The purpose of this study is to create an assessment indicator for the cleanliness of City A. The indicator is designedto improve the administrative procedures and cleaning services that require enhancement. The presently used criteria for evaluation employ identical measures for all districts which causes doubt in the accuracy of the results. To enhance the assessment criteria, representatives from city A and environmental specialists scrutinized the categories for cleaning services and sanitation evaluations. Afterwards, the evaluation criteria were ranked for a survey involving double comparison. The responses from the survey were graded based on the Analytical Hierarchy Process (AHP), taking into consideration the weight of each item. According to the AHP analysis, waste collection had the largest impact with a weight of 0.40 within the category of cleaning services. Additionally, the subdivision of "the state after waste collection" had the highest weight at 0.27.Using the AHP results, City A can determine policy directions to improve the finishing state after waste collection. It isrecommended to utilize evaluation components from City A which have unique weights assigned by different groups ofrespondents. The suggest three ways: 1) Integrating them into existing cleanliness assessment areas and items, 2) Creating newcriteria for evaluating cleanliness, and 3) Designing a "evaluation system by subject" that takes into account the specific circumstances in each location.

Chemical emissions from business establishments including that of below-threshold in Pollutant Release and Transfer Register (PRTR) in each local municipality were estimated for Osaka Prefecture area. Estimation was performed based on the chemicals’ characteristics such as gas/liquid/solid. In addition, emissions per unit area and that per business establishment were calculated. Approximately 96% of the total emissions are liquid, and almost all of them are volatile substances. In some municipalities such as Ikeda City, it is suggested that a small number of business establishments use a large amount of chemicals. In such municipality, surveys and supports for specific business establishments in such areas seems to be important. On the contrary, in some other municipalities such as Nishinari Ward and Higashinari Ward of Osaka City, it is suggested that many establishments use small amounts of chemical substances. In such areas, it is considered that grasping the used chemical substances by neighboring business establishments to prevent the mixture accidents with other chemicals is important.

After a large-scale disaster strikes, compositional information (materials and quantities), such as the ratio of flammable waste and non-flammable waste contained in disaster waste, is necessary to formulate a treatment plan and a plan for the layout of temporary treatment facilities for disaster waste accumulated in temporary storage spaces. Therefore, we have begun to develop an estimation method for the material composition of disaster waste accumulated in temporary storage spaces using near-infrared spectral information captured by a hyperspectral camera. Wavelengths in the near-infrared region used for estimating compositional information (materials) includes wavelength ranges where the spectral intensity is attenuated by water vapor in the atmosphere when taking pictures outdoors. Because of this, there is concern that accurate acquisition of spectral intensity outdoors may hinder the estimation of compositional information (material). Accordingly, as a method to solve the problem, we devised and demonstrated a method to add light with a halogen lamp. As a result, it was confirmed that the spectral intensity was not attenuated. From now on, we plan to develop a method to add light when taking pictures outdoors for hyperspectral camera.

This study analyzed the problems of public-private partnerships in primary temporary storage for disaster waste disposal in Hiroshima City. As a result, it was found that it is important to dispose of disaster waste within one's own ward as much as possible from the viewpoint of cost reduction. On the other hand, it was confirmed that there are human constraints in implementing public-private partnerships within the district, and that improvements are needed. When considering the treatment of disaster waste, it may be necessary to identify public and private facilities and human resources, and to consider in advance measures to deal with public-private partnerships, such as measures to reduce the number of personnel at primary temporary storage sites.

The purpose of this study is to clarify the current state of efforts by the local governments across Japan to promote public involvement in disaster waste governance including dissemination of information, awareness-raising, and collaboration. To this end, we conducted a questionnaire survey of local governments across Japan, asking about the content, methods, effects, and preconditions for implementation of cooperative actions on disaster waste governance. The obtained responses were tabulated, and correspondence analysis was applied to clarify the preconditions for promoting cooperative actions with residents regarding disaster waste management from normal times. As a result, it became clear that while local governments are preparing for the treatment of disaster waste, efforts to obtain residents' cooperation for proper discharge of disaster waste are not widespread, and this is recognized as an issue by local governments. It was also suggested that there are various prerequisites other than the availability of budgetary resources for active cooperation with residents.

In this paper, we conducted a workshop on disaster debris using a giant map projection mapping system, and examined situation-aware scenarios. As a result, it was shown that the medium damage scenario is more effective than the worst-case scenario in considering specific disaster countermeasures and responses, such as the establishment of temporary sites in the workshop. It was pointed out that it is important to conduct disaster waste workshops using hazard information such as half-cracks related to the Nankai Trough earthquake extra information in order to improve the effectiveness of concrete measures and disaster waste treatment plans, as well as to promote the measures for the Nankai Trough earthquake extra information.

