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21.
Takeki Maeda Juzo Matsuda Hiroshi Nakashima Koichi Yoshida Joji Suzuki 《Journal of Material Cycles and Waste Management》2000,2(2):143-149
Over a period of 21 months, we composted food refuse from a student restaurant in Hokkaido University using a commercially
available composting machine. The machine had two reactors, each with a working volume of 250 l. The refuse was mixed with
sawdust in a ratio of 5 l sawdust to 10 kg refuse, and this mixture was fed into the machine daily. We studied the characteristics
of the refuse, the composting mixture, and the finished compost in an effort to optimize the operating parameters. We also
evaluated the effectiveness of the composting process by determining the decomposition rates of the composting materials.
The optimum moisture content of the composting mixture was between 30% wet basis (wb) and 40% wb in this machine. The composting
machine worked well when the first reactor was filled with composting mixture and 0.5 kg lime was added once per week. The
mass of the materials supplied was reduced by 84% over the study period. The decomposition rate of the volatile matter in
all composting materials was 66%. The mass of the food refuse supplied was 14.8 kg/day on average, and the moisture content
of the refuse was 77% wb on average.
Received: October 4, 1999 / Accepted: April 4, 2000 相似文献
22.
Shohichi Osada Dalibor Kuchar Hitoki Matsuda 《Journal of Material Cycles and Waste Management》2009,11(4):367-375
In the present work, a shaft-type furnace model in which the furnace column is divided into multiple cells was proposed and
equilibrium reaction calculation software was used to describe the model. The model was used to study the effects of gasification
and melting conditions such as temperature, oxygen partial pressure, and chlorine content on the volatilization behaviors
of the low-boiling-point metals Na, K, Pb, and Zn during the gasification and melting process of municipal solid waste in
a shaft-type furnace. Consequently, the volatilization ratios of Na, K, Pb, and Zn compounds in the exhaust gas from a pilot
plant shaft-type furnace were found to be in good agreement with the calculation results, and the Na, K, Pb, and Zn compounds
were volatilized mainly as metal chlorides in the temperature range up to approximately 1173 K. With a further rise in temperature,
these low-boiling point metals were volatilized as metallic forms. It was found that almost 100% of Pb and Zn compounds were
volatilized regardless of the chlorine content in municipal solid waste; in contrast, the volatilization rates of Na and K
increased when the chlorine content increased. Finally, Na, K, Pb, and Zn compounds were converted from reduced metals to
metal chlorides such as NaCl, KCl, PbCl2, and ZnCl2 with an increase in the ratio of chlorine to each metal. 相似文献
23.
Mitsuhiro Kubota Masahiro Hayashi Hitoki Matsuda Hirokazu Serizawa 《Journal of Material Cycles and Waste Management》2012,14(2):132-138
Combined ultrasonic (US) irradiation and sodium peroxodisulfate (Na2S2O8) treatment has been investigated for promotion of both decomposition of (4-chloro-2-methylphenoxy) acetic acid (MCPA) and mineralization of organic residues. This treatment is expected to accelerate both reactions, because the US cavitation effect promotes the production of radicals, such as SO 4 ? · and OH·, by the decomposition of Na2S2O8 and water. In this study, decomposition experiments were performed on 100?ppm MCPA aqueous solutions in a sonoreactor at reaction temperatures of 298?C333?K with US irradiation alone, Na2S2O8 treatment alone, and the combination of US and Na2S2O8 treatment. It was found that the combined treatment achieved a higher MCPA decomposition rate and total organic carbon (TOC) removal ratio than either treatment alone. The decomposition ratios of both MCPA and TOC increased with reaction temperature, and especially steep increases were observed at 333?K due to a significant promotion of thermal decomposition of Na2S2O8. The production of radical species was also promoted by the combined treatment. These results suggest that the higher MCPA decomposition rate and TOC removal ratio are due to the increased formation of sulfate and hydroxyl radicals via thermal and US decomposition of Na2S2O8. 相似文献
24.
