Development and Application of Design and Operation Procedures for Coagulation of Dredged Material Slurry and Containment Area Effluent.

摘要

The purpose of this study was to develop guidelines for the design of facilities to coagulate the overflow from a dredged material containment area. Pilot plant studies were conducted to study the efficiency of polyelectrolyte coagulation of overflow from a dredged material containment area at an active freshwater dredging site. Full-scale studies were conducted at the same site on the feasibility of coagulating dredged material by injecting polyelectrolytes into a hydraulic dredge pipeline. Results of the pilot plant studies showed that, under the conditions tested, polyelectrolytes could be highly effective for coagulation of dredged material. Laboratory procedures were developed that can lead to the selection of the most effective coagulant, the optimum coagulant dosage, and the design parameters for a coagulation system. Examples are provided to illustrate procedures required to design a coagulation system for a containment area overflow. Results of full-scale tests on the injection of polyelectrolytes into a hydraulic dredge pipeline were highly variable. The high mixing rates and variability of composition of dredged material and flow rates caused a wide variation in treatment efficiency. Design examples are provided for the design of polyelectrolyte feed system to inject polymer into a hydraulic dredge pipeline. (Author)