Faculty Profiles - FUJIWARA Takeshi

Papers - FUJIWARA Takeshi

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Re-synthesis Mechanisms for PCBs and Chlorobenzenes in Fly Ash by Particle Size Reviewed

TAKAOKA Masaki, TANIGAKI Nobuhiro, TAKEDA Nobuo, FUJIWARA Takeshi

Journal of the Japan Society of Waste Management Experts 15 ( 5 ) 336 - 346 2004.9

Language：Japanese Publisher：Japan Society of Material Cycles and Waste Management

We focused on separating fly ash by particle size in order obtain fractions with different compositions. We then conducted heating experiments on each fraction under a variety of temperature and atmospheric conditions in order to understand the re-synthesis mechanisms of chlorinated aromatics in fly ash and the distributions of PCBs and chlorobenzenes (CBzs) by fly ash particle size. As a result, we found that the contributions of metal catalysts and unburned carbon in the formation of PCBs and CBzs were dependent on heating temperature. The homologue patterns of PCBs and CBzs were almost the same in all fractions of fly ash in the heating experiments. This indicates that all fractions of fly ash had the same formation patterns. The effect of atmosphere on the formation of chlorinated aromatics showed no difference among the fractions. HCl in a nitrogen atmosphere with 10% oxygen did not promote generation of PCBs and CBzs in fly ash. We confirmed that metal chlorides in fly ash were important as a chlorine source rather than HCl gas for the formation of chlorinated aromatics in fly ash.

DOI： 10.3985/jswme.15.336

A STUDY OF A RECONCILIATION MODEL OF MATERIAL FLOW AND STOCK ACCOUNTS WITH ECONOMIC AND INDUSTRIAL STATISTICS Reviewed

Taiyo Nakamura, Yuzuru Matsuoka, Takeshi Fujiwara

Environmental Systems Research 32 2004

The behavior of PCDD/Fs, PCBs, chlorobenzenes and chlorophenols in wet scrubbing system of municipal solid waste incinerator Reviewed

Masaki Takaoka, Peiyu Liao, Nobuo Takeda, Takeshi Fujiwara, Kazuyuki Oshita

Chemosphere 53 ( 2 ) 153 - 161 2003.10

Language：English Publishing type：Research paper (scientific journal)

Though some researchers have already reported polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) concentration in flue gas at inlet and outlet of wet scrubber (WS) in municipal solid waste incinerator (MSWI), there are few investigations about scrubbing water, suspended solid (SS) in scrubbing water and sludge. In order to understand the behavior of PCDD/Fs in WS and to make clear the effect of the residence time of scrubbing water in WS on the PCDD/Fs concentrations in scrubbing water and at the outlet gas of WS, PCDD/Fs, polychlorinated biphenyls (PCBs), chlorobenzenes (CBzs) and chlorophenols (CPs) concentrations in various media around WS were investigated at two MSWIs. PCDD/Fs concentration in flue gas at outlet of WS was higher than that at inlet of WS in both MSWIs. In WS A, it was observed that the homologue profiles changed considerably and the concentration of higher chlorinated compounds such as H7CDD/Fs and O8CDD/F increased remarkably at outlet gas of WS A. Only CPs were transferred from flue gas to scrubbing water in both WSs. As for scrubbing water, a large amount of their chlorinated aromatic compounds was detected in SS particles. According to the results, it was found that not only flue gas conditions but also operational and structural conditions in WS had great influence on minimizing the memory of chlorinated aromatic compounds in WS. © 2003 Elsevier Ltd. All rights reserved.

DOI： 10.1016/S0045-6535(03)00437-5

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Developmental Study of MSW Feed Rate Stabilization System for Stoker-Type MSW Incinerators : Lower Heating Value Presumption and Compaction Characteristic of MSW Reviewed

KAKUTA Yoshitada, NAKATSUKA Daisuke, ITO Daisuke, TAKEDA Nobuo, FUJIWARA Takeshi, TAKAOKA Masaki

Journal of the Japan Society of Waste Management Experts 14 ( 4 ) 210 - 218 2003.7

Language：Japanese Publisher：Japan Society of Material Cycles and Waste Management

The relationship between the bulky density of MSW and its lower heating value was clarified as part of research for the establishment of the MSW feed rate stabilization system in stoker-type MSW incinerator. The compaction characteristic of MSW was also examined through experimentation with artificial MSW.<BR>A strong correlation was admitted to exist between bulky density and the lower heating value of MSW. The presumption of the lower heating value became possible by measuring bulky density, although population and regional difference played an influential role in the bulky density concept.<BR>There was great volume change for MSW in the feed part, and this became crucial when considering the compaction of MSW for the presumption of the MSW feed rate. The compaction characteristic curve obtained by the experiment consisted of the part expressed in the second approximation evaluation and in the first approximation equation. Though the curves depended on the composition of the MSW and/or the compaction experimental method, their shapes were basically similar.