Regarding general waste collection in Japan, it is important to deal with issues such as the management stability of business operators and the securing of manpower for collection work. Based on this awareness of the problem, as part of a comparison with other countries, Singapore, which is characterized by a small land area and a high population density similar to Japan, has Public Waste Collectors, which is the core of the household waste collection system. Some of the three PWC companies are part of a large corporate group, while others have grown from scratch. The corporate value of each company has expanded and grown compared to around 2000, when the privatization of the collection business began in earnest, and the recently reported sale of SembWaste is expected to cost approximately 50 billion yen. It's getting bigger. It can be said that increasing the scale of collection companies is one direction for securing profitability.

This research finds that solid waste management project is developed through two positive input actions together. This research also finds self-organization positive effects to the project to be developing.

The research is using synergistics theory to analyze.

First, project system modeling, making Master equation and Fokker Prank equation to solve probability distribution. And to evaluate project potential entropy is used.developing and sustainable.

The research is using synergistics theory to analyze.

First, project system modeling, making Master equation and Fokker Prank equation to solve probability distribution. And to evaluate project potential entropy is used.

Dr. Seiichi Oi, who was appointed as the first assistant professor of the Third Department of Civil Engineering at Kyoto Imperial University at the young age of 23, laid the foundation for sanitary engineering education and research centered on water supply and sewerage, and as a leading expert in water supply engineering, he demonstrated his efforts in the construction of water supply facilities in various regions. However, it is not known at all that he was elected to the Kyoto City Assembly in Taisho 7. In this article, I would like to introduce Dr. Seiichi Oi's activities during his time as an alderman through "Kyoto City Council Minutes" and other sources.

In 1991, the Waste Disposal and Public Cleansing Law (hereinafter referred to as the "Waste Disposal Law") was amended. In response to the revision of the law, it was the first step to actively work on waste reduction by incorporating emission control and recycling from mass disposal of waste. Taking the case of Hachioji City as an example, we will consider how the local government's cleaning business responded to such a major shift in waste treatment policy. The reason why Hachioji City was selected is that from the Taisho era to the Reiwa era, it has dealt squarely with the issues of cleaning administration according to the times and carried out cleaning projects appropriately. Then, from the viewpoint of local autonomy, we will take up what kind of efforts were made.

The marine plastic litter problem is recognized as a serious social issue. The purpose of this study is to create a logic model to illustrate how current activities could lead to the "long-term outcomes" (e.g., carbon neutrality and zero pollution from marine plastic waste). Interviews were conducted with local supermarkets, retailers, local governments, manufacturers, and industrial waste disposal companies, which were reflected in the creation of the logic model, and "negative impacts" that are assumed to occur as a side effect in the process of social change were also examined and attempted to be included (in gray) in the diagram.

To evaluate the effect of 3R Plus principle, GHG reduction effect by plastic material replacement from household waste was estimated in addition to waste prevention effect.

Regarding waste prevention, 37 items that were avoidable were assumed to be reduced by 50%. For material replacement, 19 plastic items were assumed to be replaced by paper, wood, glass, and metal, respectively (bioplastics were excluded). As a result, the GHG reduction potential was estimated to be 96,000 t-CO₂eq compared to the current scenario, while the plastic material replacement was additionally reduced by 11,000 t-CO₂eq. In addition, the results showed an expected reduction of 52,000 t-CO₂eq by achieving Kyoto City's 2030 target. Other GHG reduction effects of 3R policies not evaluated in this study will be evaluated in the future.

In order to achieve carbon neutrality by 2050, we need to reduce CO2 emissions. In recent years, attention has focused on technologies that reduce CO2 emissions by using CO2 as a raw material to produce chemical substances to replace fossil fuel-derived substances. Methanation is a technology to generate CH4 by reacting CO2 and H2, and the generated CH4 can be used as a substitute for natural gas. As part of a project commissioned by the Ministry of the Environment, a demonstration test was conducted to produce CH4 on a commercial scale by extracting some of the flue gas from the No. 4 furnace at the Odawara City Waste Incineration Plant and capturing CO2. The test results confirmed that CH4 can be produced from the flue gas of the waste incineration plant, and the targeted CO2 capture rate of more than 50%, CO2 concentration of the captured gas of more than 80%, and CO2 conversion rate of more than 90% were achieved. In addition, the CO2 emission reduction effect was estimated, and it was confirmed that a reduction of approximately 0.3 t-CO2/t-captured CO2 can be expected when low-carbon H2 is used for methanation.