A comparison of CaOs produced by calcining two types of hydrated lime and calcium carbonate was made for decomposition of trichloroethylene and in-situ dry sorption of the decomposed Cl-products using a lab-scale gas flow type tubular packed bed reactor. About 20 mg of CaO sample was mixed with about 2 g of Al2O3 particles and packed in the reactor and allowed to react with a flowing standard gas containing 500 ppm of C2HCl3 (N2 balance) at 673 and 873 K, under the condition that the reaction of CaO with C2HCl3 might be completed within a few hours.It was found that no thermal decomposition of C2HCl3 at or below 673 K was observed in a reactor packed only with Al2O3 particles. However, a considerable amount of decomposition of C2HCl3 was obtained in a reactor packed with CaO and Al2O3, even at 673 K. For 1 mol of CaO prepared by calcining highly reactive Ca(OH)2 at 673 K, decomposition of 0.42 mol of C2HCl3 and in-situ absorption product of 0.53 mol of CaCl2 were obtained. At 873 K, about 46% of C2HCl3 was thermally decomposed. The total amount of C2HCl3 decomposed in CaO-Al2O3 particle bed at 873 K became nearly twice larger than that at 673 K. For 1 mol of CaO prepared by calcining highly reactive Ca(OH)2 at 873 K, decomposition of 0.59 mol of C2HCl3 and in-situ absorption product of 0.67 mol of CaCl2 were obtained. Small amounts of C2Cl2, C2Cl4, CCl4, etc. were detected during decomposition of C2HCl3 at 673 and 873 K.It was recognized that the data on decomposition of C2HCl3 as well as in-situ dry sorption of Cl-products in CaO particle bed were correlated with specific surface area of the CaO employed. 相似文献
25.
Tomoaki Tsutsumi Toshihiko Yanagi Munetomo Nakamura Yoichi Kono Hiroyasu Uchibe Takao Iida Tsuguhide Hori Reiko Nakagawa Kazuhiro Tobiishi Rieko Matsuda Kumiko Sasaki Masatake Toyoda 《Chemosphere》2001,45(8):1129-1137
Total diet study (TDS) samples of 14 food groups from 16 locations in Japan, collected in 1999 and 2000, were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dioxin-like PCBs) to estimate the update of daily intake of these contaminants from food. The mean daily intake of toxic equivalency (TEQ) for an adult weighing 50 kg, calculated at non-detected isomer concentrations equal to zero (ND=0), was estimated to be 2.25 pg TEQ/kg b.w./day. When non-detected isomer concentrations are assumed to be equal to half of the limits of detection (ND=1/2 LOD), the mean daily intake was estimated to be 3.22 pg TEQ/kg b.w./day. These values were below the tolerable daily intake (TDI) of 4 pg TEQ/kg b.w. for PCDD/Fs and dioxin-like PCBs set in Japan. In both the estimates, the mean daily intakes were highest from fish and shellfish (76.9% at ND=0 and 53.9% at ND=1/2 LOD of the total TEQs), followed by those from meat and eggs (15.5% at ND=0 and 11.7% at ND=1/2 LOD of the total TEQs). Congener specific data revealed that these total TEQ levels were dominated by 1,2,3,7,8-PeCDD, 2,3,4,7,8-PeCDF and 3,3′,4,4′,5-PeCB in each case (71.7% at ND=0 and 63.1% at ND=1/2 LOD of the total TEQs). The dioxin-like PCBs (non-ortho and mono-ortho PCBs) accounted for about 50% of these total TEQs. These data will be very useful in the risk assessment of PCDD/Fs and dioxin-like PCBs from food in Japan. 相似文献
26.
Koike Kentaro Yamaji Toru Nishida Takahiro Yonamine Kazuhide Adachi Akihiro Nakagawa Kozo 《Journal of Material Cycles and Waste Management》2022,24(4):1368-1377
Journal of Material Cycles and Waste Management - Copper slag fine aggregate (CUS) is 30% denser than normal aggregate is an effective material for port and harbor structures demanding high-density... 相似文献
27.
Shohichi Osada Dalibor Kuchar Hitoki Matsuda 《Journal of Material Cycles and Waste Management》2010,12(1):83-92
To study the volatilization and condensation behaviors of low-boiling-point elements in the waste melting process, experiments
were conducted to collect the dust from a coke-type incineration residue melting furnace. Then, a comparison was made between
the experimental results and the calculated values obtained from a thermodynamic equilibrium model in terms of the chemical
composition of the dust. The composition of the dust collected from a cylindrical filter in the exhaust gas duct was determined
by chemical methods, scanning electron microscopy/energy-dispersive X-ray spectroscopy, and X-ray analysis. As a result, the
sampled dust was classified into two different types: fine particles mainly containing Na, K, Pb, and Zn collected from the
side face of the cylindrical filter, and large particles containing Ca, Si, and Al collected from the bottom face of the cylindrical
filter. From X-ray analysis of the sampled dust, NaCl, KCl, PbS, and ZnS were identified in the fine-particle dust, while
CaO, SiO2, Al2O3 were detected in the large-particle dust. From the results of the thermodynamic equilibrium calculation in the gas cooling
process from 2000 to 600 K, it was found that Na, K, Pb, and Zn volatilized as metals in the melting furnace were condensed
as alkali chlorides such as NaCl and KCl and heavy metal sulfides such as PbS and ZnS. These computational results were in
good agreement with the X-ray diffraction results of the sampled dust at a gas temperature of 823 K for the formation of NaCl,
KCl, PbS, and ZnS. 相似文献
28.
