OPC) with large volume of fly ash waste (FA), environmental issues associated with landfill disposal and cement manufacture can be mitigated. Nonetheless, using a high amount of FA (up to 50 %) to replace cement resulted in poor strength performance, particularly during early age. This experimental study created an increased strength cement mortar containing a high volume of FA (60 %) and bottle glass waste nanoparticles (BGWNPs). In this experiment BGWNPs were prepared and 2, 4, 6, 8 and 10 vol% of them were used as a replacement of OPC-FA binder. According to the results, by adding 0–6 % of BGWNPs to a high-volume FA matrix considerably increased the bond strength (from 12.5 % to 39.1 %). On the other hand, the findings revealed that the addition of nanoparticles (up to 6 %) caused a modest reduction in strength values. Other engineering and microstructure properties showed a similar pattern. The matrix with 6 % BGWNPs displayed the best performance when compared to other levels. The results also showed that replacing OPC by high volume FA incorporating BGWNPs significantly improved the durability of proposed mortar, such as reduction in drying shrinkage and increased acid attack and abrasion resistance. Related to the environment benefits, the proposed mortars contributed in a reduction of carbon dioxide emission, energy consumption and cost of binder by 61.9 %, 54.3 % and 50.6 % compared to OPC, respectively. To conclude, the use of BGWNPs make it possible to produce high volumes of FA-based cement mortars with acceptable mechanical and durable properties for concrete repair applications in the construction industry. Additionally, sustainability can be attained by lowering pollution, recycling waste, and finding solutions to landfill problems.

Environmental Assessment of Solid Recovered Fuel Production from Screening Waste Using a Life Cycle Assessment Approach

The circular economy, as a new model of waste management through energy self-sufficiency and valorisation, can be applied to wastewater treatment plants (WWTPs). Screening waste from WWTP pretreatment is the only waste that is not energetically recovered and thus constrains the achievement of zero waste. Previous studies demonstrated the technical feasibility of producing solid recovered fuel (SRF) from this waste. Environmental benefits, including waste reduction, resource conservation, or reduced greenhouse gas emissions are analysed in this work. Environmental impact is quantified using the life cycle assessment (LCA) methodology through the SimaPro 9.2. software and the CML-IA baseline v3.08 impact methodology, that propose 11 impact categories. Five scenarios were established to compare current landfill disposal with the production of densified and non-densified SRF using solar and thermal drying. Within the system boundaries studied, from waste generation to SRF production, results show that landfill is the most environmentally damaging option while producing non-densified SRF using solar drying is the most environmentally viable scenario.

Jakarta's Readiness for the Waste Reduction Program at the Source

DKI Jakarta as the capital of Indonesia has a policy to manage waste (recycling) in a decentralized manner, namely that waste is managed as close as possible to its source, without relying on disposal in landfills anymore. This pro-environment policy targets reducing and handling waste by 30% and 70% respectively by 2030. Currently the program is being implemented, non-residual waste will be processed and recycled in decentralized processing or TPS 3R. In order to achieve this target, the community and government must work together to make changes and must have a sense of ownership, responsiveness, concern and responsibility for the waste produced. This research uses a qualitative approach with observations, questionnaires to 330 respondents and interviews with the community and local government. And this research found that TPS and TP3R public facilities still do not comply with existing regulations and do not meet the criteria for accommodating recycling activities. From 2018-2022, the reduction in waste generation was 9% from the target of 26% and the amount of waste handling was 1.66% from the target of 70%. People still don't recycle for various reasons and there is also a lack of consistency in implementing recycling behaviour due to rational attitudes such as just paying money for waste. The government is obliged to facilitate these recycling activities together with various stakeholders, by carrying out various innovations and outreach to the community, by implementing waste management based on community participation.

