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

Urban cleanliness plays a crucial role in public health, environmental quality and citizens well-being, also affecting cities resilience. However, assessing street cleaning performance objectively, to improve services and citizen’s health, remains a challenge. The present study was devoted to create a robust methodology to determine urban cleaning performance with Porto Municipality as reference. Streets were analysed before the cleaning operations and the disposed waste was characterised by typology and size as well as by the zone where it’s found. The study considered 11 waste categories and 9 city areas together with developed indicators. Waste quantification was conducted in 52 streets, with 783 samples and 116,780 m² monitored. Commercial/touristic and riverside areas were the cleanest, with cleanliness levels of 85% and 86%, respectively. Residential areas were the less clean, with cleanliness levels of 47% (social housing) and 54% (multi-family buildings), respectively. In residential and school areas, animal droppings were the most found category, corresponding to the highest annoyance level for the population, greatly affecting the streets’ cleanliness index. For Porto city, the cleanliness level obtained was 61%. According to the results obtained from 3,269 people surveyed, the cleaning status of Porto city has a score of 3.37 out of 5. Since the survey was conducted in the ‘lowest level of cleaning’, the results may be classified as good. The findings highlight the need for targeted cleaning strategies in lower-performing areas and demonstrate applicability for systematic urban cleanliness assessment. Future adaptations and optimisations could enable its use in broader contexts, supporting data-driven policymaking and improved urban management.

Large-scale religious events generate considerable amounts of solid waste calling for dedicated research to quantify wastage, explore its drivers, understand stakeholder perceptions and design effective management strategies. Responding to this call, this study investigated the generation of food and plastic waste during the 2023 Arba’een pilgrimage in Karbala, Iraq, one of the world’s largest annual religious festivals. A mixed-methods research design was employed combining quantitative waste audits, conducted over 20 days at selected mawkibs (volunteer-run foodservice stations) and municipal waste disposal points, with qualitative semi-structured interviews (n = 60) involving mawkib owners, pilgrims, religious leaders and municipal authorities. Audits revealed substantial waste: 7900 tonnes of food and 4000 tonnes of plastic. Per pilgrim, 0.36 kg of food and 0.18 kg of plastic were generated, accounting for 0.72% and 0.58% of Iraq’s total annual hospitality food waste and all-sectors-total plastic waste, respectively. Interviews explored such thematic areas as waste drivers, behavioural practices and responsibility attribution. Findings highlighted a ‘blame game’ dynamic between mawkibs and pilgrims regarding wastage. Religious leaders cited a moral tension, noting how observed excess in consumption contrasted sharply with Islamic values of modesty and resource conservation, while authorities stressed logistical constraints. This study provides novel empirical data, highlighting the complex interplay between traditional Islamic hospitality and sustainability. It outlines scope for waste reduction interventions, such as portion control at mawkibs and promoting alternative serving materials, such as bio-plastics, for future large-scale religious events.

Zimbabwe’s rapidly expanding tourism sector faces urgent sustainability challenges related to waste management, environmental protection, and reliable energy access that require innovative solutions. This research delves into the complex interplay among independent variables: food waste recycling, animal waste recycling, wood waste recycling, crop residue recycling, sewage sludge recycling, mediator: green tourism supply chain management and dependent variable environmental management and energy sustainability within the context of Zimbabwean tourism. A quantitative approach was employed, collecting data from 853 Zimbabwean tourism supply chain representatives using simple random sampling and the Krejcie and Morgan table, a method of determining the sample size. Questionnaires were distributed via Google Forms, and structural equation modeling was utilized for data analysis. The results reveal notable and positive relationships for both direct and indirect hypotheses, with each demonstrating T-statistics surpassing the 1.96 threshold, ranging from 2.204 as the minimum value to 7.802 as the maximum value. The quantitative results clearly demonstrate the environmental and economic benefits possible from sustainable waste, energy, and environmental management practices in Zimbabwe’s tourism industry. The projected reductions in emissions, waste, fuel usage, and costs provide tourism supply chain stakeholders with robust evidence to justify greater investments in green infrastructure and systems. By elucidating the sustainability improvements feasible, the findings equip policymakers with actionable data to shape policies, incentives, and public-private partnerships that accelerate the transition toward a more circular tourism economy.

