| 摘要 |
PROBLEM TO BE SOLVED: To allow using a regulating tank with a compact capacity and to easily maintain and manage the specific gravity. of muddy water always in a specified range. SOLUTION: In the primary treatment F of classifying the waste mud water sent from an excavation place by a vibration dehydrating sieve 1, then feeding the mud water contg. solid particle-components of a relatively small diameter to the regulating tank and sending the mud water stored in the storage tank thereof again to the excavation place; the mud water flow passage reaching the storage tank from the vibration dehydrating sieve 1 is branched via a flow passage switching device 10 and the respective branched flow passages are provided with the storage tanks 8A, 8B. Feeding pumps 9A, 9B to the excavation place and withdrawing pump 22A, 22B to the secondary treatment circulating line are respectively disposed by each of the respective storage tanks 8A, 8B and are made respectively independently operable. Accompanying the ground excavation in the excavation place, the mud water is circulated while the respective storage tanks 8A, 8B disposed in parallel are alternately switched by the flow passage switching device 10. |
