To evaluate the efficiency of particle removal by bag filters at incineration plants constructed to process wastes contaminated with radioactive material from the Fukushima Daiichi Nuclear Power Plant accident, PM₁₀ particle size distributions in incinerator emissions were measured at a bag filter inlet and outlet. The number concentration at the outlet for all diameters was less than 100cm^－3, which was approximately equal to concentrations of 1×10^－4 to 1×10^－6 compared with that at the inlet. The bag filters showed greater than 99.9 % particle removal efficiency for all particle sizes. Pulse cleaning of the bag filter increased the particle mass concentration at the bag filter outlet, but the effect lasted only for a second. Results show that the mass-based removal efficiency for PM₁₀ during cleaning operations was 99.78 %. For PM₁₀ , the mass-based removal efficiency was 99.99 %.

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The problems of geological engineering surveys and evaluations for improvement of final disposal sites have been noticed from the view of environmental conservation. Waste containing mercury exceeding the standard was landfilled in the Itoigawa final disposal site. To improve this final disposal site, we carried out several geological-engineering surveys, including geophysical prospecting and numerical analysis of groundwater.
The results of surveys and numerical analysis showed that internal water containing arsenic and other harmful heavy metals might leak from the landfill site with heavy rain. Therefore, if drainage wells are provided in landfill sites, they would not only act as an effective countermeasure for environmental conservation as water barriers, according to the results of our numerical analysis, but they would also effectively contribute to the mechanical stability of the landfill. This water barrier countermeasure uses a method in which the hydraulic potential of the internal water in the landfill is lower than that of the groundwater in natural ground around the landfill. For an example, there are several drainage wells (with drainage bore holes) and water treatment facilities. This countermeasure is inexpensive with good workability.

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A pottery glaze that is comprised of waste oyster shell powder for use on ceramic tableware and building pottery, was developed in this study which aims to find increased uses for waste oyster shells. The oyster shell powder is produced using a hammer mill, and is shown to be a suitable substitute for commercially available, refined CaCO₃ powder. Conditions suitable for perfect compounding and heating between the oyster shell powder and clay are elucidated. Mixtures prepared with 30 wt% or 33 wt% of the oyster shell powder in the mixed system, with natural clay (Shigaraki clay) including a small amount of iron oxides (approximately 2.5 wt%) and other impurities, were well melted at 1200°C. The 30 wt% mixture was found to have a notably higher fluidity than that of the 33 wt% mixture. In order to further prove the viability of the 30 wt% mixture, glazing and baking (at 1250°C for 1h) of the substrate was performed and a utility dish was prepared using this. The final product obtained did show a high surface quality.

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For the purpose of the early stabilization of MSW bottom ash, we investigated Pb insolubilization treatments that can be combined with water sprinkling treatments to wash out salts. For the insolubilization treatment method, we conducted column tests to verify sprinkling treatments with chemical agents in solution and accelerated carbonation treatments using CO₂ gas. We used sodium bicarbonate (SHC), phosphoric acid (PA) and organic chelate (OC) as the chemical agents.
For the chemical sprinkling treatment, we confirmed Pb insolubilizing effects for all the chemicals. In the OC group, the Pb concentration was 0.01 mg L^－1 in all layers, but in the SHC and PA groups, the reaction also progressed with Ca in the bottom ash, and the effect was reduced in the lower layers of the columns.
In the accelerated carbonation treatment, we estimated that the threshold value of the CO₂ supply amount at which the Pb insolubilizing effect is observed was about 30-40 g kgDW^－1. We confirmed that the same effect can be obtained even with the CO₂ concentration changed from 100 % to 10 %. In addition, we verified the effectiveness of the order of the combination of water sprinkling and carbonation.

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Although there has been an increase in the national recycling rate for municipal waste since the year 2000, it has now reached a saturation point. One of the reasons behind this is the existence of uncaptured municipal waste flows, which skip over municipality treatment and recycling routes. This article discusses methodologies for estimating such flows and proposes ones that are more appropriate. Further, the paper presents the application of these methodologies in a case study from Shiga Prefecture, where a recycling rate that takes into account the uncaptured flows (true recycling rate) has been estimated. Specifically, estimation methodologies for collection of recyclables at stores, collection of recyclables by recycling companies, and for mixtures of municipal waste into industrial waste are discussed. The application of these methodologies in Shiga Prefecture shows that the amount of uncaptured recycling was estimated to be about a half the total recycling amount. Moreover, even though the true recycling rate was estimated to be about 13% greater than the current recycling rate, the trends in current and true recycling rates were actually not so different. This indicates that, for Shiga Prefecture, the existence of such uncaptured flows for municipal waste is having little influence on the saturated recycling rate.

