Waste

In this study, two independent comparative Life Cycle Assessments (LCAs) were conducted to evaluate the environmental performance of food waste prevention interventions under real supply chain conditions. The first assessed a retail-level price discount intervention (PDI) for sub-optimal tomatoes implemented by an online fresh produce retailer in Spain, while the second assessed a shelf-life allocation optimisation intervention (SLOI) for yogurt implemented by a Danish dairy manufacturer in collaboration with two wholesalers. Both studies followed the ISO 14040/44 standards, adopted an attributional framework, and applied the Environmental Footprint (EF) v3.1 method across 16 midpoint impact categories, comparing each intervention against a baseline reflecting conventional practice. The PDI achieved a 98.6% reduction in unsold tomatoes ending up as waste, lowering upstream cultivation demand by 6.7% per functional unit (1 t of tomatoes sold by retailer) and key impact categories by 6.7–7.1%, with tomato cultivation identified as the dominant hotspot (60–99% of total impacts). The SLOI reduced overproduction by 76% and total yogurt output by 5.9% per functional unit (1 t of yogurt supplied by wholesalers), resulting in a 94.6% reduction in factory waste and 18.8% reduction at the wholesale level. Environmental impacts decreased by 5.8–6.7%, with milk production as the dominant hotspot (88–99% of total impacts). No burden-shifting effects were observed, and sensitivity analyses confirmed the stability of results. Overall, both case studies showed that food waste prevention interventions, whether implemented at retail or supply chain levels, consistently reduced upstream environmental burdens per unit of product delivered. Full article

The production of volatile fatty acids (VFA) through acidogenic fermentation of organic waste is a promising strategy for resource recovery in circular bioeconomy systems, especially in those conditions where efficient resource utilisation is imperative, such as in future lunar missions. In this study, in collaboration with the Italian Space Agency, the organic waste conversion was investigated to produce VFA-rich effluent obtained under optimal conditions represents a promising potential feedstock for future downstream applications, such as photofermentative hydrogen production, although downstream biological validation was beyond the scope of the present study. In this experimental work, a synthetic mixture of organic waste and waste-activated sludge was fermented across varying organic loads (20–50 g_TVS/L) with and without zeolite, supplemented as an ammonium absorbent. Results showed that VFA production increased with organic loads, with the highest volatile fatty acid yields observed at 40 g_VS/L. Keeping the organic loads constant at 40 g_VS/L, zeolite addition further enhanced volatile fatty acid concentrations in a dose-dependent manner, reaching a maximum at 15 g/L and 20 g/L; the highest yield was obtained at 30 and 40 g_VS/L with 15 g/L, reaching a peak of 0.8 g_COD/g_VS. Zeolite addition reduced the ammonia conversion by about 6% at OL 40 and 50. Full article

This study proposes a conceptual framework to operationalize the transition from conventional, technical, and material-centric circularity to an inclusive socio-technical paradigm through the deployment of a Co-Creative Digital Process Twin (DPT) framework in Progreso, Hidalgo, Mexico. The primary objective is to bridge the gap between technocentric industrial applications and the socio-technical needs of developing regions, specifically by integrating informal waste pickers (pepenadores) into a formal circular economy ecosystem. The methodology is structured into three distinct stages: a systematic scoping review following PRISMA-ScR protocols to identify architectural gaps in the current literature; the generation of a conceptual framework and Business Model Canvas grounded in participatory design; and the formulation of Key Performance Indicators for future longitudinal testing. The results indicate a profound bias in existing digital twin research toward industrial automation, with a near-total absence of social inclusion mechanisms. In response, this study presents a multidimensional business model featuring service-oriented cooperative architecture. This system utilizes open standards (FIWARE, BPMN 2.0) and crowdsourcing platforms (Ushahidi) to maximize material recovery while ensuring socio-economic equity. This will need to be verified in future studies. A limitation of this study is its specificity to a single municipality with certain characteristics, which could hinder its immediate generalization to metropolitan areas. Furthermore, the success of the model could depend on basic digital literacy and a stable telecommunications infrastructure. Full article

