ELECTRODIALYSIS TECHNOLOGY FOR ANODIZING BATH SOLUTIONS
is a process that will efficiently maintain a low metal ion concentration
in the anodizing bath solution by transporting metal ions (for example aluminum)
from the bath solution through a selective membrane into a capture media
using an electrical current to induce flow.
When anodizing aluminum, for example, the bath solution is required to be changed out and disposed of when the aluminum concentration reaches 80-100 grams/liter. The spent solution contains high levels of sulfuric acid and aluminum, requiring neutralization and metals removal for a typically large volume prior to disposal.
Electrodialysis does not affect the anodizing process. It is simply a process that can indefinitely extend the useful life of the bath solution by maintaining a low concentration of metal ions. The capture media, catholyte, removes the metal ions and forms a concentrated sludge. The sludge must be removed from the unit and the catholyte changed out on a regular basis to ensure effective metals removal from the anodizing bath solution. The recovered sludge is a hazardous waste containing high concentrations of metal that can be reclaimed by an outside company.
The addition of an
electrodialysis unit to an anodizing bath system can extend the useful
life of the bath solutions and thereby significantly reduce the volume
of hazardous waste generated. The reduction of hazardous waste helps facilities
meet the requirements of waste reduction under RCRA, 40 CFR 262, Appendix,
and may also help facilities reduce their generator status and lessen
the amount of regulations (i.e., recordkeeping, reporting, inspections,
transportation, accumulation time, emergency prevention and preparedness,
emergency response) they are required to comply with under RCRA, 40
CFR 262. In addition, because the useful life of the bath solution
is extended (i.e., less sulfuric acid is required at a facility) there
is less of a chance that the facility would meet any of the reporting
thresholds for hazardous substances/chemicals under SARA Title III (40
CFR 300, 355, 370, and 372; and EO 12856). Other compliance issues
include Energy Efficiency and Water Conservation at Federal Facilities
- EO 12902, and that additional electricity will be consumed with
|Safety and Health:||
Spent sulfuric acid
waste can be extremely corrosive to skin tissue. Contact with the body
can result in severe burns. Proper personal protective equipment should
|Economic Analysis:||The addition
of an electrodialysis unit to an anodizing bath system can significantly
reduce the volume of hazardous waste generated and the associated disposal
costs. Variables affecting the capital cost, operation & maintenance
costs, and the hazardous waste disposal costs with regard to the addition
of an electrodialysis unit include:
The cost elements for installing an electrodialysis unit to an anodizing bath at a site is provided below:
Annual Operating Cost Comparison for an Anodizing Bath System using an Electrodialysis Unit vs. using the Current Technology
Hazardous Waste Volume Reduction, 88% Reduction of Hazardous Waste Disposal
Economic Analysis Summary
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Approval is controlled locally and should be implemented only after engineering approval has been granted. Major claimant approval is not required.
*There are multiple MSDSs for most NSNs.
The MSDS (if shown above) is only meant to serve as an example.
|Points of Contact:|| Navy:
Mr. Michael Viggiano
Naval Facilities Engineering Service Center
1100 23rd Avenue
Port Hueneme, CA 93043-4370
Phone: (805) 982-4895
|Vendors:||IONSEP Corporation, Inc.|
P.O. Box 258
Rockland, DE 19732
Phone: (302) 798-7402
55 Maryland Ave
Pawtucket, RI 02860
Phone: (401) 728-7081
This is not meant to be a complete list, as there may be other suppliers of this type of equipment.