中海浚渫窪地の硫化水素発生抑制における石炭灰造粒物の適正施工量

Abstract

Dredged pits are a negative legacy of the Nakaumi Reclamation and Desalination Project, because the generation of hydrogen sulfide, which is the major cause of the destruction of the Nakaumi ecosystem. In the present study, hydrogen sulfide generation in a small pit (0.05 km 2 ) of Hosoi district was significantly suppressed by the application of granulated coal ash (30,000 m 3 , 50 cm in thick) . However, the generation of hydrogen sulfide was again observed after 1.5 years later because of consecutive organic matter sedimentation. A numerical model examination revealed 10,000 m 3 (17 cm thick) of granulated coal ash was sufficient to suppress the generation of hydrogen sulfide in the pit. It was concluded that repeating the application of the material in every few years until the pit is filled would be the best measure for preventing hydrogen sulfide generation due to the consecutive organic matter sedimentation.