Fermented fish residue (FFR) is a byproduct generated from the fermented fish industry and presents a significant opportunity for waste valorization into liquid organic fertilizer (OF). This study aimed to determine the chemical properties of FFR and its derived OF, along with the effects of OF application on soil chemical properties, nutrient use efficiency, and leafy vegetable growth. A field experiment was conducted in randomized complete block design with five treatments, including the application of inorganic fertilizer (IF) as the control and four OF to water dilution ratios (1:100, 1:200, 1:500, and 1:1000). Both FFR and OF were acidic with elevated amounts of nitrogen (N), electrical conductivity, and sodium (Na), but low levels of phosphorus (P), potassium (K), and toxic elements. Compared with the IF treatment, the OF application increases available iron (36–62 mg kg⁻¹) and the exchangeable sodium percentage to 3.2% in the 1:100 treatment, while lowering soil pH (5.8–5.9), exchangeable calcium (1.1–1.9 cmol kg⁻¹), and magnesium (0.28–0.39 cmol kg⁻¹). Plant Na concentration also increased from 4159 to 17,666 mg kg⁻¹ under OF treatments, with the highest concentration in the 1:100 treatment. The OF applied at higher dilution ratios (>500) significantly improved the partial fertilizer productivity (PFP) of N (7.2 t ka⁻¹), P (18.6 t kg⁻¹), and K (2.4 t kg⁻¹). Fresh biomass was approximately 88% lower under OF treatments than under IF. This indicates an enhanced nutrient use efficiency under lower nutrient input conditions. This improvement in nutrient use efficiency is accompanied by reduced fresh biomass and increased Na accumulation in plants, together with changes in soil Na-related properties, highlighting a trade-off between nutrient supply and potential salinity risk. These findings, therefore, suggest that FFR-derived OF when applied at 1:500 or greater has potential as a low-input fertilizer option. Full article

This study investigates the flow and economic valuation of recyclable materials across fifteen Secondary Transfer Stations (STSs) in Dhaka North City Corporation (DNCC), Bangladesh, with the aim of understanding how market dynamics influence material recovery and circular economy potential. Primary data were collected through field surveys, structured questionnaires administered to 50 waste workers, five waste dealers and five local traders. Recovered materials were classified into six major categories, paper, plastic, metal, glass, electronic waste (e-waste), and other materials with further sub-categorization, to capture price variations and material characteristics. The results reveal a highly differentiated recycling market, with prices varying by more than an order of magnitude across materials. High-value materials, including copper wire, scrap aluminum, scrap metal, and electrical wire, are consistently recovered, whereas medium-value materials such as HDPE, PET, polypropylene, PVC, LDPE, Styrofoam, plastic crates, and mixed plastics are recovered selectively depending on market demand. In contrast, low-value materials, including packaging cartons, white paper, glass items, mixed LDPE, damaged LED lights, and mixed wastepaper, are frequently discarded due to weak economic incentives. Despite spatial and socioeconomic differences across STSs, price variability remains relatively low, indicating an integrated city-wide recycling market driven by active trader networks and broader commodity trends. To the best of our knowledge, this is one of the first studies to integrate recyclable material flow with economic valuation across multiple STSs in Dhaka. The findings highlight that recovery efficiency is strongly governed by economic value and informal practices, with limited segregation efficiency and inadequate occupational safety conditions. Enhancing source segregation, improving storage infrastructure, and introducing targeted market and policy interventions for low-value materials are critical for advancing Dhaka’s transition toward a circular and resource-efficient urban waste management system. Full article

