South Korea, which has implemented advanced food waste separation and recycling policies, is once again entering an era of great change. This study aims to examine the international community's discussions on food waste and food waste management policy trends in South Korea, and to discuss the meaning of food upcycling and the limitation and challenges of existing ‘waste’ policies. Depending on the generation source, it can be represented in two ways: strengthening biogas and food upcycling. Food upcycling policy should be further strengthened not only to reduce food loss and waste, but also to foster new eco-friendly industries. To this end, it is necessary to reorganize recycling methods and the standards for evaluating circulating resources so that existing waste policy is suitable for food upcycling. In addition, it is necessary to develop indicators that can evaluate the environmental performance of food upcycling and database on food byproducts and the demand.

The soundness of furnace fireproof walls attached to boilers in waste incineration plants is confirmed by visual inspection and hammering inspection. Hammering inspection in particular is widely used due to the ease of only hearing judgment, but there are issues such as the high cost of temporary scaffolding required for large-scale inspections over a wide area and the judgment criteria being subjective. Mitsubishi Heavy Industries Environmental Chemical Engineering, in collaboration with Toin University of Yokohama, has now verified the identification performance of internal defects using the Non-Contact Acoustic Inspection (NCAI) method, which is expected to solve these issues, for specimens with simulated defects and actual refractories. This paper reports on the inspection technology and verification results using the NCAI method.

Regarding the commonly held belief that "the location of a waste incineration plant causes surrounding land prices to fall," we conducted a survey on land price fluctuations around the Meguro and Shibuya plants in Tokyo's 23 wards to clarify whether land prices fell or not.

In waste incineration facilities, regular maintenance is carried out to minimize unplanned equipment shutdowns as much as possible. However, even with regular maintenance, unplanned equipment shutdowns can sometimes not be avoided, and blockages in the fly ash conveyor are one of these. If the blockage of the conveyor could be detected in advance, it would be possible to prepare staff and equipment for remediation in advance, which would have benefits such as reducing recovery time. This development is working on the detection of signs of the operation of the torque limiter caused by the blockage of the conveyor. The current value of the conveyor motor was measured and a premonition detection algorithm was constructed from the frequency components. Ten torque limiter operations were detected in advance between 1 and 180 seconds. The breakdown was 7 times between 1 and 60 seconds before, 2 times between 61 and 120 seconds before, and 1 time between 121 and 180 seconds before. In addition, there were 13 times when the system detected an operation even though it was actually not operating

In this study, we determined the optimal placement of transfer stations and waste incineration facilities for Kyoto Prefecture in 2050 by solving a mixed integer programming problem concerning cost and energy consumption. Based on this, we evaluated the effects of regional integration and the introduction of transfer transportation methods. As a result, the number of waste incineration facilities was reduced from the current 16 facilities to 3 in the case of cost optimization and 2 in the case of energy consumption optimization. Regional integration without the introduction of transfer stations could reduce costs by approximately 25% and increase energy output by approximately 179% compared to the current situation. Furthermore, the introduction of transfer stations could additionally reduce costs by approximately 0.4% and increase energy output by approximately 7%.

Sri Lanka faces significant challenges in managing Municipal Solid Waste (MSW), due to rapid urbanization and population growth, inadequate infrastructure, and limited government resources. The surge in population and urbanization has led to a significant increase in waste generation, yet its effective management remains elusive. The overall collection efficiency is just 27%, with no 100% coverage in all 25 administrative districts in the country. While economic growth has spurred urbanization, it has also laid bare the stark disparities in waste collection services between urban and rural areas. Despite the need for research, limited studies have investigated waste collection disparities. This study explores this comparison, analyzing the practices, challenges, and potential solutions for both scenarios. The study's findings provide fact-based information about performance, enabling policymakers to make data-driven decisions for a sustainable MSWM through improved collection coverage.The study area encompasses the entire island, with HHs as respondents. Data collection used a structured questionnaire and an online survey company's monitoring service.Sri Lanka’s urban rural waste collection disparity is a complex issue demanding immediate attention, thus, a multi-pronged approach is necessary by strengthening local authorities, promoting community participation, and addressing the specific challenges of communities.

