The COVID-19 pandemic has compelled people to make significant adjustments to their work and lifestyles, which has had a profound impact on their consumption and waste disposal behavior. To identify changes in waste generation since the COVID-19 pandemic, we analyzed the results of a survey on municipal solid waste management published by the Ministry of the Environment, Japan to project waste generated over the four years from FY2020 to FY2023, assuming there had been no COVID-19 pandemic, and compared with the actual waste generated. The trends in household waste generation, commercial waste generation, the amount of recycled metals, and the amount of recycled PET bottles during the COVID-19 pandemic were clearly different from those before the pandemic. We found that municipalities with growing populations have been more affected by the COVID-19 pandemic in terms of waste generation than municipalities with declining populations. The amount of collective collection, which refers to community-based recycling, in municipalities with declining populations fell rapidly during the pandemic, suggesting that collective collection activities are declining at an accelerating rate as a result of the pandemic.

It is not only municipalities’ policies of waste collection and disposal but also socioeconomic factors such as ratio of business waste, collection frequency and type, urbanization and aging, and national policies of municipal solid waste. Existing studies have focused on the effects of unit-based pricing and waste separation considering socioeconomic factors so far. However, they have used old datasets before Japan’s municipal mergers in Heisei era, therefore, they may not fully reflect the recent situation. In addition, conventional panel data analyses do not distinguish between within-municipality time-series change and between-municipality differences of each possible factor. This study uses a recent dataset and applies a hybrid panel data analysis that can differentiate time-series variation from municipal specific factors of each variable. The study will clarify the determinants of generation and recycling rate of municipal solid waste in more recent situation.

This study examines the effectiveness of a name-labeled garbage bag policy as a form of green nudge aimed at reducing household waste and promoting waste sorting behavior. Under this policy, residents are required to write their names on garbage bags, thereby enhancing social visibility and encouraging self-regulation and intrinsic motivation. Using original data on the adoption of the name-labeled bag policy across Japanese municipalities and a staggered difference-in-differences approach, the analysis reveals a short-term reduction in combustible waste following policy implementation, but the effect attenuates over time. Furthermore, no consistent significant impact is observed for recyclable waste. These findings suggest that a single social visibility nudge may be insufficient to motivate complex behaviors such as proper sorting, and that achieving long-term behavioral change requires integration with complementary policy instruments.

This study investigates the case of Kameoka City, where efforts initially focused on river waste collection have evolved into a broader movement to prevent the generation of single-use plastics. The research aims to clarify the factors that facilitated the launch, maintenance, and sustainable development of the “River and Sea Co-Creation Project,” which served as a turning point in this transformation. The findings indicate that three key forms of capital were essential in the project's initiation: (1) administrative involvement grounded in political capital through the setting of concrete goals; (2) social capital manifested in cooperative relationships among various organizations; and (3) human capital in the form of individuals with expertise relevant to the project. Furthermore, the project's sustained development was supported by: (4) stable investment of financial and human capital through a management structure involving the local government and diverse organizations; (5) enhancement of existing social capital through regular information-sharing opportunities among participating groups; and (6) the growth of cultural capital fostered through ongoing project activities.

To quantitatively assess the amount of marine plastic litter, it is crucial to clarify defining the actual extent to which plastic litter scattered in the environment flows into rivers over time. However, while studies exist that identify waste hotspots and investigate the composition of waste (quantity, type, etc.), there is little research on the process by which waste scattered in the environment flows into rivers. Therefore, this study aimed to collect “river-floating waste,” “riverbank waste,” and “roadside waste” in the Sakai River and conduct various surveys to clarify the history, current status, and retention period required for scattered plastic packaging materials and containers to flow into rivers.

The demand for take-out from restaurants, including fast food and coffee shops, is increasing, and the use of disposable drink cups and food containers is on the rise. These containers, which are consumed for a very short time, are a waste of resources even if they are properly disposed of, leading to an increase in greenhouse gas emissions.

In the 2020s, France, Germany, and other countries implemented systems targeting disposable containers at restaurants, and new businesses, such as reusable tableware sharing services at restaurants, have been born and are beginning to spread in these countries. In addition, in other countries, including Japan, where there is still no legal system to regulate these, companies and NGOs are starting similar businesses.

This paper investigates the spread of "restaurant take-out container sharing services" that were created in these countries with the aim of reducing disposable containers, and considers the possibility of their spread in Japan.

To advance the resource circulation of waste, it is essential to establish reasonable sorting methods at the discharge stage. In recent years, efforts have been made in various countries to develop sorting systems based on a recycling perspective, designs with high visual recognition, and the use of nudges. However, there are challenges that cannot be fully addressed by visual information alone, such as the diversification of sorting targets and regional differences. Therefore, we believe that more intuitive and unified sorting methods are necessary. In this study, we conducted a survey of sorting methods at public facilities in Tokyo and identified diverse sorting methods that vary by facility. Furthermore, considering post-sorting recycling methods and conditions for undesirable substances, we conducted experimental studies toward the development of reasonable sorting methods at the disposal stage. As a result, we successfully consolidated waste contaminated with food stains into a single waste bin by installing it with the removal of undesirable substances in mind, and confirmed an increase in the recycling rate.