Fish scales are collagen-rich processing by-products with considerable potential as a sustainable source of non-mammalian gelatin. This study aimed to extract gelatin from Rohu (Labeo rohita) fish scales and comprehensively characterize its physicochemical, thermal, structural, rheological, textural and functional properties for potential food and industrial applications. Gelatin was extracted by acid demineralization followed by hot-water extraction and characterized using physicochemical analyses, Fourier transform infrared spectroscopy (FTIR), sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE), texture profile analysis (TPA) and functional property measurements. The extracted gelatin exhibited a yield of 21.86%, a protein content of 88.37%, an ash content of 1.5%, a gel strength of 182.82 g, a viscosity of 6.56 cP, a solubility of 87.49%, a melting temperature of 23.38 °C, a setting temperature of 20.4 °C and a setting time of 660 s. FTIR and SDS–PAGE confirmed the characteristic structural features of type I collagen-derived gelatin with well-preserved α₁, α₂ and β chains. The gelatin also demonstrated favorable water-holding capacity (169.70%), fat-binding capacity (188.50%), foaming capacity (193.33%) and foaming stability (77.65%), while emulsion capacity and stability increased with gelatin concentration, reaching 44.11% and 42.15%, respectively, at a gelatin concentration of 2.0%. These findings demonstrate the potential of Rohu fish scale gelatin as a sustainable, value-added non-mammalian biomaterial for food, packaging, pharmaceutical and related industrial applications while promoting the valorization of fish-processing waste. Full article

São Paulo is the largest city in Brazil and the second in Latin America. Its domestic waste production reached 3,515,678.96 tons in 2024. Historically, the city has a low recycling rate, and several laws and policies have been implemented to reverse this situation. The objective of this study was to investigate whether there have been advances in the recycling of household solid waste in São Paulo 15 years after the National Solid Waste Policy, from municipal and intra-urban perspectives. The extended period studied and segregated data by regional administration represent the innovative approach of this manuscript. The methodology consisted of a case study with an analysis of the legislation, official data research and evaluation of goals, and socio-spatial distribution. The separate collection rate grew from 0.69% in 2006 to 2.85% in 2024, but this volume represents less than 10% of the target originally projected for the period. A socio-spatial inequality was found as well as a lack of dedicated collection for the organic fraction. It can be concluded that progress is incremental, but limited by structural barriers and urban inequities. Results indicate for São Paulo and for other large cities, mainly in low and middle-income countries, recycling success cannot depend on legislation as it is also correlated with demographic factors, such as educational level, and to the need of targeted policies for a progressive increase in source-separated recycling. Full article

Urban development increases impervious surfaces and stormwater runoff, while the construction sector generates large volumes of construction and demolition waste (CDW). Pervious concrete can mitigate runoff through infiltration and may also valorize CDW, yet its production and testing procedures remain heterogeneous, particularly with recycled aggregates. This study experimentally screens practical processing parameters for pervious concrete produced with basalt and CDW coarse aggregates. The influence of chemical admixture, consolidation method, and end-surface preparation was first assessed to define suitable production conditions: adequate cohesion without admixture required raising the water-to-cement ratio from 0.30 to 0.65; high-energy Proctor compaction crushed the CDW aggregates, favoring standard tamping-rod consolidation; and end-surface preparation had only a minor effect on compressive strength. The selected procedures were then applied to an ACI 522R-based basalt mixture designed for a target void content of 25%, which achieved a fresh density of 1985 kg/m³, a void ratio of 16.88%, and a mean permeability coefficient of 12.18 × 10⁻³ m/s, about twelve times the minimum required by ABNT NBR 16416. Its 28-day compressive strength (12.75 MPa) remained below the 20 MPa pavement-surfacing requirements, although within the typical range reported by ACI 522R for pervious concrete (2.8 to 28 MPa). Overall, aggregate gradation, compaction procedure, and admixture-enabled paste cohesion emerged as the dominant factors governing the strength–porosity–permeability trade-off, guiding subsequent mix optimization. Full article