Japan's population began to decline after reaching 128 million in 2008. As the population declines, it is expected that the amount of combustible waste delivered to incineration facilities will continue to decrease. This study aimed to examine how combustible waste could be effectively treated from the viewpoint of energy in rural areas in Japan, proposing the indicator of the net energy production rate. First, we projected the future per capita combustible waste generation, physical composition, and lower calorific value. Next, four combustible waste treatment scenarios (incineration scenario, WtE incineration scenario, thermal drying scenario, and bio-drying scenario) were designed. The bio-drying scenario with RDF production had the highest net energy production, with the rates ranging from 43.8% to 60.7%.

In Japan, interest in the realization of carbon neutrality (CN) and the transition to a circular economy (CE) is growing. In order to gain insight into the potential contribution of CE to CN, we conducted a study on the future of recycling in 2050, using plastics as the subject matter. In this research, we set up a future vision based on the accumulation of the effects of measures to be implemented by 2050 according to the announcements of various organizations. After that, we organized the material flow and calculated the CO2 emissions in the manufacturing and recycling stages in the future vision.

As a result, it was found that it is difficult to realize CN in the future vision in which the existing measures are accumulated, and it was suggested that additional measures are necessary. In this research, we set three examples of measures from the perspective of resource recycling: common design, increased use of recycled plastics, and increased production of domestically produced biomass plastics. However, even with additional measures, CN has not yet been realized. It was suggested that more ambitious resource recycling measures must be developed.

There is a possibility that other environmental problems will improve or worsen at the same time as the implementation of environmental measures. Trade-offs between issues need attention, and material cycles and waste management measure themselves may lead to trade-offs that increase other environmental impacts. Since there are various trade-offs, it is also effective to organize the types in advance to prepare for measures and shift problems. It is considered to be effective in preventing In this study, trade-offs between the fields of resource circulation and waste management and other fields such as decarbonization are classified into 12 categories, focusing on four types of measures and three types of impacts. Specific examples for each category were extracted from the existing literature, and outlines and trade-off contents were extracted and organized. Furthermore, cautions regarding trade-offs were also considered.

GHG emissions from incineration and fuel use of municipal solid waste account for a large proportion of GHG emissions from municipal solid waste management and are an important emission reduction target. In this study, GHG emissions from municipal solid waste incineration plant were estimated up to 2045 for Kusatsu City, where our university’s BKC campus is located: several countermeasure scenarios were assumed, and their effects were examined. On top of this, a scenario for reduced CO2 emission factor of electricity through the introduction of renewable energy was examined.The results showed that in 2045, the waste reduction scenario, the biomass plastics introduction scenario and the methane fermentation facility introduction scenario had reductions of 15%, 31% and 42% respectively compared to the BaU scenario. As the reduced CO2 emission factor of electricity diminishes the CO2 reduction effect of waste power generation, further measures such as carbon capture, utilization and storage (CCUS) are considered necessary to reduce net GHG emissions from waste incineration facilities to below zero.

It has been pointed out that the 3Rs of disaster waste, which include not only securing treatment capacity and advanced recycling, but also reducing the volume of disaster waste, are indispensable for disaster waste countermeasures in the event of national disasters such as the Nankai Trough Earthquake and an earthquake directly under the Tokyo metropolitan area. On the other hand, Japan has declared its goal of becoming carbon neutral by 2050, aiming to reduce greenhouse gas emissions by 46% from the fiscal 2013 level by the year 2030. In the event of a disaster, CO2 emissions are expected to be generated in the process of disaster waste treatment, such as incineration, transportation, and CO2 emissions from the fixed carbon in the wood used in houses. The purpose of this study is to develop a method for estimating CO2 emissions from the treatment of disaster waste from the demolition and transportation of houses damaged by housing damage, and to estimate CO2 emissions from the treatment of disaster waste for the 2016 Kumamoto earthquake. The results showed that the transportation of disaster waste contributes significantly to CO2 emissions from the treatment of disaster waste.

In this study, we formulated the facility siting plan as a mixed integer programming problem for Kyoto Prefecture in the year 2050, and obtained an approximate solution for the optimal siting. In particular, we focused on the trade-off between economies of scale due to the expansion of the scale of treatment relocation and disadvantages due to longer transportation distances, and performed sensitivity analysis when the unit cost of transportation was varied. Compared to the current 16 facilities, the optimal arrangement resulted in 3 to 6 treatment facilities, and treatment costs were reduced by 15 to 20%. Higher unit transportation costs led to greater consolidation, while lower unit transportation costs tended to lead to decentralization. Under the condition of high unit transportation cost, treatment cost tended to increase as the minimum size of treatment facilities was increased.

