Sustainable metropolitan areas perspectives through assessment of the existing waste management strategies

Thermoactivated cement from construction and demolition waste for pavement base stabilization: A case study in Brazil

Construction and demolition waste (CDW) worldwide generation accounts 10 billion tonnes yearly. The major fraction is landfilled requiring innovative recycling methods to reduce the associated environmental impacts and to increase its circularity. Our study demonstrated the feasibility of using different CDW fines to develop recycled cements and optimized the content of CDW recycled cements with well-graded crushed stone (WGCS) for use as pavement base layer. We scaled up the study obtaining CDW cement and aggregates from a local recycling plant, as well as pilot pavement sections designed, constructed and field deflections measured. As results, the CDW cement pastes exhibited accumulated heat values of up to 111 J g-1 and achieved a compressive strength of approximately 16 MPa. The unconfined compressive strength and resilient modulus (RM) achieved using CDW cement and WGCS were 2-3 and >3000 MPa, respectively. The sections constructed using CDW cement exhibited intermediate behaviour compared to those obtained using reference materials (6% Portland cement-WGCS and a conventional granular base made using WGCS). The deflection decreased over time owing to the pozzolanic reaction.

Modelling of demolition waste generation: Application to Greek residential buildings

The construction sector in Europe is among the biggest waste generators, producing 370 million tonnes of construction and demolition waste (CDW) every year, which contain important secondary materials. Quantification of CDW is important from their circular management and environmental impact point of view. Thus, the overall objective of this study was to develop a modelling methodology for estimating demolition waste (DW) generation. The volumes (m3) of individual construction materials contained in 45 residential buildings in Greece were accurately estimated using computer-aided design (CAD) software and the materials were classified according to European List of Waste. These materials will become waste upon demolition, with a total estimated generation rate of 1590 kg m-2 of top view area and with concrete and bricks representing 74.5% of total. Linear regression models were developed to predict the total and individual amounts of 12 different building materials based on structural building characteristics. To test the accuracy of the models, the materials of two residential buildings were quantified and classified and the results were compared with the model predictions. Depending on the model used, the % differences between models' predictions and CAD estimates for total DW averaged 11.1% ± 7.4% for the first case study and 2.5% ± 1.5% for the second. The models can be used for accurate quantification of total and individual DW and their management within the framework of circular economy.

Evaluation of a data-driven intelligent waste classification system for scientific management of garbage recycling in a Chinese community

Waste classification management is effective in addressing the increasing waste output and continuous deterioration of environmental conditions. The waste classification behaviour of resident is an important basis for managers to collect and allocate resources. Traditional analysis methods, such as questionnaire, have limitations considering the complexity of individual behaviour. An intelligent waste classification system (IWCS) was applied and studied in a community for 1 year. Time-based data analysis framework was constructed to describe the residents' waste sorting behaviour and evaluate the IWCS. The results showed that residents preferred to use face recognition than other modes of identification. The ratio of waste delivery frequency was 18.34% in the morning and 81.66% in the evening, respectively. The optimal time windows of disposing wastes were from 6:55 to 9:05 in the morning and from 18:05 to 20:55 in the evening which can avoid crowding. The percentage of accuracy of waste disposal increased gradually in a year. The amount of waste disposal was largest on every Sunday. The average accuracy was more than 94% based on monthly data, but the number of participating residents decreased gradually. Therefore, the study demonstrates that IWCS is a potential platform for increasing the accuracy and efficiency of waste disposal and can promote regulations implementation.

Circularity in waste management: a research proposal to achieve the 2030 Agenda

Waste management is the main challenge in the transition away from the linear "take-make-dispose" economy. Incorporating the principles of circularity in waste management would facilitate the achievement of Sustainable Development Goals. This paper aims to provide state-of-the-art research about circular waste management in the fulfillment of the 2030 Agenda. For this purpose, bibliometric analysis by VOSviewer and SciMat software is used to define the evolution and to detect research trends. Based on the main gaps identified in studies, a research agenda to guide for further opportunities in this field is suggested. The results obtained four clusters that address sustainable industrial infrastructure, biological waste management, recycling in developing countries and recovery processes. Four research propositions are established, focusing on plastic waste management and generation trends, circular municipal waste management, more sustainable landfill management, and enablers such as indicators and legislation. The transformation towards more bio and ecological models requires social, regulatory and organizational tools that consider the best interests and capacity of companies, public authorities and consumers. In addition, policy implications are considered.

