Search Results (94)

This study investigates whether the optimal utilization of the biomass potential contained in municipal solid waste (MSW) can support the implementation of circular economy (CE) principles and contribute to climate policy objectives, particularly the reduction in greenhouse gas (GHG) emissions in the waste management sector. The analysis evaluates whether waste-to-energy recovery can support the objectives of the European Green Deal, including a 55% reduction in GHG emissions by 2035 and the achievement of climate neutrality by 2050. The assessment was conducted for two MSW streams generated in a Polish municipality: separately collected biowaste and residual MSW remaining after meeting European reuse and recycling targets. The study summarizes the results of detailed experimental investigations of the physicochemical and fuel properties of these waste streams. Proven and commercially available energy recovery technologies, including anaerobic digestion (AD) of biowaste and incineration of residual waste, were analyzed. GHG emissions were assessed using a life cycle assessment (LCA) approach, taking into account both direct emissions and avoided emissions resulting from the substitution of conventional energy and fertilizer production. The experimental results revealed significant variability in the biodegradability and energy potential of individual biowaste fractions, with the highest biogas yields observed for kitchen waste. Residual waste exhibited a considerable calorific value and a significant share of renewable energy due to its biomass content. The results indicate that the share of renewable energy in electricity generated from waste is expected to increase from 46.1% in 2025 to 49.9% in 2040. In relation to the total electricity demand of the analyzed city, energy recovered from waste accounts for 1.8 ± 0.3% in 2025 and 1.3 ± 0.2% in 2040. Scenario-based modeling demonstrated that the target system, maximizing energy recovery from both biowaste and residual waste, achieves a consistently negative GHG emission balance throughout the analyzed period (2025–2040), ranging from −72 ± 15 kg CO₂-eq/ton in 2025, through the most favorable value of −81 ± 17 kg CO₂-eq/ton in 2035, to −57 ± 12 kg CO₂-eq/ton in 2040, expressed per ton of total managed biowaste and residual waste. Full article

In this study, phenol adsorption from aqueous solutions was investigated using a carbonized adsorbent derived from a 1:1:1 mixture of banana, carrot, and potato peels, representing a major fraction of municipal bio-waste in Serbia. The material (CARB_BCP) was characterized by pH_pzc, SEM, FTIR, and BET analyses. The results indicated a highly porous structure with developed micro- and mesoporosity and a high specific surface area (S_BET = 483 m²/g). FTIR confirmed the formation of a stable aromatic carbon structure, while the high pH_pzc value (10.55) suggested a limited role of electrostatic interactions. Adsorption experiments performed at an initial phenol concentration of 1858 mg/L, room temperature, and an adsorbent dose of 0.1 g achieved a removal efficiency of 20.5%. The Langmuir model provided the best fit, indicating monolayer adsorption, with good agreement between theoretical (≈187 mg/g) and experimental (≈190 mg/g) capacities. Kinetic analysis followed the pseudo-second-order model, suggesting chemisorption as the rate-controlling step. The adsorption mechanism was mainly governed by π–π interactions, hydrophobic effects, and hydrogen bonding. These results demonstrate that CARB_BCP, derived from biodegradable waste, is a promising low-cost adsorbent for wastewater treatment. Full article

This study proposes and tests an analytical framework for interpreting digitally monitored municipal biowaste collection services through comparable diagnostics of operational performance, additional effort, and emissions intensity. The framework was applied to 572 collection services recorded between July and December 2025 in the Municipality of Barreiro, Portugal, covering seven circuits operating under different urban morphologies and collection configurations. Service-level operational records were transformed into physically interpretable performance indicators and an additional operational effort index was derived from robust normalization of serviced container density and service time per kilometer. The results showed marked heterogeneity across service regimes, with the highest effort observed in residential circuits characterized by greater spatial and temporal demand, while the non-domestic and communal circuits remained at or below municipal reference conditions. At the municipal scale, operational effort was moderately associated with mass collected per kilometer (ρ = 0.490, n = 572), weakly and non-significantly associated with mass per hour (ρ = 0.075, p = 0.074), and negatively associated with mass per container (ρ = −0.325). For services operating above municipal reference conditions (Eesf > 0, n = 286), emissions intensity was negatively associated with both effort components and with the aggregate effort index, with the strongest association observed for Eesf (ρ = −0.554). The results indicate that higher operational effort tends to coincide with greater spatial mass recovery, but not with higher container-level yield or proportionate improvements in emissions performance. More broadly, the study shows that the analytical value of digital monitoring depends not only on data availability, but also on the ability to convert routine service records into interpretable diagnostics for municipal decision-making. Full article