This study conducted interviews with six municipalities with low levels of household waste generation, aiming to clarify key internal administrative procedures related to public awareness measures for waste reduction. Focusing on two specific initiatives—Waste Reduction Promoters and Mobile Applications—the study analyzed various procedural factors that led to their implementation. The findings revealed differences among municipalities in terms of promoter recruitment methods, compensation, and local activities. On the other hand, it was common that no discussion of suspension of the mearsure so far.

While all municipalities had introduced the mobile application primarily to promote proper waste disposal, half of them also used the app to deliver messages aimed at waste reduction, such as encouraging the collection of used cooking oil or the use of reuse shops during seasonal clean-up periods. Additionally, three municipalities cited the benefit of reduced inquiry phone calls from residents regarding waste disposal as a result of introducing the app.<br data-start="536" data-end="539" />Moving forward, the goal is to build a nationwide database of internal administrative procedures in order to identify factors that effectively contribute to waste reduction.

When investigating the abundance of microplastics on the coast, quadrats are used to define the sampling area and collect coastal sediments. The size of the quadrats varies at the discretion of the researchers, but results are often presented as abundance per unit area. Particularly, the method of sampling accumulation sites at the high tide line and the supratidal zone is suitable for comparing abundance with other coasts (Ikegai et al., 2017); however, abundance per unit area is thought to differ significantly based on the size of the quadrat used. Therefore, this study aimed to gain insights into the distribution of microplastics at accumulation sites, the effect of quadrat size, and suitable quadrat size for investigating microplastic abundance in coastal sediments, using quadrats measuring 20 cm, 40 cm, and 60 cm square. As a result, it was found that the abundance of microplastics at accumulation sites is not uniformly distributed, but further investigation into the optimal quadrat size will continue.

Hydroponics has attracted attention as a sustainable cultivation method due to its superior water and nutrient use efficiency compared to conventional soil based systems. However, even in semi-closed systems, the discharge of residual nutrient solution is inevitable, which can lead to nitrogen loss and environmental pollution caused by nitrate contamination. Although preharvest nitrogen dilution has been proposed as a strategy to reduce nitrate concentration in effluent, concerns remain regarding its potential negative effects on crop growth. Meanwhile, silicon has been reported to enhance nitrogen assimilation, stabilize plant growth, and improve stress tolerance, thereby contributing to increased WUE and NUE. Therefore, this study aimed to evaluate the effects of nitrogen dilution and silicon supplementation on lettuce growth, water and nutrient use efficiency, and nitrate concentration in effluent under a semi closed hydroponic system.

This study quantifies plastic arising from End-of-Life Vehicles (ELVs) in Japan and evaluates its recovery potential. A teardown of two passenger cars manufactured in 2008–2009 yielded a component-level plastic mass inventory, which was combined with ELV numbers projected to 2050 from national statistics and logistic survival functions. The resulting polypropylene and polyethylene content of 2023 ELVs is about 152 kt; components that can be disassembled relatively quickly (groups A–D) contain roughly 93 kt, declining to 70 kt by 2050. Even the latter value could meet the draft EU ELV requirement that at least 6.25 % of the plastic in new cars originate from vehicle-derived recyclate. Broader teardown sampling and continuous monitoring of resin compositions are needed to refine these estimates.

In recent years, the diversification of lifestyles in Japan has led to a significant rise in demand for nakashoku—ready-to-eat meals prepared outside the home but consumed within it. While this trend offers convenience and meets the needs of busy individuals, it also contributes to emerging environmental issues, particularly the increase in food waste and single-use plastic waste. Takeout meals and ready-made foods sold at convenience stores, supermarkets, and restaurants tend to have short shelf lives, making them major sources of discarded food and plastic packaging. As these waste streams grow, there is an urgent need to understand their current status and to develop effective reduction strategies. This study aims to quantify household emissions of food waste and food-related plastics in Tokyo, identify key challenges, and provide foundational data to support the development of sustainable waste management and recycling systems. Through this analysis, the study contributes to ongoing efforts to mitigate the environmental impact of modern food consumption patterns and promotes a more circular, resource-efficient society.

This research, conducted in Toyama Prefecture, quantifies and characterizes plastics within municipal household waste to estimate the volume of unutilized material. Additionally, scenarios for effective utilization are proposed, incorporating two key technologies: advanced sorting processing and a melting technology that converts the post-sorting residue into fuel.

