We propose a convenient method for monitoring hazardous gas based on the determination of ppm-level concentrations of CH₄ in ambient air. The proposed method can be applied during the excavation of landfill or dumped waste at reclamation sites, and we investigated its usability in an actual field. A portable open-path type analyzer and a retroreflector were used to determine the CH₄ concentration.
The hazardous gas in landfill gas emitted from final disposal and illegal-dumping sites always contains CH₄ and H₂S occurring together, with the latter considered to be the main hazardous component. The maximum concentration ratio (H₂S/CH₄) at final disposal and illegal-dumping sites was expected to be about 10⁻¹. This study showed clearly that the ambient CH₄ concentration could be useful as an indicator for the monitoring of hazardous gas for the evaluation of potential danger.
It was also shown that the proposed method could be useful for monitoring as a safety control at a reclamation site. This method works by comparing the measured ppm concentration levels of CH₄ with a management value that is decided by considering the maximum concentration ratio (of the hazardous gas that was most harmful at the site, such as H₂S/CH₄), its acceptable concentration and a safety ratio.

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A mesophilic non-dilution methane fermentation reactor for wet-biomass was operated continuously using dosed shredded paper, reducing nitrogen components to avoid inhibition of the reactor caused by ammonia accumulation. Simultaneous investigation was conducted using the 16S rRNA gene clone library and quantitative PCR (Real-Time PCR). When wet biomass alone was fed to the reactor, ammonia accumulated and the reactor performance deteriorated. A closely related clone showed predominance of 45% in Finegoldia magna, which were the ammonia-producing bacteria. Shredded paper was added to the reactor to decrease the ammonium concentration, thereby inhibiting the clone. However, results show that the density of Archaeal cells in the reactor was decreased (two orders) by their addition. Consequently, propionic acid accumulated in the reactor. Even a batch test using sludge in the methane fermentation reactor and shredded paper produced a similar result. Clonal bacteria belonging to the phylum Firmicutes in domain Bacteria and hydrogenotrophic methanogen (genus Methanobacterium, genus Methanoculleus) in the domain Archaea were implicated as the dominant Bacteria in the reactor.

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The purpose of this study was to examine the dehydrochlorination of a flexible polyvinyl chloride (PVC), which was comprised of 59.2% PVC, 29.7% dioctyl phthalate (DOP) and approximately 12% stabilizers, and a rigid PVC that were treated with a 2-16mol/L NaOH concentration, and then microwave-heated at a temperature between 100-200°C for 0-60 minutes. At this time, 0-0.2g of polyurethane cushioning materials used in packaging were added to each sample. 98% of all chlorides were removed in 30 minutes by heating at 190°C, in a 2-mol/L NaOH solution with 0.02-g of polyurethane additives, and the residue was converted into carbon and hydrogen compounds. We presumed this to be the result of the organic amines detected in the NaOH solution and the hydrolysis of polyurethane. Since we presumed that the amine promoted dehydrochlorination, we further investigated dehydrochlorination results by using hydrazine hydrate, aqueous ammonia, trimethyl amine, and 2-amino ethanol additives that were heated at 190°C in a 2-mol/L NaOH solution for 30 minutes under the same conditions. As a result, we found that chlorides were removed at maximum rates of 99.6%, 94.6%, 96.3% and 92.9%, respectively. This study discovered that amine additives are effective dehydrochlorination additives since they allowed for similar results using a 2-mol/L NaOH solution that was only 1/8 the NaOH concentration of known methods, and it was possible to lower the heating temperature compared to conventional methods as well.

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This paper analyzes the initial expenses and running costs for MSW (municipal solid waste) landfills based on data collected through a questionnaire-style survey. Landfills used in the study were selected according to their different characteristics, which included size, site conditions, leachate treatment process, and with roof/without roof. The study incorporates detailed data collected from 123 landfill sites.
Most expense items show a scale of economy: unit-cost per scale index (construction cost per one cubic meter of landfill volume, for example) increases as the size of the landfill increases. This effect was modeled in the form of a logarithmic linear equation made between scale index and unit cost. Each of the cost items is roughly proportionate to 0.5-0.6 power to scale index. Monitoring costs are the only exception, remaining constant regardless of landfill size. This is due to the fact that monitoring was carried out to meet regulations for frequency and numbers, in most landfills. The total cost for the landfills was calculated for various possible scenarios by combining all the expenses.

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In this paper, solid fuel production from waste polyurethane is proposed. Waste polyurethane was transformed thermally into a brown substance with plasticity through thermal treatment with used vegetable oil at 340-360°C for 1-2 hours. Unlike polyurethane pyrolysis, this treatment was carried out without coke formation. The vacuum residue of the reaction product melts above 140°C, and can be shaped into pellets. For example, pellets of 3.5-mm diameter have a bulk density of 0.7 and a real density 1.1g/cm³. The resulting pellets have a higher heating value of 37.5kJ/g.

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