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Dioxin Leakage Accident
in Municipal Solid Waste Incineration Plant
in Central Tokyo Metropolitan Area
Komichi Ikeda
Environmentarl Reserch Institute
Source:@IPEN Dioxin, PCBs and Waste Working Group
NEWSLETTER Vol. 3, No. 1, March 2012

@Independent Media ‚d|‚—‚‚–‚… Tokyo

What's IPEN ?

@The Clean Association of Tokyo 23, the public organization who is responsible for the intermediate treatment (separation, fragmentation and incineration of collected wastes), announced on 13th June 2011 that one of the incineration plants that they are taking charge of had stopped because of the high dioxin concentration level in the working area of the plant. It was Setagaya Incineration Plant located in the midst of residential area of Setagaya-ward, Tokyo (see picture below).

@The announcement of the accident was made 2 weeks after the accident happened in the plant. The citizens of Setagaya-ward and other Tokyo Metropolitan had known this accident by the newspaper on 14th June.

@The Clean Association of Tokyo 23 announced that gThere is no impact to the surrounding environment of the plant by this accident, but we are monitoring the ambient air dioxin level on the roof top of the planth. The actual dioxin level in the working area was reported as follows:Sampling Date Report Date Dioxin Level (pg-TEQ/m3)
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20th May, 2011 30th May, 2011 14.4 (Prompt result)
31st May, 2011 8th June, 2011 15.0 (Final result)
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Photo Setagaya Incineration Plant@

@This was quite big news for the residents near this incineration plant, as Setagaya-ward is the most qualified and populated residential area in Tokyo.

@People were very anxious about the leakage of dioxin to the environment around the incineration plant. On 21st of June, the Clean Association of Tokyo 23 announced the results of ambient air dioxin level monitored on the roof top of the plant building. It was as follows: gThe ambient air dioxin was monitored after the accident was low enough compared to the regular monitoring data. The air sampling was 7 days from 3rd June to 10th June 2011.

@The result of dioxin level of the ambient air was 0.033 pg-TEQ/m3. The average dioxin level of the ambient air at Setagaya Monitoring station in FY 2010 was 0.018 ? 0.047 pg-TEQ/m3.

@This is a kind of safety declaration towards citizens of Setagaya-ward that the accident was nothing to do with the surrounding environment. However, only this single data was not sufficient to show or prove the safety or cleanness of the environment around the incineration plant.

@Finally, on 5th September 2011, the Clean Association of Tokyo 23 announced the re-start of the incineration plant with explanation of the cause of the accident and the counter measures for it as follows: gThe suspended 2 incinerators of Setagaya Plant were both re-operated on 1st and 2nd of September 2011.

@The investigation and the construction for countermeasures were applied during 2 months from July to August. It was found that the main cause of this accident was leakage of emission gas from the expansion*1 at the lower part of waste gasification furnace.

@ The constructions for the countermeasures for improving the working area were

(1) Improving the durability and sealing power of expansion by changing the material from heat-resistant cloth to that of metals,

(2) Improving the working environment by preventing the reflux from inspection area of the dust catching equipment (belt conveyer and bunker) to incineration space by adding dust catcher for air suction and

(3)Installing air cleaner in the B1 floor room of the incineration area to improve the environment of working area and also strengthen the measures to protect the outer environment of the incinerator building. Finally, these measures made possible to improve the condition and levels of dioxin pollution at the working area and Level 3 became Level 1 control. Thus the 2 incinerator started again with no specific problems concerning dioxins.

@The accident described above contains very important and fundamental problem of Japan, as one of the most waste incineration dependence country in the world. Following are the major problems that we are confronted with a harsh reality in order to shift our waste management to incineration free and zero-waste management in future.

1) All the inspection and investigation were done by among those concerned.
Therefore, all the process and approach for clarifying the accident and effects of the dioxin leakage was not sufficient from both scientifically and socially especially concerning citizen involvement and participation.

2) The background of this kind of accident should be precisely analyzed from the impartial observer for not repeat the same accident. The Clean Association of Tokyo 23 insisted that this was the first case they experienced so far, but people outside of the incineration plant cannot identify the truth. Setagaya Plant is one of the most fragile (frequently malfunctioning) plants among 21 plants in Metropolitan Tokyo.

3) The former employee of the incineration plant says that this kind of accident should be noticed by regular inspection and daily check done by the workers of the plant. This means plant workers are not professional enough to control this very complicated and dangerous system as a whole. Lack of training or lack of professional awareness is to be pointed out.

4) For this specific case, the Kawasaki Heavy Industry (the plant maker) paid the repair cost of plant. The plant maker has to safely control and maintenance the plant based on the contract of Clean Association of Tokyo 23. The responsibility of the plant maker should be pursuit fully by the Municipality of Setagaya ward and also from the Association.

5) Citizens are so much accustomed to the incineration of waste for these decades; they do not have much interest in dioxin and other chemical pollution caused by waste incineration plants near their residents. Public is well controlled by the information from the government and Association who takes charge of waste treatment.

6) Labor Union of the employees of the incineration plants does not have much power to cope with the accident like this to protect the health and welfare of the workers. It is necessary to monitor the health condition of the workers working at the troubled plant during the dioxin leakage accident.

@As a whole, we Japanese are heavily dependent on hardware and high technology for waste treatment such as incineration, gasification and melting furnaces, same as the nuclear power plant rather than alternative energy sources. No technology is perfect and safe enough for human beings.

@They need burst amount of money to construct and maintenance and they continue emitting the hazardous chemicals in working area and to the outer environment of the residential area during its operation period. It is necessary to change our mind drastically to shift more environmentally sound and sustainable waste management policy by evaluating this gsmallh accident again with full participation and involvement of citizens and local municipalities as well.