The concepts of circular economy increase the need to recycle bio-waste. Effective implementation requires knowledge about associated risks and environmental concerns. This study examines the composition and heavy metal content of bio-waste from municipal waste in western Poland, considering waste type, location, and season. Food waste constituted 36.7% to 47.6% of the total bio-waste, while garden waste accounted for 35.8% to 52.8%, with a strong seasonal dependency. Impurities such as plastics and glass were significant issues for urban and multi-family houses (16.6%), whereas rural and single-family home bio-waste had much lower impurity levels (10.0%). Heavy metals were identified in bio-waste, with the highest concentrations found in inedible food and garden waste. The ecological risk and cumulative effects of heavy metals were assessed using the contamination factor (CF), pollution index (PI), Nemerow Pollution Index (NPI), potential ecological risk index (Ef), and potential toxicity response index (RI). Urban bio-waste exhibited slightly higher levels of heavy metals and impurities compared to rural bio-waste. Zinc was the most abundant heavy metal, while cadmium had the lowest concentration. A seasonal pattern was observed, with winter bio-waste showing the lowest heavy metal concentrations. The results indicate that, despite localized elevated ecological risks, bio-waste recycling can be considered a conditionally safe waste management strategy, although localized and fraction-specific ecological risks, particularly related to cadmium and chromium, were identified. Full article

Separate collection and treatment systems for municipal solid waste (MSW) are designed to support efforts in sustainability. Biowaste accounts for the majority of MSW; thus, its proper management is essential. This study analyzes the impact of the presence of composting or anaerobic digestion (AD) facilities on MSW management. The management systems in Poland with composting and AD facilities were compared. Five fractions, including mixed/residual waste and biowaste, were collected in the analyzed regions; however, the rules for sorting biowaste varied. A drop in the collected residual/mixed MSW was noticed (by 3.8% to 6.6% year-on-year), while the biowaste stream increased, resulting in a 4–10% increase in the share of biowaste. The proportion of the organic fraction in biowaste was found to be 85–88%, but the proportion of food waste was slightly higher in the region with an AD facility (by about 3%). Plastics were the primary contaminants, accounting for approximately 5.5%. The presence of AD facilities has a positive impact on MSW management, including higher biowaste collection levels (67.5 kg per person versus 48.1 kg per person). Furthermore, under comparable regional conditions, economic gains were observed, such as relatively lower gate fees for biowaste (about 57 EUR per ton versus about 62 EUR per ton) and greater differences in fees between biowaste and residual/mixed MSW (about 80 EUR per ton versus about 14 EUR per ton). Full article

Slovakia’s biomethane production potential represents up to 10% of Slovakia’s natural gas consumption, which is largely unexploited. The aim of this paper is to develop a model of each available technology (continuous, dry batch, and wet batch) as well as that of a biogas treatment unit and evaluate the energetic, economic, and environmental potential of building a new anaerobic digestion plant in Slovakia, considering four plant locations with feedstock abundance within a 30 km perimeter. Feedstock composition and availability, energy integration, and product usability are evaluated. The applied multi-criteria decision analysis (MCDA) considers four evaluation criteria: return on investment (ROI), CO₂ emissions production, potential industrial biowaste revenue, and municipal density within the operational region. Biogas plant deployment analysis yielded the Levice facility as top-ranked, primarily due to its minimal environmental impact and superior logistical performance, closely followed by the Žilina, Michalovce, and Prešov facilities. When comparing biomethane production facilities, the Levice plant was excluded due to economic infeasibility, and the Žilina facility emerged as the optimal choice, particularly due to its superior ROI performance and the largest biomethane production potential of over 1 million m³ biomethane per year. Thus, biomethane station deployment in Slovakia has proved feasible and can enhance the energy self-sustainability of the country and contribute to meeting the decarbonization goals. Full article