After the adoption of Paris Agreement in 2015, efforts to reduce GHG emissions had been great issues globally. Incineration is commonly used as intermediate disposal of MSW. However it generates not only greenhouse gases but also air pollutants. In this study, GHG emissions from incineration of MSW was calculated between 1996 and 2021 in Korea, using the GHG emissions calculation tool provided by the Korea Environment Corporation. We also conducted scenario analysis to predict the amounts of MSWI and GHG emissions from 2022 to 2050. Business-as-usual and five scenarios were set and evaluated. This study found that the incineration of MSW and GHG emissions had continuously increased since 1996. Among municipal solid wastes, incineration of plastic accounted for over 90% of total GHG emissions during the year. Based on scenario analysis, S5 (replacement with bioplastics) showed the largest reduction rate. In the case of BAU, GHG emissions in 2050 is expected to increase by 80% compared to 2021. Adopting the S5 can be expected to reduce total GHG emissions by 95% during the same period. The results of this study may serve as basis data for reducing GHG emissions in the waste incineration sector and moving toward a carbon neutral society in Korea.

Single use plastic bags (SUPB) consumption soared with industrialization, spreading all over the world, and becoming the leading face of plastic pollution. Kenya adopted a SUPB ban in 2017 prohibiting manufacturing, importation, distribution, and usage. Current research indicate that the non-woven polypropylene (NWPP) bag is the most preferred bag in the country. Using life cycle assessment (LCA) a comparative environment impact, reuse potential and waste reduction effect was performed to assess the ban. The SUPB was adopted as the reference bag and NWPP as the main alternative and including woven PP bag (WPP) from cradle to gate. Process contribution results indicate for all bags, material extraction occurring outside the country primarily dominates GWP and fossil depletion while ozone depletion, particulate matter formation and human toxicity dominate bag production and distribution. For all emissions, SUPB has the least environmental impact since it is the lightest and WPP the highest, at the point of production and delivery. In terms of waste reduction, the substitution effect in waste reduction for the bags ranged from 98% to 67% with incremental usage of reusable bags from 2 bags to 21 bags. This suggests consistency in reuse to attain waste reduction and offset their environmental impacts.

The objective of this study is to develop a theoretical framework for quantitatively deriving the ideal state of the introduction of CCUS technologies in the waste sector in a carbon cycle that satisfies carbon neutrality, including carbon sources other than waste. For this purpose, the following mathematical optimization problem is formulated in this study. The objective function is "Annual system costs," the main constraints are "Conservation of mass," "Upper supply limit for storage and utilization technologies," and "zero CO₂ emissions," and the variables are "Amount of MSW treated by composition and treatment technology," "Carbon flow by origin," and "Facility installation amount”. The analysis was conducted under hypothetical conditions assuming incineration, gasification, and anaerobic digestion as waste treatment technologies, and methane synthesis and fixation in concrete as applications of CCU technologies. In the future, we will expand the time scale, waste treatment and CCU technologies, refine the inventory data for each technology, and implement this model with real space as input.

In one of the main cultivation methods for shiitake mushrooms, known as the spawn-based cultivation method, expanded polystyrene (EPS) caps are used as covers for the mushroom spawn. However, due to the lack of established proper disposal methods for the large quantities of EPS caps used, their disposal becomes challenging, potentially leading to microplastic pollution. In this study, chitosan was investigated as an alternative material to replace EPS.

However, the current chitosan-based caps used in the cultivation process under natural environmental conditions, such as in log cultivation, do not function properly as the cap sizes expand or contract depending on weather conditions. Therefore, the objective of this study was to develop a technique to improve the water resistance of chitosan-based caps, enabling them to function effectively as spawn caps even in natural environments.

For improving water resistance, methods such as incorporating insoluble chitin or applying coatings to the cap surface were attempted. As a result, a certain level of improvement in water resistance of the caps was achieved in this experiment.

In order to promote recycling of plastics, it is necessary to separate and collect waste plastics. Of course, it is effective to collect a large amount of waste plastics in one place and sort them by type using large-scale equipment, and this technology should be developed. On the other hand, it would be even more desirable if waste plastics could be easily sorted at each household. This is because, when the authors examined the percentage of plastic waste generated per week in a household of four, about 40% of the total could not be sorted because the materials were not marked or for other reasons. Therefore, we focused on near-infrared spectroscopy in order to propose a system to easily identify the type of plastic at home. In this study, we measured the near-infrared spectral characteristics (absorbance) of plastics and attempted to determine the type of plastic using the MT (Mahalanobis-Taguchi) method of quality engineering. We report the results of experiments conducted to determine four types of plastics (PE, PP, PS, and PET) using this method.