Automotive paint sludge (APS) is a hazardous industrial waste generated during automotive coating operations and is characterized by high moisture content, variable organic and inorganic composition, volatile organic compounds, pigments and heavy metals. Conventional disposal methods, including landfilling and direct incineration, present increasing environmental and regulatory challenges, thereby motivating interest in thermochemical conversion technologies for APS valorization and energy recovery. This review evaluates the current state of research on APS thermochemical conversion through incineration, pyrolysis and gasification pathways. The review compares the major operational characteristics of thermochemical pathways, including reactor conditions, temperature ranges, product yields, energy recovery potential, pollutant formation and downstream cleanup requirements. Also, techno-economic considerations such as drying energy demand and scale-up limitations are discussed. According to the current literature, incineration is the most industrially mature route for APS destruction, whereas pyrolysis offers more flexibility for fuel and material recovery. Gasification shows potential for syngas and hydrogen production but remains insufficiently studied for APS applications. Despite growing interest in APS valorization, a lot of research gaps remain regarding standardized feedstock classification, pilot-scale validation, process integration, environmental risk assessment and techno-economic optimization. Conclusively, future approaches towards managing APS would need to incorporate process optimization for specific APS types, incorporation of co-processing techniques, as well as an overall assessment for both environmental and economic feasibility. Full article

Conventional thermal disposal of chlorinated hydrocarbon (CHC) waste poses high risks of dioxin, furan, chlorine, and phosgene formation, while plasma destruction remains energy-intensive. This work determines the optimal thermodynamic conditions for the allothermal, non-catalytic steam—carbon dioxide gasification of various CHCs utilizing high-temperature detonation gases (2450–2850 K) expanded to atmospheric pressure to achieve non-toxic, valuable syngas and commercial-grade hydrochloric acid. Thermodynamic modeling ensures complete soot- and hydrocarbon-free conversion with 100% carbon conversion efficiency, dry syngas yield up to 5.7 Nm³/kg, and cold gas efficiency reaching 138%. For highly chlorinated (above 70 wt.% chlorine) or unsaturated feedstocks, a co-feeding method using external hydrocarbons (C₄H₈O₂ as an example) was validated to suppress the formation of major ecotoxicants like Cl₂, COCl₂, and C₂Cl₂. As for other chlorine-containing ecotoxicants, including highly toxic dioxins, their concentrations in the equilibrium gasification products remain negligibly small, even in the absence of dilution. Importantly, a solvent mass fraction of no more than 0.33 in the initial blend is sufficient to entirely achieve this toxic species suppression. For all considered CHCs (undiluted or diluted with C₄H₈O₂), chlorine is shown to bind exclusively to hydrogen chloride (HCl), with all hazardous emissions remaining below the conditional 1 ppm safety limit. To achieve this, a chlorine capture algorithm was substantiated based on the dissolution of generated HCl within the residual steam condensate or externally delivered water upon cooling the gasification products to 293 K. The proposed technology offers an efficient and environmentally safe alternative to expensive plasma methods for toxic organic waste disposal. Full article

Household food waste remains a huge challenge for solid waste management in municipalities worldwide, especially in the Global South. Existing studies that measure food waste (FW) in cities are scarce, have limited geographic scope, and have limited timeframes. In that direction, the current investigation provides data on the FW composition of nine regions of the municipality of Rio de Janeiro (Brazil), based on a three-year sampling across 155 neighborhoods. Waste samples were collected from 2021 to 2023. In total, about 24,038 kg (fresh weight) was analyzed. Results showed that FW accounts for an average of 47.7 ± 1.9% of household waste in the study period. The FW composition in the city of Rio de Janeiro ranged from 60.3–76.5% for fruits, vegetables, and salads, 15.0–25.1% for fine aggregate (small-sized food residues < 2.54 cm, like rice, beans, grains, and fragmented food particles), and 3.2–5.8% for proteins (discarded animal-based protein foods like chicken and meat). The chi-square goodness-of-fit test was applied to evaluate whether the FW composition in each of the nine regions differed from the mean FW composition of the Rio de Janeiro municipality. The findings revealed statistically significant differences (p-value < 0.05) in the average FW fractions in specific regions and years compared with the city’s average composition. Thus, one of the key takeaways of this investigation was that the percentages of discharged food waste fractions vary over time and across locations, even within the same municipality. The present research took a first step toward understanding the food waste problem in Rio de Janeiro (Brazil) and underscores the importance of monitoring food waste data to guide the development of locally specific strategies for sustainable urban food systems, including waste prevention, recycling, and food recovery. Full article