Green Economy and Waste Management as Determinants of Modeling Green Capital of Districts in Poland in 2010-2020

Waste management must comply with the principle of sustainable development. A green economy is one of the paths to sustainable development and response to environmental problems. Waste should be a raw material that can be reused, processed, or turned into energy. The aim of the article is to assess the relationship and present the concept of zero waste and green economy, and to show selected framework conditions for their development in the county. To study the formation of phenomena depending on the location of a given object in the socio-economic space, a synthetic measure, the similarity matrix, the Gini coefficient was used. The analysis took into account features describing the condition of the natural environment, links between the natural environment, economy and society, the quality of life of the population, economic policy, and instruments influencing the economy, society and the environment. Empirical data were obtained from the local database of the Central Statistical Office for the years 2010-2020. The obtained results indicate the existence of dependencies in the development of a green economy and waste management in the region. The synthetic measure of waste management is from 0.43 to 0.61 in 2010, from 0.39 to 0.55 in 2020; green economy from 0.42 to 0.55 in 2010 and from 0.43 to 0.56 in 2020. Waste management is based on multidimensional waste management, taking into account economic, ecological and social aspects. Economic activity is related to the degradation of the natural environment. The green economy should assume the elimination of waste and environmental threats and the preservation of their value. The green economy is becoming a factor inducing structural changes in the economy and social life, helping in the most effective, sustainable and efficient use of limited resources. In the literature on the subject, this type of research is carried out at the level of regions or voivodeships. The authors use their own sets of indicators or their own indicators aggregated according to the available data at the poviat level. The obtained results can be an important source of information for local government authorities about disproportions between units.

Carving out a Niche in the Sustainability Confluence for Environmental Education Centers in Cyprus and Greece

Given the environmental issues that today’s societies confront, such as climate change, waste management, ecosystem deterioration, etc., environmental education is becoming increasingly important. Adoption of environmental education as an integral part of the educational system is required for the Environmental Education Center (EEC) to be able to provide knowledge, skills, and values so that society can become active and environmentally responsible through awareness-raising. According to the scholarly published research, EECs can positively affect local communities and create an environmentally friendly culture. In addition, given that EECs can even play a significant part in the development of lifelong learning activities at the education and sustainable development nexus, it is considered critical to establishing future potentials and dynamics. Thus, aiming to analyze EECs’ strengths, weaknesses, opportunities, and threats (SWOT analysis) within our complex and ever-evolving world, educators, students, and other fellow citizens in Cyprus and Greece participated in a survey in which they were asked to fill in a questionnaire, specifically developed for each group category. The findings of this study provide a deeper understanding of the implications arising as a result of effective environmental education absence, as well as the importance of a holistic approach through EECs. Moreover, it offers the research community a solid framework for future innovation in citizen engagement and training.

Study on the Relationship between Low-Carbon Circular Farming and Animal Husbandry Models and Human Well-Being: A Case Study of Yongchang County, Gansu Province