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The bromination of metallurgical grade silicon (MG-Si) was investigated in a flow reactor in the presence of iron under various conditions. The reactivity of Si samples was evaluated with respect to HBr conversion and SiHBr₃ selectivity, while product purity was analyzed after hydrolyzing them to silicon dioxide (SiO₂). The concentration of metal elements in the product were much less than those in MG-Si. The addition of iron resulted in no significant increase in metal impurities. Rather, it resulted in an improvement of reaction kinetics in a temperature range of 380-400°C, probably as a result of better catalytic action in the reactant due to the substance accelerating the catalysis of iron. The activation energy for the overall bromination reaction in the presence of iron was estimated to be 129 kJ/mol.

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Japan has been exporting a portion of its post-consumer polyethylene terephthalate (PET) bottles for recycling, mainly to China. However, now that China has regulated its import of solid waste, including PET bottles, Japan’s current recycling system needs to be reviewed. When designing the recycling system there are several constraints, including the amount of PET bottles being collected, the capacity of recycling facilities, and the acceptable amount of recycled resin. Therefore, any discussion on this must take into account the entire material flow process for PET resin products.
　In this paper, we construct a framework for designing recycling scenarios and apply it to the post-consumer PET bottles being collected in Japan. We first analyze the domestic material flow of PET resin products as a means of estimating acceptable amounts for recycled PET resin as the raw material in each product. In addition, based on interviews and a literature review on the uses of recycled resin, we summarize the acceptability of recycled resin for the intended products. This acceptability varies on how PET bottles are collected and what recycling technology is applied. Based on such constraints related to the amount and quality of recycled resin, we propose recycling scenarios that will allow for management of the whole post-consumer PET bottles domestically.

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Recently, many pig farmers have faced the issues of odor suppression and water quality standards for wastewater discharge during the treatment of manure. As a solution to these issues, a small-scale, distributed methane fermentation system was developed and introduced to a pig farm in April 2016. This system had a lower manufacturing cost and was constructed considering the profitably of a medium-sized pig farm in Japan. This study aims at clarifying the carbon and nitrogen flows, power generation from biogas and benefits of the system in view of providing more details about its functionality. The results indicated that 51% of the carbon had been decomposed into biogas, and the denitrification of wastewater treatment unit in the system was functioning as required. In addition, the monthly electricity production was about 9900kWh. When the selling price of the electricity produced by the biogas was 39yen/kWh, it was estimated that the power generated by the system could be sold for 4.6 million yen per year. Therefore, the initial cost could be recovered in less than 11 years.

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The main sources of information about incinerated waste quality in operating MSW incinerators are usually periodical surveys of waste sampled from a waste bunker. However, the thus-obtained LCVs of fed-waste are occasionally inappropriate for ascertaining the average heat value of actually incinerated waste, although LCVs are indispensable parameters for evaluating the incineration process performance.
To overcome this unfavorable situation, the author proposes the utilization of combustion gas properties which are more stable than fed-waste quality and which present the estimated mean LCVs of incinerated waste with the aid of ideal boiler efficiency (IBE).
This report mainly describes the available annual operational data of FY2012-2017 collected from combustible MSW incinerators in Tokyo special ward district, presented along with statistical analyses of LCVs of incinerated waste with the aid of an elaborate IBE, and with statistics related to the heat values of incinerated waste sufficient to evaluate and to examine the corresponding heat inputs to incinerators. The results reveal that a set of sufficiently usable LCV related parameters is obtainable using these statistical analyses, even though the original waste sampling data might include some unavoidable bias.

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Power generation per unit mass of waste, one MSW incinerator power generation performance index, can be measured precisely, although gross thermal efficiency, the performance index of WtE system itself, cannot escape a certain amount of error caused by difficulties of measuring the calorific values of fed-waste.
The author conducted a systematic analysis of WtE systems, with enhanced accuracy of annual heat inputs using the estimated annual mean LCVs of fed-waste calculated from ideal boiler efficiencies based on less changeable properties of combustion gases.
This study examined responses of WtE systems relative to energy conversion under various combustion conditions including waste quality and excess air ratios, using available operational data of FY 2012-2017 collected from twenty-two combustible MSW incinerators operating in Tokyo special ward district. Results demonstrate that three incinerator replacements have contributed to a 6.9% increase in overall gross thermal efficiency from 0.145 to 0.155.