The implementation of river waste traps and temporary storage sites in Jakarta, Indonesia, has been crucial for managing waste in its waterways. However, the system’s effectiveness relies heavily on efficient river waste collection and transportation. This research aims to provide insights into further optimizing the river waste collection and transportation process, thereby enhancing the overall efficiency of the river waste management system. GIS-based documentation through iterative data cleaning of government-provided spatial information on river waste traps and temporary storage sites was followed by sets of algorithms to create the transportation road and calculate the distance covered between facilities. Facing recurring fluvial and coastal floods, Jakarta ensures a swift removal of riverine waste and flood debris by deploying 1,130 waste traps and nine temporary storage sites that highly correspond to the area of water bodies within Jakarta’s administrative cities. The uneven distribution of these facilities has led to overlapping coverage areas, resulting in one facility covering 3,059 km for transportation, while others averaged 279 km. This highlights the necessity for optimization. Transporting river waste to a nearby facility is expected to mitigate social issues, foster a more cooperative and supportive environment, and reduce transportation costs.

In order to formulate disaster waste treatment plans, information on the composition of disaster waste, such as the proportion of combustible and non-combustible materials, is required. Composition information changes depending on the work situation. The authors set out to develop an estimation method that focuses on spectral information in the near-infrared region, which allows for rapid compositional analysis of disaster waste accumulated in temporary storage sites. Disaster waste stored in temporary storage sites for long periods of time is expected to deteriorate and change in properties, and there were concerns about the impact on composition estimation. In this study, we confirmed changes in spectral information of materials whose surfaces have deteriorated by exposing them outdoors for a long period of time, and the effects on estimation results. There was a large change in the spectral information of wood chips due to deterioration due to ultraviolet rays, etc., and the composition estimation results resulted in erroneously classifying wood chips degraded by ultraviolet rays, etc. as incombustible materials. As a workaround, we were able to avoid misclassification by adding estimation using spectral information of wood chips degraded by ultraviolet rays to the training data.

After a large-scale disaster, at present information on the composition of disaster waste accumulated in temporary storage sites is obtained by empirical rules and sampling methods, and the amount of the target material cannot be grasped efficiently and quantitatively. Therefore, the authors developed a tool for estimating composition based on spectral information in the near-infrared region captured by a hyperspectral camera, and proposed a method for estimating composition with a certain accuracy. However, the spectral information in the near-infrared region used for estimation varies depending on the amount of moisture on the surface of the disaster waste. Thus, the estimation results may be affected. Therefore, as a result of conducting a test to understand the impact on spectral information, it was suggested that spectral information may change depending on the immersion status of waste after the occurrence of a disaster, the weather at the temporary storage site, etc. In addition, it was clarified that the discriminating results of the estimation tool may be affected.In the future, we plan to improve the estimation tool in consideration of the influence of moisture on the surface of the material.

Recently, Sustainable Society Promotion Consultant Association has also been conducting initial response activities within the framework of D.Wste-Net in the event of a large-scale natural disaster. While it became possible to dispatch many people from each member company, differences in response capabilities based on experience have emerged, and there is a need to pass on and accumulate skills and experience. In this study, using the Noto Peninsula earthquake disaster response as a case study, a timeline was created for engineers in the resource circulation field to provide initial response to disaster. The support contents are classified into three categories: "disaster waste," " public expenditure disassembly," "human waste, shelter waste, and daily life waste," and the timeline is summarized in a table format as "early post-disaster," "mid-term initial response," and "late initial response. The Timeline was created so that supporters could have images of the actual action. The contents of this report have been improved with the advice of experts, after being expanded by experienced disaster response personnel from each company. In addition to disaster waste, we were able to expand the content of human waste treatment, but many issues remain. We would like to receive advice from the participants and utilize this opportunity for further improvement.

This paper discusses the estimated amount of disaster waste from the Noto Peninsula Earthquake of 2024, the issues involved, and approaches to information sharing using mapping applications. As a result, the amount of disaster debris from the 2024 Noto Peninsula earthquake was estimated to be 806,000 tons in Ishikawa Prefecture. In addition, we have made an effort to map temporary storage sites and share information by using a mapping application. It was indicated that it is possible to share information on temporary storage sites among the national government, prefectures, local governments, and the private sector.

It has been reported that many volunteers have participated in support activities during disasters. However, they are limited to activities such as soup kitchens, debris removal, and so-called "eating to support," and there are few reports on disaster waste disposal, and the issues are not recognized. Furthermore, from the perspective of the administrative affairs of basic local governments and the social welfare councils (syakaifukushi-kyougikai) that act on behalf of the disaster volunteer centers, volunteers are treated as only "guroup" and are simply beginners, and their abilities are not utilized and the issues are not visualized.On the other hand, disaster volunteers have accumulated experience, and many volunteers are well versed in the Building Recycling Law(Kennsetsu-Recycling-Law). Rather, they are at the mercy of insufficiently studied local assembly members, disaster victims, administrative officials, and social welfare council officials, and are even looked upon with unnecessary suspicion. The author believes that the efficiency of disaster waste disposal can be improved by deploying a large number of experienced disaster volunteers. I would like to have frank discussions with members of the Society of Waste Management and Recycle to solve the problem.

