The gasifier was designed to equipped with opening system to correct particles with maintaining the shape and place of the particles inside the gasifier. By quenching the gasifier while the target point of the experiment/operation, the state of solid particles can be kept the state in any operation point. The bottom of fixed bed reactor is able to open after quenching, keeping the solid particles by covering with a transparent cylinder. Also, since only the lower part of the reactor is opened, it is possible to effectively reduce the labor required for collection / visualization work without requiring work such as transporting, sideways, or splitting the reactor main body. Furthermore, collected particles is packed in the cylinder, it is able to observe cross-sectional distribution both vertical and horizontal by cutting the packed particles with cutting cylinder in half. The gasification performance under several conditions was investigated with considering the distribution of the kind and property of particles inside the gasifier using this system.

The present work aims to investigate the existence form of potassium in Palm Kernel Shell (PKS) and predict the mechanism of potassium removal by hydrothermal treatment at different temperature. In this work, hydrothermal treatment were conducted at 100, 140, 180 and 220°C with biomass-to-water ratio of 1:10 and holding time of 30 minutes. We found that potassium exists as inorganic form (KCl and K₂SO₄) and organic form (feldspar group) in raw PKS. Potassium removal rate increases with temperature and reached the highest removal rate of 60.11% at 220°C. This study also confirmed that after hydrothermally treated at 140°C, potassium in inorganic form were completely removed from PKS, while potassium in organic form continued to exist even after hydrothermally treated at 220°C. We suggest that subcritical water generated during hydrothermal treatment is the key agent which enhance the ion exchange process and remove potassium in inorganic form. However, another ion exchange agent is needed to dilute potassium in organic form for enhanced removal process. Similar analysis with additional independent variables (holding time, vapor quality, biomass-to-water ratio) is suggested to be conducted to other lignocellulosic biomass with higher potassium content (e.g. Empty Fruit Bunches (EFB)) to further investigate the potassium removal mechanism

The "Tobu Chita Clean Center (nicknamed Ecori)" was constructed in March 2019 as a new facility to replace the old existing one, and started to dispose the general waste of Tobu Chita Sanitary Association (composed of 2 cities and 2 cities, Obu City, Toyoae City, Higashiura town, and Agui town). This facility is "The advanced shaft furnace" that is the latest type, and it is possible to reduce CO2 while maintaining the following function of shaft furnace type gasification melting furnace, (1) To Melt a wide range of waste completely and turn it into slag and metal, (2) To Minimize the final disposal volume. We proved that this type of furnace can significantly reduce the amount of coal used as fuel while inheriting the features of a conventional shaft furnace through performance tests. We will contribute to the formation of a recycling society and a low carbon society by working on the development of waste disposal process and the innovation of equipment technology in the waste treatment system.

"Tobu Chita Clean Center (nicknamed Ecori)" constructed in March 2019 was introduced "advanced shaft furnace", and it is possible to reduce CO₂ emission while maintaining the follwing function of shaft furnace type direct melting system: material recovery from various kind of waste with high reliability, and minimizing the final disposal volume. In these facilities, selective non-catalytic reduction (SNCR), which contributes to enhancement of heat recovery, is applied to deNO_x process. The combination of SNCR and low NO_x combustion technology developed in facilities with conventional shaft furnace enabled stable decrease in NO_x emission, without exhaust gas recirculation. We realized low NO_x combustion by optimal combustion air distribution based on the reaction analysis, which resulted in mean NO_x generation of 59 ppm. With SNCR, mean NO_x emission was 33 ppm, which was greatly below 70 ppm: the reference value of it.

“Recycling incineration residue” is important for those countries which can’t secure enough landfill site. Melting technology is a recycling technology that converts incineration residue into slag and ferrous or non-ferrous raw materials (metal, fly ash) by high-temperature treatment at 1,300 ° C. Reducing the fuel cost of the melting furnace is effective for reducing the cost of "recycling incineration residue".