In Indonesia, the amount of waste plastic generated is on the rise in line with the growing demand for plastic due to economic development. Currently, much of the waste plastic is not collected and is either disposed of or improperly treated, and it has been reported that Indonesia is the second largest producer of waste plastic in the world. Despite this situation, there is no clear statistical data on the amount and type of waste plastic generated in Indonesia, especially the amount collected, which is necessary to consider new recycling projects. For this reason, we conducted a survey of government published data, existing literature, and interviews with local stakeholders in the Jakarta area. The survey revealed that the informal sector and a unique initiative called waste banks play an important role, and also estimated the contribution rate of each. In addition, we estimated the amount of waste plastic collected in Jakarta to be 531,690 tons in 2022, and predicted that the amount of waste plastic generated in Jakarta in 2030 will increase by approximately 100,000 tons per year from 2022.

The collection and incineration of waste generated by human activities are one of the causes of carbon dioxide emissions, which contribute to global warming. Therefore, reducing waste not only reduces the financial burden on local governments but also contributes to solving environmental problems. Many local governments in Japan have implemented a garbage bag fee system, and its effectiveness has been proven in numerous previous studies, both in Japan and abroad. In this study, we use conjoint analysis to conduct a resident evaluation of waste reduction policies, including the garbage bag fee system, to examine the possibility of future waste reduction. The results showed that consumers are more satisfied with the installation of free collection boxes at convenience stores and supermarkets and the promotion of separate collection of garbage bags than with the garbage bag fee system. This suggests that the financial cost of implementing a fee system is greater than the cost of travel when taking garbage to supermarkets for collection and the hassle of sorting.

We collected and organized information on industrial waste disposal companies in Hokkaido that disclose their disposal fees on the web, and attempted to understand the trends in disposal fees by item and by region, using waste plastics as an example. As a result, the data revealed that the prices of styrene foam and FRP vary greatly from region to region, and that extremely high disposal costs are incurred in certain regions. On the other hand, sheet/film and pipe/tube items were in the relatively low to medium price range, but again, the prices varied by region and condition.

The Adopt Program is a collaborative initiative between citizens and local governments for public space beautification in Japan.While nationwide adoption progressed initially, growth stagnated around 2010, with only 521 municipalities (approximately 30%) implementing the program by 2024. This study analyzed survey data from adopting municipalities in 2011, 2014, 2017, and 2022 to examine temporal changes in perceived challenges and differences between government levels. "Aging of participants" was consistently rated as the most critical issue, with its importance increasing over time. "Decline in participating groups" also showed growing concern. Prefectural governments prioritized structural and organizational issues, while municipal governments emphasized field-oriented challenges such as insufficient public awareness and activity stagnation. For future program expansion, key recommendations include implementing safety measures and burden reduction for elderly participants, transitioning from reactive cleanup to proactive maintenance approaches, and enhancing public recognition through improved outreach efforts. Addressing these municipality-identified challenges is crucial for sustained program growth and volunteer participation.

This study examines whether presenting waste as art can reduce negative perceptions—particularly disgust—that hinder recycling behavior. The hypothesis is that artistic representations of waste may induce cognitive dissonance between its perceived ugliness and aesthetic appeal, prompting a reevaluation of its value. A pilot survey was conducted with 36 participants in Japan and China using four visual stimuli that varied in artistic presentation and transformation salience. Structural equation modeling was applied to assess the model’s validity. Contrary to the hypothesis, images that appeared more like conventional waste led to higher acceptance of recycled products. This unexpected result may be due to insufficient contrast between stimuli, lack of clarity in the presented information, or issues in questionnaire design. Future research will refine the visual stimuli and measurement tools to further explore the potential of art in promoting recycling behavior.

Department of Transdisciplinary Science and Engineering, School of Environment and Society, Institute of Science Tokyo (formerly Tokyo Institute of Technology) offers a course for undergraduate students. In this course, students designed and fabricated PET bottle recycling bins to collect more PET bottle, encourage cap removal, and to decrease other waste contamination. The fabricated recycling bins were set for one week for PET bottle collection experiments in Ookayama campus. According to multiple comparison test (Tukey-Kramer method) and multiple regression analysis, design preference toward each recycling bin, which was scaled using pairwise comparison method (Nakaya variation of Scheffe’s method), it gave no significant impact on cap removal and other waste contamination. On the other hand, recycling bin locations gave insignificant impact on other waste contamination. However, this work also found that location effect was negligibly small when the model included other factors to explain the other waste contamination.

In recent years, China’s rapid economic growth and the expansion of consumer activity have led to a sharp increase in household and corporate waste, creating a serious social problem. Building a sustainable society therefore requires actions that curb waste generation, particularly at the point of purchase. While prior studies have emphasized rational factors such as “attribution of responsibility” and “perceived response efficacy,” more recent psychological research highlights the role of emotions—especially guilt and shame in the Chinese cultural context (Bedford, 2004). This suggests that rational factors alone are insufficient to promote waste-reduction behaviors during purchasing. Yet how these emotional factors interact with rational determinants and the extent to which they influence actual behavior remain unclear. Accordingly, this study investigates the current state of waste-reduction behavior at the purchasing stage and elucidates both the emotional and rational factors that govern such behavior.