The rapid establishment of temporary storage sites for disaster waste during the initial phase of a disaster is crucial for preserving the living environment in affected areas. However, due to the lack of organized candidate sites, there are cases where setup takes time. In this study, we constructed a management database system for potential temporary storage sites and examined methods for sharing this information. We registered the results of field surveys conducted in Toyama prefecture into the prototype database and attempted to share the data using GIS and Google My Maps. Municipal staff provided positive feedback on its usefulness. The field surveys revealed issues such as discrepancies in usable area, obstacles to use, and impacts on the surrounding environment, confirming the effectiveness of preliminary surveys and information organization. Moving forward, we aim to add features for integrating hazard maps and estimated disaster waste generation results, and to expand this system to other municipalities.

Waste management can be represented by the Master equation, and Information entropy can be utilized to evaluate a project.

The "Circular Economy," which has been in the spotlight in recent years, is a concern that it may also affect the business conditions and business content of related industries. Based on this concern, I selected two companies with sales of approximately 10 billion yen and total assets of approximately 20 billion yen from among listed companies in the waste management industry, conducted a profitability analysis based on data from securities reports,

Looking at the performance trends over the past five years, the two companies analyzed have been showing an increase in sales and profits, and their total asset operating profit ratio, which indicates asset efficiency, has reached a good level, and they continue to post favorable financial results. In addition, a break-even analysis of both companies shows that they are in a stable state that sets them apart from small-scale waste collection companies and exceeds that of major US company, whose businesses are becoming larger in scale, and is thought to form the basis of future management strategies.

A discharge of the garbage increased a bedroom town of the Tokyo downtown area by the improvement of the civic life by a population rapid increase by becoming it, the merger with neighboring municipalities and the economic development after World War II steadily. Whereas, according to 1955 and the national census of 1965, the population is 1.6 times, the quantity of collection of garbage really of a little over 4 times was terrible. It may be said that the problem of the refuse disposal was a big problem.

In the correspondence to rapid population increase by a series of mergers and urbanization, I examine it including the actual situation, the execution system of the cleaning labor how was the actual situation of the cleaning business of Hachioji-shi and what kind of role you played.

It is known that in waste treatment, hydrogen gas is generated by the reaction of metallic Al contained in incineration ash and water under high alkaline conditions. A life cycle assessment (LCA) of a hydrogen gas recovery system was conducted with the aim of recovering and effectively utilizing this hydrogen gas. Specifically, the life cycle cost (LCC) and LC-CO₂ emissions of the hydrogen gas recovery system were evaluated for the western Fukuoka City waste incineration plant, the functional unit of hydrogen gas was 1Nm3, and the system boundary was from the hydrogen generation stage to the storage and transportation stages. The LCC was calculated for several cases based on the use application and the amount of hydrogen generated per ton of incinerated ash. The unit cost of hydrogen production was higher than the market price in the case of fuel cell use and synthetic methane use with a hydrogen production rate of 11.4 m3/t-ash per ton of incinerated ash, but was lower than the market price when the hydrogen production efficiency increased to 50 m3/t-ash. LC-CO₂ was lower than that of the case using water electrolysis hydrogen derived from green hydrogen under the same conditions.

Recently, environmental impacts of textiles including the climate change impact attract increasing attention across the world. Measures to reduce the environmental impacts associated with textiles include reuse and recycling of used textile products; however, the actual status of used clothing exported for the reuse purpose is unclear and the domestic markets for reuse and material recycling are limited. In Japan, monomerization of polyester has already been operated, whereas mixed textiles which account for the majority of textile products are hard to recycle. Against this backdrop, gasification technology is expected to be applied for recycling of mixed textile waste and further to be effectively combined with chemical recycling of polyester products. The objective of this study was to quantitatively evaluate the climate change impacts of gasification recycling of textiles. The amounts of CO₂ emissions were calculated by LCA based on results of bench-scale gasification tests. Here, recovered gas from gasification was assumed to substitute fossil fuels. The results showed that the emission reductions were largely dependent on the electricity consumption of gasification. We determined the requirement on the electricity consumption of a gasification process per kg of textiles for reducing CO₂ emissions compared with conventional incineration of mixed textile waste.