Analysis of the Prices of Recycling Byproducts Obtained from Mechanical–Biological Treatment Plants in the Valencian Community (Spain)

Municipal solid waste (MSW) management in Spain, particularly in the Valencian Community, heavily relies on mechanical–biological treatment (MBT) plants followed by landfill disposal. These MBT facilities utilize mechanical processes like shredding, screening, and sorting to segregate recyclables (metals, plastics, paper) from organic material and other nonrecyclables. While public funding supports these plants, private entities manage them through complex, long-term concession contracts. This structure restricts access to crucial data on the sale prices of the byproducts generated during MBT. Publicly available information on relevant company and administration websites is typically absent, hindering transparency surrounding byproduct revenue. This study addresses this gap by analyzing 2012’s available data on revenues obtained from byproduct sales following mechanical treatment at MBT plants within the Valencian Community and comparing them with Spanish national data. This research revealed a significant finding—the statistical distribution of average prices obtained from Ecoembes auctions in the Valencian Community mirrored the corresponding distribution for prices calculated from auctions conducted in other Spanish regions. This suggests a potential uniformity in byproduct pricing across the country. It has also been found that none of the analyzed price distributions exhibited a normal (Gaussian) distribution. The findings also highlight the need for alternative pricing models that move beyond simple averages and account for regional variations and outliers. As actual prices are not available after 2012, this lack of transparency poses a challenge in comprehensively evaluating the economic viability of MBT plants. Furthermore, it raises concerns regarding whether the revenue generated from byproduct sales reflects fair market value. Limited public access to this information can potentially indicate conflicts of interest or inefficiencies within the waste management system.

Enhancing Durability of Concrete and Mortar with Ceramic Waste: A Comprehensive Review

The construction industry continually seeks sustainable materials to enhance the durability of structures while minimizing environmental impact. Ceramic waste, a by-product of the ceramic manufacturing process, presents a promising alternative. Traditionally used for tiles, sanitary ware, and bricks, ceramic materials are valued for their high strength, aesthetic appeal, and thermal insulation properties. The study indicates that ceramic waste enhances the durability of construction materials due to its inherent properties, such as low water absorption and high abrasion resistance. Additionally, utilizing ceramic waste addresses environmental concerns associated with landfill disposal, which include soil and water contamination, greenhouse gas emissions, and the depletion of landfill space. Incorporating ceramic waste into construction materials not only offers environmental benefits by reducing landfill waste and conserving natural resources but also provides economic advantages through cost-effective waste management and material production. This research explores the incorporation of ceramic waste into construction materials, emphasizing the enhanced durability properties like water absorption, Chloride test, UPV test, Electrical resistivity test, freezing and thawing test, drying shrinkage test and sulphate attack test of concrete and mortar mix while highlighting the dual benefits of improved material performance. The results of water absorption increases with ceramic amount increment, resistance to chloride ion rises to 20% replacement, drying shrinkage and electrical resistivity decreases with increase in amount of ceramic waste, freezing and thawing & sulphate attack showed that ceramic waste material used as aggregate increases, mass loss reduces due to freezing and thawing cycles and the amount of ceramic waste material used increases, compressive strength increases up to a certain limit when immersion in sulphuric acid solution.

Unlocking the application potential of superabsorbent polymers in landfill leachate treatment

The leachate generation is an inevitable consequence of landfill disposal, and thus it is critically important to acquire effective approach to preventing contamination of the underlying soils and groundwater aquifers. Currently, there is no consensus on the best approach; the biological treatment and the membrane technology are widely tested but each has its own drawbacks. On the other hand, superabsorbent polymers are nowadays widely used in many liquid-absorbing applications but have rarely been assessed for the application of landfill leachate treatment. In this study, a comprehensive analysis of the physicochemical parameters, ionic parameters, and trace elements of the collected leachate was carried out, and four commercially available superabsorbent polymers with different chemical compositions were tested in respect of their kinetics of adsorption and desorption, both load-free and under-load, in deionized water, tap water, and leachate, respectively. The results are of significant importance in elucidating the application potential of commercially available superabsorbent polymers in landfill leachate treatment.