Sub-Sahara African countries face challenges of waste management due to rapid population growth and urbanization. It is revealed that the number of technical and financial cooperation projects for waste management in Africa undertaken by Japan International Cooperation Agency has been growing since 2011, with increased number of countries where such projects have been implemented. To show the impacts, a project worked on improving financial sustainability of waste management services provided by Maputo city, Mozambique was referred to. Lastly, challenges that need to be addressed are discussed; 1) sustain outcome of cooperation projects beyond their end in African countries with unstable domestic circumstances, 2) enhance collaboration with region-wide platform, and 3) support transition to circular economy.

With the aim of building a sustainable world, discussions on the “circular economy (CE)” as a new social and economic concept, taking into account not only pollution prevention but also decarbonization and resource constraints, have become active since around 2010.This paper analyzes the CE policies of devolved governments in the UK for the period after 2020, focusing on policy objectives, main contents, priority areas, handling of Extended Producer Responsibility (EPR), collaboration among stakeholders, and links with industrial policies.

The results are as follows.•Wales: The shared vision that CE promotes societal well-being, the promotion of policies considering the interconnections among the 3Rs(Reduce, Reuse, Recycle) and proactive investment in recycling facilities has contributed to the continued improvement in recycling rates. Policies also emphasize collaboration with local communities. •Scotland: Although a CE strategy was established early on, the development of recycling infrastructure has been slow, leading to a policy focus on reducing waste generation.・England: CE strategy formulation was delayed, and recycling rate improvement has plateaued. There is a tendency to rely on industry-led voluntary standards and compliance rather than regulatory measures.・In all regions, the positioning of CE within industrial policy and specific implementation strategies are not yet clearly defined.

This analysis suggests that promoting CE requires a comprehensive approach that includes sharing a vision, advancing integrated policies, fostering stakeholder collaboration, and making proactive investments in infrastructure. However, integrating circular economy policies with economic policies and establishing a CE promotion framework that includes the business sector remain key challenges. Further research on the theoretical and political aspects of these challenges, as well as case studies from other countries and regions, is necessary.

Access-based Consumption (ABC), where consumers access products or services without transfer of ownership, is gaining attention globally as a sustainable alternative to conventional ownership. However, its adoption remains limited in Japan, particularly in the context of occasional fashion such as graduation ceremony attire. This study investigated ABC in a localized Japanese context by examining attire choices and consumption methods among students at the Institute of Science Tokyo. An online questionnaire survey was conducted in January 2025, collecting 70 valid responses. Attire types were categorized as suit, academic gown, traditional or cultural attire, and daily wear; consumption methods included purchasing, renting, using pre-owned items, and customization. Analysis using Pearson’s chi-square test and correspondence analysis in R revealed that suits (32%) and academic gowns (24%) were most chosen, while rental was selected by only 10%. Budget, accessibility, and peer influence were major decision factors, while sustainability concerns ranked low. The results indicate a significant association between gender and attire type, while consumption method choices tend to reflect students’ environmental awareness and engagement in 3R practices.

In Japan, approximately 1.79 million tons of vegetables are not shipped each year due to failing to meet market standards, contributing significantly to food loss. According to the 3R principles, reducing food waste at the source is a top priority, and the promotion of food sharing is essential. This study aimed to effectively utilize substandard vegetables through sharing services. A vegetable market was held on a university campus, where a total of 130 vegetables were sold, generating a profit of 2,000 yen. In addition, a questionnaire survey was conducted with 53 farmers and 20 consumers. The results showed that more than half of the consumers expressed strong interest or interest in a sharing app for substandard vegetables, indicating high demand. On the other hand, farmers identified burdens related to packaging and unfamiliarity with app usage as barriers to adoption. Key factors they emphasized were low transaction fees (average: 4.6) and ease of operation (average: 4.55). To promote sharing services, it is crucial to enhance customer satisfaction through offering processed food options and to develop systems that reduce the burden on producers. Future research should also include large-scale farmers, who were not fully examined in this study.

This study aims to quantitatively assess the impact of changes in consumer behavior on household food waste generation. Based on two internet surveys conducted in March 2023 and March 2024, we employed ordinal logistic regression to identify behaviors that significantly reduce food waste and to estimate the extent of reduction. The analysis focused on three types of food waste: disposal due to expiration, over-preparation, and leftovers. Additionally, by using data from a municipal waste composition survey, we distinguished between "recognized" and "unrecognized" food waste, enabling a realistic estimation of potential reductions. The results indicated that behaviors such as checking refrigerator contents before shopping and avoiding impulse purchases of discounted items were particularly effective. Under the assumption that all consumers fully adopt effective behaviors, the projected household food waste in 2050 could be reduced by up to 56% compared to 2024 levels. These findings suggest that improving consumer food management practices has significant potential to reduce household food waste.

