This study aimed to design a multi-faceted intervention system for reducing household food loss and waste among young people in the 20-30 year age range and from various family configurations. The intervention system combined several methods, such as recording and feedback, communication, and prompts.
　The results showed that food photography and feedback were the most effective intervention methods. Participants were impressed by the large amount of CO₂ generated by food loss and waste, the fact that the wasted food was still edible, and the knowledge that the peels of wasted vegetables and fruits were rich in nutrients. Based on our findings, we believe that a combination of these documentation recordings and creative educational methods could be an effective way to reduce food loss and waste overall.

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As one way to reduce CO₂ as a greenhouse gas, CO₂ is fixed in industrial byproducts and buried in landfill sites. We are researching the feasibility of Carbon dioxide Capture and Storage (CCS) in landfill sites.
　Retention after CO₂ fixation has not been clear, however, and we are concerned about CO₂ reemission due to external factors. In this study, we verified the reemission caused by acid rain of CO₂ that had been fixed in industrial byproducts and examined the potential application of CCS in landfill sites.
　Therefore, we fixed CO₂ fully in fly ash, an industrial byproduct, and mixed in a solution that simulated acid rain. Then, we evaluated CO₂ reemission by measuring the volume of carbonate in the solid after solid-liquid separation. As a result, we clarified that at least 0.820m³ of acid rain is necessary for reemission of all the CO₂ in 1g of fly ash. This showed that, assuming that CO₂ was captured in landfill sites, the rate of reemission due to acid rain was very low at 7.84 × 10⁻⁴% over 30 years.

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In the field of waste and resource recycling, there is increasing activity in carbon capture, utilization, and storage (CCUS) efforts. The carbonation of incinerator ash is a technique that can be expected to suppress the elution of lead, for example, at the same time as fixing CO₂ by forming carbonate. However, to ensure the insolubilization of incinerator fly ash, which has a high concentration of heavy metal elution, combining carbonation with chemical treatment is desirable. In this study, the effects of carbonation and the addition of chelating agents to incinerator fly ash from industrial and general wastes were verified. The possibility of reducing the amount of chelating agents used was also examined. In addition, under a high salt concentration condition, which is likely to promote lead elution, an elution test (immersion and centrifuge method) was performed at a low liquid-solid ratio. The results suggested that the amount of chelating agent could be reduced by adding the agent after carbonation. Moreover, under these conditions, carbonation promoted the elution of lead in some fly ash. However, it was hinted that elution might be suppressed even under the same conditions by combining carbonation with a chelating agent.

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To evaluate the environmental safety of waste silicon solar panels as fine aggregate, JIS A 5011-1 leaching and content tests were conducted for cover glass (CG), wet specific gravity separation residue (WSGSR), which were separated from the waste solar panels, their mixture (waste panel aggregate, WPA), a simulation sample made from WPA and cement, and a cement paste sample made from only cement. Although Pb content in WSGSR was 1.5 times higher than the Environmentally Sound Quality Standards (ESQS) value for Content, Pb content in WPA met the ESQS for Content because of the dilution effect of mixing CG and WSGSR. Although Sb leaching concentration from CG was 1.1 times higher than the guideline value of the Environmental Quality Standards for Groundwater Pollution, Sb leaching concentration from WPA met the guideline. Because WPA met both ESQS for Content and Leachate, the simulation samples also met both standards. Therefore, based on the evaluation of both aggregate and simulation samples, it was concluded that the silicon solar panel waste used in this research could be used as fine aggregate in a manner that is environmentally safe.

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The reduction of plastic waste and the implementation of chemical recycling are strongly recommended, but appropriate treatment methods for halogenated plastics such as polyvinyl chloride (PVC) have not yet been fully established. Results of this study contribute to the effective chemical recycling of PVC by hydrothermal processing. The reaction behavior of PVC was investigated under hydrothermal conditions to clarify the dechlorination process, surface morphological evolution, and product structure. Three distinct reaction environments were applied: liquid phase (stirred), liquid phase (static), and vapor phase. The results indicate that the reaction products’ morphology is influenced strongly by both solvents or additives and the reaction environment. The reactivity in aqueous ammonium solutions ((NH₂)₂CO and NH₄OH) and amine additives (triethylamine and polyethylenimine) under stirred conditions was notably effective. The findings demonstrate that different physical and chemical changes imposed on PVC during the initial stages of the reaction yield marked variations in dechlorination behavior. Furthermore, these changes affect the morphology and structure of the resulting product. Various controls of hydrothermal reaction conditions suggest the usefulness of the chemical recycling of PVC.

