A closed landfill in Hokkaido, Japan has been studied to examine landfill temperature and gas composition.89 new passive LFG extraction wells have been installed for stabilization of this landfill since the completion of landfilling in this landfill. Especially gas components of passive wells and monitoring wells for evaluation of the end of aftercare of this landfill are focused. It is confirmed that this landfill is stabilizing, however, the guideline about landfill gas for the end of aftercare is not satisfied.

Industrial waste landfill sites basically have a semi-aerobic structure that functions as a bioreactor. But there are some area generating gas due to special kind of waste. We found the new knowledge to improve the area by supplying leachate into degassing pipe.

This study organized data on relationship between watering and leachate quality in 11 closed system disposal facilities. Particularly, relationship between leachate-solide ratio and COD, nitrogen and cloride ion concentrations to consider monitoring toward stabilization of waste.

Aluminosilicates (microcline or feldspar synthetic reagent) capture Cs in CsCl by co-heating and make Cs insoluble. However, the coexistence of fly ash greatly reduces its capturing efficiency. In this study, the reason on the low efficiency caused by fly ash was assumed to be the alkali element in fly ash. And the purpose of the study was set to clarify the element concretely, to clarify the form of the element inhibiting the capturing, and to establish the means to avoid its inhibition. As a result, it was found that Ca in fly ash mainly inhibits Cs capturing by the aluminosilicate, and most significant inhibition caused by CaCl₂. Pretreatment to change the form of Ca from CaCl₂ to CaCO₃ improved the capturing ratio of Cs. However, when the amount of fly ash increased, the capturing ratio tended to decrease again, indicating that the increase in other alkali elements had an influence.

There are many wastes and construction materials such as incineration ash and cement-based modified soil, which exhibit alkaline pH of leachate. When exuding leachate out of the system, it is necessary to adjust the pH to a range that does not affect environmental protection. Here, the eluate after the leaching test of incineration ash often exhibits alkalinity of pH 12 or more immediately after filtration, but if the filtrate is left as it is, it absorbs CO 2 in the air and calcium carbonate is generated, and the pH gradually decreases. If it is possible to sufficiently lower the pH of the leachate exhibiting alkalinity using this phenomenon, there is a possibility that the impact on organisms and ecosystems can be reduced reasonably in terms of cost. In this study, we discussed the mechanism of incinerator ash eluate neutralization by CO2 in the atmosphere, and the prediction calculation method of the pH value when the atmospheric equilibrium condition was reached.

At the sea surface disposal site, it takes time to stabilize the reclaimed waste, which increases the cost of maintenance and smooth land use, and requires measures for early stabilization.It is known that incinerator ash with a small particle size contains a large amount of pollutants, and early stabilization is expected by removing the fine particle classification (particle size 0.425 mm or less) from incineration ash and performing sea surface disposal. In this study, focusing on open channel classification, we conducted open channel classification demonstration experiments.As a result, about 60% of fine particle classification was able to be removed among input incineration ash.The sedimentation velocity of incineration ash in the open channel was slower than the theoretical value, and the sedimentation velocity of the classification object particle diameter (particle diameter 0.425 mm) was about 80% of the Allen equation.In addition, it was confirmed that the amount of pollutant components was larger in the runoff ash than in the sedimentary ash, and a stabilization promotion effect by open channel classification was expected.

A large amount of chlorine remains in the incineration residue. Therefore, in the final disposal site, the chloride ion concentration in the leachate increases, and there are cases where the proper operation of the leachate treatment facility is hindered. In addition, although chlorine is not included in the water quality control items, if it is discharged into the water environment at high concentration, it will affect agricultural damage and ecosystem. Further, if desalting treatment is carried out for the countermeasure, by-product salts are generated. Also since fly ash is a specially managed general waste, insolubilization treatment mainly using a chelating agent treatment is performed to prevent elution of Pb and the like. However, when fly ash insolubilized with a chelating agent is disposed in landfill, residual chelates increase the concentration of nitrogen and COD in the leachate, which interferes with leachate treatment. For this reason, we have confirmed that switching to inorganic drugs can solve these problems. However, compared to chelating agents, inorganic agents may be added in a large amount, which may cause economic disadvantages. Therefore, we report on basic experiments to reduce the addition rate using "Eco-acid" and inorganic phosphorus-based chemicals generated from by-product salts this time.