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Recently, the high amount of plastic waste has become a serious environmental problem. Recycling is one of the best ways to reduce the amount of waste. However, the mechanical properties of the products that are produced from waste plastics are lower than those made from virgin plastics. The main reason is thought to be that recycled plastics are degraded by chemicals that have the effect of shortening molecular chains. In our previous work, it was found that physical degradation is the main cause of poor mechanical properties in pre-consumer polypropylene, which is used as an example of general waste plastics. Furthermore, it is worth noting that suitable compression molding conditions can improve the mechanical properties of polypropylene from sorted waste container and packaging plastics. In this study, the mechanical properties of unsorted waste container and packaging plastics are investigated with different compression molding conditions. The suitable conditions that can improve the mechanical properties of recycled products are the main targets.
　The results indicate that recycled containers and packaging plastics can maintain mechanical properties similar to virgin plastics and can be widely applied to various value-added applications.

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The promotion of formal behaviors for the disposal of home appliances has its limits when it comes to how much consumers can actually be positively influenced. In fact, change in behavior may greatly depend on improved consumer understanding of recycling systems. For example, although the Home Appliance Recycling Law came into effect back in 2001, rates for End-of-Life products covered under this law show room for much more improvement. One possible alternative is to introduce a deposit-refund system into the recycling system. This may, however, give rise to concerns that product demand could decrease due to the mandatory deposit payment. This paper analyses the relationship between provision of information regarding recycling systems and consumer perceptions concerning the burden of bearing costs for recycling. Using home appliance recycling (namely TVs) as an example, the paper begins by outlining a deposit-refund system in the current recycling scheme and introduces a design for a model of intervention to evaluate how consumers comprehend recycling-related product attributes based on action identification theory. The authors use a conjoint analysis to estimate impacts on the perception of the burden, and verify the effectiveness of the model for TV sets. Our results suggest that payment of a deposit is seen as a burden to consumers, and manipulating action identification of the purchase is suggested as an effective means of alleviating this perception.

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Crystalline phases, major elements and trace elements in municipal solid waste (MSW) fly ash classified into different particle sizes with six divisions were analyzed by XRD, XRF and ICP-AES. According to particle size dependence of trace element concentrations, Mn and Ni existed in large particles, while Se, Cd and Pb existed in small particles. Among them, concentrations of Cd and Pb showed high particle size dependence. By taking into account elution tests, some Sr and Pb were assumed to form chloride compounds in MSW fly ash. Cadmium showed high correlation with MgO, Al₂O₃, SiO₂, P₂O₅, Cl, CaO, Fe₂O₃ and amorphous concentrations. Lead showed high correlation with MgO, Al₂O₃, SiO₂, Cl, CaO, Fe₂O₃ and amorphous concentrations. These results show that the elements were contained as not only oxide and chloride but also as silicate and composite crystalline phases, and some Cd and Pb were included in the amorphous phase.

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In response to requests for wide-area treatment plans that promote restrictions on plant location and energy recovery such as power generation and heat utilization, it is necessary to construct a comprehensive evaluation system that expands collection and transportation within the waste management field. However, the conventional Grid City Model that has been used for the evaluation of collection and transportation has non-linearity, rendering it unable to respond to simulation of wide-area and energy recovery. It has also been difficult to evaluate regional characteristics. We therefore worked to construct a model that can be applied over a wide area and addresses regional characteristics through a process of manageable calculations.
　In this study, we develop a modified model for improving the conventional Grid City Model :. With Aichi Prefecture as the target site, our results advocated optimization for transportation and a multi-regression model for collection. The collection and transportation models must be constructed to calculate and evaluate costs and carbon dioxide emissions from the entire process using public statistics. As a result, we were able to successfully develop a reproducible regression Grid City model, a linear collection-transportation model, and a model that can evaluate the cost, CO₂ emissions, regional characteristics, and collection time per staff member.

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A recycling scheme for containers and packaging waste was introduced in Belgium and Japan at the same time. Belgium has since achieved the highest recycling rate for containers and packaging waste among EU membership countries. Moreover, Belgium has achieved this rate while maintaining a low management cost. Fost Plus is a non-profit organization set up and financed by industry; it has coordinated and financed the selective collecting, sorting, and recycling of household containers and packaging waste in Belgium. In this study, Fost Plus staff members were interviewed and surveys were conducted on related literature that examines recycling accomplishments for containers and packaging waste in Belgium from the quantitative and financial viewpoints. Lastly, the study also analyzes factors such as cost efficiency of recycling in Belgium as compared to that of Japan. Results suggest that certain improvements in the recycling scheme for household containers and packaging waste need to be made in Japan.

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