In this study, to secure remaining volume in landfill site and establish cycle of useful metal, the possibility of separation and recovery of ferrous metal contained in municipal solid waste incineration bottom ash was investigated by analyzing its component. The daily necessities and metal fittings appeared frequently. It may be effective to prevent the inflow of ferrous metal blocks and part of machines by advance separation measurements. Compared to the previous data, the quantity of cans was significantly reduced due to the reduction of steel cans consumption and the separation of spray cans. Whereas, the quantity of batteries increased, which it is necessary to consider about some measures to strengthen recovery. With a mass of 17.20% of total, ferrous metal contained 79.01% Fe and 90.13% Ni of total while non-magnetic metal contained 43.25% Cr of total. It is important to recover metals both for resource recovery and effective utilization of bottom ash.

A demonstration test of on-site aging using a container was conducted to promote stabilization of MSW bottom ash. The test equipment used was a modified container (3600×1910×970Hmm) made of SUS with a double-floor structure, with a space at the bottom for separation of the load and wastewater and gas ventilation. Incinerated bottom ash was directly loaded into the container from the ash crane at the incineration plant and used for the test without classifying and sorting (about 2 tons each time). Two tests were conducted, one with carbonation treatment only and the other with water sprinkling and carbonation treatment. The CO2 for the carbonation process came from a liquefied CO2 cylinder, and the water sprinkling process used a unique water sprinkler control system. A temperature measurement in the container confirmed that the temperature of the entire bottom ash increased, implying the carbonation reaction had progressed. The elution test after the treatment confirmed the insolubilization of Pb by carbonation and the washing out of Na, K, Cl, and B by water sprinkling, revealing that the effect was equivalent to that of previous laboratory tests even at full scale.

Many incinerator fly ash contains unreacted slaked lime sprayed for acid gas treatment, but their effect on carbonation treatment has not been clarified. In this study, we measured the CO2 absorption rates of incinerator fly ash and slaked lime, and evaluated the difference in the progress of carbonation depending on the presence or absence of slaked lime in incinerate fly ash and the type of slaked lime. The reaction rate constant with CO2 was 0.62 to 0.87 L / (mmol · h) for slaked lime and 0.22 to 0.74 L / (mmol · h) for incinerated fly ash. The reaction rate constant of highly reactive slaked lime was larger than that of JIS special slaked lime. It was suggested that the reaction rate constant of incinerator fly ash containing slaked lime is governed by the slaked lime contained. In addition, the alkali concentration in the incinerator fly ash is higher in the incinerator fly ash containing JIS special slaked lime than in the incinerator fly ash containing highly reactive slaked lime, and there is less excess slaked lime in the highly reactive slaked lime. It seemed to indicate that it would be.

Regarding the stabilization treatment of incineration bottom ash, carbonation is expected to be effective at lowering the pH and reducing Pb elution. However, it has been reported that Cr(VI) elution is promoted. Therefore, it is necessary to take measures to prevent Cr(VI) elution when carbonation treatment is used for recycling such as with civil engineering materials. In this study, for handling non-industrial waste bottom ash, we investigated changes in heavy metal elution characteristics caused by carbonation and a difference in curing times by adding a divalent iron agent as a reducing agent to untreated ash and carbonated ash. The elution characteristics when carbonation was further promoted by exposing the cured sample to the air were also evaluated. As a result, Cr(VI) elution concentration increased due to carbonation and air exposure, but the elution concentration decreased when a divalent iron agent was added. It was also clarified by comparing samples which had not been carbonated in advance that the increase in elution due to air exposure was reduced when the carbonic acid treatment was performed.

This study focused on the liquid temperature and gaseous temperature for the treatment of fly ash by exhaust gas bubbling into liquid with suspended fly ash for carbonation. The experiment was conducted to (1) clarify the effects of liquid temperature and gaseous temperature on carbon dioxide absorption rate to liquid in CO₂ gas bubbling, (2) clarify the effects of liquid temperature on alkali substances (AS) dissolution rate, and (3) compare the rate of CO2 absorption an the rate of AS dissolution to find the rate-limiting factors. As a result, (1) the gaseous temperature affected the overall mass transfer coefficient and the liquid temperature affected the steady state concentration. The liquid temperature had a significant effect on the CO₂ gas absorption rate. (2) The average AS dissolution rate in distilled water was independent of temperature under the conditions of this experiment. Finally, it was suggested that the gas absorption rate could be the rate-limiting factor for fly ash neutralization under the conditions of this experiment.

In waste landfill sites, it is required to monitor landfill waste properties, leachate quality, the composition of gas generated, temperature, and the deterioration and damage of facilities to prevent environmental pollution. It is expected to build an advanced environmental monitoring system by utilizing IoT sensors, of which technological development is advancing dramatically in recent years. Under such circumstances, securing a power source for wireless communication and installing an IoT sensor that does not use a power line has become an urgent issue. As a solution, it is expected to develop an energy harvesting technology that secures electric power at the sensor installation location. In the landfill waste layer, soluble chlorides and similar compounds in the incineration residues dissolve in internal water. With the dissolution of strongly alkaline substances from the incineration ash, the pH of the retained water shows a high value. Since ash residues contain large amounts of electrolytes, the electrical conductivity also increases. Therefore, when metals having different ionization tendencies are immersed in the retained water, an electric current is generated, and a battery circuit is formed. In this research, a "garbage battery" was developed that uses leachate at the waste landfill site as an electrolyte.