Brackish-water aquaculture provides important livelihoods for many coastal regions worldwide, but it also generates nutrient-rich wastewater that may cause eutrophication if untreated. The use of plants to absorb dissolved nutrients and convert them into harvestable biomass has become an important research direction in aquaculture wastewater management. This study evaluated the performance of Sesuvium portulacastrum L. grown on floating rafts placed directly on the water surface of 0.5 m³ plastic tanks used for Litopenaeus vannamei culture under controlled salinity conditions ranging from 5 to 25‰. During the 28-day experiment, plant growth, shrimp growth performance, plant nutrient accumulation, and nitrogen/phosphorus mass-balance partitioning were assessed. The results showed that S. portulacastrum grew well under brackish conditions, with stronger biomass production at salinities below 15‰, while shrimp growth performance was most favorable at 10–15‰. Nutrient analysis of harvested S. portulacastrum biomass showed that the plant accumulated 19,735–29,433 mg N kg⁻¹ DW and 1099–1912 mg P kg⁻¹ DW, indicating its capacity to recover inorganic N and P through harvestable biomass. At 10‰ salinity, the integrated system reached the highest apparent total nitrogen removal/recovery efficiency of 46.98%, calculated from system-level mass-balance partitioning rather than water-concentration reduction alone. The areal nitrogen recovery rate in harvested S. portulacastrum biomass reached 383 mg N m⁻² day⁻¹. Although S. portulacastrum is a salt-tolerant plant, higher salinity levels (≥20‰) reduced plant biomass production and nutrient recovery efficiency. These findings indicate that integrating floating-raft S. portulacastrum into brackish shrimp-culture systems at moderate salinity, particularly 5–15‰, is a feasible strategy for converting dissolved nutrients into harvestable plant biomass. Full article

This study examined the scale of informal metal recycling in the King Sabata Dalindyebo (KSD) Municipality and evaluated its socioeconomic and environmental impacts through a circular economy lens. While formal recycling programs have received research attention, informal recycling systems have been less examined despite their critical contribution. A mixed-methods approach was employed, combining quantitative surveys and material measurements with qualitative field observations. Data were collected through focus groups and surveys administered to 48 active recyclers operating along the N2 and R61 highways, supported by systematic field observations and quantification of all recovered materials. The results showed that steel and aluminum were the most recovered metals at 41.7% and 20.8%. Recyclers collected an average of 15.3 kg/day (SD = 4.2) during periods of high material availability and accessibility and the materials are close to market points. The study underscores the socioeconomic and environmental impacts of informal recycling within the circular economy framework, with most participants (85.42%) indicating that recycling was a significant livelihood while 74% cited difficulty transporting bulky materials, often manually. Therefore, the study emphasizes that informal recyclers play a vital role in sustaining the local economy by offering key waste management and resource recovery services. Acknowledge of these informal systems will contribute to a more inclusive understanding of waste management in developing contexts. Full article