To achieve greenhouse gas (GHG) reduction in a night soil treatment plant (NSTP), this study proposes a sludge carbonization system to produce biochar and generate negative CO2 emission by sequestration of biogenic carbon. To dry dewatered sludge, it uses the heat source from a waste incineration plant (WIP). The purpose of this study was to build a sludge carbonization system and to evaluate carbon sequestration effect of biochar. First, I compiled population data to decide the treatment population. Next, I constructed a model to calculate GHG emission of the system targeted for NSTP and WIP. The result shows that a sludge carbonization system not only reduces GHG emissions from solo incineration, but also achieves net zero limited a dewatered sludge process.

In Hokkaido, the need for cost reduction and improved energy efficiency has led to a focus on scaling up and integration of waste incineration facilities. This study examines the optimal layout of waste incineration and transfer facilities in Hokkaido for the year 2050. Annual costs for these facilities were calculated as the sum of transportation, construction, and operating costs, while energy consumption was calculated as the total of fuel consumption for transportation and the use and supply of electricity and heat at the facilities. Using a genetic algorithm, optimal facility layouts were determined for different conditions of municipal and industrial waste. The results showed that for cost optimization, 8 to 15 incineration facilities and around 10 transfer facilities are needed, while for energy optimization, if transfer facilities are sufficiently available, 1 incineration facility for municipal waste and 6 for industrial waste are required.

In order to achieve carbon neutrality by 2050, decarbonization efforts should be promoted in all sectors, and the same applies to the waste and resource recycling sectors. In recent years, a decline in the efficiency of waste management due to population decline has become an issue. In this study, GHG emissions from municipal solid waste treatment were projected to 2050 according to eight scenarios for waste incineration plants in the Tohoku region, Japan, where the population is likely to decline rapidly in the future. As a result, it was confirmed that the scenario with steam supply would result in significant GHG reductions. The wide-area treatment scenario also resulted in savings in the energy input for treatment, and thus in a highly efficient treatment. However, it was considered necessary to introduce carbon capture and storage technology because carbon neutrality could not be achieved in many scenarios when the emission factors of the different types of energy were reduced. It is therefore important to try to reduce waste generation in order to reduce the amount of carbon to be stored as much as possible.

The maximum utilization of regional resources is important for to establish a Regional circular and ecological sphere. However, few regions understand how to utilize resources within their own region and the resource circulation structure. In this study, we proposed and demonstrated a "Regional resource circulation map" for visualization the resource circulation structure and conducted a network analysis of the resource circulation structure in the region in Okoppe town to clarify the intra-regional resource circulation structure in small-scale municipalities. To create the map, we surveyed the resource flows of regional business through interviews, and visualized the resource flows among industries in the region by integrating them into each industrial category. In the network analysis, We calculated PageRank and betweenness centrality and created zP matrix to analyze the characteristics of the resource circulation structure. As a result, the intra-regional resource circulation structure was visualized through the Regional resource circulation map in Okoppe town. Furthermore, the network analysis showed that BGP, roadside station, and dairy industry play an important role in the resource circulation structure of Okoppe Town.

Greenhouse gas (GHG) emissions from the waste sector in Japan are estimated to be approximately 40 million t-CO2eq/year as of 2019. In response, the Ministry of the Environment has proposed a long-term scenario for achieving net-zero GHG emissions in the waste and resource circulation sector by 2050. CCUS in waste incineration facilities is highlighted as one of the options to achieve this goal.

This study aims to propose a methodology for evaluating the CO2 reduction effect of introducing CCU technology to waste treatment facilities in Japan. Specifically, referring to the concept of the "LCA Guidelines for GHG Reduction Effects in the Hydrogen Supply Chain," we investigate cases of waste treatment facilities with CCU in Japan and analyze and evaluate the CO2 reduction amount of waste treatment facilities with CCU systems in 2024 and 2050 scenarios.

Unit-based pricing for combustible garbage bags has been implemented to reduce household waste emissions in Japan, and a certain effect has been confirmed. From the viewpoint of creating a recycling-based society, further promotion of recycling as well as reduction of waste emissions will be necessary in the future, but there is concern that charging for recyclable garbage bags may have the opposite effect, given the mechanism of the monetary incentive. The purpose of this study is to quantitatively understand how setting a price difference between bags for combustible and recyclable waste would affect the amount of combustible and recyclable waste generated, using panel data from the Tama region of Tokyo. Our results suggest that while charging for bags for combustible waste reduces the amount of combustible waste, the impact of charging for bags for recyclable waste on the amount of combustible waste and recyclable waste may not be statistically significant.

