Waste Management & Research: The Journal for a Sustainable Circular Economy

The increasing demand for sustainable radiation shielding solutions has prompted a transition from traditional materials such as lead and cement-based concrete towards environmentally friendly alternatives. Despite their effectiveness in radiation shielding, traditional shielding concrete faces challenges such as toxicity, high cost and environmental degradation. This literature review examines the potential of agricultural waste materials (AWMs) as partial substitutes in cement-based concrete composites for radiation shielding applications. Agricultural residues such as rice husk, sugarcane bagasse and coconut shell exhibit pozzolanic properties and offer mechanical benefits, improved durability and enhanced radiation attenuation capabilities. The article examines the key physical and chemical properties of various AWMs, highlighting their potential to improve concrete strength and shielding performance against gamma and neutron radiation. In addition to mechanical and shielding characteristics, the environmental and economic ramifications of AWM reuse are evaluated, including reductions in carbon footprint and waste management benefits. The article also identifies challenges like standardization issues and the requirements for long-term durability data, highlighting how AWM-integrated concrete can be a feasible, cost-effective and sustainable solution for contemporary radiation shielding, supporting the objectives of the circular economy and green building.

Effective liner materials must be installed in landfills to prevent leachate leakage. Traditional liner layers are typically composed of compacted clay (CCL) or geosynthetic materials (or a combination of both). Due to limited clay resources in many areas and the relatively high cost of geosynthetic materials, landfill managers are seeking suitable alternative materials. In recent years, geopolymer materials (GPMs), as an environmentally sustainable soil modification material, have become a candidate for landfill liner materials due to their ability to significantly enhance the engineering properties of soil and their excellent adsorption performance for various pollutants. This study evaluates data from existing literature and assesses the suitability of geopolymer-modified soil as landfill liners based on three factors: strength, permeability and adsorption performance. The study results indicate that the strength of geopolymer-modified soil exceeds 200 kPa, meeting the requirements for landfill liner layers; The permeability coefficient k of geopolymer-modified soil decreases with increasing geopolymer content and curing age. As the geopolymer content increases and the curing time extends, it meets the minimum requirement of 1 × 10⁻⁷ cm s⁻¹ specified by the U.S. Environmental Protection Agency (EPA) for landfills. Geopolymers have good adsorption effects on a variety of pollutants. Among them, the removal rate of heavy metal ions generally exceeds 90%, and the removal rate of organic dyes generally exceeds 80%. This mini-review provides a reference for the selection of landfill barrier materials and the assessment of the long-term safety of barrier layers.

Rapid urbanisation and population growth have increased the demand for glass as a building material, but its environmental friendliness is questioned partly due to the lack of recycling. The production of flat glass is energy-intensive and contributes to significant greenhouse gas emissions, while the raw materials used are finite resources. This research article explores the challenges and opportunities for recycling flat glass in the construction sector in Sweden. Despite its ability to be endlessly recycled without degradation, flat glass is rarely recycled and often ends up in landfills. Barriers to circular handling of flat glass include economic imbalances, high transportation costs and lack of collection and sorting facilities. The research was conducted using a qualitative case study approach, including a workshop and semi-structured interviews, to identify registers of valuing flat glass recycling. The results highlight the different roles of glass, its economic and ecological values and the tensions between different registers of valuing glass. Understanding these values and tensions can contribute to more precise measures for integrating flat glass into a circular economy and valorisation of post-consumer flat glass.

