Whether motivated by a need for disposal of contaminated sediment, a reduction in the size of confined disposal areas, or the scarcity of acreage adjacent to dredge sites, solids containment and dewatering practices have increased in importance in recent years. The material handling aspect of a dredging project must now be regarded as a solids dewatering project. The selection of equipment and chemical additives designed to optimize the sediment dewatering process plays a critical role in project production rates and profitability.

Environmental engineering firms, government agencies, and dredging companies have become increasingly aware of dewatering processes used by industrial and municipal entities and the economic benefits derived from them. However, the results from adapting these technologies to sediment dewatering have not always been favorable. With several different dewatering methods available, the selection process can be a difficult and arduous task requiring the investigation of many influencing variables. In an effort to simplify the decision-making process, the authors endeavor to provide some basic information to assist the end-user in the selection of mechanical dewatering technology.

Typically, sediment dewatering requires that the dredged solids be screened of large detritus, collected in a staging area, and thickened prior to dewatering. This paper will briefly describe the various types of equipment used in solids dewatering - including Belt Filter Press, Plate and Frame Press, Screw Press, Centrifuge, and Geotube - and the chemical additives used to improve their operating performance.

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