Characterization of heat-processed artificial lightweight aggregates from polyethylene terephthalate plastic waste

Plastic waste is an undeniable source of pollution that threatens the existence of the earth’s flora and fauna. The bulk of plastic waste generated globally does not go through the proper methods of disposal but is carelessly discarded into the aquatic or terrestrial environment. Current recycling efforts are largely inadequate and disposal in landfills is still fraught with environmental and land use challenges. The proper disposal of plastic waste, as well as mitigating the environmental, social, and health impacts of extracting natural aggregates can be achieved by incorporating plastic waste as aggregates in the construction industry. This paper presents a characterization of aggregates manufactured from polyethylene terephthalate plastic waste using thermal/mechanical methods. From the cost analysis, 24,341.67 Ugx (6.09 USD) was spent to produce 1 kg of PET aggregates. Morphological, intrinsic and mechanical characteristics of the produced aggregates were established using standard procedures and equipment. The results of morphological characterization indicate an irregular shaped aggregate with smooth surface, a dense graded aggregate with a fineness modulus of 4.25, flakiness index of 26%, elongation index of 16% and particle index of 13. Intrinsic characterization yielded particle density of 1330 kg/m3, bulk density of coarse aggregates of 715 kg/m3 and water absorption of 0.445%. Mechanical characteristics of aggregates were evaluated, with compressive strength of 50Mpa, Aggregate Crushing Value of 37%, Ten Percent Fines Value of 71KN, Aggregate Impact Value of 24% and Aggregate Abrasion Value of 20%. The characteristics of PET aggregates confirm their suitability for application in structural lightweight concrete and rigid pavement. The produced PET aggregates can be considered in mix design as a total or partial replacement of natural aggregates in concrete.

Compressive behavior of concrete-filled FRP tubes with FRP solid waste as recycled aggregates: Experimental study and analytical modelling

The disposal and recycling of FRP (Fiber-Reinforced Polymer) solid waste pose significant challenges globally, with a recycling rate of less than 10 %. Current methods of handling FRP solid waste (FSW), including landfill disposal, incineration, chemical treatment, and thermal cracking, face limitations in achieving large-scale recycling and resource utilization. In civil engineering, FRP is widely employed for retrofitting structures and holds promise for new constructions. A new approach has emerged for recycling FSW by using it as aggregates in concrete, offering lower costs and reduced environmental impact. Research on using FSW aggregates in plain concrete shows that optimizing replacement ratios and aggregate shapes can enhance split tensile strength and toughness without significantly lowering compressive strength. To further improve the mechanical performance, this study investigated concrete-filled filament-wound FRP tubes with FSW aggregates (FSW-CFFTs) under axial compression. 35 specimens were tested to evaluate the influence of granular FSW aggregates (i.e., replacement ratio = 0 %, 20 %, 40 %, 60 %, and 80 %) and FRP thickness (i.e., 0 mm, 3 mm, and 5 mm) on their axial compression behavior. The experimental study revealed that: incorporation of FSW aggregates in unconfined concrete cylinders led to a notable decrease in Young's modulus and compressive strength, while concurrently increasing the peak compressive strain; as the replacement ratio of FSW aggregates increased, there was a tendency for the peak stress of FSW-CFFTs to decrease, while their ultimate axial strain tended to increase; compared FSW-CFFTs with unconfined concrete cylinders, the FRP confinement helped to mitigate the reduction ratio in axial compressive strength induced by the inclusion of FSW aggregates in the concrete, particularly at higher FSW aggregate replacement ratios; specimens with a thicker FRP tube exhibited higher secondary stiffness, along with higher strength and larger ultimate compressive strain. The modeling work indicated that accurately predicting axial stress-strain curves requires consideration of the bi-axial stress state of filament-wound FRP tubes.

Crystalline Phase Regulates Microbial Methylation Potential of Mercury Bound to MoS2 Nanosheets: Implications for Safe Design of Mercury Removal Materials.