This study examines the relationship between income and municipal waste generation within the Waste Kuznets Curve (WKC) framework, with a focus on selected disaggregated household waste fractions (paper and cardboard, glass, bulky waste, and biowaste). The aim is to assess whether increases in earnings per capita are associated with non-linear waste dynamics once spatial interactions and local socio-demographic characteristics are taken into account. The study employs a spatial panel dataset for 378 Polish counties over the period 2017–2024. Fixed-effects panel models, supplemented with random-effects panel models with Mundlak’s approach, are estimated alongside spatial panel specifications. Control variables include population ageing, urbanisation, and tourism, while spatial effects are decomposed into direct and indirect impacts. The results indicate that, in non-spatial models, an inverted U-shaped relationship between earnings and waste generation is observed for most waste fractions. However, once spatial dependence is explicitly incorporated, income effects weaken. In contrast, demographic structure—the share of retirement-age population—emerges as a robust and spatially persistent determinant of waste generation. Urbanisation and tourism exert only a limited influence across waste fractions. The paper advances WKC research by using spatial econometric methods and disaggregated waste fractions at the county level. The evidence suggests that conclusions about income-driven waste decoupling are sensitive to spatial dependence, emphasising the need for locally tailored waste management strategies. Full article

Anaerobic co-digestion of agro-industrial and municipal biowastes can enhance methane production, but the optimal mixture depends on nonlinear interactions among substrates. This study evaluated swine wastewater (SW), cheese whey (CW), and the organic fraction of municipal solid waste (OFMSW) under mesophilic batch conditions to quantify composition–response relationships and identify a robust operating window. A restricted simplex-centroid mixture design was tested; linear, quadratic, and special cubic models were fitted and evaluated using ANOVA, diagnostic plots, and optimization with desirability mapping. Cumulative methane yield (CMY) ranged between 251 and 295 NmL CH₄ g VS⁻¹ in the mixtures, outperforming SW as single component. All mixtures maintained neutral pH and moderate alkalinity ratios. The special cubic model provided the best performance (high R² and R²pred) and revealed significant ternary interaction. The optimization indicated a composition near 63% SW, 10% CW, and 27% OFMSW with a predicted CMY of 300 NmL CH₄ g VS⁻¹; a high-performance band (desirability 0.90–1.00; corresponding to CMY ≥ 294.8) defined a robust window of ~60–66% SW, 6–20% CW, and 20–31% OFMSW. Overall, balanced ternary co-digestion showed synergistic effects beyond additive expectations, and the response surface model based on mixture design proved effective in capturing interactions and providing flexible guidance for practical implementation. Full article

The water sector faces a dual challenge: reducing energy consumption and carbon footprint while improving wastewater treatment efficiency. Anaerobic digestion (AD) remains the primary method for energy recovery in wastewater treatment plants (WWTPs). To enhance methane production and move toward carbon neutrality, co-digestion of sewage sludge with external substrates is gaining attention. This study evaluated nine organic substrates for their methane potential using the standardized Automatic Methane Potential Test System (AMPTS). The highest methane yield was obtained from sediment from a wine tank, reaching 1387 NmL CH₄/g VS, followed by yeast slurry, with 524 NmL CH₄/g VS. These values were over 6 and 2.5 times higher, respectively, compared to the methane potential of conventional mixed municipal sludge. Apple pomace, whey, food biowaste, and herbal maceration waste showed moderate improvements (301–388 NmL CH₄/gVS). When considering methane yield per gram of wet substrate, herbal maceration waste was the most efficient. A techno-economic analysis revealed that this substrate consistently achieved a net-positive energy balance (up to 170%) in large WWTPs, even at transport distances of 50 km. Other substrates also showed high potential, covering nearly 100% of energy demand under optimal conditions. In contrast, whey showed limited applicability due to transport constraints. These findings highlight the importance of substrate selection, particularly in practical efforts aimed at achieving energy self-sufficiency in wastewater treatment plants. It also provides WWTP operators with clear and practical insights into enhancing methane yields from anaerobic digesters while minimizing the risk of process inhibition. Full article