In order to prevent contamination of the ground and groundwater by waste and leachate from waste, impervious works are installed in final disposal sites. Since the oxidative degradation of plastics starts at the surface and eventually decreases with the diffusion of oxygen in the air to the deeper layers, it is important to analyze the degradation of impervious sheets from the surface to the depth. In this paper, to obtain information on the depth of degradation of impermeable sheets, which is not well known, samples of impermeable sheets cut from the surface by SAICAS were analyzed by FT-IR to evaluate the degradation by depth. As a result, the following points were found. Oxidative degradation was limited to a depth of about 30 μm from the surface, and progressed near the surface of the barrier sheet. In the depth range of 0-20 μm, CI(-) tended to increase as the acceleration time of the weathering test increased. For samples in the same slope direction, the degree of oxidative degradation was smaller for samples that were under protective mats or buried than for samples that were exposed without protective mats.

In solid waste landfill sites, the period from closure of the landfill to release from aftercare is said to be 18 years on average; this is a very long period of time. Therefore, early stabilization of landfills has become a critical focus. In industrial waste landfill sites, the functioning of a semi-aerobic bioreactor landfill system based on the utilization of natural purification processes and the associated decomposition mechanism are important for stabilization. Therefore, the selection of waste to be received and strategies adopted for the landfill method should be based on leachate and landfill gas monitoring. In this study, to understand the status of the landfill site, the raw leachate was monitored through chemical analysis and bioassay, and the effectiveness of the bioassay was evaluated.

The introduction of bioassays to landfills will improve the safety and reliability of landfills by assessing the ecotoxicity of landfill wastewater and surrounding environmental water and representative visualized impact on the ecosystem. It can be positioned as an important tool. For the A city disposal site, we obtained data on the water quality and ecotoxicity of the leachate and surrounding environmental water for the three years of 2011, 2019, and 2021, so we evaluated the secular change. Groundwater and downstream ponds are affected by leachate, but as of 2011 it was clear that they were more toxic nearer the landfill site. However, as of 2021, no toxicity was observed in any of the acute and chronic test items, and it can be evaluated that the toxicity was improved within 10 years. In this paper, we will consider the factors of this change and summarize and present the issues for the introduction of the disposal site bioassay.

The washout model has been investigated to promote early stabilization and to predict the operation period in landfill sites receiving incineration residue mainly. The past model for total organic carbon (TOC) required the elution potential as critical parameters. But it was estimated by batch tests, which might overestimate the elution potential. In addition, the mass transfer coefficient in the past model was constant, but it might be changed depending on the water content in the waste layer. This study attempted to improve the past washout model regarding chloride ion in a bottom ash layer by 1) investigating the difference in the elution potential between the batch test and saturated permeance test and 2) introducing the mass transfer coefficient which is a function of water content in the waste layer.

Since fly ash is a specially managed general waste, insolubilization treatment mainly using a chelating agent treatment is performed to prevent elution of Pb. Landfill with stable fly ash. However, an excessive amount of chelating agent is added to prevent elution of heavy metals such as Pb. Therefore, the leachate contains a high concentration of remaining chelate. It has been confirmed that the remaining chelate causes nitrification inhibition in the leachate treatment process and increases the COD and T-N concentrations.which are considered to be derived from chelate, are within the time required to decompose the remaining chelate. It is difficult to remove. This time, for the piperazine-based chelating agent, a basic experiment was conducted for the purpose of decomposing and removing the remaining chelate and COD and T-N derived from the chelate in the simulated leachate obtained by adding the chelating agent to salt water by electrodialysis.

It did the simulated reclamation experiment that assumed the repository site of the surface of the sea. The waste used for an experiment used a incineration residue. The exhaust gas treatment system of incinerator is dry process processing by the lime.

We used 4 simulators, 2simulators adding 2 kinds of chelates (DTC and PIP), one simulator adding inorganic phosphorus stabilizer. Another one is no stabilizer added simulator(control simulator). The phosphorus and control simulator were stabilized early.

2 simulators were high concentration COD and T-N exuded for a long time by the influence of a chelate. All simulators pH was high by the influence of the lime and wasn't stabilized.The stabilization of the leachate quality of the sea area land reclamation repository takes an extended period.

Since fly ash is a specially managed general waste, insolubilization treatment mainly using a chelating agent treatment is performed to prevent elution of Pb. Landfill with stable fly ash. However, an excessive amount of chelating agent is added to prevent elution of heavy metals such as Pb. Therefore, the leachate contains a high concentration of remaining chelate. It has been confirmed that the remaining chelate causes nitrification inhibition in the leachate treatment process and increases the COD and T-N concentrations.which are considered to be derived from chelate, are within the time required to decompose the remaining chelate. It is difficult to remove. This time, for the piperazine-based chelating agent, a basic experiment was conducted for the purpose of decomposing and removing the remaining chelate and COD and T-N derived from the chelate in the simulated leachate obtained by adding the chelating agent to salt water by electrodialysis.