Transition-metal dichalcogenides (TMDs) have shown great promise as selective and high-capacity sorbents for Hg(II) removal from water. Yet, their design should consider safe disposal of spent materials, particularly the subsequent formation of methylmercury (MeHg), a highly potent and bioaccumulative neurotoxin. Here, we show that microbial methylation of mercury bound to MoS2 nanosheets (a representative TMD material) is significant under anoxic conditions commonly encountered in landfills. Notably, the methylation potential is highly dependent on the phase compositions of MoS2. MeHg production was higher for 1T MoS2, as mercury bound to this phase primarily exists as surface complexes that are available for ligand exchange. In comparison, mercury on 2H MoS2 occurs largely in the form of precipitates, particularly monovalent mercury minerals (e.g., Hg2MoO4 and Hg2SO4) that are minimally bioavailable. Thus, even though 1T MoS2 is more effective in Hg(II) removal from aqueous solution due to its higher adsorption affinity and reductive ability, it poses a higher risk of MeHg formation after landfill disposal. These findings highlight the critical role of nanoscale surfaces in enriching heavy metals and subsequently regulating their bioavailability and risks and shed light on the safe design of heavy metal sorbent materials through surface structural modulation.

Compressed stabilised earth block synergistically valorising municipal solid waste incinerator bottom ash and sisal fiber: Strength, durability and life cycle analysis

Compressed stabilized earth blocks (CSEB) represent an eco-friendly substitute for traditional building materials, predominantly utilizing earth. Municipal Solid Waste Incineration Bottom Ash (MSWIBA) is a by-product of municipal waste treatment that can be creatively repurposed in construction projects. This research explores integrating MSWIBA as a substitute for Earth in CSEB production to conserve natural resources and repurpose waste, potentially reducing its landfill disposal. The sisal fibers (SF), often regarded as by-products of agricultural processes, offer an intriguing research material. The SF was treated with a 5 % NaOH alkaline solution to improve the CSEB bonding, increasing the flexural strength. The study aims to determine the optimal mix of stabilizers, in addition to a 10 % cement content, using various percentages of MSWIBA (10–40 % by weight of dry sand) and SF content (0.25–1 % by weight of dry soil). These blocks undergo comprehensive tests to determine their strength and durability. Wet and dry compression, flexural tests and indirect tensile tests were used to assess strength qualities, while wetting-drying cycles and acid exposure were used to determine durability. MSWIBA replaces 20 % sand in CSEB satisfying the strength. However, exceeding this amount increases void content and lowers strength, emphasizing the importance of balanced proportions for best performance. The 20 % MSWIBA and 0.75 % SF combination enhanced the compressive strength by 6.45 MPa, flexural strength by 0.92 MPa and water absorption by less than 18 %. The durability test displayed increases in compressive strength of 14.7 % and flexural strength of 93.48 % and optimized water absorption rate. Furthermore, microstructural analysis has been performed on CSEBs and the results highlight the importance of balanced cement and SF proportions for structural integrity. Life Cycle Analysis (LCA) investigation shows that construction costs using CSEB are 12.24 % higher than those with FCBs. Additionally, the study suggests that CSEB with MSWIBA and SF will be an environmentally sustainable construction material, considering factors such as energy usage, Global Warming Potential, and other environmental considerations

Geopolymer Materials from Fly Ash-A Sustainable Approach to Hazardous Waste Management.

This study explores the utilisation challenges of fly ash from municipal waste incineration, specifically focusing on ash from a dry desulphurisation plant (DDS), which is categorised as hazardous due to its high heavy metal content. The ash's low silicon and calcium contents restrict its standalone utility. Laboratory investigations initially revealed that geopolymers derived solely from fly ash after flue gas treatment (FGT), in combination with coal combustion fly ash, exhibited low compressive strength (below 0.6 MPa). However, the study demonstrated significant improvements by modifying the FGT ash through water leaching. This process enhanced its performance when mixed with high-silica and -aluminium fly ash, resulting in geopolymers achieving compressive strengths of up to 18 MPa. Comparable strength outcomes were observed when the modified ash was blended with commercial cement. Leachability tests conducted for heavy metals (HMs) such as copper, zinc, lead, cadmium, and nickel indicated that their concentrations fell below the regulatory limits for landfill disposal: 2, 4, 0.5, 0.04, and 0.4 mg/kg, respectively. These results underscore the effectiveness of water-washing FGT ash in conjunction with other materials for producing geopolymers, contributing to sustainable waste management practices.