In order for generators to fulfill their responsibility to dispose of industrial waste and engage in proper disposal, it is necessary for them to fully understand the points to be considered when disposing of industrial waste, which differ for each type of industry.

Therefore, JW center conducted a survey of the automobile industry, one of Japan's major industries in 2024, in which a wide variety of businesses are involved in manufacturing and sales, and a wide variety of industrial waste is generated, to learn about initiatives for the proper disposal of industrial waste, examples of the use of e-manifest and recycling initiatives. The survey results were compiled with the aim of improving understanding and awareness of the proper disposal of industrial waste.

This report presents case studies from the survey results on the proper disposal of industrial waste, as well as on initiatives for resource recycling and decarbonization.

In this study, we aimed to simplify the composition analysis of municipal solid waste by verifying the effectiveness of image analysis methods using deep learning. Semantic segmentation (PSPNet) was applied to waste images to estimate composition ratios. The mean Intersection over Union (mIoU) was 0.414, with particularly high classification accuracy for paper/fabric and incombustible categories. In contrast, accuracy decreased for wood/bamboo/straw and kitchen waste due to diversity in shape and appearance as well as overlapping. Furthermore, weight ratios for each waste category estimated from the area proportions showed good agreement with measured values. Future improvements, such as increasing sample size and refining the methods, are expected to further enhance accuracy.

In this study, a model was developed to estimate the error due to sample pretreatment methods for measuring the biomass content of household plastic waste. After pretreatment of the collected plastic samples with “sorting and foreign material removal” and “crushing and shrinking”, ¹⁴C analysis was performed to determine the biomass content. A model was examined for the crushing and shrinking process for plastics with biomass labels and with biomass carbon in the main plastics. Model input values (e.g., pre- and post-crushing weight) were determined by an individual survey of the target plastics, and an error estimation model was created by Monte Carlo simulation. Comparison of the model estimates with the ¹⁴C measured values confirmed the effectiveness of the method to correct for the left-right bias of the sample in the shrinking process using a sample splitter. Future tasks are to apply this method to plastics in combustible waste, to develop an error estimation model for the sampling process, and to develop a model for the crushing and shrinking process that can be applied to the entire waste plastic sample.

In Japan, the target of halving avoidable food waste compared to the level in year 2000 was achieved in 2022 for the wholesale, food retail, and food service sectors. However, the target is yet to be met for food waste from households. There is a need to develop effective measures for the prevention of household food waste. Based on evidence that awareness raising does not directly invoke behavioural change, the authors discussed the possibilty of suggesting practical measures for action. The authors distributed refrigerator management tools for food waste reduction to a community of about 230 households. Social experiments were conducted in Maizuru City, Kyoto Prefecture in 2022 and in Arakawa Ward, Tokyo in 2023. In Maizuru City, food waste reduction in the control area was greater than in the experimental area, and we could not indicate that the intervention was effective. Reasons and factors were analysed, and an improved intervention was introduced in Arakawa Ward. As a result, it was shown that food waste decreased in the experimental area. We suppose that the nature of the locality and the community, as well as the effect of the improved social experiment methods, had an impact on the results.

The authors conducted food waste reduction campaigns titled the “Nokori-Fuku Campaign” in 2022 and 2023, focusing on food retailers in Okayama City. In November 2024, the third phase—“Nokori-Fuku Campaign 2024”—was implemented. Activities included the webcasting of discount foods and presentation of awareness-raising materials on “Temaedori (picking up from the front)” and “Purchase of discount foods” such as posters, POPs, leaflets, and digital signages at six stores in Okayama city.

This study aimed to evaluate the impact of the 2024 campaign by comparing food waste, customer traffic, and food sales before and during the campaign. The analysis was based on food purchase data (ID-POS) from one participating store. During the campaign period, food waste value decreased by 33.6%, the number of store visitors increased by 6.9%, and sales rose by 2.0%, compared to September 2024, which served as the control period. The Cooked Rice category showed a reduction in food waste with minimal sales promotion, indicating improved efficiency. The Unchilled Side Dish category demonstrated both increased sales and reduced waste, suggesting the campaign’s dual effectiveness in this area.

Overall, ID-POS data proved valuable in evaluating the campaign’s effectiveness and can offer more detailed breakdown by factors like attributes.

As global concern over marine plastic pollution has grown, waste management—particularly landfilling—has been identified as a significant source of environmental plastic emissions. International assessments have shown that mismanagement of plastic waste constitutes the largest source of such emissions, underscoring the urgent need for measures to prevent plastic release into terrestrial and aquatic environments through improper treatment and disposal. Although the impact of waste management on plastic emissions in Japan is considered relatively low due to the current system's integrity, quantitative evaluation of emission pathways and volumes is essential for assessing the effectiveness of various policies aimed at promoting plastic recycling, resource circulation, and emission reduction. We have been developing a model that estimates environmental emissions of plastics from waste management processes, taking into account the degradation and fragmentation behavior of plastics. This presentation reports the results of a scenario analysis evaluating the environmental emissions of microplastics in response to the introduction of advanced recycling technologies for municipal solid waste plastics.

