Increasing the Beneficial use of Dredged Bottom Sediment by means of a High Pressure Solidification System

摘要

In recent years an increasing amount of dredging activity has been taking place with the purpose of improving water quality through the removal of bottom sediment in harbors, rivers, lakes and marshland. However, because of the large amount of water contained in this dredged material, the use of such material without treatment has not been feasible. Consequently a wide variety of methods employing water-removal techniques to reduce volume have been developed, including sun drying, mechanical dehydration, chemical solidification processing, and so on. None, however, has completely succeeded in treating the material to a point where it can be used like regular earth and sand. To promote beneficial use of dredged material, it has become necessary to dehydrate the material more fully, and achieve dener and stronger material. In response to such needs a dehydration system for dredged material has been developed that uses a high-pressure filter press which generates an unprecedented 4 MPa of pressure. After numerous experiments at a number of construction sites, A full scale process plant has now been completed that can be used for actual construction work. Through our dehydration process, a volume reduction of 40% has been achieved for material with water content of 450-550%. and strength of the processed sediment has been raised to 600 (KN/m~2) (cone index) and sediment originally containing high amounts of water is now being used as material for land reclamation in sites not requiring foundation improvement In addition to soil for land reclamation, tha processed sediment is being used in a wide variety of other applications, ranging from material for backfills and embankments to farming soil, and is thus making a major contribution to finding beneficial uses for dredged material.