Influence of interior condition in the hazardous waste landfill on the leaching behavior of heavy metals were examined from the accelerated weathering experiments for dust which is a kind of wastes to be disposed of at the hazardous waste landfill. Among the main components, a decrease in the leaching amount of Cd, Pb, Mn, and Zn was confirmed in a wet environment where adsorbed water was present on the particle surface. On the other hand, in the dry and CO₂ saturated environment, an increase in leaching amount was observed. The former phenomenon was thought to be the formation of hydroxide through particle surface adsorbed water, and the latter was considered to be the influence of adsorption of gas phase CO₂ to Fe₃O₄ and ZnO. However, further scientific verification is required for each phenomena. The findings obtained in this study indicate that the leaching of heavy metals from hazardous wastes disposed of in the hazardous waste landfill may change over time.

We researched new spray dry processing technology for storage radioactive contaminated water in Fukushima Daiichi Nuclear Power Station.

This technology can control that the exhaust gas is regulated less than government regulated value, and zero emission of the water drainage.

In addition, we developed large scale system for above in the limited time of treatment.

Simple and rapid detection method of asbestos (chrysotile) in waste building materials was established by selective dyeing. The building debris collected at disaster areas was crushed to 1~2 mm in size and treated with 20% formic acid. A few particles of the washed sample were taken on a filter paper and dried on a hot plate for 5 minutes, and then stained with dyes. Asbestos in building materials is chrysotile over 95 % that is positively charged. On the other hand, main component in building materials is calcite and negatively charged. Therefore, chrysotile was stained with anionic dyes, such as erythrosine and the main component in building materials was stained cationic dyes such as methylene blue. Chrysotile was stained in pink by erythrosine and main component in building debris in blue by methylene blue. The chrysotile in the building debris was easily detected by a stereomicroscope (x 45 times). Erythrosine did not stain crocidolite and amosite, and methylene blue stained crocidolite and amosite in blue and not chrysotile. Glass wool, ceramic wool and rock wool were not stained with both methylene blue and erythrosine.

Short-chain chlorinated paraffins (SCCPs), which are alkanes containing 10–13 carbons and several chlorines, have been manufactured extensively and are used as preservatives. In 2017, at the 8^th annual conference of the Stockholm Convention in Geneva regarding persistent organic pollutants, SCCPs were included in Annex A (elimination), resulting in the complete ban of both the production and usage of SCCPs. Therefore, the destruction of SCCPs present in products or waste is important for reducing their harmful effects on the environment. It is apparent that combustion of SCCPs likely generates chlorinated organic compounds. Due to the harmful effects they have on the environment, it is imperative that further research is conducted on SCCPs and their unintentional combustion by-products. In this study, we focused our efforts on materials containing SCCPs and their decomposition rates in heating tests.

In 2015, The law Act on Preventing Environmental Pollution of Mercury is established and material flows of mercury is made by Ministry of the Environment in Japan. However, There are two problems that Material balance is not maintain in whole flows and understanding of stocks are insufficient. This paper consider about some of the mismatch of material balance in material flows of mercury. Specifically, this paper convert the material flows of mercury to Input-output table made of about 40 processes and goods, and check these material balance, consider issues and improvement plans which have difference over 1t-Hg. As a result, many of issues of mismatch are unrecognized of input and output. Especially in iron manufacture, emission reduction effect by dust collector is not accounted, and this paper estimate of it to eliminate the dirrerence.

According to high toxicity, mercury applications have been reduced and it will raise a large concern about environmentally safe disposal of unused mercury. In Japan, mercury has been known well as a hazardous element owing to Minamata disease. Therefore, mercury immobilization facilities and final disposal landfill sites might be regarded NIMBY and it will be greatly difficult to build them for mercury management in terms of public acceptance. If Japanese citizens have a strongly negative perception of mercury, it makes mercury management, in particular mercury final disposal, more and more difficult. In this context, this study quantitatively measured the perception of mercury that Japanese citizens have with employing pairwise comparison method.

In 2016, approximately 32.9 million tons of municipal solid waste were incinerated that led to the generation of about 3.5 million tons of solid residues. The majority of the incineration residues including fly ash were then landfilled. Fly ash contains heavy metals including lead (Pb). Currently, there are different methods for stabilizing the heavy metals, which might be costly and not eco-friendly or might cause an increase in the volume of residues to be landfilled. In the present research, an effort was made to use waste fishbone material as an environment-friendly substance for heavy metal stabilization in fly ash with emphasis on Pb. Hydroxyapatite is the main component of fishbone that can react with divalent heavy metals including Pb to form a highly insoluble phases such as lead-apatite product. The experiments indicated that HAP in fishbone is a promising material for stabilizing Pb in fly ash; however, it has not yet been possible to achieve the levels below the standard landfill criterion. Therefore, additional techniques were employed to enhance the effectivity of Pb stabilization in fly ash by using HAP of waste fishbone. We examined the influence of various settling times, liquid/solid (L/S) ratios