λ Bioplastics are reviewed with focus on anaerobic biodegradation behavior.
λ Abiotic and biotic factors influencing anaerobic digestion are systematically analyzed.
λ Pretreatment methods enhance bioplastic degradation and methane production.
λ Additives can hinder biodegradability and cause microplastic formation.
λ Sustainable use requires tailored processes and next-generation bioplastic feedstocks.
In recent decades, the rate of construction and demolition (C & D) waste has risen due to urbanization, population growth, and large construction projects like roads, bridges, etc. Utilizing recycled coarse aggregate (RCA) as a sustainable material in concrete helps to preserve natural resources, and reduce landfill waste and construction costs. Making use of RCA has a negative impact on the mechanical properties of concrete. Because, RCA tends to absorb more water, and has lesser density and crushing index than the natural coarse aggregate (NCA) due to the presence of old adhered mortar. Hence, the performance of concrete is degraded. In addition, RCA has a larger Interfacial Transition Zone (ITZ) than conventional concrete which is the weaker zone of concrete. For better performance of recycled aggregate concrete (RAC) various techniques have been adopted for enhancing the quality of RCA. On the other hand, by strengthening old ITZ, between old mortar and NCA, and new ITZ, which is between RCA and new mortar, the mechanical and durability properties of RAC can be enhanced. The present study confers about the optimized parameters of various treatment methods adopted for RCA for efficacious process and their influence on the ITZ of RAC. From the discussions, it was formulated that the treatment methods make a significant impact on the ITZs, which results in a stronger RAC than an untreated RAC.
This study develops an innovative approach for phosphogypsum (PG) valorization through a two-stage calcination process to produce modified PG (MPG). The thermal treatment effectively eliminates residual acidic impurities while optimizing particle size distribution and phase composition, significantly enhancing the material’s cementitious properties. On this basis, a novel all-solid-waste cementitious material (PGSC) by integrating modified PG (50 wt%) with ground granulated blast-furnace slag (GGBS, 40 wt%) and steel slag (SS, 10 wt%) was proposed, where sodium hydroxide (NaOH) served as an efficient alkaline activator. NaOH activation facilitates the dissolution of silica-alumina phases from GGBS/SS, enabling synergistic formation of ettringite (AFt) and calcium silicate hydrate (C-S-H) gel through reaction with Ca2+ liberated from MPG. The PGSC with 2.00 wt% NaOH achieved remarkable 3-day and 28-day compressive strengths of 30.5 MPa and 56.8 MPa, respectively. Under hyperalkaline conditions, the excessive formation of AFt crystals compromised structural integrity, triggering microcrack development and consequent strength reduction. Microstructural analysis identified AFt and C-S-H gel as the dominant hydration phases, whose interpenetrating network architecture governed the macroscopic mechanical behavior. This work provides a high-efficiency solution that addresses solid waste recycling, demonstrating significant potential for developing eco-friendly cementitious materials with industrial byproducts.
This study explores the synthesis and application of hydroxyapatite nanoparticles (nHAPs) derived from eggshell waste as a sustainable alternative to chemically synthesized nHAPs, with a focus on agricultural applications. Using techniques such as SEM, EDX, FTIR, and XRD, the eggshell-derived nHAPs were found to exhibit a more uniform size distribution and higher calcium content compared to their chemically synthesized counterparts. Hydroxyapatite (HAP), a calcium phosphate compound, is increasingly recognized for its potential as a nanofertilizer in promoting sustainable agriculture. The synthesis of nHAPs from eggshells involves cleaning, drying, calcination, and chemical transformation, offering a cost-effective approach compared to chemical synthesis, while still allowing for controlled particle size and composition. Both types of nHAPs were functionalized with natural humic substances (HS) to enhance their efficacy as fertilizers. A comparative study using chilli plants as a model showed that those treated with eggshell-derived HAP exhibited accelerated growth and flowering, with 50% flowering achieved within 40 days. These findings highlight the potential of eggshell-based nHAPs as plant growth enhancers and sustainable agricultural inputs, addressing challenges in both agricultural productivity and waste management to support an eco-friendly future.
This study addresses the significant concern of contaminated soil resulting from oil leakage and explores the influence of indirect heated microwave thermal desorption technology on geotechnical properties. Geotechnical engineers increasingly worry about the repercussions of hydrocarbon-induced soil pollution on infrastructure stability. This research aims to fill a gap by investigating how the thermal treatment process affects soil characteristics and functions. Soil samples from a railway subgrade construction site were subjected to varying temperature conditions (300, 450, and 600 °C) and treatment durations (5, 15, and 30 min) to remediate diesel-contaminated soil with a 10% TPH (Total Petroleum Hydrocarbons) concentration. The findings encompass changes in particle-size distribution (PSD), shear strength parameters (cohesion and internal friction angle), maximum dry density (MDD), and the California bearing ratio (CBR) for natural, diesel-contaminated, and thermally treated silty sand (SM). Significantly, the results underscore the effectiveness of precise control of heat exposure duration in minimizing soil degradation during oil-contaminated soil remediation. In conclusion, this study provides invaluable insights into the geotechnical properties of railway subgrade soil when treated with indirect heated microwave thermal desorption technology, offering a highly promising approach to effectively address oil-contaminated soil issues and safeguard infrastructure stability.
