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A new leakage detection system was developed with the optical fiber sensor that was able to be applied to the surface of the sea landfill with a geomembrane. It reports on the content of the confirmation experiment.

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This paper shows development and application potential of H-jointed steel pipe sheet piles (SPSPs) with H-H joints on vertical cuttoff barriers used in coastal landfills. The authors have developed a number of technologies such as developing the H-jointed SPSPs and H-H joints for SPSP joint sections aimed at improving performance and widening application areas of SPSPs. Hydraulic conductivity of the H-jointed SPSPs with H-H joints was evaluated by experimental studies. As a result, hydraulic conductivity of 10-8 cm/s is proposed for use in design of H-jointed SPSPs with H-H joints sealed with this water-swelling hydraulic sealant sheet in applying as a hydraulic cutoff wall in coastal landfills.

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This study combined surface-wave inquiry technology used for engineering works geological surveys with a bowling result and grasped buried wastes and the ground situation of existing landfill with high precision. As a result, depth of the impermeable layer ground and the distribution of waste in landfill were supposed. As for this experiment result, a business effect may be provided in correct closure or reclamation project of improper landfill sites at precision of investigation and economy.

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[in Japanese]

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In this study, we tried to examine the accuracy of estimation for stress-strain curve in biaxial extension condition which was calculated by strain energy density function of waterproof sheets laid on a seepage structure in a controlled waste disposal site. The partial differential value of the strain energy density function was determined by the pure shear test. After a comparison between calculated stress-strain curve and that from the biaxial extension test, calculated values were correspond with the testing data within 10 % error for the range from 0 to 42 % strain for PVC, 0 to 4 % for HDPE and 0 to 15 % for SMePE. The previous study says that the strain of waterproof sheet made of PVC laid on backfilling unevenness was at most 15 %. Thus, we suggest that the application of strain energy density function for the evaluation of waterproof sheet deformation due to unevenness of backfilling slope in a controlled waste disposal site should be possible.

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We evaluate the intrusive resistance performance with ASTM D 4833. Protection performance of protection mat can be requested by subtracting the performance of the geomembrane unit from the experiment result of two layers.

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We performed a laboratory scale test and examinations of using a lysimeter (id200mm * 1,000mm) and a large-scale tank (W1,750mm * L7,000mm * H2,000mm) to prove an effect of the method that accelerates waste stabilization by decomposing the hard degradable organic matter directly with oxidizing agent (the chemical oxidation Method).The mixture of bottom ash and compost was used as sham wastes. We carried out the chemical oxidation for the wastes by a hydrogen peroxide (H2O2). As a result, it was confirmed that the hard degradable organic matter decomposed and changed to the easy biodegradable organic matter, the oxidation effect improved when orthophosphoric acid was used as an assistant agent. In addition, with the chemical oxidation, air was supplied into the waste at the examination of using a large-scale tank, thereby COD and bio-chemical oxygen demand (BOD) in leachate remarkably decreased, it was suggested that chemical oxidation method could accelerate stabilization of landfill sites furthermore simultaneously aerating to keep aerobically could promote it.

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It is known that the temperature rises up to 80 centigrade in the early stage of landfill site mainly disposed municipal solid waste incineration (MSWI) ash. It is thought that the heat are evoluated from the hydration of the hydraulic minerals in MSW incineration ash. However, quantitative research for its hydration have not proceeded. Ettringite in the ash after landfilling was quantified and the heat evolution rate for the ash before landfilling was caluculated. Ettringite,Friedel's salt and portlandite were generated within 5 hours hydration, and the maximum heat evolution rate was 80 J/g/hr. The high temperature in the early stage of landfilling can be explained by the hydration of MSW incineration ash. However, it is speculated that the hydraulic heat generation will be affected by not only mineralogical composition but also hydration progress before landfilling.

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The solidification phenomenon of incineration residue from municipal solid waste (MSW) after filling is one of the reasons for delaying stabilizaton of filled waste. To reveal the solidification mechanism, XRD, XRF and TG-DTA analyses were carried out for some MSW incineration bottom ashes before and after landfilling. Ettringite and Friedel's salt have been already existed in many kinds of bottom ashes before filling. Mineralogical composition affected the ash solidification degree after landfilling, consequently belite rich ash tends to more solidify. It is concluded that ash solidification after landfilling is mainly attributed to the growth of C-S-H phase that is hydrated product from belite.

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Incineration ashes (Bottom ashes) form about 75% of the amount of the waste substances disposed at landfill sites in 2002. As the result of progress of intermediate process and recycling process, waste substances will change to melting fly ashes, crushed incombustibles, etc. We investigated the effects of watering process on bottom ashes and melting fly ashes in management process of landfill sites.This research examined the landfill management process by leaching tests and watering, in order to evaluate the characteristic of the leachate from bottom ashes and melting fly ashes.As results of examination, melting fly ashes had different results of leaching test from bottom ashes. And leachate from melting fly ashes had different leachate characteristics of higher salt content and delay of concentration reduction. Therefore, the necessity of proposing a suitable management process was suggested.

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For the early stabilization of wastes, a system to decompose the hardly-degradable organic matters are developed, using high-pressured air. Lysimeter tests were done as preliminary experiments, and then, large-scale tests has been planned to validate the facilitated degradation of the organic matters. In this paper, the results from the lysimeter experiments (especially, on the transition time from the aerobic conditions to the anaerobic conditions) are presented and it was the first year study of the three-year project. This research was supported by the grant from the City of Kitakyushu on Business Promoting the Development of the Futuristic Environmental Technology.

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Refuse carbonization facility has been developed as a technology enabling thermal recycling/material recycling. Refuse carbide produced in the facility has been used as a fuel substitute material in cement manufacturing industry or vice-material of steel industry. However, it is expected to use it as recycling material from a viewpoint of geotechnical engineering.This study investigated effect for purification of leachate of municipal solid waste incineration (MSWI) bottom ash by the refuse carbide produced in carbonization facility. Column tests for MSWI bottom ash with the refuse carbide were performed. The value of pH and concentrations of Ca, Pb and TOC (Total Organic Carbon) leached from MSWI bottom ash can be reduced by using the refuse carbide. It was clarified that the refuse carbide is effective for purification of leachate of MSWI bottom ash. It is therefore suggested that the refuse carbide may be useful as intermediate cover soil in final disposal site.

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The authors have started a series of experiments in which six large-scale raishimatar 1.8 m in diameter and 4 m in height (thickness of landfilled waste layer: 2.5 m) were made and filled with mixed ash (incinerator residue + compost + macadam), and oxygen-enriched water and a chelating agent were sprinkled over the waste to mineralize and stabilize it in a short term. This paper outlines the method and describes the tests, which have just started.

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We rineseardhed on the present condition and problems of offshore disposal sites in 2006.We repot the productions in this paper.

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To evaluate an ecotoxicity of leachates, we conducted an ecotoxicity test using earthworm. We evaluated the ecotoxicity of leachate by avoidance behavior. Earthworm avoided several somple of leachates. These results paralleled with the results of toxicity test of Daphnia magna. Our results revealed that avoidance behavior was caused by some organic compounds as well as salts in leachates.

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