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A structural stability evaluation of isolation-type waste landfills against Level 1 and Level 2 seismic motions was conducted using seismic analysis. The material thickness of reinforced concrete used at waste containment facilities has been changed from 150 mm to 350 mm due to the revision of structural standards in 1998. Focusing on isolated landfill sites before and after this revision of Japanese standards, the effects of ground and landfill conditions on the width of the cracks that become sources of hazardous leakages were investigated. It was found that if sound strength of the RC was maintained at the regulated standard, the crack width remained at less than 0.5 mm, the design tolerance level. However, the fact that the waste layer was filled with water led to the development of a crack that reached the maximum largest width for an earthquake. This means that this method for analysis may be applicable for design and also indicates that it is an effective means for making the various conditions more precise. However, it is important to take into consideration the surrounding ground conditions in response to demands for improved safety, including suppression of rainwater infiltration, reduction of seismic loads, and prevention of outflow for chemical substances in landfill waste.

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The stabilization process is an important issue for landfill sites, and one of the indicators for this is leachate monitoring, which can be used to evaluate entire sites. Since leachate contains a wide variety of chemicals, there is a need to utilize bioassays that can complement conventionally conducted chemical analysis. In general, bioassays have not been reported to be utilized in the management of landfill sites because of their long testing times and high costs compared to chemical analysis. Therefore, as a method that can be conducted easily at simple local facilities in as little as 24 hours, an acute toxicity test was developed and applied successfully for two years using red finfish (Tanichthys albonubes). The results demonstrate that this rapid bioassay was useful in local maintenance and management.

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Although data on the reactivity of strontium compounds are important for assessing the behavior of strontium-90 during the incineration and melting treatment of waste contaminated by radioactive species released from nuclear power plants following accidents, limited information is available on strontium compounds compared to the abundant experimental data available on the reactivity of calcium compounds. In this research, using lab-scale experimental set-ups, we studied the reactivity of strontium compounds such as strontium hydroxide and strontium carbonate in two different atmospheres: a combustion atmosphere and a flue gas cooling unit atmosphere. The results showed that in the flue gas cooling unit atmosphere, set at 180°C in the presence of HCl gas, strontium hydroxide reacts with HCl gas to yield several chloride compounds. Meanwhile, in the combustion atmosphere, set at 850°C with silicate minerals, strontium carbonate probably decomposes into oxide and reacts with colloidal silica, quartz, and bentonite to yield strontium orthosilicate, Sr₂SiO₄.

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In order to clarify the application possibilities of okara, which is a byproduct of tofu production, as moisture absorbing biomass filler, polypropylene (PP) sheets mixed with okara at 33, 40, 51 and 60 wt% were prepared by compression molding. Mechanical properties, including the yield stress and yield elongation, of these sheets decreased with increasing okara mix ratios due to low adhesive strength between okara and PP. In addition, the decrease of elastic modulus was particularly remarkable in PP sheets mixed with 60 wt% of okara because of crack formation on the sheet surface. However, hygroscopicity was improved by mixing okara because the amount of adsorbed vapor increased with higher okara ratios. Furthermore, when these okara mixed PP sheets were kept at 40℃, 93% R.H., mechanical properties and dimension stability decreased while the amount of adsorbed vapor increased significantly in the first 7 days due to voids forming on the sheet surface. However, changes in these properties were considered to be within an acceptable range in practical use. Finally, it was thought that okara mixed PP sheets could be used as a packaging material that suppresses moisture absorption by the contents.

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The actual situation and characteristics of waste-related work undertaken at municipalities in normal times is investigated from the viewpoint of disaster waste management, based on the results of 747 responses from our national municipality questionnaire survey. At the same time, we examined the effectiveness of disaster waste countermeasures taken during normal times.
　As for smaller municipalities, works related to waste management are being conducted in a state of staff shortage. As a consequence, while the works conducted in response to inquiries from residents and waste collection and transportation are prioritized, a high percentage of smaller municipalities do not perform the work for the formulation of waste management plans. The survey results suggest that the formulation of a waste process implementation plan would be effective, as it will draw an overall picture of the business flow, calculate the planned process amount, and develop contracts. The results also suggest that the opportunity to systematically understand and organize the flow of waste treatment would be a strengthening point for measures to be taken in normal times, along with responding to resident inquiries.

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This study aimed to make effective use of waste glass cullet (GC) as a fill material in the sand drain (SD) method, which is a method for accelerating consolidation, from the perspective of waste resource management. A soil consolidation test was devised and implemented with a 1/10-scale model, and an experimental study was conducted using GC, sea sand (which has been demonstrated to be effective as an SD material) and GC mixed sand, which is a mixture of GC and pit sand (decomposed granite soil). Pit sand is unsuitable in isolation as an SD material. The following results were found. 1) The accelerated consolidation effect of SD with GC and of SD with sea sand were found to be largely equivalent. 2) The grain size of pit sand (decomposed granite soil) can be improved by mixing it with GC to achieve an accelerated consolidation effect similar to sea sand. 3) The accelerated consolidation effects of SD materials that have coefficients of permeability _mli006b_mls0073 in a range of 5.5× 10⁻⁵-1.7×10⁻³ m/s do not differ greatly.

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