Geotube Shell Scotford Effluent Pond De-Sludging

LOCATION: Ft Saskatchewan, Alberta

TIMEFRAME: April – May 2012 SCOPE OF WORK: Removal of Accumulated Sludge from Effluent Holding Pond & Effluent Release Pond

PROJECT PARTNERS: Owner: Shell Canada Energy Geotube® Supplier: Tencate Polymer Supplier: WaterSolve LLC Pump Supplier: Canadian Dewatering Dewatering Contractor: Layfield Environmental Systems Ltd.

Shell Canada was having problems sustaining operation of their suction line as it was becoming clogged with vegetation which had accumulated within the pond since it was constructed in 2000. Initially Shell would not allow the pond to be drained for cleaning. Due to this requirement Shell contacted Layfield to assist with this de-sludging project by utilizing a couple of Layfield solutions (Aqua Dam and Geotube).

Shell contacted Layfield with the hopes of utilizing Aqua Dam® to section off the pond to allow for cleaning utilizing Geotubes® while leaving a large amount of water within the remaining sections of the pond. Eventually it was decided that the pond level could be lowered to allow for the cleaning of the entire pond at once. At this point it was discovered that the pond base was actually flat and that approximately 2,000m3 of sludge had accumulated within the pond. A combination of Aqua Dams® and Geotubes® would be utilized to complete this de-sludging project.
As the Dewatering Contractor on site Layfield installed Enviro Liner to create Geotube® laydown area as well as a containment area to house the pumps and polymer make down equipment.
Due to the large size of the pond and because the pond base was flat, Aqua Dams® were installed to create manageable sections within the pond.

To move the sludge Layfield utilized 4” Trash Pumps to transfer the sludge from within each section of the pond to the 6” pump which fed the Geotube® containers. Prior to the sludge entering the Geotube® a polymer solution was added to bind the sludge particles together, increase the rate of dewatering, increase retention of suspended solids and contaminants, increase clarity of effluent in NTUs (Nephelometric Turbidity Units) and increase the percentage of dry solids. Water was then pumped back from the Geotube containment area to feed the wash down equipment to assist with the chasing of the sludge towards the 4” pumps.

In this instance the use of Aqua Dam® and Geotube® containers aided in the de-sludging of this pond. The combination of the 2 products enabled Layfield to clean the pond to a near new state without compromising liner integrity throughout the process. The Geotube® containers were successful in trapping the sludge particles which will be removed from site at a later date.

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