Effects of Mechanical Agitation on Drying Rate of Fine-Grained Dredged Material.

摘要

This report is part of research to determine a method for efficient evaporative dewatering of fine-grained dredged material slurry placed in confined disposal areas. Two conflicting schools of thought were found to exist. One favored continuous agitation of slurry to prevent desiccation crust formation, which supposedly inhibited drying, while the other postulated that the key to dewatering was to maintain good disposal area surface drainage and thus maximize the rate of crust formation. Controlled agitation experiments were conducted as well as a 6-month field demonstration of periodically mixing surface desiccation crust and underlying very wet dredged material at the Upper Polecat Bay Disposal Area of the U.S. Army Engineer District, Mobile, Ala. It is recommended that Corps of Engineer Districts interested in dewatering fine-grained dredged material placed in confined disposal areas from slurry to normal soil form expend maximum effort in improving surface drainage to remove decant water and precipitation as rapidly as possible so that available evaporative forces may be used to dry the dredged material into crust. Use of mechanical agitation on either a continuous or periodic basis is not recommended.