Flocculent Settling Above Zone Settling Interface

Abstract

Column settling test procedures are used in designing confined dredged material disposal areas for effective sedimentation and initial storage of solids. The results of a study in which the test procedures were refined to allow a prediction of the effluent suspended solids concentration for conditions normally found in the disposal of saltwater sediments are presented. For this case, the dredged material normally settles as a slurry by zone settling, forming a clarified supernatant in the disposal area. The study determined the settling behavior of the fine particles initially remaining in the supernatant and developed procedures for predicting the effluent concentration as a function of retention time and other pertinent operating conditions. The ability to make such predictions is essential to the estimation of total release of contaminants in the effluent from confined disposal sites.