Concrete with Accelerated Naturally Carbonated Recycled Concrete Aggregates

Recycled concrete tends to be increasingly investigated with respect to the environmental needs, such as resource depletion, circularity and lack of landfill disposal spaces. A naturally accelerated carbonation procedure by using atmospheric CO2 concentration level and a cyclic wetting and drying of the recycled concrete aggregates was applied. A two stages carbonation process was applied. The recycled concretes exhibited similar mechanical properties of the reference concrete or even better durability as compared to the reference concrete prepared with natural rock aggregates. The carbonation of the outer layer of the recycled concrete aggregates was achieved with a simple method that can be widely applied and is sufficient to significantly increase the properties of the recycled concrete aggregates.

Eco-friendly, lightweight, and high-strength sandwich corrugated particleboard from tea oil camellia (Camellia oleifera Abel.) shells

This study investigates the potential of developing corrugated panels from tea oil camellia shell (TOCS), an abundant agricultural waste in the southern provinces of China, with an annual production of approximately 4 million tons, using experimental and computational methods. Hence, various corrugated geometries were designed using AutoCAD software, and finite element analysis (FEA) was conducted using Ansys Mechanical software to optimize the panel geometry based on TOCS engineering data. Bending performance simulations revealed that a trapezoidal geometry with a 3 mm edge radius exhibited superior bending performance. Therefore, this geometry was selected to fabricate corrugated panels of different densities to assess the impact of density variation. Mechanical characterization included evaluation of bending stiffness, maximum moment, total deflection, compression strength, ultimate strength, dowel bearing strength, and face screw resistance of the panels was performed. Furthermore, specific energy absorption and failure mechanisms of mechanical tests were analyzed. The results indicate that TOCS-based sandwich panels, characterized by their lightweight and sustainable nature, not only meet, or exceed the criteria specified in APA PS 2–10 for use as structural materials but also mitigate the environmental hazards associated with landfill disposal or burning of agricultural waste.

Preparation of Al-doped carbon materials derived from artificial potassium humate prepared from waste cotton cloth and their excellent Cr(VI) adsorption performance

Millions of tons of cotton textile waste are generated annually worldwide, and most of it enters the municipal solid waste (MSW) stream for landfill or incineration disposal, resulting in a significant waste of resources and environmental pollution. This article developed an innovative low-temperature pyrolysis process for producing artificial humic acid (HA) from waste cotton textiles. Subsequently, Al3+ was introduced for a secondary pyrolysis to prepare an Al-doped biochar (Al/BC) with superior adsorption properties. The experimental results show that the presence of Al3+ has an important influence on the pyrolysis process of cotton fabric and the formation and structure of Al/BC. This is the first time to synthesize low-cost adsorbent by pyrolysis and aluminum mixing process of waste cotton cloth and explains the mechanism. This increased in defects (ID/IG = 0.76 to ID/IG = 0.92), a larger specific surface area (6.47 m2/g to 566.94 m2/g), and an increase in oxygen-containing functional groups (from none to C-O-C, OC-O, etc.) when compared to the undoped Al3+ biochar. The optimum Al3+-doped biochar (Al/BC-15) prepared with HA as a precursor exhibited a superior adsorption capacity for Cr(VI) of up to 176.23 mg/g, surpassing the results reported for similar materials in the literature. The adsorption mechanism of Cr(VI) is primarily based on physical adsorption, with some chemical adsorption. At a lower pH, the Al/BC-15 surface exhibits a high positive charge (46 mV). The Al3+-O-Cr(VI) association group is formed through rapid electrostatic attraction between C-Al and Cr(VI). Due to the strong positive electronegativity of Al3+ and the negative electronegativity of C in the vicinity of Al, Cr(VI) is further reduced to Cr(III) by C-Al. Therefore, the method proposed in this paper for preparing Al-doped carbon materials from waste cotton fabric offers a new approach and potential application for the production of high-performance adsorbent materials from waste cotton fabric.

