抄録
To root out Minamata disease, caused by the sewage accumulated in fish and shell fish, a large-scale sediment disposal work was conducted with a special care to prevent a new pollution. The basic approach to sediment disposal was to construct a highly watertight revetment for reclaiming the inner area of the Bay and then to confine sediment, dredged from the remaining contaminated area. Before sediment disposal, boundary nets were installed to enclose the work area to prevent the mixing of contaminated and non-contaminated fish. Dredging work was successfully done by using four cutterless suction dredgers, newly developed in advance for minimizing muddiness due to dredging work. Sediment, discharged into the reclamation area, keeping it under water, was covered with a sandproof membrane, particular volcanic ash earth with light weight, and mountain soil, successively.