The government has set targets within its plastic resource circulation strategy, aiming to achieve a cumulative 25% reduction in one-way plastics by 2030. Since April 2022, the reduction of disposable plastic products has been mandated. This includes cutlery such as forks, knives, spoons, as well as straws for which measures such as charging fees, lightweighting, and material changes are required. However, these items are also highly convenient due to their ability to save time and effort in washing, their lightweight and compact nature for easy transportation and storage, their constant newness ensuring hygiene, and their cost-effectiveness in large or time-constrained dining events. Therefore, their reduction poses challenges. This survey aims to understand the discharge status of cutlery in combustible waste, for which the actual situation is not yet fully understood, in order to obtain foundational data for future reduction of disposable plastics.

In order to achieve a material-recycling society, the recycling of plastics is required. The government plans to increase the amount of plant-based biomass plastics, such as polylactic acid and biopolyethylene, to 2 million tons by fiscal year 2030. Although biomass plastics are carbon neutral because they are made from plants, it is preferable to chemically recycle them after use rather than incinerating them. We are working on recycling polylactic acid, which is relatively inexpensive and widely distributed among biomass plastics, by incorporating anaerobic digestion. After hydrolyzing used polylactic acid cups collected at a beer event by heat treatment at 130°C, sewage sludge and polylactic acid decomposition products were continuously digested using a field test device installed at a sewage treatment plant. No instability of methane fermentation due to the addition of polylactic acid decomposition products was observed, and the amount of biogas generated was increased to three times that of the digestion conditions at a normal sewage treatment plant.

Chemical recycling of Polyvinyl chloride (PVC), a widely used general purpose resin, is considered to be difficult because chlorine is released mainly as hydrogen chloride by pyrolysis of PVC. However, it is thought that pyrolysis residue of PVC (PVC residue) can be used as a fuel by decreasing chlorine content through the pyrolysis. In this study, the optimal heat treatment conditions for chlorine and additive removal from soft PVC was investigated. In adddition, the chlorine content and calorific value of PVC residues was evaluated. As a result, chrorine and additive contained in soft PVC was decreased by heat treatment below 300 ^oC. In addition, the calorific value of PVC residues was higher than that of wood pellets and comparable to or greater than refuse-derived fuel (RDF), and PVC residues generated by heat treatment at 250°C and 300°C satisfied the chlorine content standards for solid fuels derived from paper and waste plastics (RPF). These results suggested that these PVC residues could be used as a fuel.

An increasing number of municipalities collect and recycle plastic product waste. They collect plastic product waste in different methods, such as collecting together with plastic containers and packaging, or not collecting products that may have negative impacts on the sorting and recycling process. This study aims to assess the impact of these differences in collection methods on the amount of collected plastic product waste. We conducted a quantitative analysis using data provided by the Japan Containers and Packaging Recycling Association and data on collection methods, organized by the authors, based on the web pages of municipalities. As a result, even when considering the influences of other collection method items, such as when municipalities started the collection and charges for combustible waste, municipalities that collect products that contain some materials other than plastic were found to collect more plastic product waste than municipalities that collect only products made solely of plastic.

Biodegradable polymers are materials that can be decomposed into carbon dioxide and water by microbial action under normal environmental conditions. The objective of this study was to verify whether alkaliphilic bacteria can biodegrade biodegradable plastics in order to develop a waste treatment method that can efficiently degrade biodegradable plastics. In this study, we evaluated the degradability of commercially available biodegradable plastic products using a reaction system in which biodegradable plastic and bacteria react in a test tube in a laboratory. The results will be reported at this conference.

A life cycle analysis was conducted to estimate the life cycle CO₂ emission for each PLA recycling method, including a system in which polylactic acid (PLA), a biodegradable plastic, is hydrolyzed and then converted to biogas at a sewage treatment plant. The functional unit was defined as "provision and processing of 20 t-dry beverage cups for events," and it was assumed that the raw material for PLA was corn, which was made into PLA resin in the United States and then imported to Japan. As a result, the scenario in which PLA is treated by sewage digestion after dissolution and biogas is introduced into the urban gas pipeline resulted in the lowest GHG emissions. In addition, the urban gas substitution effect was larger than the electricity substitution effect, and the latter tended to be superior even when GHG emissions associated with gas purification were taken into account. The scenario in which CO₂ in biogas is converted to methane gas by methanation and then purified and introduced into the urban gas pipeline consumes a large amount of electricity to obtain the hydrogen needed for methanation by electrolysis, resulting in large GHG emissions.