Anaerobic digestion is a key technology for treating organic waste, but high total ammonia nitrogen (TAN) concentration can cause ammonia inhibition, impacting system stability and biogas production. Ammonia stripping is an effective solution that prevents inhibition and recovers nitrogen. The study is a narrative review that examines the ammonia inhibition threshold and evaluates various stripping methods, including pre-treatment, post-treatment, in-situ, and side-stream stripping. The applicability and efficiency of these methods were compared, with a focus on in-situ and side-stream stripping for nitrogen recovery and inhibition alleviation. Through analysis of the ammonia inhibition threshold, the TAN concentration in the digester has been controlled below 5 g/L, which may effectively avoid ammonia inhibition risks. From an economic standpoint, there is no need for further reduction. This significantly improves the feasibility and cost-effectiveness of in-situ or side-stream ammonia stripping technologies. Furthermore, this study discussed the optimization of ammonia stripping parameters from the perspectives of ammonia inhibition threshold, differences in protein, uric acid, and carbohydrate degradation, which have rarely been described in previous literature. In-situ and side-stream ammonia stripping are also affected by anaerobic digestion conditions, reactor configuration, and digestate composition, which restrict the ammonia removal efficiency. It is necessary to achieve effective matching between fermentation conditions and stripping processes. Advances in stripping technology are expected to enhance its role in anaerobic digestion, achieving environmental and economic benefits.
This research examines Rudrapur’s municipal solid waste management amid rapid urban growth. As the population increases, so does waste volume. Utilizing secondary data from the Rudrapur Municipal Corporation, the study analyzes waste generation, collection, management, and disposal, assessing waste composition and management variations across wards using ArcGIS mapping software. A Composite Z-score statistical technique was applied to evaluate the disparities in waste management among wards. Approximately 80–85% of MSW is collected, while the leftover garbage builds up in tiny open landfills or on the streets. Of the collected waste, 12% undergoes composting, currently the only treatment method, and 15% is recycled, while the remainder is disposed of in uncontrolled open landfills on the city outskirts. Advanced tools like Geographic Information Systems (GIS) and remote sensing offer potential improvements in waste management practices. The paper also discusses policies and initiatives proposed by the local government and Rudrapur Municipal Corporation to enhance the MSW management system.
Municipal solid waste characterisation is a crucial aspect of sustainable waste management, as it provides guidance on appropriate management approaches and promotes circularity. Spatial and seasonal MSW characterisation was conducted using the American Society for Testing and Materials (ASTM) methods, with samples from transfer stations in eight zones across monsoon, winter, and summer seasons analysed through physical sorting, proximate, and ultimate analyses. The organic (44%) and recyclables (33.5%) were the major constituents of MSW. Moisture content and volatile solids value peaked during the monsoon. Calorific values averaged 3417.8 cal/g. One-way ANOVA analysis results indicated significant seasonal variations in the composition of plastic, glass, organic, and inert wastes, whereas paper, metal, and textile wastes showed significant spatial variation in the study area. A carbon-to-nitrogen ratio (C/N) of 33:1 and a high-temperature range in the study area support biogas production. Waste-to-energy generation estimates showed that thermochemical conversion yields higher electrical power (18.79 MW) than biochemical conversion (8.3 MW). Landfill gas estimates revealed annual methane emissions of 38.56 Gg in the study area. The study’s approach and findings provide valuable insights that can inform policy reforms to improve waste management practices and serve as a baseline for other urban settings.
Accurate forecasting of lithium-ion battery (LIB) retirement volumes is critical for optimizing recycling infrastructure and supporting China’s circular economy. However, existing studies typically rely on sales-based models that overlook battery chemistry differences and replacement dynamics. To address these limitations, this study proposes a novel forecasting framework that integrates Triad Feature Selection, Support Vector Regression, and the Weibull distribution. Triad Feature Selection identifies the principal determinants—namely the NEV market penetration rate and GDP—by integrating grey relational analysis, Pearson correlation analysis, and LASSO regression. SVR is then used to predict battery installation capacity, while the Weibull model simulates retirement behavior over time. The model achieves superior accuracy (MAE: 2.91 GWh for NMC, 17.35 GWh for LFP; R2: 0.9915 and 0.9724, respectively) compared to benchmark models. Scenario analysis reveals that under the medium scenario, NMC battery retirements peak at 140 GWh in 2042, while LFP batteries, driven by strong policy incentives and significant cost advantages, are projected to reach 852.35 GWh by 2050. This disaggregated and scenario-based forecasting framework provides robust insights for targeted recycling strategies, policy formulation, and sustainable resource management, aligning with China’s 2060 carbon neutrality goal.
The continuous growth of the global population has led to a market rise in food waste (FW) generation, posing serious environmental and economic challenges. Improper and inadequate FW management negatively impact soil, water, and air quality, contributing to environmental degradation, and hampering economic progress. The conventional methods of managing FW, such incineration and landfilling, remain widely practiced, however, these practices often result in the release of harmful by-products, such as greenhouse gas emissions which undermine environmental sustainability. While current standalone conversion technologies, including gasification, pyrolysis, anaerobic digestion, hydrothermal carbonization, composting, and fermentation, have shown potential for energy recovery and resource valorization, they often lack integration and scalability. Nevertheless, these technologies still face limitations, such as incomplete waste conversion, low process efficiency, and the generation of toxic intermediates or inhibitors. To address these limitations, integrated valorization approaches should be adopted to enable the production of high-energy-yielding products, including solid biofuels (hydrochar), liquid biofuels (biodiesel), biogas (methane), and hydrogen-rich syngas. The successful implementation of advanced and sustainable food waste valorization strategies can play a pivotal role in realizing a circular bioeconomy and mitigating the global food waste crisis. Achieving this requires interdisciplinary collaboration among researchers, stakeholders, and policymakers to ensure strong alignment with the sustainable development goals.
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