Knowledge of the true social benefits of pro-environmental activities is limited due to the difficulty of evaluating and quantifying the non-market benefits of such actions. Valuing non-marketed compost benefits and impacts is difficult because they do not have market prices, as they are not bought and sold (i.e. traded) in markets. This article fills this gap by quantifying the non-market benefits of compost use in agriculture. As an initial contribution, this study applied revealed preference methods to quantify the economic values of important non-marketed compost benefits to plant and soil systems in tree and shrub nursery production. The estimated benefits were compared for compost produced using two windrow composting methods, namely: aerobic or thermophilic composting and fermentative or static pile inoculated composting. Specific compost benefits considered included: (i) medium in potting soil mix; (ii) Nitrogen Phosphorus and Potassim (NPK) nutrient supply; (iii) improved nursery plant yield/performance; (iv) disease, pest and weed control and (v) reduced branch pruning. Total economic value, aggregated for the compost benefit types considered, was lower for thermophilic compost applied (CAD$192 per tonne per year) than for fermentative compost (CAD$385 per tonne per year), due to lower fermentative compost production cost. Among the compost benefit types considered, improved nursery plant yield and performance accounted for the highest proportion of quantified benefits; 75% of total economic value for thermophilic compost and 93% for fermentative compost. Further studies considering all important compost benefits beyond those considered in this study, and compost use in other agricultural production systems will be useful.

Industrial waste salts, laden with toxic organic impurities, pose significant environmental hazards. Thermal treatment has emerged as a promising strategy to reduce these contaminants. However, previous studies have focused on total organic carbon removal. Still, this work utilizes advanced two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOFMS) and pyrolysis gas chromatography-mass spectrometry (PY-GC/MS) to provide unprecedented detail on the release and transformation pathways of specific organic groups (aromatics, nitrogenous, halogenated, etc.) in pesticide waste salts. This study investigates waste salts under medium-temperature conditions (400–500°C) in inert and oxygen-containing atmospheres. Results indicate that under an oxygen-containing atmosphere, the removal rate surpassed 99% within 20 minutes at 400 and 500°C. Oxygen-containing conditions significantly improve the removal efficiency but leave more complex organic residue in the treated salt, which retains nitrogen-containing compounds, aliphatic hydrocarbons and oxygenates. Organic impurities follow distinct transformation pathways: volatile P-xylene produces styrene, ethylbenzene and benzaldehyde; nitrogen-containing compounds (e.g. amines) form complex nitrogen- and oxygen-containing products; and halogenated compounds cleave into shorter-chain halogenated derivatives. These findings offer crucial insights into the thermal behaviour of organic contaminants in waste salts and guide the further treatment process of waste salts.

Previous studies have investigated the critical factors influencing waste separation intention (WSI). However, it is essential to examine how individuals, particularly in ethnically diverse countries with WSI – and among them, those who have experienced adverse health effects from solid waste, referred to here as ‘ready victims’ (RVs) – prioritise capacity-building and inducement policy tools in resource-constrained rural settings of developing countries. This cross-sectional study collected data from 1,345 Punjabis and 1,214 Pashtuns, the two major diverse ethnicities in Pakistan. Controlling for socio-demographics, the binary logistic regression results indicate that Punjabis with WSI were more inclined to favour Internet of things-connected separate waste bins, the establishment of recycling plants, composting centres, civic education and awareness, economic incentives, and public praise. They were less inclined towards door-to-door waste collection, financial penalties, and waste charges than their counterparts who had no intention of waste separation. Pashtuns with WSI showed a stronger preference for recycling plants, composting centres, waste-to-energy (WtE) plants, civic education and awareness, economic incentives, and public praise compared to their counterparts who had no intention for waste separation. In comparison to ‘ready non-victims’ (RNVs) within the Punjabi ethnic group, RVs exhibited a greater preference for door-to-door waste collection, WtE plants, and civic education and awareness initiatives. RVs from the Pashtun ethnicity showed a loweress willingness to accept the establishment of composting centres and waste charges compared to their RNV counterparts; they demonstrated a heightened preference for recycling facilities and civic education and awareness. The study suggests that cultural and health diversity should be considered when designing waste management policies in resource-constrained rural areas.