On the other hand, due to the ocean plastic problem, the embargo policy in plastic importing countries, and the amendment of the Basel Convention, "domestic treatment and recycling of waste plastic" became a global challenge. Utilization of the waste plastic which is not suitable for material recycling (high chlorine concentration, composite materials and stubborn dirt) is essential in the final stage.

The use of waste plastic as alternative fuel in the melting furnace is the technology that simultaneously realizes the “domestic treatment and recycling of waste plastic” and the “recycling incineration residue” cost reduction. The Urasoe Clean Center has been conducting demonstration tests on the technology since 2017 and started using waste plastic as alternative fuel. In this report, we evaluated the commercial furnace operation data for 308 days before and after introducing the technology.

Incineration residue of temporary incineration facilities in Fukushima prefecture which is contaminated by radioactive materials from the accident of Fukushima-Daiichi Nuclear Power Plants will be treated in volume reduction facilities from March, 2020. Their by-poducts is molten fly ash with high radioactivities and various studies have been made for its final disposal. In order to find its necessity and main targets of research and development and to investigate the reasonable disposal scenaios, it is important to understand the mass balance of treatment process.

In this report, calculation method of the mass balance was outlined and its examples were shown. And the influences of operation parameters on mass and radioactivity of each product were investigated.

To investigate mercury removal from incineration flue-gas in a clinical waste incineration plant, mercury concentrations in the incineration flue-gas were measured at the both side (inlet and outlet) of fabric filters. On the measurement conducted in 2015, more than 90% of mercury in the incineration flue-gas was removed by passing the fabric filters. However, on the measurement conducted in 2019 mercury was hardly removed by fabric filters although there is no change in the plant. It is difficult to explain this result because there is very limited information. Further studies on the chemical speciation of mercury in the flue-gas are needed.

Slaked lime is commonly used as alkali agent for dry scrubbing of hydrogen chloride and sulfur oxides in flue gas discharged from municipal solid waste incinerators (MSWIs). As the utilization amount of slake lime is the most among chemicals used in MSWI, its impact on the operating cost is significant. For this reason, the on-site production of slaked lime was attempted by using cheap quicklime and a simplified hydrator in MSWI. However, the discharge problem of fly ash occurred at the hopper of bag filter (BF) owing to the poor flow property of on-site produced slaked lime when it was tested in the demonstration facility. In this study, we developed lab-scale of flowability tests to evaluate the flow property of produced slaked lime as well as to find the optimum condition of on-site production.

Twenty two MSW incinerators (systems) involved in combustible waste incineration in Tokyo Special Ward District in the FY2012-17 period. During this period, 3 systems finished operation while 3 newly-built systems started operation.

In this study, performances over the multiple fiscal years of the top 6 systems in terms of gross thermal efficiency η_G among the current operating systems (19 operating systems in FY2017) are examined, together with corresponding degrees of generator utilization.

Results show that the 3 newly-built systems whose η_Gs exceed 19% present better performances in boiler efficiency and turbine steam utilization fraction out of three η_G factors in comparison with conventional systems, and that generator utilization fractions of the 3 newly-built systems in FY2017 do not reach 61.4%, the average value of the current operating systems.

Although thermodynamic equilibrium calculation has been applied to analyze the fate of heavy metals in waste incinerations, in some cases calculation could not represent the actual vaporization behavior of some minor heavy metals in the incinerator. Possible reason of the disagreement between the modelling result and the actual vaporization behavior of heavy metals may be that waste is not a single kind of material, and the reactions and physical changes occurring in the waste incinerator does not reach equilibrium, however, from previous calculations we noticed that the thermodynamic data for minor heavy metals had been quoted from old literature and did not contain all possible gas phase species, which also could have affected the calculation results. In this study, we have checked the literature on the thermodynamic parameters of compounds including heavy metals (Cd, Cr, As, Cu, Pb, Zn), and modified the database for the equilibrium calculation. Using the updated database, we run multizonal thermodynamic equilibrium calculations for the RDF incineration in a rotary-kiln incinerator that had already reported in the latest presentation on this conference.