DOI： 10.3985/jswme.14.210

ESTIMATION OF HEMISPHERE TEMPERATURE OF ASH USING THE COMPOSITION AND DIFFERENTIAL THERMAL ANALYSIS DATA Reviewed

TAKAOKA Masaki, FUJITA Jun, FUJIWARA Takeshi, TAKEDA Nobuo

土木学会論文集 727 ( 727 ) 91 - 101 2003.2

CLASSIFICATION OF FUSION PATTERNS OF BOTTOM ASH AND FLY ASH USING DIFFERENTIAL THERMAL ANALISIS Reviewed

TAKAOKA Masaki, FUJIWARA Takeshi, FUJITA Jun, TAKEDA Nobuo

土木学会論文集 727 ( 727 ) 77 - 89 2003.2

A Study on the Scale of Waste Centralized Treatment from the viewpoints of Environmental Impacts, Traffic Loads and Total Cost Reviewed

Tsutomu Sasaki, Takeshi Fujiwara, Yuzuru Matsuoka

Environmental Systems Research 31 2003

Control of mercury emissions from a municipal solid waste incinerator in japan Reviewed

Masaki Takaoka, Nobuo Takeda, Fujiwara Takeshi, Masato Kurata, Kimura Tetsuo

Journal of the Air and Waste Management Association 52 ( 8 ) 931 - 940 2002.8

Language：English Publishing type：Research paper (scientific journal)

The control of Hg emissions from a municipal solid waste incinerator (MSWI) is very important, because more than 78% of municipal solid waste (MSW) is incinerated. The Hg content of coal used in utility boilers is relatively low in Japan. In this study, recent trends in the Hg content of MSW in Japan and activated carbon (AC) injection as a control technology of Hg emission from an MSWI are discussed.The effect of AC injection on Hg removal from flue gas in an MSWI was investigated by pilot-scale experiments using a bag filter (BF). The injection of AC increases the Hg reduction ratio by 20–30% compared with cases without AC injection. The Hg reduction ratio increases as the flue gastemperature decreases. The Hg reduction ratio is closely related to the inlet Hg concentration and was expressed with a Langmuir-type adsorption isotherm. © 2002 Air & Waste Management Association.

DOI： 10.1080/10473289.2002.10470831

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Feasibility Study on Heavy Metals Recovery from Fly Ash of Ash Melting Furnace by Utilizing Existing Production Facilities as Social Resources Reviewed

FUJIWARA Takeshi, TAKEDA Nobuo, NAKAHARA Keisuke, AKASHI Tetsuo, TSURUI Minoru, NAGASAKI Hidenori

Energy and resources 23 ( 1 ) 55 - 60 2002.1

A model on household waste generation and goods preference. Reviewed

Takeshi Fujiwara, Tomohiro Ueno, Yuzuru Matsuoka

Environmental Systems Research 30 2002

Modeling on Emission of Domestic Waste Considering Flow and Stock of Consumer Goods. Reviewed

Yuko Kanamori, Takeshi Fujiwara, Yuzuru Matsuoka

Environmental Systems Research 30 2002

A Study on Production of Gaseous Components from Batch Combustion of Plastics Waste. Reviewed

Norikazu Iwata, Takeshi Fujiwara, Nobuo Takeda, Masaki Takaoka, Syoji Eguchi

Environmental Engineering Research 39 2002

Surface Shape Measurement of Waste Stacked on Hopper in Municipal Refuse Incinerator by Using Stereo Image Processing Reviewed

ITO DAISUKE, FUJIWARA TAKESHI, TAKEDA NOBUO, TAKAOKA MASAKI, KAKUTA HIDETADA, NAKATSUKA DAISUKE

EICA 6 ( 1 ) 37 - 43 2001.9

EXPERIMENTAL STUDY ON INHIBITION OF CHLORINATED AROMATICS FORMATION ON FLYASH USING SODIUM SULFIDE Reviewed

TAKAOKA Masaki, NAKAMORI Ken-ichi, TAKEDA Nobuo, FUJIWARA Takeshi

Proceedings of JSCE 685 ( 685 ) 91 - 102 2001.8

Language：Japanese Publisher：Japan Society of Civil Engineers

The effect of sodium sulfide (Na₂S) on the formation of chloribnated aromatics such as polychlorinated biphenyls (PCBs) and chlorobenzenes (CBz) in post combusiton zone (200-500°C) of municipal solid waste incinerator was investigated. When fly ash was heated with mixture of 2% Na₂S at the condition of 300°C and 30min in air with 500ppm hydrogen chloride, total levels of CBz and PCBs decreased by 49% and 22% compared with that of fly ash without addition of Na₂S, respectively. The analysis using the sequential chemical extraction method indicated copper compounds in fly ash changed into copper sulfide. The main inhibiting mechanism was estimated to be the reduction of catalytic activity of fly ash.