This study assesses operational and financial performance, as well as social and labour aspects, of 12 material recovery facilities (MRFs) in 4 Brazilian regions, using monthly data from 2024. An analytical framework consisting of 13 metrics was developed to evaluate productivity, costs, revenue and labour indicators. Statistical analyses were conducted to explore the relationships between these metrics and their effects on MRF outcomes. Results reveal significant variability in productivity across facilities, with a negative correlation between processing costs and productivity, but no direct link to revenue generation, suggesting external market influences. Rejection rates ranged from 10.07% to 42.38%, with moderate effects on productivity. The cost per mass processed varied significantly, from 11.13 to 41.08 USD tonne⁻¹, with an average of 23.63 USD tonne⁻¹. Financially, only two MRFs achieved over 70% self-sufficiency, with most relying on external subsidies. Labour costs dominated operational expenses. Worker turnover ranged from 17% to 81%, negatively impacting costs and efficiency. The study also explores revenue models and their influence on operations and concludes that MRF sustainability requires not only operational improvements but also innovative financing models, including service fees, public-private partnerships and extended producer responsibility mechanisms. Policies addressing technical efficiency, social equity and revenue stability are crucial for strengthening MRFs. The findings offer insights for similar contexts in developing countries, and the metrics and indicators proposed can be viewed as operational key performance indicators that can be applied globally to assess MRF performance in diverse settings, offering a valuable tool for future studies and standardising performance evaluation.

People are usually not aware of returning their unused or expired medicines or not ready to practice pharmaceutical waste management (PWM) safely. The present research aimed to explore Malaysians’ awareness, readiness and practice (ARP) on safe and sustainable PWM. The research was conducted from April 2023 to April 2024 among 318 randomly selected people having unused or expired medicines. A cross-sectional survey was conducted with a semi-structured questionnaire. Exploratory factor analysis was performed sequentially among ARP domains. Reliability of research instrument was checked with Cronbach’s alpha. Correlation among ARP scores was analysed with Pearson’s correlation, and generalized linear model was performed to analyse statistical relationships of outcome variables with various predictors. Data were analysed in SPSS 29.0 considering p-value <0.05 statistically significant at 95% confidence interval. A total of 112 (35.2%) respondents had good awareness, but 176 (55.3%) had sub-optimum readiness and 130 (40.9%) had sub-optimum practice level in terms of safe and sustainable PWM. Though there were positive and significant correlations (p < 0.001 in all) between awareness and readiness (r = 0.339), readiness and practice (r = 0.414) and awareness and practice (r = 0.420), their strengths were small. It means the aware people may also not be ready to practice safely. Hence, policymakers should encourage people’s participation in managing pharmaceutical wastes effectively. The present research has implications on Sustainable Development Goal 12, that is, rational consumption and production by its exploration of people’s ARP constructs on safe and sustainable PWM.

The use of thermal hydrolysis (TH) in the treatment of biosludge has several significant benefits, such as increased biogas generation. However, this advantage is limited by the production of recalcitrant compounds, which increase the complexity of waste management and subsequent treatment stages. It has been observed that certain undesirable processes can lead to the formation of these recalcitrant compounds during the TH of biosludge, generating compounds such as melanoidins resulting from Maillard reactions, caramelization products, soluble lignin derivatives and potential inhibitors, which can be detected mainly in the liquid phase. The detection and monitoring of the increase in these compounds by easily applicable variables and tests are crucial for process optimization. This study focused on the generation of recalcitrant compounds during the TH of sludge from the effluent treatment of the Kraft cellulose industry. Indirect quantification methods, such as the measurement of absorbance at certain wavelength characteristic of compounds such as soluble lignins (205 nm), melanoidins (420 nm) and humic-type compounds (254 nm), have been employed. Increases of up to 15 times in the absorbance at 420, 254 and 205 nm were recorded with the application of TH compared with those of the untreated samples. However, no known inhibitors, such as hydroxymethylfurfural or furfural, were found. An increase in soluble organic nitrogen and residual postdigestion chemical oxygen demand was observed, which was related to the severity of the thermal treatment, suggesting significant correlations among the analysed variables.