The global plastic waste generation exceeds 300 million tons per year, raising concerns about increased environmental burdens such as its release into the environment and the generation of greenhouse gases through incineration. In Japan, out of a total plastic waste discharge of 9 million tons, container packaging accounts for 4 million tons. Japan has set a target to achieve a 25% cumulative reduction in one-way plastic by 2030 and has been working towards the mandatory reduction of disposable products since April 2022. Plastic is widely used in the food manufacturing due to its lightweight, durability, ease of processing and coloring, and storage capabilities due to its low permeability to moisture and oxygen. However, the increasing use of various resins and materials for multi-layering complicates proper sorting during disposal, making recycling difficult. Therefore, this study aims to compare and analyze multiple identification methods for the resins and materials used in food packaging with high usage of layered plastics and to clarify the associated challenges

Aiming for a resource-recycling society, the cyclical use of plastics is required. The government plans to increase the use of plant-based biomass plastics, such as polylactic acid and bio-polyethylene, to 2 million tons by FY2030. Although biomass plastics are made from plants, it is desirable to chemically recycle them after use rather than incinerate them. We are working on the biogasification of polylactic acid, which is relatively inexpensive and widely distributed among biomass plastics. This section introduces the status of efforts and test results.

Waste of used diaper from adults is increasing due to aging society. Main treatment is incineration now, but there are some issues like, additional fuel is required, combustion control is difficult, and so on. Sorting method by disintegrating and washing has already implemented but taking out step from collection bag was necessary. In this research, breaking bag function was installed to the sorting machine. Installed inside blade could break collection bag and disintegration and separation in one machine was achieved. Working environment and efficiency was improved by this apparatus.

The technology to feed woody biomass materials in powder form into a reaction tube at 800°C and react them in a high-temperature steam atmosphere to produce combustible gases such as H2, CO, and CH4 is applied to plastics. Based on the knowledge of the thermal properties required to gasify plastic materials, gasification experiments were conducted using polystyrene beads as raw material in carbon dioxide and nitrogen atmospheres, using a simple gasification apparatus capable of conducting gasification experiments in a high-temperature steam atmosphere. In the experiment, in the carbon dioxide atmosphere, the highest amount of combustible gas was generated from 7 to 15 minutes after the start of gasification, and gasification was considered to have been most accelerated. The composition of the combustible gas after 8 minutes was H2: 10.2%, CO: 22.1%, and CH4: 0.13%. In the nitrogen atmosphere in the comparison zone, unlike the carbon dioxide atmosphere, carbon monoxide was hardly generated, and hydrogen tended to be generated mainly, and the composition of the gases was H2: 7.1%, CO: 13.6%, and CH4: 0.10%, indicating that the proportion of combustible gas was small.

Recycling plastics is a very important step for the solution of climate change, foreign waste import regulations and marine plastic pollution. ｢The Act on Promotion of Resource Circulation for Plastics｣ newly added to ｢The Containers and Packaging Recycling Law｣ and enforced on April 1st 2022. The selection by kinds of plastic materials is an important process in recycling plastics and the near infra-red spectrophotometer (NIRS) is applied as a popular optical apparatus in the mechanical selection.

In our study, we examined the infra-red spectroscopic analyses of various plastics by the portable NIRS combined with a plastic identification program. As a result, we could understand the analytical precision of the above apparatus and confirm the kind of plastic material and the component weight percent in multi-material plastics (laminated film) by using the database (DB) added by us.

We focused on improving the performance and downsizing of precipitation separation in plastic material recycling. It was improved a vertical device to the conventional horizontal device. It was used for sample agitation by installing a spiral plate inside the devise, except for the driving device required for the horizontal type device. These parts are manufactured using a 3D printer from 3D CAD data, and a digital twin method is adopted that enables both flow analysis inside the equipment. We tried to make it smooth design.

An effect of metal hydroxide-based flame retardants on shape collapse of thick-walled mouldings in an industrial composting environment was evaluated for polylactic acid (PLA) composites. PLA composites with 30 wt% aluminium hydroxide (Al(OH)₃) and magnesium hydroxide (Mg(OH)₂), selected as flame retardants, were prepared and PLA and PLA composite specimens (t = 4 mm) were produced by injection moulding. These specimens were buried in an industrial compost environment for 60 days and evaluated for changes in the shape and mass of the specimens. The shape collapse of the PLA composites with 30wt% Al(OH)₃ was less than comparable to neat PLA, which split to the cm scale and lost 14% of its mass in 60 days. PLA composites with 30wt% Mg(OH)₂ added fined and reduced in mass by 55% in 7 days and by 84% in 60 days. Therefore, the addition of Mg(OH)₂ in PLA composites accelerated the shape collapse of thick-walled moulds in industrial compost.