Carbonation treatment of incineration residue (Bottom ash(BA) and Fly ash(FA)) was performed using exhaust gas and CO2 separated and recovered from Saga city’s incineration plant in order to develop carbonation technology by exhaust gas from incineration plants. We investigated the influence of the difference in supply gas on pH and Pb concentration in the eluate. At the same time, we also estimated the amount of CO2 absorbed. By the carbonation treatment, in the BA, no significant difference was observed in TC (total carbon content) of ash and pH in the eluate due to the difference in the supplied gas. In theFA, the increase in TC in the upper part of the recovered CO2 treatment was hardly recognized, suggesting a shortage of CO2 supply in the upper layer. With regard to Pb concentration, in the bottom ash, the recovered CO2 had a higher elution reduction effect after carbonation, but in the fly ash, no influence of the supplied gas was observed. In addition, the amount of CO2 absorbed is 24-28 g / kg DW for BA and about 48 g / kg DW for FA(excluding recovered CO2 zone upper layer), and FA is more reactive with CO2 than BA was suggested.

Since municipal solid waste incineration (MSWI) fly ash contains heavy metals; Pb and Zn. Chelate treatment is mainly used to solve the problem. However, this treatment method has possibility to leach organic hydrocarbons to the soil during the long-term disposal. In this study, the authors employ the Geocasting method as an alternative treatment to enhance the particle size and apply the treated MSWI fly ash for fluidized bed sand replacement. The results show that geopolymerization affected the properties of the samples. The geocasted fly ash can be used as a heat carrier to immobilize toxic heavy metals. Moreover, physical and chemical characteristics and the immobilization performance onto the geocasted samples were changed as the effect of the calcination temperatures.

For offshore landfills, the pH and the organic matter of the leachate may continue to be above the emission standards for a long time due to highly alkaline incinerator ash under anaerobic conditions, resulting in delaying the stabilization of offshore landfill. Therefore, column experiments were carried out to evaluate the effect of carbonation treatment of incinerator ash on the stabilization of offshore landfills, especially focusing on the pH and concentration of organic matter in leachate.

As a results of these experiments, the carbonation-treated incinerator ash showed a marked decrease in TOC and pH in the early stage. This implies that calcium carbonate surface coating by the carbonation treatment retards the release rate of organic matter from incinerator ash.

Even if the drainage from the leachate treatment facility satisfied the standard value of water quality control items etc., it is often opposed to discharge from local residents. In this study, we conducted a bio-toxicity test using Medaka on the leachate samples and treated leachate, where the landfill was completed and awaited for termination, and the pond water on the located upstream. As a result, in the leachate samples, Lethal Concentration, 50% (LC50) is 10.4 to 17.5 mg / L and No Observed Effect Concentration (NOEC) is 5.6 to 8.5 mg / L in terms of CODMn concentration. No toxicity was observed in the pond water and treated leachate. The results of gene expression analysis also showed high toxicity of the leachate samples. We also grasped the tendency of expression fluctuation. In addition, the characteristics of each gene expression level were understood. The genetic analysis is expected as a simple method of eco-toxicity in the future.

In Japan, industrial waste landfill is classified into three types and the one is hazardous waste landfill. This type of landfill accepts hazardous industrial waste (e.g. sludge or dust which exceeds the leaching criteria on hazardous substances) and isolates the waste from external environment by rigid structure with impervious thick concrete walls. It was reported that at present there are 24 sites in Japan according to a report by Ministry of the Environment. However, there are many unknowns, since few researches had been performed up to now. Thus, in this study, the objective was set to identify the current situation of these hazardous waste landfills, especially regarding the kinds of waste disposed of into such sites. Interview and questionnaire survey for companies which contracted their waste disposal to the hazardous waste landfill were conducted. As a result, the largest fraction of the waste was the refractory material used in thermal treatment plant of the solid waste, because it contains hexavalent chromium. Residue generated from recycling facilities of home electric appliance was also disposed of into the landfill.