The dynamic properties of mechanically biologically treatment (MBT) waste are vital for the seismic design of landfills. This study employs a centrifuge shaking table to experimentally investigate the behaviour of MBT waste using sinusoidal and Taft waves. The results reveal the following key findings: (1) MBT waste exhibits a certain degree of dilatancy under low confining pressure. (2) The natural frequency range of MBT waste is determined to be 1–7 Hz, with pronounced resonance effects observed at frequencies of 1.506, 2.97, 4.028 and 6.226 Hz. (3) The dynamic amplification factor decreases with increasing peak ground acceleration (PGA), ranging from 1.024 to 1.506. (4) For the same waveform, the equivalent shear modulus decreases with higher PGA, while for identical PGA, the equivalent shear modulus is greater under Taft wave than sinusoidal waves. (5) The excess pore water pressure (EPWP) ratio declines with increasing burial depth, and liquefaction does not occur at any of the monitoring locations. (6) The EPWP ratio increases with strain, and an empirical relationship between the EPWP ratio and shear strain is proposed. (7) A comparative analysis is conducted between the EPWP ratio of MBT waste under shear strain, and the experimental results reported in previous studies. These findings provide a valuable reference for the dynamic-stability analysis of MBT waste landfills.

This study investigates the impact of adding residual ashes in anaerobic co-digestion of olive mill wastewater (OMWW), poultry manure (PM) and cheese whey to boost methane production. It evaluates the effects of olive pomace bottom ash, slaughterhouse waste incineration bottom ash and biochar on methane yield. These specific biomass ashes are utilized for the first time in anaerobic digestion. Experiments were conducted in two phases: (1) anaerobic digestion of agro-industrial waste and (2) effect of ash and biochar on anaerobic digestion. Kinetic models including Logistic function (LF), Modified Gompertz (MG) and Reaction curve-type were used to analyse production dynamics. The results revealed that the optimal substrate ratio was the one with highest content of OMWW (60%) that produced 447.5 mlCH₄ gVS⁻¹. Second phase showed the highest methane yield of 688.5 mlCH₄ gVS⁻¹ from slaughterhouse ash at 0.75g gVS⁻¹, followed by 612.5 mlCH₄ gVS⁻¹ with biochar at 0.50 g gVS⁻¹. In contrast, olive pomace ash generally yielded lower methane production compared to control, likely due to high chloride content and potential polycyclic aromatic hydrocarbons. MG and LF explain better the experimental data. The findings underscore the potential of anaerobic co-digestion to valorize agricultural and agro-industrial waste, advancing sustainable energy production and waste management strategies in alignment with circular economy principles.

Effectively addressing municipal solid waste (MSW) generation and management is critical to achieving sustainable development. As waste volumes grow and environmental pressures intensify, the need for effective strategies becomes increasingly urgent. In Portugal, more than half of MSW is still sent to landfill, despite national and European Union efforts to promote waste reduction and recovery. Identifying the main drivers of waste generation is essential to support evidence-based policies, guide infrastructure investments and accelerate the transition towards a more circular economy. This study analyses MSW generation across 23 Portuguese regions from 1995 to 2022, assessing economic, socio-demographic and policy drivers while accounting for the COVID-19 pandemic. Results show the strong influence of economic drivers (p < 0.001) in MSW generation while demographic variables show limited impact, except for population age. Tourism also contributes to regional waste generation, primarily due to interregional differences in tourism intensity. The COVID-19 pandemic increased MSW generation in the country (p < 0.05). Current policy instruments lack the strength or scope to influence MSW generation, reinforcing the need for more robust approaches. MSW generation is also strongly shaped by structural regional characteristics and year-specific conditions, with most variation explained by these factors, while the included predictors capture additional within-region differences. Overall, the findings underscore the importance of regional and temporal factors and emphasise the need for integrated, regionally tailored strategies to improve waste management and support sustainable policy development.

