| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1999: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
Miscellaneous Drainage Trench which utilized the soil was constructed as waste water treatment countermeasure of the Omura Bay coastal zone in the preparation of the public sewerage. The assistant industry to "the miscellaneous drainage trench" for the purpose of holding the eutrophication of inland waterway, is cheap home kitchen drainage, and it expects the immediate effectivity. This assistant industry is promoted since 1985, and initial purpose has already been finished, and many trenches are already scrapped. This assistant industry is promoted since 1985, and initial purpose has already been finished, and many trenches are already scrapped.
However, it is used in zone outside of the public sewerage at present too. We sampled the soil in the trench which passed through the construction post-10 year, and reduction situation of the phosphoric acid absorption coefficient was investigated, and the service life of facilities was examined. As a result of the investigation, though phosphoric acid absorption coefficient in the beginning was about 1000〜1200, it decreased at about 500 at present. Therefore, it became clear that the service life of "trench" was 5〜7, 8 year.
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