The massive accumulation of plastic packaging wastes in the natural environment is surging at a breakneck pace, highlighting the significance of sustainable alternatives. We have previously reported that Kraft paper (KP) coated by crosslinked poly(vinyl alcohol) (PVA) (henceforth referred to as KP-PVA) features remarkable oxygen and water vapor barrier along with mechanical properties comparable to most commodity plastics. Here, we demonstrate that this same KP-PVA can be significantly biodegraded in the marine environment. The biodegradation test was conducted by employing respirometry per ASTM D6691-17. The KP-PVAs were mineralized (59.2–81.6%) into CO₂ in 111 days. Depolymerization of polymer chains and surface degradation of KP-PVAs were evidenced using Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The intensive disintegration of KP-PVA was synergistically driven by both biotic and abiotic factors (mechanical stress). Moreover, the in vitro biocompatibility test for MEF (mouse embryonic fibroblasts) and HEK293 (human embryonic kidney cells), and in vivo biocompatibility test with mice proved that the KP-PVA is safe and does not endanger marine life. These results suggest that the KP-PVA could be a sustainable alternative to non-degradable plastic packages polluting the marine environment.

While developed countries generate a lot of plastic waste, exporting it to developed countries has led to environmental and health problems in the developed countries. Some developing countries have recently restricted imports, and developed countries need to find new export destinations. In addition, international cooperation for waste management increased in recent years, and the presence of international aid affects the differences in trade volume and in response to the plastic revision of the Basel Convention. This research examines whether the waste management aid motivates the waste trade and whether there is a heterogeneity in the effect of the Basel Convention revision in 2021. Our results indicate that the lower income recipient countries reduce the waste plastic trade, and suggest the necessity of international aid for transboundary pollution and the efficiency of the international policy mix.

Since the mid-2010s, the plastic resource circulation has entered a new phase due to marine plastics and other factors, and many countries are taking actions to address this issue. This report analyzes the responses of the UK and Japan, which are both non-EU developed countries, from the perspective of EPR (Extended Producer Responsibility), and discusses the differences and meaning of them. We categorized the changes in producer responsibility under the new policies of both countries into three categories: physical, financial, and informational, and further analyzed each from four aspects: collection, recycling and proper treatment, product design, and institution building. The results showed clear differences between the two countries. The UK is strengthening producer responsibility through a combination of physical, financial, and informational policy measures. In contrast, Japan does not adopt measures that involve financial responsibility, but focuses on voluntary efforts, with the goal that each actor in the product chain (production, distribution/sales, use, and recycling) should work together to fulfill their respective roles. Future studies are needed to examine the causes of the difference between the two, as well as to demonstrate the policy effects.

In the Chikugo area of Fukuoka, the plastic resin composition survey was conducted with the aim of promoting "visualization" through material recycling. In this survey, plastic products were classified into “toys/sporting goods/musical instruments”, “stationery”', “tableware/dietary goods”', and “daily necessities/miscellaneous goods”. Resin classifications were PE, PP, PS, PET, PVC, ABS, PC, PA, other resins, unknown, and different materials. Plastic products collected at bases was further classified into “single resin”, “composite resin”, and “composite of different materials”. As a result, regarding site collection system of plastic products, 1) there are local governments that bring in more items for site collection than for bulk collection, 2) many of them are composed of PP, and 3) it is possible to reduce inappropriate materials made from different materials. 4) It was also suggested that quality improvement effects can be expected according to the circumstances of local governments, such as sorting and classification at collection sites. As a conclusion, it is thought to be effective to use point collection in addition to the promotion of bulk collection.

In 2019, the Japanese government formulated the "Plastic Resource Circulation Strategy" and set multiple targets related to emissions reduction and recycling. To effectively set policies to achieve these goals, it is necessary to clarify the actual situation of plastic waste emissions. However, in Japan, there has not been sufficient research on the amount of plastic waste generated at the regional level. In this study, We estimated the potential emissions of plastic waste for all municipalities in Japan based on the composition survey results of incineration facilities, and analyzed the regional factors that influence per capita emissions. As a result, a relationship was found between the expenditure on processed foods (snacks, prepared foods, beverages) and the value added in the accommodation and food service industry, and it was suggested that the overall emissions may be larger than previous estimations.

The introduction of bioplastics is being promoted in Japan, with a roadmap for bioplastic set for 2021. There are many challenges in implementing bioplastics in society, and it is important to evaluate their life-cycle greenhouse gas (GHG) reduction and the social role of their biodegradable function. This study conducted a life cycle analysis of the GHG reduction effect of introducing PHBH food waste collection bags and PHBH food containers made from waste cooking oil into a resource circulation system for the sorted collection and biogasification of household food waste, using Kyoto City as a case study. The results confirmed the superiority of the scenario introducing PHBH products compared to the scenario assuming a general municipality. On the other hand, since food containers made of PHBH have a higher calorific value than food waste, incineration with energy recovery has a certain GHG reduction effect, and further application and evaluation of such applications, such as products prone to unintentional environmental spills, are required for the utilization of biodegradability.