Kazuhide Matsuda Yoshifumi Fujimura Kentaro Hayashi Akira Takahashi Ko Nakaya 《Atmospheric environment (Oxford, England : 1994)》2010,44(36):4582-4587
In order to increase knowledge of aerosol dry deposition for the regional assessment of acid deposition and transboundary air pollution in East Asia, an experimental study on PM2.5 sulfate deposition was implemented in the early summer of 2009. The experimental field was located in a deciduous forest at the foot of Mt. Asama, central Japan. Aerosol fluxes were obtained using the aerodynamic gradient method. Three aerosol samplers were placed on an experimental tower at 21, 24 and 27 m above the ground surface, and collected PM2.5 on filters for chemical analysis. Vertical concentration differences between 21 m and 27 m of PM2.5 sulfate were detected significantly when the concentration exceeded 1 μg m?3. Mean deposition velocity was estimated to be 0.9 ± 1.0 cm s?1 in the daytime and 0.3 ± 0.3 cm s?1 in the nighttime. In the case that a height-dependent correction in the roughness sub-layer was taken into account, the deposition velocities increased more, especially in daytime. Higher deposition velocities in the daytime were associated with larger friction velocities and unstable conditions. The deposition velocities observed in this study were in agreement with other experimental results found in the literature. On the other hand, they were higher than those calculated by theoretical models. Two empirical parameterizations (Wesely, M.L., Cook, D.R., Hart, R.L., 1985. Measurement and parameterization of particulate sulfur dry deposition over grass. Journal of Geophysical Research 90, 2131–2143; Ruijgrok, W., Tieben, H., Eisinga, P., 1997. The dry deposition of particles to a forest canopy: a comparison of model and experimental results. Atmospheric Environment 31, 399–415) were validated by the observations. The general trend of higher daytime and lower nighttime deposition velocities was similar among the observation and the two parameterizations. The large variability found in the measurement was not reproduced by the parameterizations, because it is attributable to random error from the differences between the samplers. The observations were in accordance with the parameterization of Ruijgrok et al. (1997) for a forest, although much larger than that of Wesely et al. (1985) for grasslands. This indicates the large difference in aerosol deposition velocities between forests and grasslands. 相似文献
29.
K. Ootsuka N. Arashi Y. Hishinuma S. Matsuda F. Nakajima M. Mukai 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1053-1056
The body of information presented in this paper is directed to those individuals concerned with the catalytic NOx removal reactor for a dirty (containing dust) flue gas. In the case of treating a dirty flue gas, the concentration of dust is the most important factor. While the dirty gas passes through the catalytic reactor, dust particles deposit and plug up the catalyst causing the reactor pressure loss to rise. As a result, the NOx reduction efficiency decreases more and more, and continuous operation becomes impossible. A new type of NOx removal reactor for dirty flue gas, the intermittent moving bed reactor, has been developed. The following characteristics have been evaluated: (1) method of calculating reactor pressure loss caused by dust particles, (2) static pressure distribution across the catalyst bed in the reactor, (3) method of evaluating uniform movement of catalyst and (4) reentrainment pattern of dust by catalyst movement. After carrying out various successful pilot plant tests, the information needed for construction and operation of a commercial plant has been developed. 相似文献
30.
S. Matsuda M. Takeuchi T. Hishinuma F. Nakajima T. Narita Y. Watanabe 《Journal of the Air & Waste Management Association (1995)》2013,63(4):350-353
The body of Information presented in this paper is directed to those Individuals concerned with the removal of NOx in combustion flue gases. A catalytic process for the selective reduction of nitrogen oxides by ammonia has been investigated. Efforts were made toward the development of catalysts resistant to SOx poisoning. Nitrogen oxides were reduced over various metal oxide catalysts in the presence or absence of SOx(SO2 and SO3). Catalysts consisting of oxides of base metals (for example, Fe2O3) were easily poisoned by SO3, forming sulfates of the base metals. A series of catalysts which are not susceptible to the SOx poisoning has been developed. The catalysts possess a high activity and selectivity over a wide range of temperatures, 250—450°C. The catalysts were tested in a pilot plant which treated a flue gas containing 110-150 ppm NOx, 660-750 ppm SO2, and 40-90 ppm SO3. The pilot plant was operated at 350°C and at a space velocity of 10,000 h-1. The removal of nitrogen oxides was more than 90% for several months. A mechanism of the NO-NH3 reaction has also been investigated. It is found that NO reacts with NH3 at a 1:1 mole ratio in the presence of oxygen and the reaction is completely inhibited by the absence of oxygen. The experimental data show that the NO-NH3 reaction in the presence of oxygen is represented byNO + NH3 + 1/4 O2 = N2 + 3/2 H2O. 相似文献