Life cycle assessment of alternative pulp mill sludge treatment methods in Finland

Proper management of wastewater treatment plant side streams in pulp and paper mills is a matter of great interest. This study evaluates the environmental impact of different strategies in the management of biosludge from pulp and paper mills in Finland through a Life Cycle Assessment methodology. The base industrial standard practice, biosludge incineration for energy recovery and ash landfill disposal (Scenario 1), was compared to the alternative process of hydrothermal carbonization. The hydrochar generated from hydrothermal carbonization was evaluated for energy recovery through incineration (Scenario 2), or for use in composting for nutrient recovery (Scenario 3). The results showed that the hydrothermal process improved the overall environmental performance of the sludge management, particularly in terms of energy consumption and greenhouse gas emissions. The use of hydrochar as a soil amendment in composting also resulted in a significant reduction on the environmental impact compared to the other two scenarios. Overall, this study highlights the potential of hydrothermal carbonization and hydrochar utilization as sustainable options for managing biosludge from pulp mills.

Insect Biodegradation of Plastic: A Review

Plastic poses a persistent threat to various ecosystems and organisms due to its prolonged environmental existence. Traditional methods of managing plastic waste, such as landfill disposal and chemical treatments, have proven environmentally harmful. Despite the recognition of insects as potential agents for plastic degradation, the practical application of this concept remains limited. While the exact mechanisms of insect-mediated plastic breakdown are not fully understood, utilizing insect larvae for this purpose offers advantages such as cost-effectiveness and minimal secondary pollution. This review aims to comprehensively analyze recent research on plastic degradation by insects and microorganisms, shedding light on the processes involved and exploring the potential applications, challenges, and future directions in plastic biodegradation.

Indoor paint life cycle particle release: Safer-by-design products and the importance of choosing the right formula

In 2020, the European Commission published a regulation that states all producers of white paints containing titanium dioxide (TiO2) must provide a warning label on their products. Exposure during the production and application of products containing TiO2 can be harmful, and therefore these products must be labeled as “may cause cancer.” The paint industry is a major user of TiO2 pigment. This study focuses on pigment release from three TiO2-based paints and discusses the effect of paint formulation, more precisely the Pigment Volume Concentration (PVC), to predict TiO2 pigment release from the paints during a simulated use phase and at the end of life (EoL). The use phase considered mild abrasion of painted panels that simulated cleaning or touching. The EoL phase was studied using leaching tests simulating landfill disposal. TiO2 release during both activities was evident with a high discrepancy between the three paints. While dry rubbing was similar for all paints, activities involving water present a high release link to paint matrix degradation. The paint pigment volume concentration and the paint permeability determines the TiO2 release during wet rubbing and leaching. This work represents an attempt to identify the paint permeability as a matrix-related parameter to predict TiO2 release and a way to use of this parameter to develop safer products.

Preparation and application of alkali-activated cementitious materials in solidification/stabilization of chromite ore processing residue.

Chromite ore processing residue (COPR) is a typical hazardous waste, which contains Cr(vi) and poses a great threat to the ecological environment and human health. In this study, solidification/stabilization (S/S) of COPR was carried out by using blast furnace slag (BFS) and fly ash (FA) to prepare alkali-activated cementitious materials (AACM). The influence of different factors (water glass modulus, liquid-solid ratio, alkali-solid content and curing temperature) on compressive strength was investigated by single-factor experiment. Additionally, solidification effect of AACM was determined according to the compressive strength and the leaching concentration of chromium (Cr(vi) and total Cr). According to the optimal conditions of the single-factor experiment, the highest compressive strength of 147.6 MPa was obtained after using the water glass modulus 1.0, liquid-solid ratio 0.28, alkali-solid content 8%, curing temperature 45 °C. The COPR was solidified in the AACM sample having highest compressive strength. The solidified body still has a good mechanical property (38.2 MPa) with 60% addition COPR. According to leaching tests, the leaching of Cr(vi) and total Cr of solidified body with 50% COPR was far lower than the limit value, which met the purpose of construction and landfill disposal. X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis proved that heavy metal chromium was solidified in AACM by physical and chemical means.