Ammonia (NH₃) is a major air pollutant and a key contributor to odor issues in livestock farming. In Jeju, Republic of Korea, the intensification of pig farms has raised concerns over odor impacts on nearby communities. This study investigates NH₃ emission trends and simulates its dispersion using the CALPUFF model. Field measurements were conducted at a fattening pig farm in Hallim-eup, Jeju, from March 21-23, 2025, with NH₃ concentrations recorded inside and outside the facility using LSE-1700 sensors. Micrometeorological data were collected at one-minute intervals. Emission rates were estimated based on a national emission factor and applied to 38 surrounding farms. CALPUFF simulations for March 22 showed NH₃ concentrations peaking during the day(2.74-3.73 mg/m³) and declining at night (0.32 mg/m³), consistent with observed patterns. The results highlight the influence of farm operations and weather conditions on odor dispersion. The CALPUFF model demonstrates potential as a tool for managing livestock-related air quality issues. Future work will compare measured and modeled data to validate simulation accuracy.

This study explores the question of “Who are the volunteer litter pickers?” This will promote better understand diverse actors involved in marine litter issues and to enhance sustainable support frameworks. Interviews were conducted with marine litter groups and community groups conducting litter pickup activities in Osaka Prefecture, and qualitative data analysis was conducted. Both groups have differences which is organizational types and activity areas, but, both groups reported common social outcomes such as “Increased environmental awareness” and challenges to continuation such as “Aging of the population”. Furthermore, there are differences in the way of involvement with local government. In order to enhance the sustainability of voluntary litter pickup activities, it is necessary the creation of a flexible support system by the government and building a relationship in which diverse actors support each other through dialogue, while taking into consideration the actual conditions and opinions of the groups.

In recent years, the increasing presence of lithium-ion battery-powered appliances has heightened the risk of fire in waste treatment facilities. This paper introduces two AI-based detection systems developed to address this issue. The first is “Think View® for Fire-Smoke,” which continuously monitors refuse pits via camera feeds and detects early signs of smoldering or fire. To overcome the lack of training data, synthetic fire images were generated using image generation AI, and false positives were reduced by incorporating equipment status logic. The second system explores the use of large language models (LLMs) to detect improper waste—such as lithium-ion batteries and gas canisters—on pre-shredder sorting conveyors. Through careful prompt design, the LLM was able to infer and identify hazardous items from appearance and context, even without prior category-specific training. These AI technologies are expected to contribute significantly to improving both the safety and operational reliability of waste treatment plants.

This study aims to identify key challenges in enhancing the educational quality of field trips to waste treatment facilities within the fourth-grade social studies curriculum in Japanese elementary schools. Through an analysis of changes in the national Course of Study, the research emphasizes that such visits should reflect the current pedagogical focus on “proactive, interactive, and authentic learning.” The study explores the complex involvement of various stakeholders—incineration and recycling facilities, waste collection and planning departments, teachers, and boards of education—and highlights issues such as a lack of coordination among these actors and inconsistencies in the availability and usability of educational materials. An attempt was made to visualize students’ levels of interest during visits through direct observation; however, challenges arose in obtaining reliable quantitative data due to students’ performative behavior in the presence of observers. Despite the ambiguity surrounding final responsibility among stakeholders, the study concludes that continuous improvement is essential—not only to elevate the educational value of such experiences but also to support public awareness through student engagement.

Since a large amount of resources are used in construction, the impact on local resource circulation is significant, and the improvement of the resource circulation performance of buildings is considered to make a significant contribution to the realization of a circular economy. In this study, we organized the requirements for buildings that lead to the improvement of resource circulation in the 5Rs by adding two Rs to the 3Rs, and verified practical technical issues through the design and construction of experimental prototypes that take these into consideration. In addition, at the time of prototype planning, we examined and tested a method for evaluating resource recyclability.

According to a survey by the Ministry of the Environment, more than 30% of litter that drifts ashore originates from fishing activities. On the other hand, fishermen are also victims of marine litter and conduct collection activities voluntarily. This study quantitatively clarified the actual situation and contribution of fishermen's collection activities and external diseconomies in the Tsushima region, Nagasaki Prefecture, and evaluated the sustainability of the collection project until 2050 by using system dynamics. As a result, fishermen were accounted for 97.0% of the marine litter collection in Tsushima (83.7% of the collectors), and their collection efficiency was also higher than the national average. On the other hand, the results of the environmental and economic analysis also revealed economic burdens. The scenario in which the amount of marine litter collected decreases from 7,968 m³ to 4,172 m³ suggests that future collection projects may be difficult to continue due to a decrease in the number of fishermen, requiring multifaceted measures that include economic incentives and collaboration with other entities.

