|
GEOTEC Associates: Jack Fowler, Ph.D., PE
Abstract:
Municipal sewage sludge was placed in geotextile bags for the purpose of evaluating the dewatering and consolidation capabilities of large geotextile tubes and effluent water quality. A proposed ASTM test method for determining the flow rate of suspended solids from a geotextile containment system for dredged material was used to conduct tests to determine the efficiency of different combinations of geotextile filters. Prior to filling the large geotextile tube, two small geotextile bags 48 inches in circumference and 70 inches long were supported vertically in a wooden frame and filled to a depth of about 60 inches or about 48 gallons of sewage sludge from the primary sludge digester. As water passed through the geotextile bag, samples were collected during, immediately after, and for several days to determine the total percent suspended solids (TSS), heavy metals, and bacterial count. The test results indicated significant consolidation or reduction in the form of the sludge volume in the bag. There was also a significant reduction in the TSS, heavy metals, and bacterial count in the effluent water. These test results led to filling a large geotextile tube 15 ft. wide, 30 ft. long and filled to a height of 5 ft. with sewage sludge.
The quality of pore water or effluent passing through the geotextile container systems proved to be environmentally acceptable for subsequent discharge into the Mississippi River and/or return to the treatment plant.
This new and innovative technology has been successfully used to dewater fine-grained, contaminated dredged material that contains dioxins, PCB's, PAH's, pesticides and heavy metals for Miami River and the Port of Oakland, CA. This is the first successful use of geotextile tubes for dewatering sewage sludge for beneficial uses in the United States. Research using this process for dewatering port and dairy farming waste, paper mill waste, fly ash, mining waste, chemical sludge lagoons and several other waste streams are being conducted.
This concept of containing sewage sludge has proven to be construction-practical, technically and economically feasible and environmentally acceptable.
IMS Versi-Dredges® can work easily with geotextile tubes.
FOR MORE INFORMATION, CONTACT:
Ryan Horton
IMS Marketing Director
Ph (913) 642-5100
Fax (913) 642-5119
(return to news archives and dredge case studies)
|