DOI： 10.2208/jscej.2001.685_91

ANAEROBIC DIGESTION OF SEWAGE SLUDGE FROM PRE-COAGULATION Reviewed

TAKAOKA Masaki, HIROTA Junichi, TAKEDA Nobuo, FUJIWARA Takeshi

Proceedings of JSCE 685 ( 685 ) 17 - 26 2001.8

ESTIMATION OF SPIECIES OF ZINC, LEAD, COPPER AND CADMIUM IN FLY ASH BY A SEQUENCIAL CHEMICAL EXTRACTION METHOD Reviewed

TAKAOKA Masaki, KURAMOTO Yasuhiro, TAKEDA Nobuo, FUJIWARA Takeshi

Proceedings of JSCE 685 ( 685 ) 79 - 90 2001.8

X-ray photoelectron spectroscopy analysis for a reaction on the surface of tin metal in a continuous mercury analyzer Reviewed

TAKAOKA Masaki, SHIMAOKA Yutaka, TAKEDA Nobuo, FUJIWARA Takeshi

BUNSEKI KAGAKU 50 ( 7 ) 501 - 507 2001.7

Language：Japanese Publisher：The Japan Society for Analytical Chemistry

In order to understand the reaction in a continuous mercury analyzer with the dry-type reduction process, the surface of granular tin metal in a dry-type reduction process was characterized by X-ray photoelectron spectroscopy (XPS). First, the method for chlorinating the surface of tin metal was investigated. It was found that the surface of tin metal was more deeply chlorinated by impregnating with 1 mol/l hydrochloric acid for 2 hours than by passing 600 ppm hydrochloric acid gas through the reactor for the number of same hours. Subsequently, the change on the surface of granular tin metal by impregnating with 1 mol/l hydrochloric acid was observed in the case of passing air with mercury (II) chloride gas and moisture through the reactor. Tin (II) chloride on tin metal changed into tin (II, IV) oxide upon exposure to air or moisture. Depth profiles indicated that a tin (IV) oxide layer was formed on a tin (II) oxide layer. These results suggested that the reducibility of tin metal depended on the ratio of the chlorinated surface. As for the reaction on the surface of tin metal pre-coated with 1 mol/l hydrochloric acid, the resulting X-ray photoelectron spectra were in good agreement with the reaction estimated from the mass balance in the actual experiment.

DOI： 10.2116/bunsekikagaku.50.501

Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10895046

Speciation of Zinc, Lead and Copper on Fly Ash by X-ray Photoelectron Spectroscopy Reviewed

TAKAOKA Masaki, KURAMOTO Yasuhiro, TAKEDA Nobuo, FUJIWARA Takeshi

Journal of the Japan Society of Waste Management Experts 12 ( 3 ) 102 - 111 2001.5

Language：Japanese Publisher：Japan Society of Material Cycles and Waste Management

It is very important to know the dominant forms of heavy metals in fly ash generated from municipal solid waste incinerators or ash melting plants for consideration of detoxification and recycling. In this study, zinc, lead and copper in fly ash sampled in twenty municipal solid waste incinerators and five ash melting plants were analyzed using X-ray photoelectron spectroscopy. The dominant zinc compounds were 2ZnCO₃⋅3Zn (OH) ₂on the surface of fly ash and Zn or ZnO within the fly ash. PbCO₃and/or PbCl₂on the surface of fly ash were estimated. The chemical forms of copper did not depend on the fly ash type or depth and CuCl₂was not detected. Zinc and lead are therefore predominantly concentrated on the surface of fly ash.

DOI： 10.3985/jswme.12.102

Recovery of Phosphate and Ferric Chloride from Pre-Coagulated Sludge with Ferric Chloride. Reviewed

Masaki Takaoka, Jyunichi HIrota, Nobuo Takeda, Takeshi Fujiwara

Environmental Engineering Research 38 2001

Measures to prevent emissions of PCDDS/DFs and co-planar PCBs from crematories in Japan Reviewed

Nobuo Takeda, Masaki Takaoka, Takeshi Fujiwara, Hisayuki Takeyama, Shoji Eguchi

Chemosphere 43 ( 4-7 ) 763 - 771 2001

Language：English Publishing type：Research paper (scientific journal)

In this study, PCDDs/DFs and co-planar PCBs concentrations in flue gases from 17 crematories and in fly ashes and bottom ashes (mainly bone) from several crematories were measured to grasp the present state of PCDDs/DFs emissions from crematories. The effects of several factors were discussed to prevent PCDDs/DFs emissions from crematories. Total concentration (normalized by 12% O2) of PCDDs/DFs was ranged from 4.9 to 1200 ng/m3 N, and toxic equivalent concentration was ranged from 0.064 to 24 ng TEQ/m3 N. As the results obtained in this research, the following measures to reduce PCDDs/DFs emission are recommended for existing crematories: (1) keeping the temperature at 800°C in main/secondary chambers during a whole cremation, and (2) lowering the temperature in the dust collector. For newly installed crematories, following measures to prevent PCDDs/DFs emission including the measures for existing ones are recommended: (1) connecting one secondary chamber to one main chamber, (2) installing the high efficiency dust collector and reducing dust concentration to less than 0.01 g/m3 N, and (3) installing the sampling point for monitoring of PCDDs/DFs. © 2001 Elsevier Science Ltd.

DOI： 10.1016/S0045-6535(00)00431-8

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