| 摘要 |
PROBLEM TO BE SOLVED: To cost effectively and efficiently deal with the increase of night soil septic tank sludge, the insufficiency of the ability of existing wide-area night soil treatment plants and the inadequacy of making preparations to receive such sludge by installing simple and small-scale intermediate treatment facilities to which even small self-governing bodies can afford even without newly constructing or extending the large-scale wide-area night soil treatment plants. SOLUTION: The sludge dipped up by sludge transporting cars 11 from the night soil septic tanks of respective houses is transported to the regional night soil intermediate treatment plant smaller in scale than the wide-area night soil treatment plant. In this regional night soil intermediate treatment plant, the sludge is stored through a coarse screen 12 into a sludge storage tank 2. The stored sludge is advected through a fine mesh screen 13 into an activated sludge treatment vessel 3 where the sludge is subjected to activated sludge treatment by aerobic bacteria. The sludge is dewatered in sludge thickening and dewatering vessel 5 and 6 and thereafter the sludge is transported in the state of the aerobic activated sludge to the wide-area night soil treatment plant by the sludge transporting car 15 and is retreated in the wide-area night soil treatment plant.
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