The detrimental effects of climate change require countries and regions to use green and low-carbon strategies as the basis for economic development. Agriculture and livestock industry have become among the main industries that emit greenhouse gases. Yongchang County is suitable for the development of large-scale livestock operations due to its unique geographical advantages. However, the potential effects of the carbon dioxide emissions and the environmental impact potential of various farming and animal husbandry farming models on human well-being need to be considered. The purpose of this paper is to use life cycle assessment (LCA) to comprehensively assess the carbon emissions and environmental impact of circular agriculture and livestock industry and to provide important decision support for the establishment of a low-carbon circular agriculture and animal husbandry model. It uses a 75 kg dairy sheep as a functional unit to combine a noncircular farming model (S1) and a circular farming model (S2). The degree of carbon emissions, environmental impact potential and human well-being environmental effects are compared. The results show that the carbon dioxide emission of S1 is 891.3 kg, while the emission of S2 is 647.3 kg, and the difference between the two is 244 kg. S2 has a lower global warming potential than the S1 model; hence, the S2 model, which uses biogas for power, has lower carbon emission than the S1 model. From the perspective of human well-being and environmental benefits, the S2 model of biogas power generation is a low carbon emission and high-benefit model. The biogas power generation model lays the foundation for the realization of the “peak carbon dioxide emissions” and “carbon neutralization” goal, strengthens ecological protection on the north side of the Qilian Mountains and improves human well-being in the region.

Solid waste generation indicators, per capita, in Amazonian countries

Countries participating in the Amazon Cooperation Treaty Organization have few options for the environmentally appropriate final disposal of municipal solid waste. Thus, sustainable practices aimed at reducing the negative effects of such a disposal on the environment are complex and hard to accomplish, since solid waste generation per capita proportionally increases as populations grow (≈ 2.7% > world average), mainly in countries inserted in Amazon Cooperation Treaty Organization. Thus, demographic, socioeconomic, management, and ecological factors represented by 18 independent variables were statistically analyzed to explain waste per capita variation in Amazonian countries and sub-regions. Multiple Kruskal-Wallis tests were applied; 13 of them recorded significant results (p < 0.05). Subsequently, simple and multivariate regression analyses were carried out by taking into consideration waste per capita and significant variables. Simple regression results recorded for variables "IAC" and "Gini index" were significant (R_IAC² = 60.09%, R_Gini² = 30.83%), with emphasis on "Amazon biome" (DF = 33, p < 0.01, R_Biome² = 5.34%). Multivariate models resulted in wide explainability variation, depending on the number and type of available variable (54.47% ≤ R_aj² ≤ 70.83%), with emphasis on "IAC," "Ptot," "Purb," "Wton," "Lon," Area, "HDI," "Gini," and "SDG11" (p < 0.01). In conclusion, waste per capita estimation models can present variations and geographical interdependencies due to different variables and factors that reflect the current public policies and municipal solid waste management practices.

Environmental impacts of hazardous waste, and management strategies to reconcile circular economy and eco-sustainability

The rise in living standards and the continuous development in the global economy led to the depletion of resources and increased waste generation per capita. This waste might posture a significant threat to human health or the environmental matrices (water, air, soil) when inadequately treated, transported, stored, or managed/disposed of. Therefore, effective waste management in an economically viable and environmentally friendly way has become meaningful. Prominent technology is the need of the day for circular economy and sustainable development to reduce the speed of depletion in resources and produce an alternative means for the future demands in the different sectors of science and technology. In order to meet the potential requirements for energy production or producing secondary raw material, solid waste may be the prime source. The activities of living organisms convert waste products in one form or another in which electronic waste (e-waste) is a modern-day problem that is growing by leaps and bounds. The disposal protocols of the e-waste management need to be given proper attention to avoid its hazardous impacts. The e-waste is obtained from any equipment or devices that run by electricity or batteries like laptops, palmtops, computers, televisions, mobile phones, digital video discs (DVD), and many more. E-waste is one of the rapidly growing causes of world pollution today. Plenty of research is available in the scientific literature, which shows different approaches being set up and followed to manage and dispose of waste products. These strategies to manage waste products designed by the states all over the globe revolves around minimal production, authentic techniques for the management of waste produced, reuse and recycling, etc. The virtual survey of the available literature on waste management shows that it lacks specificity regarding the management of waste products parallel to ecological sustainability. The presented review covers the sources, potential environmental impacts, and highlights the importance of waste management strategies to provide the latest and updated knowledge. The review also put forward the countermeasures that need to be taken on national and International levels addressing the sensitive issue of waste management.

