PROBLEM TO BE SOLVED: To provide a treatment method and a treatment system for dredged soil in which water produced in a final treatment step is not discharged to the outside and is effectively utilized within treatment steps and an unnecessary load is not applied to an external environment. SOLUTION: In a first treatment step T1, coarse gravel A are removed from dredged soil S using a first vibrating sieve 1. In a second treatment step T2, a remaining gravel fraction A1 and a sand fraction B are removed from treated soil S1 passing through the first treatment step T1 using a second vibrating sieve 5 and a centrifugal separator 9. In a third treatment step T3, a silt fraction C is removed from treated soil S2 passing through the second treatment step T2 using a third vibrating sieve 10 and a centrifugal separator 14. In a fourth treatment step T4, an inorganic coagulant H1 and a polymer coagulant H2 are added to treated soil S3 passing through the third treatment step T3. Then, the treated soil is separated into a soil fraction D and water W using a fourth vibrating sieve 15, and the separated water W is circulated by the first treatment step T1 and is utilized for a specific gravity adjustment of the treated soil S1 to be sent to the second treatment step T2. COPYRIGHT: (C)2012,JPO&INPIT
