Abstract: Make-up water derived from an on-shore treatment facility is returned to a slurry processing unit on board a dredge by means of a water supply pipeline floating alongside a slurry delivery pipeline that conveys dredged material to the on-shore treatment facility. After separation from the slurry solids, the return water is pressurized to a transport pressure at the treatment facility with a centrifugal pump and then boosted to the desired working pressure once aboard the dredge. This two-stage pumping and re-cycling process reduces the amount of clear make-up water needed for proper operation of the slurry processing unit by more than 50%. This has resulted in a substantial reduction in the overall cost of remediation by reducing the amount of water that must be cleaned prior to disposal.

Abstract: Make-up water derived from an on-shore treatment facility is returned to a slurry processing unit on board a dredge by means of a water supply pipeline floating alongside a slurry delivery pipeline that conveys dredged material to the on-shore treatment facility. After separation from the slurry solids, the return water is pressurized to a transport pressure at the treatment facility with a centrifugal pump and then boosted to the desired working pressure once aboard the dredge. This two-stage pumping and re-cycling process reduces the amount of clear make-up water needed for proper operation of the slurry processing unit by more than 50%. This has resulted in a substantial reduction in the overall cost of remediation by reducing the amount of water that must be cleaned prior to disposal.

Abstract: By utilizing two inlet pumps and one discharge pump, and controlling the speed of the discharge pump, the pressure in a slurry processing unit can be controlled to facilitate measurement and handling of compressible slurry. It has been found that multiple specific gravity measurements with water injection between the measuring stations can provide an accurate indicate of clear water to be added, even though the slurry is compressible and of varying composition, by allowing controlled undershooting of the required water at one or more injection stations, followed by accurate specific gravity measurement under closely controlled pressure and flow rate conditions, followed by a small final clear water addition.