PFAS have been used in various products due to their excellent functionality, but in recent years, concerns about environmental pollution have increased. The purpose of this study is to investigate the application of total fluorine analysis by wavelength dispersive X-ray fluorescence spectrometry (WDX) to the screening analysis of PFAS. The study started with paper products, which are readily available and easy to sample.26 commercially available food contact paper products that had been analyzed by CIC were cut into appropriate sizes and analyzed by WDX. Although the WDX analysis value was about three times higher than the CIC value, a strong correlation (correlation coefficient of 0.914) was obtained between the WDX and CIC analysis values. It was confirmed that WDX can be used for screening analysis to determine whether fluorine compounds are used in paper products. Further validation with other materials will be an object to be considered in the future.

In this study, we estimated the amount of waste plastic present in the Minami-Chikugo area, Kurume City, and Fukuoka City, which have different urban characteristics, and constructed a material flow of waste plastic. For the constructed flows, scenarios were set up to reach the target of 100% reuse/recycling by 2035, and environmental aspects were evaluated using LCA. Based on this, appropriate collection, sorting, and processing rates were identified for each region.

The world has recognized the severity of global warming, leading to the establishment of various international agreements to address this issue. The European Commission announced the European Green Deal, and Korea declared the "2050 Carbon Neutral Vision (Net-Zero)". In line with these policies, the cement industry is working towards carbon neutrality by replacing fuels used in the production process with circular resources, to increase fuel substitution to 65% by 2030. However, waste polymeric compounds such as waste plastics, waste tires, and waste synthetic resins contain low-melting trace components such as chlorine. These components exhibit the behavior of volatilization and condensation in kilns and areas where hot gases pass through, causing coatings on the inner walls of the equipment. Chlorine, in particular, can be unnecessarily present in the cement produced, and high chlorine content can oxidize rebar and leach heavy metals, causing environmental pollution. Therefore, it is essential to install a chlorine bypass (CBP) system to rapidly cool and remove high concentrations of volatile chlorine in particulate form. To do this, it is important to understand the behavior of the volatile chlorine circulating within the system along with the flow in the rising ducts and identify where it stagnates at high concentrations. This study utilized Ansys Fluent 2024 R1, a computational fluid dynamics (CFD)-based analysis program, to analyze the flow in the rising duct.

This study evaluated the use of rubber lids as an alternative to expanded polystyrene lids in the cultivation of shiitake mycelium. In adhesion experiments, the rubber lids adhered well to the mycelium blocks, demonstrating performance comparable to expanded polystyrene lids. Toxicity tests showed that the rubber lids did not negatively impact shiitake growth in any of the cultivation environments. In UV resistance experiments, the rubber lids did not exhibit physical deterioration after prolonged UV exposure, although chemical structural changes were observed. Additionally, the leaching of CaCO₃, a component of the rubber, was observed due to the effects of rain and other factors. The long-term effects of pH changes caused by this leaching on shiitake fungi are uncertain. These results suggest that rubber lids are a promising alternative to expanded polystyrene lids, but further research is needed to understand their long-term effects.

In recent years, the adoption of recycled plastics has been advancing globally, with Europe leading the way by implementing regulations mandating their use in various products. Japan is expected to see a similar increase in demand for recycled plastics, yet current usage has remained flat over the past three decades. This study aimed to analyze the future balance of supply and demand of recycled plastics in Japan and identify potential bottlenecks.This study focused on packaging plastics as a source of recycled plastics. Two scenarios were considered: minimum demand and maximum potential demand. The results indicate that by 2030, the minimum demand will be about 26–28% of the packaging waste generation, rising to 54–58% by 2050. Additionally, the maximum demand is expected to reach approximately 150% of the packaging waste generation.The current recycling rate in Japan is only 31–33%, underscoring the need for significant improvements in collection and processing. To meet future demand, it is crucial to enhance sorting facilities and promote the recycling of not only container and packaging plastics but also product plastics. Furthermore, advancements in recycling technologies, particularly in material and chemical recycling methods, are essential to increase efficiency and output.

This study focused on resource collection stations in Tachiarai-town, Fukuoka prefecture, Japan. The survey asked residents about "how to redeem points", "how long it takes to get from their homes to the pickup location", "when they use the pickup location", and "what features they want in a pickup location". Using the results of the questionnaire survey, a choice conjoint analysis was performed to quantitatively evaluate the utility value of each item. As a result, “time required from home to the collection site” was given the highest importance. Principal component analysis and cluster analysis were conducted to divide the respondents into four clusters and quantitatively analyze the trends of each cluster. The results clearly indicated that the geographical and temporal characteristics of the stations and the multifunctionality of the stations in combination with other uses (local community activities, shopping, etc.) are factors that promote the use of resource collection stations.