Enhancing plant nutrient use efficiency, yield, and quality without compromising sustainability remains a critical challenge in agriculture. Utilization of materials such as biowaste derivatives as alternatives to conventional agrochemicals (e.g., fertilizers, biostimulants) can be leveraged to optimize crop productivity and resilience while adhering to sustainable practices. A soluble bioproduct (BP), isolated from the hydrolysis of anaerobic digestates derived from organic residues of urban waste, was examined for its capacity to enhance tomato (Solanum lycopersicum) production and quality. Five basal fertilization treatments were applied: conventional (CF), conventional/organic (CF + OF), bioproduct at 150 kg ha⁻¹ (BP), and conventional/BP at 150 and 300 kg ha⁻¹ (CF + BP, CF + 2BP), without or with supplementary fertigation (SF). The experiment was arranged in a Randomized Complete Block Design. Intermediate plant growth under BP was comparable to CF, while their combination enhanced growth parameters. However, addition of BP to CF did not affect final plant growth, biomass, and yield compared to CF alone, though non-significant reductions of height (5.37%), leaf number (15.89%) and fresh weight (36.09%) were observed with BP alone. The same treatment reduced intermediate leaf macronutrients (N, K, Na), whereas this was ameliorated with CF + BP. The use of BP without fertigation enhanced final P content in leaves and roots. However, fruit P declined, reflecting delayed P availability and translocation. The use of BP induced plant stress responses, accompanied by stimulation of phenolic and antioxidant accumulation in leaves, with fruit exhibiting comparable increases only without fertigation. Fruit lycopene and total soluble solids were enhanced by CF + BP, with fertigation mediating differences. Combined CF and BP application promoted tomato fruit quality, without diminishing growth, while the performance of BP alone was improved with supplementary fertigation to maintain tomato growth, yield, and quality. Full article

In the circular economy framework, municipal wastes are seen as secondary raw materials that can be used to fertilize agricultural soils. This study assessed the effect of different biowaste and green waste treatment schemes on P fertilizer value to learn about the optimal valorization of these feedstocks. The wastes were used either fresh, after composting or anaerobic digestion, or as biochars produced at various pyrolysis conditions. The fertilizer value was determined from the change in soil concentration of plant-available P (P_CAL) in incubation experiments with different soils and the temporal dynamics of fertilizer-induced growth and P accumulation of ryegrass in a pot experiment with eight harvests. The mode of waste treatment significantly influenced the P fertilizer value in the incubation and in the pot experiment. In the incubation experiment, the amendment-induced P_CAL increase varied between 22% and 33% of applied P on low-P acidic soil and between 55% and 88% of applied P on high-P acidic soil, whereby the amendment effects were mainly determined by their effects on soil pH. In the pot experiment with low-P acidic soil, the apparent P recovery in the plant biomass (APR) varied between 2% of applied P for fresh green waste and 42% for fluid digestate. The amendment effects on APR were not related to soil pH but to the P_CAL supply with the amendments and amendment effects on soil P supply. Our data show great potential for increasing the P fertilizer value of organic municipal waste materials through appropriate processing prior to application. Full article

The transition to a circular economy requires effective food waste (FW) collection and recycling systems. This study aims to evaluate general public attitudes, behaviours, and systemic challenges related to FW sorting in Latvia, in light of the recent mandate for separate biowaste collection. The study covers two important sections—assessment of the amount of FW generated in primary production sectors, and a pilot case study of biodegradable waste sorting in selected households in Latvia. A mixed-methods approach was used, combining a nationwide survey of 458 entities involved in primary food production and 115 households, followed by 99 households with backyards voluntarily participating in a pilot case study to evaluate their BW management practices. The research findings reveal that there is a need to establish a precise/specific framework for the evaluation of FW for each sector; the development of appropriate coefficients would facilitate the process of estimating waste generated by primary production in the future. Research findings revealed that inhabitants are interested in home composting; however, the implementation of home composting requires active support from project implementers, including increasing environmental awareness and providing financial incentives. These results offer practical insights for municipalities and national stakeholders aiming to increase biowaste collection rates and support country-level broader sustainability goals. The research results have practical application with the possibility to replicate the best practices and recommendations to other countries or regions within the EU and beyond. Full article