Solid waste management (SWM) remains a major environmental and public health concern of Southern cities as the urban population continues to increase, and consumption patterns change. Accra like many African cities is grappling with a challenge that was non-existent about six decades ago. Extant literature reveals that the macro SWM sector in Accra is inadequate for ensuring efficient and effective SWM service delivery. The challenge of SWM is compounded in the city’s open-air markets (OAMs), given the volume of waste generated as well as the intense competition for space by traders and investors within the context of limited planning and solid waste infrastructure. Using a mixed methods approach, this study set out to examine SWM practices which are relevant in reducing flows of urban market waste (through reuse and recycling), reclaiming SWM cost and ensuring efficient SWM service delivery. The findings reveal a coexistence of multiple SWM practices in each of the surveyed OAMs, which further highlights how SWM practices are complex, dynamic and socio-spatially uneven. Finally, it calls on city authorities to pay attention to the current and emerging practices of SWM in OAMs and offers recommendations for future improvements.

There is currently no publicly available, scientifically sound data on solid waste generation in German hospitals, which is one reason why the implementation of circular economy initiatives on this subject has so far been largely unsuccessful. Therefore, this study aims to conduct a nationwide field study on waste generation in German hospitals. To this end, waste and structural data from 122 German hospital locations covering the 4 clusters of general hospitals, university hospitals, specialist hospitals and other hospitals in all 16 German states were collected in 2024 and statistically analysed. A total of 103,432 Mg of waste from these hospitals was documented, of which around 9% was hazardous and 1.4% infectious. The results show strong correlations between waste generation and staffing levels. Furthermore, differences between general and university hospitals were found for all eight key performance indicators examined. Based on the results, a differentiated extrapolation model for the mass of waste from German hospitals, which uses the number of beds as a reference value, is proposed.

Tourism-related waste generation poses a significant environmental challenge, particularly in ecologically sensitive areas. This study investigates the quantity, composition and associated carbon emissions of solid waste generated by tourists over four weekends at Lata Sempeneh, Batu Kurau, Perak, Malaysia. The waste characterization was conducted following the Malaysian Standard MS 2505:2012 for household solid waste composition, whereas greenhouse gas emissions (methane (CH₄) and carbon dioxide (CO₂)) were estimated using the Intergovernmental Panel on Climate Change (IPCC) 1996 mass balance methodology. The average waste generation rate was found to be 0.174 kg per capita per day, with an estimated 259 tourists visiting the site each weekend day. Food waste constituted the majority (63.92%) of the total waste, indicating a significant potential for CH₄ generation if landfilled. The average carbon emission attributable to tourist-generated waste was estimated at 0.138 kg CO_2-eq per capita per day. Scenario analysis demonstrated that diverting 50% of food waste through composting could reduce this number by nearly half, to 0.069 kg CO_2-eq capita per day. This study highlights the practical sustainable waste management strategy for tourist-generated waste in natural recreational areas like Lata Sempeneh. Unlike conventional disposal methods, this approach not only diverts organic waste from landfills, thereby significantly reducing carbon emissions but also promotes resource recovery by transforming food waste into compost, which can benefit local agriculture or landscaping efforts. Such a localized, circular intervention tailored to tourist hotspots in Malaysia remains underexplored and adds a practical dimension to sustainable tourism management.

The agricultural sector is a major source of environmental pressure due to excessive chemical inputs and mismanagement of crop and orchard residues. The circular economy offers a pathway to close resource loops through waste recycling and valorization. This study integrates the Theory of Planned Behavior and the Norm Activation Model to examine the psychological and behavioural drivers of agricultural and horticultural waste recycling among farmers in western Iran – one of the country’s most important agricultural regions. A stratified sample of 384 farmers completed a culturally adapted and pilot-tested questionnaire. Partial least squares structural equation modelling revealed that recycling intention is significantly predicted by attitudes (β = 0.34), personal norms (β = 0.41), subjective norms (β = 0.07) and perceived behavioural control (β = 0.05). Recycling behaviour is shaped by intention (β = 0.25) and perceived control (β = 0.12), but a notable intention–behaviour gap (Q² = 0.055) suggests structural and contextual barriers. The findings underscore the interplay of social influence, moral obligation and individual agency in shaping pro-environmental practices. The study offers targeted policy and extension recommendations, including participatory training and infrastructure support, to advance rural circular economy practices.