We conducted a questionnaire survey on user attributes, the actual use of resource recovery sites, and frailty factors for 303 users of environmental facilities and facilities for the elderly in Fukuoka City. As a result, there is a significant difference in the number of collection sites used and the number of types of resources sorted between the healthy group and the frailty group, meaning a relationship between the resources recycling action of elderly people and their health. In addition, the number of collection sites used by the elderly people in a physically weakened state tended to be small. It indicates the need for arranging collection sites that are easy to use for elderly people with physical abnormalities in order to increase the resource recovery rate. Furthermore, there was no significant difference between the healthy group and the frailty group in the number of collection sites used and the number of sorted resources among users of environmental facilities, suggesting that the environmental awareness fostered during healthy conditions would work preferentially in resource recovery action even if they had physical abnormalities.

Although plastic resins are used in a wide variety of products, including electrical appliances, stationery, and daily necessities, their use in material recycling is limited to industrial and building materials. Therefore, in this study, we aim to propose optimal recycling strategies by evaluating the challenges and possibilities in the plastic value chain for each product using the Circularity Matrix (CM), which visualizes the recovery and recyclability of waste plastics. The current status of products such as dry cleaning hangers and toys in Japan was evaluated using two evaluation axes: "access," which indicates the ease of recovery, such as the state of recovery infrastructure and recovery costs, and "process," which indicates the ease of value extraction, such as the presence or absence of dirt and the homogeneity of resin. The results were presented in a four-quadrant diagram. As a result, the characteristics of individual products were clarified, such as stretch film, which is discharged in large quantities at logistics centers and is made of a single material, receiving high marks in both resource recovery and value extraction.

In this study, we prepared simulated recycled pellets by repeated extrusion of a mixture of polypropylene (PP) and polyethylene (PE), which are polyolefin resins used in large quantities as plastics for packaging materials, and evaluated the effects of the number of recycling repetitions on mechanical and flow properties. In addition, we attempted to evaluate the degradation state using thermogravimetric analysis (TGA). As a result of the evaluation of mechanical properties, the charpy impact strength tended to decrease as the number of recycling repetitions increased. On the other hand, the tensile strength values little or no change with the increase in the number of recycling repetitions. The melt flow rate (MFR) value simply increased with the number of recycling repetitions. Thermogravimetric analysis (TGA) showed little difference in the 10% weight loss temperature between before and after recycling repetitions.

Recycling waste plastic is a very important problem for the solution of climate change, marine plastic pollution and resource cycle. ｢The Act on Promotion of Resource Circulation for Plastics｣ was newly added to ｢The Containers and Packaging Recycling Law｣ and enforced on April 1st 2022. The discrimination/selection by kinds of plastic materials is an important process in recycling waste plastic and the infra-red spectrophotometer (NIRS) is applied most popularly in the optical discrimination/selection.

In our study, we examined the estimation of component material and weight percentage in the composite plastic (e.g. laminated film) by the portable NIRS combined with a plastic identification program. As a result, we could confirm the kinds of plastic material and the weight percentage in the composite plastic (3 layers or more laminated film) by using the database (DB) prepared by us or the combination separation process using organic solvent and the above DB.

In its plastic resource circulation strategy, the Japanese government aims to design plastics so that they can be reused and recycled by 2025, and to make 100% of used plastics effectively used through reuse and recycling by 2035. To promote recycling, currently collected plastic containers and packaging and product are sorted by material for chemical recycling and material recycling. At the sorting facility, plastics are crushed and then separated using near-infrared light into PE, PP, PS and other plastics, which are then used as raw materials for pellets, etc. However, since near-infrared light cannot be used for sorting, it is often unclear what material these plastics are made of. For this reason, pyrolysis GC/MS was used to analyze the material of black plastics.

Considering that various trial and error for collection and sorting have been continued in each municipality, the plastic resin composition survey in the Chikugo area of Fukuoka was conducted and reported while comparing them with those of neighboring municipalities. The weights of each plastic product collected at the base were measured and it was classified by resin using a handy classification device. The results of an inspection for plastic sorting facilities were also considered together. As a result, it was clarified that the frequency distribution of the weight per product varies greatly depending on the municipality, that relatively large plastic products are often made of polypropylene (PP), which has a high market demand, and that other resins are in contrast rare. According to the results of the inspection, PP sorting work is performed visually by on-site staff in Oki Town and Yanagawa City. In contrast, at the sorting facilities of the preceding municipalities, shaking sorting is often performed before optical sorting to separate heavy and light items. It was suggested that pre-processing by separating heavy and light items is effective for both manual and optical sorting.