The present article examines the relationship between the changing residential net floor area of residential units in Warsaw, driven by ongoing urban growth, and the spatial requirements for household municipal waste collection. Analyzing 20 years from 2003 to 2023 across 18 districts of Warsaw, this article examines how the interplay between building morphology, demographic structure, and municipal waste generation influences the spatial and infrastructural requirements for separate collection. The study panel regression and volume simulations were applied to assess these dynamics. The results demonstrate that the number of residents per unit is the strongest predictor of waste generation, while the effect of floor area is less robust but still relevant. Waste generation per unit increased by 20% during the study period, accompanied by a sevenfold rise in plastics and a nearly eightyfold increase in biowaste, which together impose growing spatial burdens on households and collection infrastructure. The study emphasizes the significance of integrating waste infrastructure planning with housing design, considering the urban areas’ heterogeneous and evolving nature (identified at the district level). In the transition to a circular economy, the results highlight the need for locally sensitive strategies that link everyday household waste management with systemic urban sustainability goals. Full article

Municipal solid waste (MSW) management is identified as a significant sustainability concern. Source segregation (SS) is the most effective method of managing MSW, and anaerobic digestion (AD) is the most efficient treatment method. The aim of this study was to analyze the impact of waste collection rules on the efficiency and performance of AD. The potential biomethane yields for SS-kitchen waste and SS-biowaste were calculated, determined in laboratory tests, and verified full-scale. The content of the organic fraction in SS-biowaste reached about 81 to 86%; however, regarding SS-kitchen waste, it reached almost 92%. The primary contaminants were plastics. The obtained biogas yield was slightly higher for SS-kitchen waste (136.2 m³/ton), compared to SS-biowaste (116.6 m³/ton). The pH values, acidity, and alkalinity indicated no risk of exploitation using both feedstocks. However, in the case of SS-kitchen waste, the acetic acid content was about 2.5 times higher than that of SS-biowaste. Furthermore, the acetic acid was noted in the outlet section (about 140–160 mg/kg), indicating no complete organic matter decomposition. Regarding SS-kitchen waste, the calculated methane yield reached 137.1 m³_CH4/ton and laboratory tests showed a methanogenic potential of 129.7 m³_CH4/ton, while at full-scale, it reached about 82.2 m³_CH4/ton. The research confirmed that the SS of biowaste positively impacts MSW management by improving waste composition and increasing recycling possibilities. AD is an effective biowaste treatment process, allowing energy recovery from waste. Full article

Given the increasing volume of selectively collected bio-waste and the requirement to increase waste treatment system energy efficiency, dry anaerobic digestion (DAD) represents a more sustainable choice for the treatment of municipal organic fraction instead of conventional technologies. The current paper provides an overview of the existing knowledge on DAD of green waste or kitchen waste collected selectively. Key substrates characteristics (chemical composition, methane potential), novel reactor design and process conditions relevant to effective digestion at elevated dry matter content are considered. Of special interest is the process intensification techniques, impact of contamination and co-fermentation opportunity with other biodegradable wastes. This article also discusses energy and economic performance of DAD plants and puts their environmental burden in perspective versus other bio-waste treatment processes. The current legislation and DAD’s role in the circular economy are also considered. Selectively collected biowaste has significant energy potential and dry anaerobic digestion is an effective technology, especially in areas with limited water availability, offering both waste volume reduction and minimized energy losses. The aim of this work is to introduce the potential of this technology as a sustainable option within the context of renewable energy and modern waste management. Full article