Polylactic acid (PLA) is bio-based and biodegradable. If PLA is used for plastic containers and packaging (C&P), the characteristic of biodegradability is an obstacle in mechanical recycling, and it is assumed that PLA will be sorted and incinerated. This means that the GHG reduction by conventional plastic recycling is taken away and there is a possibility that the GHG emissions will increase if PLA substitutes items with a high recycling rate. In this research, firstly we investigated current PLA usage information for plastic C&P, then we considered the recycling rate of each item, and finally we estimated the intersection point at which the GHG emissions of PLA production using domestic surplus biomass is the same as the GHG reduction by substituting conventional plastics. As a result, it became clear that if more than 65% of plastic C&P that flow into household are properly recycled thorough promotion of recycling, it is not good for GHG reduction to introduce PLA in all possible alternative uses.

With the promotion of the circular use of plastics, there is a growing recognition of the need to eliminate chemical substances from plastic recycling. In this study, we investigated the concerning substances present in plastic products and discussed the substances that are particularly concerned for their inflows to plastic recycling. We reviewed the overlap between the approximately 400 chemicals listed as widely used plastic additives by the European Chemicals Agency (ECHA) and the chemicals identified in the literature as concerning substances in plastic products. From this review, 22 substances, most of which are internationally regulated substances or substances classified as Substances of Very High Concern (SVHC) under the EU REACH regulation, were found to be of particular concern in plastic recycling. Given the potential of these substances to hinder plastic recycling, it is crucial to understand their presence in plastic products, waste streams, and the actual circularity of their use. Additionally, there are approximately 70 SVHCs that may be used in plastic products beyond the substances listed as widely used plastic additives by the ECHA, highlighting the need to assess their actual usage as well.

Based on the questionnaire survey on steel can recycling fpr the local government that is conducted every year, we target the questionnaire which have continued to answer for three consecutive years. For those who answered, we analyzed an impact of the new coronavirus infectious disease on the sorted collection, group collection, and collection amount of steel cans.

Consumers are important stakeholders in the reduction and resource circulation of plastics. However, it has not been clear how consumers perceive the issues related to plastic usage and how their perception leads to pro-environmental behavior regarding plastic products. This study aimed to understand the consumers’ perceptions of issues related to plastic usage and to analyze the psychological determinants of pro-environmental behavior regarding plastic products using a questionnaire survey. The results revealed that approximately 46% of the respondents in Japan considered the mismanaged plastics leaking into and adversely affecting marine and terrestrial ecosystems to be important among plastic problems. The covariance structure analysis of psychological model indicated that, among the determinants, perceived effectiveness and social norm evaluation significantly influenced goal intention and behavioral intention, respectively. On the other hand, psychological determinants did not significantly differ according to the perception of plastic issues, suggesting that further analysis is needed in future research.

The joint collection and recycling of plastic packaging and other plastic products from households is expected to increase the amount of collected and recycled plastic waste. However, at the same time, it may cause negative impacts on the current plastic circulation. According to our interview surveys to municipalities and mechanical recycling companies, various products are considered to cause negative impacts on plastic circulation, such as by stopping the collection or separation of plastic waste. Potential measures to them are to restrict the plastic products to be collected and to modify the collection and separation methods of plastic waste. However, tradeoffs may occur due to the measures, notably the decrease in the amount of collected plastic waste or the increase in plastic waste management costs. Therefore, it is important to evaluate the effectiveness of the measures and their combinations based on the amount of collected and recycled plastic waste as well as waste management cost.

The new plastic law lays out the role of each business entity and consumers in the processes they are involved in, and encourages them to take action to reduce the use of plastics and recycle waste plastics throughout the value chain. However, business operators are only involved in the processes related to their respective operations, and it is difficult to say that efforts are being made across the entire value chain. Therefore, in this paper, we interviewed business operators at different stages in the value chain related to plastic recycling and experts specializing in plastic issues. As a result, rather than focusing on the development of individual technologies, it was demonstrated that cross-industry dialogue should be accelerated, and that vertical discussions and systems that transcend industry lines are essential for the collection of waste plastics. The efforts of individual companies are not fully utilized as a system, and it became clear that it is necessary to understand and review the operational status of technology and systems on site.

Tonle Sap Lake in Cambodia has a boating community where plastic waste is dumped into the lake. Plastic waste discarded in the water may reach the Pacific Ocean through the Mekong River, and from the viewpoint of controlling the generation of marine plastic waste, it is desirable to separate and recycle plastic waste in floating villages. Therefore, as a JICA grassroots technical assistance project, we are trying to set up a participatory plastic waste separation and recycling system in Phat Sanday Village, Kampong Thom Province. Specifically, surveys on the composition of plastic waste from households, questionnaire surveys on villagers' environmental awareness, examination of plastic recycling routes, simulation of sorting and recycling, preparation of textbooks for educational enlightenment, training for local leaders, and citizen enlightenment. We hold events, etc. This paper reports the summary of those results and the participation of village representatives.