Demographic changes resulting from a declining birthrate and population, coupled with an increase in the elderly population due to rising life expectancy, are exerting wide-ranging effects on various aspects of society. The purpose of this study is to empirically examine the current implementation status and associated challenges of waste separation and collection support systems for the elderly. To this end, a questionnaire survey was conducted targeting all 1,741 municipalities across Japan. The study investigated the status and operational challenges of these support systems, with a particular focus on municipal size and the proportion of elderly residents. The analysis showed that municipalities with larger populations are more likely to have implemented such support systems and to have undertaken waste management and environmental initiatives. Furthermore, while financial and human resource constraints were found to be common challenges across all municipalities, a general trend emerged indicating that staff shortages are perceived as a more critical issue than budgetary limitations.

Nigeria is facing challenges in waste management due to urban population growth accompanying economic development. In healthcare waste management, issues such as inadequate separation, collection, transportation, treatment, and disposal, as well as insufficient knowledge among healthcare workers responsible for waste management, have emerged. To address these challenges, a technical cooperation project was implemented by the Japan International Cooperation Agency (JICA). This project designated the Abuja Environmental Protection Board (AEPB) and the Health, Services and Environment Secretariat (HSES) as counterpart agencies and worked to develop a healthcare waste management basic plan for Federal Capital City (FCC) of Abuja and enhance the capacity of healthcare waste management personnel. During the development of the basic plan, two waste treatment methods were discussed: Centralized Treatment System and Hybrid Treatment System. After considering technical, cost, and institutional aspects, Hybrid Treatment System was adopted. Under this method, HSES-affiliated core healthcare institutions will operate and maintain incinerators under the supervision of AEPB, ensuring stable and appropriate operation.

Plastic pollution has emerged as a pressing and persistent global environmental challenge, prompting governments to adopt a wide array of policy instruments targeting the production, use, and disposal of plastics. While initial interventions—such as bans and taxation—primarily aimed to mitigate immediate environmental harms, recent developments reflect a growing interest in more integrated and innovation-oriented approaches. Nevertheless, there remains a lack of systematic academic analysis on how these policies are evolving over time and whether they are capable of supporting long-term structural transformation. This research addresses the critical need for a more comprehensive understanding of the evolving global plastic policy landscape by constructing a typology of plastic-related policies and evaluating their transformative potential. By linking theoretical inquiry with applied policy analysis, the research seeks to contribute a robust analytical foundation for understanding plastic policy transformation and informing the design of more coherent, forward-looking governance strategies.

This paper reports on the progress of JICA's waste management improvement activities in the Republic of the Sudan and the Republic of South Sudan, where unrest continues, based on requests from both countries.

We asked a neighborhood association in Okayama City to complete a questionnaire survey to find out the current number of people who have difficulty taking out the trash, the reasons for their difficulties and requests for support, the need for support from the neighborhood association, and the willingness to cooperate as individuals. We also asked about voluntary and paid support. The most common answers were: "Help is needed for elderly households who have difficulty taking out the trash, and it would be best for the city or the neighborhood association to handle it. If the neighborhood association decides to provide support, we can provide volunteer support (free of charge). If it is paid, the compensation is about 100 to 500 yen per trash takeout. The acceptable range of help is "about two 45L bags (about 5 kg), within a distance of 100 m, and within 10 minutes." The working generation, mainly in their 40s, have difficulty helping because they have a lot of time." As only 4.1% of households in this town currently have trouble taking out the trash, the burden on those who help is small and there is a great possibility that the community can provide support.

Unlike in European countries and the United States, fruits and vegetables are rarely sold by weight in Japanese supermarkets and are often individually packaged in plastic. Therefore, in this study, we surveyed about 50 supermarkets to investigate the actual situation of plastic packaging of fruits and vegetables. Based on the results, we also examined how the plastic packaging of fruits and vegetables could be reduced.

The wider area expansion and consolidation of multiple general waste incineration facilities is being promoted. Even if the facilities are managed in wider area, there are cases where it is not possible to consolidate them into one facility. When there are multiple incineration facilities in each expansion block, city, town, or municipality, it is necessary to decide which incineration facility combustible waste should be brought to for each district in order to process the waste in a planned manner. In this case, it is often studied as a delivery plan problem, such as searching for a route with the shortest driving distance for collection and transportation vehicles. In this paper, we considered a collection and transportation plan that maximizes the amount of electricity generated by incineration at multiple facilities in the jurisdiction of the expansion block, city, town, village, or municipality, and suppresses CO2 emissions from power generation and collection and transportation, and conducted a case study. By using this planning method, the city, town, village, or municipality was able to create a plan to appropriately transport combustible waste to the facility for each district.

