Takuma Technical ReviewTECHNOLOGY

VOL. 9 NO.2 (published in Dec-2001)

Photo in Cover : Sapporo City Seibu-Sludge Center
VOL. 9 NO.2 (published in Dec-2001)
Transition in Dioxin Reduction Methods in Existing Incinerators
(Plant Planning Department, Techno-Consulting Division)


As the restrictions on dioxins emission intensify, existing waste incinerators have been remodeling and renewing their flue gas treatment units in order to meet the national limits or stricter municipal limits. The methods for preventing the generation of dioxins and their removal are well known, and each existing plant chose appropriate system suitable to its own conditions (available space, existing equipment, anticipated usage period, etc.). At present, many facilities are in the process of upgrading dioxins-prevention measures in time for the December 2002 deadline. This is a report on the details of renewal and its results from the facilities where such work has been completed.

Comparative Study of PCDDs/DFs Emission and Atmospheric Environment in the Pre- and Post-Retrofitting MSW Incineration Plant
Hajime TEJIMA* and Shigehiro SHIBAKAWA**
(*New Energy and Environmental Div.**Environmental Engineering Dept.1)


Reduction of polychlorinated dioxins and furans (PCDDs/DFs) emission from MSW (municipal solid waste) incineration is still an urgent issue in Japan. In January of 1997, the "Guideline for controlling PCDDs/DFs in MSW Management-PCDDs/DFs Reduction Program-" (commonly known as the New Guideline) was announced, and since December of 1998, Air Pollution Control and Waste Management Laws have been revised to control PCDDs/DFs emissions strictly.

Recently, a continuously operating MSW incineration plant in accordance with the New Guideline was built in the neighboring site of an old batch- operational MSW incinerator that had been in operation for almost 20-years. In order to evaluate the effect of environmental emission reducition by means of PCDDs/DFs control technologies, we have obtained comparative data on PCDDs/DFs emission from the plants under operation. PCDDs/DFs concentrations in the neighboring atmospheric environment were also measured and compared.

Measures for Reduction of Dioxins in Industrial-Waste Incinerators
Koichi MOTOMURA*, Yoshinori TAMADE**,
Ryuichi HAYASHI**, Hiroaki HYUGA**,
and Takashi AMEMORI**
(*Tochigi High-Trust Co., Ltd.
**Environmental Engineering Department,Energy & Environmental Division)


Currently, regulations aimed at reducing emission of toxic materials from waste incinerators and industrial plants are being strentghened one after another. Existing industrial-waste incineration facilities are pressed to improve the operation controls and to rebuild equipment in order to meet increasingly stringent restrictions on emissions of particulates, dioxins (PCDDs/DFs + Co-PCBs) and carbon monoxide (CO). Dioxins control, above all, is a very critical issue, and the following items are to be considered for this purpose.

-Controlling waste itself is of utmost importance. The nature and conditons of wastes coming to the facilities constantly vary as time goes by, and by the introduction of new products to the market. The nature of in-coming wastes should be understood before incineration with better inspection, and homogenizing them by crushing, storing and mixing is necessary. When the wastes thus treated are fed to the incinerator at a constant rate, stable combustion can be attained.

-If it is difficult to meet the emission regulations with existing equipment, the facility must be rebuilt. It may include various measures such as improving the combustion, adding combustion chambers and bag filters, according to the existing plant conditions.

In this article, we will report on the dioxins reduction measures applied to the existing industrial-waste incinerator we built for Tochigi High-Trust Co., Ltd.

The Deodorizing Effect of Plasma Deodorizer on Low Concentration Odor from Sewage-treatment Plants
Yosuke MAEDA**, Yukio WATANABE**
Kenichi SHISHIDA***and Hiroki FUJIHIRA****
(*Tokyo Metropolitan Government Bureau of Sewerage,
**Amenity System Department,
***Sewerage Designing Department,
****Research Center)


Ever since sewage treatment plants began operation, adsorption method using activated carbon has been the mainstay for the odor control. Activated carbon has a high adsorption capability at first, but it is difficult to determine the saturation points with sharply fluctuating odor elements. When it is exceeded, bad smell often leaks out.

This paper reports on the deodorization of low concentration odor using plasma technology that can be adopted by sewage treatment plants. We aim to develop this new system that can treat odor with better efficiency and lower costs.

By our research, we have confirmed that plasma deodorizer can reduce the raw gas odor concentration of 5,000 to roughly 300(maximum concentration at exhaust point permitted by the Tokyo Metropolis)by electric power use of 0.2Wh/m3, and that the deodorization effect can be revived by no-load running.

Method of Analyzing Dioxins
Satoshi OGURA
(Kankyo Sol-Tech Co., Ltd.)


This article reports on the method of analyzing dioxins mainly in the exhaust gas and work environment, currently adopted by Kankyo Sol-Tech Co., Ltd.

The method of analyzing dioxins in the exhaust gas is based upon JIS K0311(Analysis method of dioxins and coplanar PCB:1999)1). The analysis of dioxins in the work environment complies with Kihatsu No. 401-2 (Prevention of exposure to dioxins within the work environment of waste incineration facilities:issued April 25, 2001 by the director of labor standards, Ministry of Health, Labor and Welfare)2) as per attachment 1.

Measuring Technology by Laser and its Application in Waste Incinerators
Dawei Liu,Satoshi Yoshimotoand Shizuo Kataoka
(Energy and Environmental Development Department)


Laser technology is being used in many fields such as optical telecommunication, various measuring devices and material processing. Recent rapid progress in this technology has brought about a phenomenal expansion of its application in many areas. In order to improve the combustion efficiency of incinerators, we pursued laser measurement application that would enable high-speed, quick-response noncontact measuring. Experiments were conducted in areas such as measuring gas flow and gas mixing characteristics by LDV, real-time measurement of O2 concentration and controlling combustion by absorption spectroscopy using diode laser in waste incinerator. In this paper, the theory about this measuring technology, the conditions, methods and results of the tests will be reported with our observations and evaluations.