It is not clear how the waste plastics discharged from commercial facilities are sorted. In addition, for industrial waste, each business operator concludes an individual contract with a licensed collection company. There is no unified separation rule because the type of sorting and discharge methods are determined through consultation between the two parties. In order to promote the recycling of waste plastics, we assume that it will be possible to efficiently collect waste plastics by understanding the characteristics of plastics discharged from respective buildings with specific uses and understanding their suitability for recycling. In this study, we conducted a survey on the current situation and composition of plastic emissions as well as the pellet evaluation (physical properties testing and food sanitation evaluation) targeting commercial facilities. As a result, we confirmed the recyclability of flexible plastics ((1) LLDPE only and (2) mixed PE/PP) that are often discharged from commercial facilities.

Waste fresh concrete at construction sites is estimated to be generated in a huge amount of about 2.5 to 4.1 million cubic meters annually in Japan. In this paper, a nationwide survey was conducted on the shape of concrete block products. As a result, it was clarified that there were not so many differences in the shape of each region and that the shape was categorized into four shapes nationwidely. In the future, it is expected that such results will be used to devise recycling strategies.

Geopolymer is a material that is hardened using alkaline solution and active fillers such as coal fly ash. One advantage of geopolymer is that it allows for the utilization of by-products in the material. This study aimed to effectively utilize by-products in civil engineering materials and investigated the relationship between uniaxial compressive strength of geopolymer and the concentration of sodium hydroxide using various by-products: municipal solid waste incineration ash, municipal solid waste incineration fly ash, coal fly ash, and steel slag. Leaching tests were also conducted using each filler and alkaline solution to examine the dissolution concentration and ratio (Si/Al) of silicon (Si) and aluminum (Al), which are believed to be related to the solidification process. As a result, coal fly ash exhibited a significant increase in strength. When focusing on the Si/Al ratio, it was found to be around 1, suggesting that the balance of dissolved Si and Al played a crucial role in the strength enhancement. Furthermore, for almost all fillers, higher NaOH concentrations resulted in increased strength and higher concentrations of dissolved Si and Al. This indicates that not only the balance of dissolved Si and Al, but also their absolute concentrations, are important for strength enhancement.

Using construction sludge, which is considered to be inadequately recycled, as an example, this report summarizes the issues involved in promoting the utilization of recycled sludge and presents methods for expanding its use. In-situ use of construction sludge is progressing because it is economically advantageous under the right construction conditions, but the use of recycled products between construction projects and through recycling facilities has not progressed sufficiently due to institutional restrictions as well as economic efficiency and confidence in quality. The "Construction Sludge Recycled Products Certification System" is a system to certify that the construction sludge is recycled and used as valuable resources, as indicated in the Ministry of the Environment's July 2020 notice, The certification system for recycled construction sludge, which was notified by the Ministry of the Environment in July 2020, will enable the treatment of recycled construction sludge as valuable resources at the manufacturing stage if certain conditions such as quality and certainty of use are met, thereby promoting the utilization of recycled construction sludge in a systematic and economical manner. If both the certification system for valuables and the certification system for recycling (individual designation) are applied to shield construction projects and other construction projects that generate large amounts of construction sludge, the application for individual designation will be sufficient for the construction companies alone, and the recycling and utilization of construction sludge will be efficiently and dramatically promoted. It is expected that the certification system for valuable materials will be expanded to include tile chips and other items with similar problems.

More than half of the disaster waste is estimated to be concrete debris. As one of the options for rapid and large-scale processing of concrete debris, a plan to submerge a large portion of concrete debris to the seabed without crushing it and utilize it as an artificial submarine mountain range is noteworthy. Generally, it is not well known what kind of leaching characteristics are exhibited when using concrete debris in seawater, and how to evaluate environmental safety can be an issue. Therefore, we focused on hexavalent chromium, which is known to be leached from concrete debris, and conducted various leaching tests using seawater to investigate the impact of the material on the seawater environment.

With the recent increase in demand for remodeling in the residential building and construction industry, construction mixed waste, including ceramic siding materials, is being generated as a result of demolition. Among cementitious materials, siding material has a remarkably low recycling rate because it contains organic admixtures. This study aims to contribute to the SDGs by investigating the possibility of using siding material as a ground improvement material. As a material condition, heat treatment of siding chips will be considered since they contain organic matter, and cement-added specimens will be prepared for comparison with siding chips. The strength of the specimens will be confirmed by uniaxial compression tests, and qualitative and quantitative analysis of the products will be conducted by SEM-EDS analysis. In the uniaxial compression test, it was confirmed that the strength increased with and without heat treatment. SEM-EDS analysis indicates that the water absorption of the siding chips may have affected the solidification process.