Water and Sediment Produced from Dredge Operation needed Filtration Solution Before Discharge During 3rd Avenue Bridge Replacement in Harlem

The plan was to have a diving contractor spot-dredge the areas where the cables were suspected to be located.  Any water or sediment removed during the project could potentially contain hydrocarbons, oils, metals, and any number of other unknown contaminants that would require treatment prior to discharge of the dredge water. 

The diving contractor planned to dive during the day and fill a hopper barge with the dredge spoils and water.  The barge would need to be emptied of water each night so the dredging operations could continue the following morning, an estimated treatment rate as high as 1,000 GPM.  Because of space considerations on the beautiful Harlem riverfront the entire water treatment system also needed to be mounted on a barge.

Waste Recycling Solutions, the contractor hired to treat the water, called the New Jersey Branch to design a system.  They worked with our Specialty Rental Division and the Engineering Department to quickly design the filtration system.   The proposed system consisted of double-diaphragm pumps (free oils could be present) to pump the water from the hopper barge.  The water was then run through three 25-yard filter containers fitted with filter bags to remove large amounts of solids, then gravity fed to six oil water separators. 

The OWS units were manifolded to an 8” suction point.  A DV-150 pump then pumped the water through a 48-4 sand media filter, BF/PF 1000 bag filter, and then through 10-2,000 lb. carbon vessels prior to discharge.  A duplicate back-up system consisting of an additional DV-150, 48-4 SMF, and BF/PF 1000 also needed to be mounted on the barge.  Chitosan biopolymer was introduced as the dredge water entered the hopper barge to aid in settling of solids. 

After many months, many meetings, and many phone calls the project was approved and the RfR system was chosen to treat the dredge water.  The project would need to be delivered and operational within two weeks!  The New Jersey Branch team started to scramble to put together the necessary equipment and manifolds. 

When the Branch team arrived at the project site to start putting the system in place, a major snag was revealed.  The prime contractor needed to keep a 100-ton crane on the barge where the treatment system was supposed to be set up!  Thanks to our Specialty Rental Division and great support from the Branch team,  the system was re-designed to wrap around the crane and fit on the barge, barely.

The system was tested and functioned great.  The barge was moved into place on the project and remained there for approximately 3 months, one month longer than originally expected.