The implementation of a metering and charging system for municipal solid waste (MSW) presents a promising policy avenue for source reduction. But few cities have applied the metering and charging system of MSW for residents in China. The aim of this study is to propose a metering and charging model of MSW for residents by taking Shanghai, a megacity expected to introduce the practice, as a case study. A metering and charging model of MSW for residents based on two-part tariff (MC-TPT) was proposed, which integrated the advantages of both fixed rate method and quantity-based method. The key parameters for MC-TPT model, as well as the economic feasibility were also considered. Results indicate that key parameters for MC-TPT model, including the average profit margin, average annual fixed cost and average annual operating cost, are estimated at 12%, 169.9 million RMB year⁻¹ and 716.5 million RMB year⁻¹, respectively. The pricing structure of two-part tariff comprises a fixed fee of 17.8 RMB month⁻¹ and a specific fee of 289.8 RMB (tonne·month)⁻¹. Furthermore, the study explores metering and charging criteria for MSW across five household population levels. Economic feasibility analyses reveal that, despite an increase in MSW disposal fees under the proposed scheme, the resulting relative charging rate remains within an acceptable range. This study contributes to the academic discourse on sustainable MSW management practices, particularly in the context of megacities like Shanghai.

Steel slag (SS), a by-product of the steel-making process, can serve as an alternative to high-carbon aggregates in urban road construction, thereby reducing the ecological burden associated with its disposal. However, most existing studies have not considered the greenhouse gas (GHG) emissions impact arising from governmental promotion of this alternative, and they lack systematic sensitivity analyses, leaving the results insufficiently validated. This study utilizes a Life Cycle Greenhouse Gas Emissions Assessment model to derive the carbon labellings for various urban pavement materials. It then evaluates the net carbon benefits and feasibility of using SS substitutes in China’s future urban transport infrastructure, within the context of current urbanization trends and relevant policies. Additionally, an embedded uncertainty analysis module is used to verify the reliability of the results. The findings indicate that while replacing natural aggregates in urban road pavements with SS leads to an increase in actual GHG emissions by approximately 3.11–4.97 kgCO₂e·m², it also generates additional carbon sequestration of 2.49–5.27 kgCO₂e·m², alongside recycling benefits of 10.40–15.99 kgCO₂e·m². Furthermore, when the proportion of SS pavements in urban reaches 80%, it enables urban road construction to achieve net-zero emissions, thereby transforming the potential threat posed by urbanization to the global climate system into an effective solution for mitigating climate change.

Graphical Abstract

In this study, waste polypropylene (PP) was pyrolysed together with marble processing industry effluents physicochemical treatment sludge (named as K1) catalyst, and the valuable component recovery and usage potential from resulting liquid and gaseous products were investigated. In the fixed bed pyrolysis reactor under inert conditions with N₂ gas, the studied experimental variables were temperature and mixing ratio. The resultant liquid and gaseous fractions were characterized via GC-MS, Fourier transform infrared, thermogravimetric analysis and calorific value analyses. Liquid products contain predominantly paraffinic and olefinic, but minor aromatic hydrocarbons (HCs) and also minor amounts of oxygenated compounds with 20–30% K1 catalyst. Heating values of the liquid products were around 10 kcal.g⁻¹. The gas products predominantly contain alkanes, alkenes and aromatic HC compounds with economic value such as benzene isotridecanol, heptanol, ketone and terpene. Ca and Mg carbonate structure of K1 catalyst increased the compound diversity in the pyrolysis gas, especially in the aliphatic groups. The detected low C number alkane compounds were pentane, heptane, cyclohexane and high C number long-chain n-alkane aliphatic compounds were docosane, hexacosane and hexatriacontane. The recoverable compounds are economically and environmentally important as they can be used in many industries such as cleaning, cosmetics, pharmacology and petrochemistry as feedstock. The proposed pyrolysis provided symbiotic solution to these two types of wastes and the resultant products of this application have potential for energy and compound recovery. Recovery methods can be further studied.