Japan has difficulty constructing new final disposal sites due to its small land and the different technologies for prolonging the lifetime of final disposal sites have been developed. One of them is a development of biodegradable cover material as an alternative to cover soil which accounts for 20 to 25% of the capacity of municipal final disposal sites. This has been worked on in order to prolong the lifetime of the sites. However, that technology has not been put into practical use yet owing to the cost-related issues.

We are taking advantage of an Australian dust suppression agent used on haul roads at mining sites, on runways at airports and also use for slop protection, and are developing an economical alternative material to cover soil with it.

In the experiment we have kept conducting, the alleviation of leachate pollution and tendence of neutralization of leachate pH on early stage by the agent application were observed and we will reporte this summarizing the experimental results.

Most of the fly ash generated in the incineration process of municipal solid waste is treated with organic chelating agents to inhibit the elution of heavy metals, but it has been found that organic chelating agents inhibit the nitrification reaction in leachate treatment. However, the behavior of organic chelating agents in landfill sites has not been clarified. In this study, we investigated the presence of two types of organic chelating agents in the inner pond and wastewater treatment facilities of three sea-based landfill sites for seven months, and conducted laboratory experiments on the chemical stability of organic chelating agents with pH. As the results, it was estimated that organic chelating agents were chemically unstable and decomposed due to the neutralization reaction of inner pond water in the sea-based landfill sites by the dissolution of CO2 from the atmosphere, although the organic chelating agents contained 3 to 62 mg/L in leachate and pore water of the landfill layer.

The wastes will be stabilized by microbial activity in waste landfills. In the stabilization processes, the toxic metals in the wastes are directly and indirectly immobilized by microorganisms. This study investigated the effect of microbially induced carbonate precipitation (MICP) by ureolytic bacteria on immobilization of cadmium (Cd). The results showed that immobilization rate of Cd is low owing to redissolution of calcium carbonate generated by urea hydrolysis.

This study presents mathematical model for predicting the leachate concentration from the waste landfill layer and its model validation results. The mathematical model was well-known advection-dispersion equation with the results of serial batch leaching tests added as source/sink term. One of the problems of this method is that the serial batch leaching tests evaluate at a liquid-solid ratio of 10, whereas landfill layer targeted for prediction has low liquid-solid ratio of about 0.5. This study focused on the difference of such liquid-solid ratio and improved accuracy of numerical simulation. The long-term batch leaching tests were conducted with different liquid-solid ratios from100 to 0.5. Then, the leaching model was verified by comparing the measured values in this liquid-solid ratio batch leaching tests with the predicted values obtained from numerical simulation using the results of the serial batch leaching tests. It was found that leaching monovalent concentrations can be predicted with good accuracy, but divalent concentrations can be practically estimated using the correction coefficients obtained by batch leaching tests with different liquid-solid ratios.

Hazardous waste landfill where waste exceeding the leaching criteria is disposed of doesn't allow rainwater or air are entering. As the results, waste may keep its leaching potential similar to that at the time of disposal. In this study, numerical calculations were performed in order to confirm whether or not the leaching suppression of heavy metals, which occurs in non-hazardous waste landfill, occurs, when the internal condition of hazardous waste landfill is intentionally controlled. The model used was a combination of a landfill simulator that mainly calculated degradation process of organic matter and a geochemical model (PHREEQC). MSW fly ash was subjected to the calculation. And although no intrusion of rainwater was set, the initial moisture content was set to be maintained during entire calculation period. In addition, regarding gas composition, CO₂ concentration was changed for 350ppm, 50%, 80%, and 100%. The calculation was performed for 100 years. In case of Pb, the mineral species produced were Pb(OH)₂, PbCO₃, Pb₃(OH)₂(CO₃)₂. And the higher the CO₂ concentration, the faster the time when PbCO₃ becomes the main component. And the liquid phase concentration of Pb was dominated by it.

Regarding municipal solid waste incineration ash, which accounts for most of the waste disposed of in the coastal landfill. In general, the smaller particle size contain more pollutant components ,and the fine particle classification (d < 0.425 mm ) is removed. By disposing of it in the sea, it is expected that the landfill site will be stabilized at an early stage.Maeda et al. Focused in on channel classification technology as a means to efficiently remove fine particle classification, studied flow and particle advection, and created the numerical model of the flow.

The author conducted the numerical simulation of a practical scale on channel that was examined on the desk in advance, and proposed a new practical scale. Then, in this study, in order to verify whether the proposed on channel effect is optimal, an on channel classification demonstration experiment was conducted, and the validity of the channel conditions was verified from the indicators showing the fine particle classification removal rate and classification ability. In addition, when charging incinerator ash on an actual scale, it is necessary to know the charging speed that does not affect the classification, so experiments were conducted with different charging speeds to verify the effect.