Olive pomace is a major side stream originating from olive processing for the production of olive oil. This waste material bears a load of polyphenolic antioxidants, and thus it might serve as a source of precious phytochemicals. This work had as its objective the development of an extraction process for the efficacious recovery of polyphenols from dried olive pomace (dOP), employing eco-friendly extraction media. To this end, environmentally benign solvents were first compared for their efficiency in obtaining increased yields in total polyphenols, and 40% aqueous isopropanol was selected as the best-performing mixture. Further examination of the role of acidification showed that mineral acid addition (sulfuric, hydrochloric) had a rather negative effect on polyphenol yield. To the contrary, incorporation of oxalic acid into the solvent at a 10% level provided significantly higher extraction yield (p < 0.05), which reached 27.1 ± 1.1 mg caffeic acid equivalents (CAE) per g dOP. This solvent system (40% isopropanol/10% oxalic acid) was additionally scrutinized for its effectiveness by studying the role of process severity and response surface optimization. Out of both approaches, it was demonstrated that polyphenol extraction yield, but also antiradical activity, was directly correlated with residence time and temperature, within the limits tested. Moreover, a high correlation between polyphenol concentration and antiradical activity was also revealed. Liquid chromatography-tandem mass spectrometry analyses showed that the extract obtained with the solvent system used (40% isopropanol/10% oxalic acid) was characterized by the presence of both hydroxytyrosol and the flavone luteolin (242.1 and 178.6 μg g⁻¹ dOP, respectively), but, in the absence of isopropanol, the extract produced was largely dominated by hydroxytyrosol (4629.7 μg g⁻¹ dOP). Thus, it was concluded that the solvent system could fundamentally diversify extract composition. It is proposed that, when combined with integrated biorefinery technologies, this approach could effectively contribute to reducing environmental impacts while enabling the production of valuable natural antioxidants or platform chemicals that are vital for the food, pharmaceutical, and cosmetic industries. Within the broader context of sustainable food waste management, such strategies might be key elements of a circular economy framework. Full article

This review synthesizes current advances in the biocatalytic upcycling of plastic waste through microbial and enzymatic systems, emphasizing the transformation of recalcitrant polymers into high-value products. A narrative review methodology was adopted to integrate interdisciplinary findings across microbiology, enzymology, biotechnology, and waste management. Significant progress has been achieved in the depolymerization of plastics such as polyethylene terephthalate (PET), polyurethane, and polyolefins into intermediates, including terephthalic acid and ethylene glycol. These intermediates are subsequently valorized into products such as polyhydroxyalkanoates (PHAs), lipids, terpenoids, organic acids, aromatic compounds, and bacterial cellulose. Quantitative performance metrics demonstrate the potential of these systems. Notably, PHA production from PET-derived substrates has reached up to 1.10 g L⁻¹ (22.7% cell dry weight) and as high as 46% intracellular accumulation, while bacterial cellulose production from PET hydrolysates has achieved ~3.0 g L⁻¹. High conversion efficiencies have been reported in several pathways, including ~90–99% conversion of PET-derived intermediates to catechol, ~91.6% yield of glycolic acid from ethylene glycol (up to 31.4 g L⁻¹), and ~71–79% molar conversion of terephthalic acid to vanillin. Despite these advances, critical limitations persist, including low volumetric productivity in some systems, metabolic imbalances, substrate toxicity, feedstock heterogeneity, and challenges in process integration and scale-up. Future research should prioritize enhancing metabolic flux, improving enzyme efficiency, optimizing microbial consortia, and developing integrated, low-energy depolymerization–bioconversion systems. Full article

The activated sludge process is pivotal in wastewater treatment, with ongoing research into its process control methods. Modeling treatment plants aids in analyzing relationships among variables, supporting fault detection and operational decision-making. However, datasets from real-world treatment plants often contain outliers and missing values due to sensor faults, maintenance activities, and operational disruptions, making outlier handling and data imputation essential for reliable modeling. Existing studies on data imputation for activated sludge systems are often based on synthetic or short datasets, limited method comparisons, or inconsistent evaluation metrics, which reduces their applicability to full-scale operational settings. This study addresses these limitations by presenting a comprehensive, head-to-head comparison of Kohonen Self-Organising Maps (KSOM) with widely used multiple imputation and tree-based methods, namely Amelia II, MICE, missForest, and missRanger. The methods are applied to a real-world multivariate dataset comprising 19 process variables collected over 8.5 years from a full-scale activated sludge treatment plant, containing 39% overall missing data with highly uneven missingness across variables. A validation framework based on held-out observation data is used, and performance is assessed using complementary metrics, including the coefficient of determination (R²), average absolute error (AAE), relative average absolute error (RAAE), mean squared error (MSE), and root mean squared error (RMSE). Results show that KSOM consistently outperforms the competing methods across most variables and evaluation metrics. KSOM achieves near-perfect R² values (≈1) for many process variables, with lower absolute and relative errors, even for variables with very high (>70%) and irregular missingness. These findings highlight KSOM’s robustness in capturing multivariate relationships and cluster structure in complex, operational WWTP data. Full article