In this study, we investigated the bromination volatilization process with bromine in brominated flame retardants by using thermodynamic equilibrium calculations and experiments. The aim of the study is to achieve both the appropriate treatment of resins containing brominated flame retardants and the efficient recovery of valuable metals contained in WPCBs. In the experiments with metals and TBBPA, comparison with the results of the analysis showed that the reaction rate of the bromination reaction had to be considered. The results of the thermodynamic equilibrium calculations also confirmed that the bromination volatilization rate of each metal is affected by the coexisting elements.

Wire harnesses (WH), which are mainly used as automotive components, are mostly composed of copper wires covered with polyvinyl chloride (PVC) of a few millimeters in diameter. Although the recycling of automotive parts has become increasingly important in recent years, an effective method for recovering copper wire and PVC from the thin wire of WH has not yet been developed. In our laboratory, we have succeeded in stripping thin wires of about 20 cm in length by the wet swelling and milling method, in which thin wires are swollen by submerging it in an appropriate organic solvent and then stripped by applying an appropriate impact to the wire using a ball mill. In this study, the wet swelling and milling method using a bench-scale reactor was conducted to investigate the stripping behavior of thin wires of 60 to 150 cm in length. As a result, 100% of the copper wire and coating material were successfully stripped at the appropriate amount of treatment and temperature at the time of wire swelling. We expect to increase the amount of treatment and realize stripping without crushing the copper wire and coating material by further examining the optimum conditions.

In recent years, incidents of smoke and fire caused by lithium-ion batteries (LIBs) mixed in waste during the crushing process of waste collection and treatment have been increasing. Countermeasures for fire accidents during waste collection and treatment include visual monitoring to remove mixed LIBs, early detection of smoke and fire, and the introduction of automatic fire extinguishing systems. However, these measures mainly address post-fire incidents. This study aims to realize the practical application of a detection system using RFID tags currently under development. It examines the variability in detection results by humans and explores the use of a metal cylinder to improve detection rates, followed by reception experiments. As a result, all five subjects were able to identify the presence or absence of tags with 100% accuracy, although it took 1 to 4 seconds to read the tags. Furthermore, it was found that even if tags were mixed with metallic or non-combustible waste, the reading of tags was possible due to increased reception strength when the waste bags themselves were surrounded by metal, such as a metal cylinder.

The global market for automotive rechargeable batteries is projected to grow more than tenfold over the next 30 years. In Japan, which primarily relies on imports from China for battery metals, the stable supply of raw materials through recycling of spent rechargeable batteries is considered an urgent necessity. This study focuses on the Black Mass of spent rechargeable batteries obtained by roasting and crushing used rechargeable batteries at high temperatures. The research includes compositional analysis, examination of the feasibility of physical separation, and acid leaching experiments using inorganic acids. The findings of this study are as follows:

For physical separation, the effectiveness of particle size separation using a 45 µm sieve was confirmed for the black mass of Lithium-ion Batteries (LiB). In the acid leaching experiments, more than 80% extraction rates of Li, Ni, Co, and Mn were achieved for the LiB black mass using 2 M sulfuric acid at 70°C with a solid-liquid ratio of 1/40 g/mL. Additionally, even without using inorganic acids, an extraction rate of 40% for Li was achieved with hot water extraction alone. For the black mass of nickel-metal hydride (NiMH) batteries, hydrochloric acid demonstrated higher extraction rates.

Mitsubishi Electric Corporation has realized “closed-loop recycling from household appliances to household appliances” in which polypropylene (PP), polystyrene (PS) and acrylonitrile-butadiene-styrene (ABS) are collected from a mixture of residual plastics contained in discarded household appliances and sorted for recycling.

However, engineering plastics, which are plastics with a density of 1.1 g/cm³ or more, are not effectively utilized because they cannot be separated from plastics containing brominated flame retardants and metals.

In this study we confirmed whether engineering plastics contained in mixed plastics with a density of 1.1 to 1.5 g/cm³ were sorted using existing sorting methods and whether material recycling was possible.

As a result, recycled POM, recycled PC/ABS, recycled PC, and recycled PBT are possible to mechanical recycle, but recycled PA is difficult to mechanical recycle.