SETTLING / THICKENING
Settling/Thickening of dredged sediments to obtain a clear overflow by injecting polymer:
- Directly into hopper dredges – to enhance settling rate of sediment and clarify overflow water for discharge
- Prior to settlement ponds – improved settling rate of sediment and solids capture mean less land and fewer ponds necessary, with cleaner overflow water for reuse or discharge
Dewatering of dredged or pre-thickened dredged sediments in order to produce friable cake solids capable of being reclaimed or disposed of. Some of the common dewatering methods used in dewatering dredge sediments with the aid of SNF polymers, equipment, and service are:
- Geotextile tubes
- Belt filter presses
- Plate and frame presses
- Screw presses
SNF’s proposal is a change from the traditional lagooning process for dredged sediments from port construction or waterways dredging projects. Typically after many years of natural drying in upland or nearshore containment ponds or lagoons, the resulting dried sediment is heterogeneous.
However, with the use of SNF polymers injected prior to settling/thickening within a containment pond or lagoon, homogeneous flocs comprised of sand and fine particles leave valuable land or dewatered solids after only 6 months of drying time.
Our process means that less acreage is required for settling areas, and land can be re-used after only 6 months. It is a cost-effective alternative, as there is less capital investment needed, and our process is less expensive overall to operate than conventional sediment settling and disposal on a total cost basis.
In the case of contaminated sediments, SNF polymers are able to enhance dewatering of those sediments, resulting in cleaner discharge water and reduced volume of solids that need to be transported and disposed of in an approved hazardous waste landfill.
SNF SERVICES FOR DREDGING PROJECTS
- Review of project objectives and treatment plan
- Polymer selection and supply
- Makedown equipment design and supply
- Field start-up
- Field technical support