This paper describes the development of an automated solid waste sorting system that integrates advanced computer vision pipelines with a robotic manipulator for real-time classification and actuation. The system consists of a Deep Neural Network (DNN) and a YOLOv8-based perception module. Thedeveloped model is capable of accurately detecting and classifying objects with confidence scores exceeding 0.71, and the overall system attained a sorting accuracy of approximately 81.8% across multiple test batches. From an integration perspective, the coordination among the Intel RealSense camera, Raspberry Pi 5, Arduino Uno, ultrasonic sensors, relay-switching circuit, and SCORBOT-ER 4U robotic arm demonstrated reliable communication and execution, enabling accurate pick-and-place operations. Overall, the results confirm that the proposed system provides a functional and scalable proof of concept for automated waste segregation in controlled environments. The study highlights that while current performance is sufficient for low-speed applications, further improvements in dataset diversity, perception robustness, mechanical gripping, and feedback control are necessary to achieve higher accuracy, reliability, and industrial applicability. Full article

Rambutan peel, an abundant agro-industrial by-product, is a rich source of ellagitannins (ETs) and represents a promising substrate for the sustainable production of ellagic acid (EA) through solid-state fermentation (SSF). This study aimed to optimize EA release from rambutan peel ETs by SSF using Saccharomyces cerevisiae 227 in column reactors. We applied a central composite design (CCD) to evaluate and optimize the effects of temperature, NaCl concentration, and peptone supplementation on EA production. We also used HPLC/ESI/MS to identify and quantify EA. Maximum EA yields were obtained under central experimental conditions (treatments 15 and 16: 35 °C, 0.53 g/L NaCl, and 8 g/L peptone), reaching 8.36 ± 1.58 and 8.23 ± 0.52 mg/g, respectively. The predictive model estimated a maximum EA production of 8.29 mg/g, experimentally validated, at 34.6 °C, 0.58 g/L NaCl, and 8.26 g/L peptone, yielding 8.27 ± 0.47 mg/g. HPLC/ESI/MS analysis further confirmed EA formation and the presence of biodegradation products derived from geraniin and corilagin, indicating effective ET biotransformation. These findings establish optimized conditions for EA production from rambutan peel ETs via SSF and demonstrate the feasibility of implementing a sustainable bioprocess for the valorization of this agro-industrial residue. Full article

The growing generation of household hazardous waste (HHW) presents critical environmental and public health challenges worldwide. This study investigates prevailing trends in HHW management and analyzes the socio-economic and demographic determinants that influence public perceptions, attitudes, and behaviors toward HHW recycling practices. A comparative mass flow analysis is also conducted to evaluate the limitations of current HHW management practices in Greece and outline policy implementation plans. Statistical findings indicate that income significantly influences recycling behavior. Individuals with annual incomes between €10,001 and €30,000 are less likely to engage in HHW recycling, whereas those earning over €70,000 demonstrate higher levels of recycling participation. The public recognizes the need for green collection points for appropriate HHW management. However, no statistically significant correlation is found between income levels and perceived importance of these facilities. This outcome is attributed to the high proportion (46.7%) of dichotomous variables in the χ² independence test, exceeding the recommended threshold of 25%, which limits interpretability. Such findings indicate the complex interplay of behavioral and socio-economic variables in HHW recycling. The study highlights the importance of targeted public policies, educational interventions, and infrastructure improvements to increase recycling participation and promote sustainable HHW management in Greece. Full article