Study On Comprehensive Treatment And Disposal Of Sediment In Dagu Sewage River

For the reason of building an ecological city, achieving the objectives of energy saving and emission reduction and consolidating the results of creating national model city for environmental protection, the Dagu Canal rehabilition project is being carried out in Tianjin. Dredging project was not proceeded for the river for decades, so the river is seriously silted up by a large number of sediment. At present, the rehabilition project has been initiated completely, resulting in a lot of sediment excavated and removed in a short time. The pre-designed total capacity of the landfill is 450,000 cubic meters, which can not meet the actual need. To prevent the dispersion of pollution and reduce the secondary pollution, it is important for us to find a rapid approach to dispose the sediment. This study mainly focuses on sediment reduction and resource utilization.In the feasibility study on advanced reduction of the sediment, three kinds of method, including concentration, mechanical dewatering, drying are compared and analyzed. The Centrifugal belt filter with a very mature technology, characterized by the excellent effect, has been widely used for the treatment of the sediment. The volume of sediment can largely reduce by the way. But the technology of centrifugal belt filter has many problems, such as the operational difficulties, intense production schedule, the high cost of equipment, and the volume of the sediment dehydrated still exceeds the total capacity of the existing landfill. If conditions permitted, it is proposed to extend the duration of sediment disposal in order to save cost, and a natural drying method associated with human intervention in off-site can be accommodated to reduce sediment volume.Through undertaking engineering-economic analysis to the ways of the utilization of the sediment, including landfill, incineration, production of building materials, and roadbed filling, the program of roadbed filling with a reliable technology, a reasonable economy, and a good effect is recommended. This program can reduce the volume of sediment in large scale simply and quickly. Mixed with the construction waste, the sediment can be directly used for roadbed construction. The sediment with high moisture content can be utilized and construction waste has been effectively exploited. Therefore, this study suggests that this approach should be used to dispose the sediment in the Dagu Canal, and further applied research should be carried out through the outdoor test and the road test.