Bio-based or biodegradable plastic, together defined as bioplastics, are often perceived to have lower environmental impacts. However, given the pathway of plastic waste management, bioplastics can cause negative environmental impact. This study quantitatively evaluated the environmental impacts of substituting fossil-based packaging plastics with bioplastics. We assumed 100% substitution of conventional fossil-based, non-biodegradable packaging plastics with bio-based or biodegradable plastics (bioplastics). To assess environmental impacts, GHG emissions, the amount of plastics disposed of in landfills, and the amount of plastic that leaks and remains in nature were calculated.Sum of greenhouse gas emissions in the seven regions totaled 1.4 ×10² Mt CO₂e for conventional plastic packaging, and 2.4×10² Mt CO₂e for bioplastic packaging. Landfilled plastic waste totaled 2.9×10² Mt for the conventional plastic packaging, and 2.1×10² Mt for the bioplastics. The quantity of plastic waste that leaks into and remains in natural environments was 1.8 Mt for conventional plastic packaging and 1.6 Mt for bioplastics. In future research, the authors will assess waste management pathways that maximize environmental benefits of bioplastics, in terms of greenhouse gas emission reductions, landfill capacity preservation, and prevention of environmental plastic leakage into nature.

This study aims to links artificial intelligence (AI) techniques with a human mobility monitoring system (location data) in waste management through the use of MATLAB. Based on electronic manifests from a local recycling company in Fukuoka, Japan, we developed a two-step AI-based approach for predicting the collection demand of industrial plastic waste (IPW) from a hospital. We newly introduced the GPS-observed daily hospital user numbers as an independent variable in the IPW collection demand prediction. We achieved a high monthly mean accuracy (85.1%) in predicting daily IPW collection demand, which exceeded the accuracy of predictions using models without user records (84.4%). This result demonstrates the effectiveness of introducing the user variable into IPW collection demand pre-dictions and implies potential policies to regulate future visitor numbers in hospitals to control future IPW generation. Based on the findings of this study, we propose several strategies for waste management: enhancing prediction models, controlling visitor flow, and analyzing working patterns.

Despite the uprising direction on implementing a sustainable approach to manage solid waste, there has been no significant improvement in effort to address the waste pickers’ situation in developing countries. Through a questionnaire survey and correspondence analysis, this study aims to reveal waste pickers’ preference towards various life aspects and how these preferences vary by landfill location. This study reveals the noticeable difference of waster pickers’ preferences on life aspects identified at two landfill sites in Indonesia, emphasizing their varying selection patterns. At the Bantargebang landfill in the Jakarta area, participants prioritized aspects such as “house,” “nutritious meal,” “income,” “physical health,” and “life in community,” indicating a preference that is predominantly individualistic and material-oriented. In contrast, at the Sarimukti landfill in West Java, waste pickers emphasized “religion,” “physical health,” “house,” “child rights,” “nutritious meal,” and “income,” revealing a tendency toward sociocultural and family-focused values. These findings provide valuable insights into the preferences and needs of waste pickers, serving as a foundation for policy development aimed at improving their living conditions.

This study is evaluation of multiple municipal solid waste management system on plastic sorted collection in Tottori Central Region. In consequence plastic sorted collection and methane fermentation can reduction of greenhouse gas releases. But, it should be noted that it is costly. To be cost effective, the Monetary Values of greenhouse gas emissions should be about 43,000 yen/t-CO2.

This study conducted an online survey in September 2024, and examined the determinants of behavioral intention to sort among Nagoya City, which started bulk plastic collection in April 2024, and other municipalities in Aichi Prefecture that had already introduced bulk collection by April 2024, as well as those that had not yet done so.Multiple regression analysis showed that social benefits had the strongest positive influence on the intention to cooperate in all three regions, and procedural justice also had a relatively strong positive influence. As for the perceived fairness of the results, burden on some people had a significantly weak influence only in Nagoya City and the municipalities other than Nagoya City that implemented sorting, while perceived unfairness of sorting itself had a significantly weak negative influence in all three regions. Perceived implementation level of sorting as a descriptive norm had a weak positive effect only in the municipalities other than Nagoya City. In order to increase the intention and raise the sorting rate under the new system, in addition to promoting the social benefits of bulk collection, it is necessary to decrease the unfairness of separating waste.

This paper presents the Sid Model, developed from 2021 to 2024 during the Japan International Cooperation Agency’s “Project for Capacity Development of Solid Waste Management” in Serbia with the goal of reducing waste management (WM) costs. The Sid Model addresses the challenges associated with WM faced by small municipalities upon joining the Regional Waste Management System (RWMS). Focused on Sid Municipality, the Project conducted six surveys to understand the existing WM situation and identified key issues such as high landfill disposal rates and illegal dumping. In formulating the Technical System for Sid, the Project separated waste into categories of recyclable, landfill, and specific waste, evaluating and then implementing cost-effective collection and transportation options suitable for each category. Pilot projects were conducted to test the system, resulting in decreased landfill disposal and increased recycling rates. The Sid Model includes modules based on project stages and activities, and aims to guide other municipalities in adopting sustainable WM practices, tailored to their specific conditions. The Sid Model was finalized with a workshop and disseminated through a seminar, with plans for further dissemination by the Serbian Ministry of Environmental Protection (MEP).