Evaluation and optimization of a circular economy model integrating planting and breeding based on the coupling of emergy analysis and life cycle assessment

The sustainable development of agriculture is facing problems such as high resource consumption and serious environmental pollution. The development of the circular economy model integrating planting and breeding (CEMIPB) has become an effective way to realize the sustainable development of agriculture. Due to the great difference of natural resource attributes in different regions of China, CEMIPB shows diverse characteristics on the whole. Based on this, this paper constructs a coupling model based on emergy analysis (EMA) and life cycle assessment (LCA) called EM-LCA model and conducts an empirical analysis using a typical CEMIPB in Fujian Province, China, as a case. By comparing the results of the EM-LCA and EMA models, the former effectively compensates for the deficiencies of the latter in terms of economic and environmental impact assessment, and the evaluation results can better reflect the actual situation of the system. Furthermore, sensitivity analysis is introduced to identify key processes and substances. Based on the reduce-reuse-recycle (3R) principle, several optimization suggestions, such as reducing the input of corn and veterinary drugs, are put forward. The construction of the aforementioned methodology system can provide a new perspective for research in similar fields and provide a scientific basis for local government decision making.

An Integrated SWOT-PESTLE-AHP Model Assessing Sustainability in Adaptive Reuse Projects

In the recent past, sustainable development has been considered a major issue for urban and regional studies. Adaptive reuse appears to be a practical solution for sustainable urban development. Beyond and in addition to a conceptual base consistent with circular economy and sustainability principles, how do we know if adaptive reuse is actually sustainable, provided that it constitutes a multidisciplinary and multilevel process? The present study aims at evaluating, in as much as feasible quantitative terms, adaptive reuse practices sustainability. This was attained using a set of indicators, developed combining PESTLE (the Political, Economic, Technical, Social, Legal, and Environmental aspects) and SWOT (the Strengths, Weaknesses, Opportunities, and Threats) approaches, of which the results were subjected to evaluation by experts (pairwise comparisons), following the Analytic Hierarchy Process (AHP). The indicators representing strengths and opportunities of the process were calculated to be of higher value (overall level of final cumulative indicators values; 70.4%) compared with indicators representing weaknesses and threats. Enhancing strengths and opportunities and counteracting weaknesses and threats contribute making the potential of adaptive reuse practices in urban sustainability more evident. Among analysis dimensions, political and economic aspects rank first, followed by environmental, socio-cultural, technological-technical, and legal aspect. The empirical results of this paper serve as a useful reference point for decision-making and policy formulation addressing adaptive reuse practices in sustainable development strategies.

Measuring the Level of Environmental Performance on Coastal Environment before and during the COVID-19 Pandemic: A Case Study from Cyprus

Tourism activities are considered, among others, the backbone of the local economies. However, tourism activities lead to adverse environmental impacts, especially in coastal zones. Coastal areas are considered and recognized as of strategic importance due to the fact that several activities take place, from leisure to business. At the same time, coastal areas are under pressure from tourist activities, and the waste generated is a very serious issue. Therefore, there are limited studies related to the environmental dimensions of the COVID-19 pandemic in the coastal environment. This paper provides answers to the hypothesis that the pandemic lockdown scenario would improve environmental performance due to reduced usage and, therefore, waste, taking into account specific key performance indicators (KPIs) as these KPIs are used to evaluate the performance of an area. The results showed that the study area improved, as did the selected KPIs, i.e., clean coast index (CCI), waste accumulation rate (WAR), and waste accumulation index (WAI). Additionally, according to the final results, the concentration of micro-, meso- and macroplastics on the beach reduced, and the main issues remained the solutions on cigarette butts, straws, and other plastic containers. Furthermore, the final results are considered very useful to local authorities, stakeholders, consultants, policymakers, and any other competent authorities, to reschedule their waste management strategies, to improve waste infrastructures and their level of services (LOS), as well as, to suggest frequent awareness-raising activities to their visitors on how to protect the coastal environment, taking into account a pandemic scenario, as well as, the policy alternative impacts on EU coastal zones 2000–2050.