Waste pickers are workers exposed to several occupational risks. This cross-sectional study investigated hazards associated with occupational accidents among waste pickers in the largest open dumpsite in Latin America before its closure. A survey was conducted with 999 waste pickers, collecting data on accidents and work characteristics. Among those interviewed, 686 (68.7%) of waste pickers reported having suffered accidents at work. Of these, 68.7% of them were related to exposure to sharp objects, and 62.5% were unable to work due to the accident. Work shift and work environment were significantly associated with accidents (p < 0.001). It indicates that workplace hazards are stronger predictors of accidents than personal characteristics. This article demonstrates the necessity for integrated and multi-sectoral strategies and surveillance systems that monitor environmental, animal and human health indicators aligned with the One Health approach in municipal solid waste management. This epidemiological study provides data to support dump closure in similar contexts, especially in countries in the Global South.

Efficient urban waste collection requires solutions that balance environmental performance, economic feasibility and social acceptability while minimizing spatial and ecological impacts. This study assesses the sustainability of vacuum waste collection systems in comparison with underground containers and indoor bins, using data from approximately 2500 households in a Norwegian city. Four waste fractions: plastic, residual and paper/cardboard were analysed across two scenarios: a fully vacuum-based system for all households, and a hybrid solution combining underground containers for 1500 households with indoor bins for 1000. The evaluation integrates three sustainability dimensions: climate impact through life cycle assessment, economic performance through lifecycle cost analysis and social aspects through qualitative assessment. Findings reveal that vacuum systems achieve the lowest climate impact, although the differences between systems are modest. For vacuum systems, emissions are dominated by the construction of pipe networks and terminal facilities; for underground containers, by the number of units and for indoor bins, by transport and operational activities. Economically, vacuum systems incur 22% higher costs than the hybrid solution. However, economies of scale are evident: increasing connected households from 2500 to 3100 reduces costs by 14%, positioning vacuum systems more competitively. Socially, vacuum systems offer notable benefits, including reduced odour and noise, improved traffic safety and decreased physical strain on personnel. Overall, the study concludes that waste collection solutions must be tailored to site-specific conditions but highlights the scalability and social advantages of vacuum systems, which may render them a viable option for sustainable urban waste management when integrated with commercial streams.

For preparing daily utensils, aluminium is repeatedly recycled globally by physical methods. However, after multiple recycling cycles, it often becomes contaminated by unwanted metallic parts, which are persistent. This contaminated aluminium is a threat to food safety. Herein, we chemically extracted aluminium in the purest form as sulphate from multiply recycled aluminium utensils. The synthesized coagulant was used as a potential water purifier and paper filler. The synthesis process was optimized, with the highest yield (85.6%) achieved using 12 M H₂SO₄ at pH 2, and 55°C temperature. The prepared sample was characterized using surface morphology, energy dispersive X-ray spectroscopy analysis and Fourier transform infrared spectroscopy (FTIR) spectra. In case of water treatment, 0.8 mg of synthesized Al₂(SO₄)₃ achieved the highest mud deposition (46 mg/10 mL), exceeding the commercial alum by approximately 4.5%. Statistical analysis by means of t-test confirmed the repeatability and significance of this improvement (p = 0.03). In case of application as paper filler, the ink absorptivity was found to be reduced, whereas the sheet strength was increased significantly. These findings demonstrate that synthesized Al₂(SO₄)₃ can serve as a safe and effective alternative to commercial alum, contributing to waste valorization, food safety and sustainable materials development.

Solid waste management is key to achieving zero-waste cities, encompassing waste reduction, recycling and the circular use of resources. This not only alleviates environmental pressure but also serves as a crucial avenue for sustainable development and the protection of natural resources. With the ongoing advancement of zero-waste cities, reducing solid waste generations has become a focal point of interest for policymakers and the academic community alike. Previously, the majority of academic research concentrated on green finance and environmental pollution, with a particular focus on green credit at the micro-level, yet in-depth studies on solid waste management were scarce. To bridge this research gap, this article introduces spatial econometric models, mediating effect models and threshold models, concentrating on analysing the impact pathways of green credit on solid waste management. The study reveals: (1) green credit significantly suppresses solid waste generations in Chinese provinces, but this effect exhibits regional disparities; (2) green credit exhibits a threshold effect in mitigating solid waste generations, implying that an appropriate level of green credit and environmental governance investment enhances its inhibitory effect on solid waste and (3) research and development investment intensity and industrial structure upgrading serve as intermediary factors in the process of green credit inhibiting solid waste. These research conclusions can provide valuable references for local governments and businesses to enhance solid waste management.