Measuring the level of environmental performance in insular areas, through key performed indicators, in the framework of waste strategy development

To measure "something that is not there", is not easy and at the same time not fully understandable and perceived by the citizens. Several elements (such as, waste production, waste management cost, social attitude and behaviour, etc.) interrupt and disturb any strategy in the framework of waste management. Additionally, through the European Green Deal (EGD), Europe is trying to achieve climate neutrality by 2050, taking into account the Circular Economy Strategy (CES) and the United Nations Sustainable Development Goals (UNSDGs). A Driving Force-Pressure-State-Impact-Response (DPSIR) breakdown was applied, to establish and organize key information's on the environmental performance (E.P) taking into consideration the existing pollution, reviewing the contemporary knowledge and existing implemented waste strategies on the driving forces, pressures, states and impacts. This paper includes several key performed indicators (KPIs), in order to evaluate the E.P of an area, through hybrid approach which cover among others, the waste compositional analysis, SWOT and PESTEL analysis, waste recycling and waste accumulation index, prevention activities, awareness activities etc. The results indicate that, the selected areas implement periodic measures, but they need to put more effort to boost their citizens to participate in any proposed waste strategy. Furthermore, the results are very valuable and helpful to policy makers, consultants, scientists, competent authorities, stakeholders etc., in order to design and promote synergies and activities (mainly in Local Authorities), to reach the proposed figures that EGD, proposed in relation with the CES as well as with the SDGs.

Compression behaviors of mechanically biologically treated wastes of Tianziling landfill in Hangzhou, China

This study aimed to investigate the compression behaviors of mechanically biologically treated (MBT) wastes. For this purpose, the short-term compression-rebound and long-term compression tests were conducted on MBT wastes collected from Hangzhou Tianziling landfill in China. The results showed that the duration of immediate compression was obtained as 15.17-36.67 h and was comparable to municipal solid waste (MSW). The immediate compression ratio was 0.233-0.247, and it was comparable to the aged high food waste content (HFWC)-MSW, fresh and aged low food waste content (LFWC)-MSW, but much lower than the fresh HFWC-MSW. The mechanical creep ratio (C'_αc) was 0.012-0.018, being close to the fresh and aged MSWs. The bio-induced compression ratio (C'_αb) was 0.143-0.174. The compression ratio rose exponentially with temperature (5-42 °C) in both mechanical creep stage and bio-induced compression stage, and it increased much faster in the bio-induced compression stage. The resilient strains was only 2.1-3.3% of the compression strain at the same stress interval, suggesting that the compression strain consisted of mostly plastic deformation and negligible elastic deformation. The above findings can provide a reference for settlement prediction and storage capacity estimation of an MBT waste landfill.

Considering Urban Development Paths and Processes on Account of Adaptive Reuse Projects

This article, as part of the ‘SUMcity’ research program, aims to give a comprehensive account of the regeneration that occurred in Athens by the adaptive reuse of the old FIX Brewery to house the new Hellenic National Museum of Contemporary Art (EMST). Adaptive reuse is an urban sustainability development evolving process, used to manage assets and resources efficiently, resulting in economic development, increased local attraction, and revitalized community engagement. Other than that, modern societies experience the dynamic stream of social media and smart city initiatives, amid a long-discussed and complex cultural heritage preservation backdrop. Notwithstanding the value added to the city, the interaction of sustainable development with adaptive reuse projects, culture, tourism, social media use, and smart city initiatives, along with the impact of this intangible relationship, has yet to be set in a more tangible form. Methodologically, a newly developed conceptual framework is used in order to re-define the (cor)relations among the existent concepts of sustainable development, smart city and cultural heritage. Subsequently, a primary questionnaire-based research is conducted on Instagram users’ geotagging the Hellenic National Museum of Contemporary Art (EMST), analyzing their views in an attempt to demonstrate the arising local potential and sustainability.