Type: E
Accession Number: 57549
Code: Completed
Narrative:
Treatment of abrasive blasting wastes with a strong acid, such as sulfuric acid, was expected to render cadmium, chromium, and lead contaminants soluble. The treated and washed media residue would be expected to be nonhazardous. The acid extract, and subsequent rinse waters, would be treated by metal hydroxide precipitation. On an industrial scale at an Army depot, this could be done either in a separate process facility or possibly in the existing industrial waste water treatment facility. A series of laboratory experiments were performed at CERL to determine the feasibility of the process.
Application/Source: POLLUTANT CATEGORY:
Status:
- Experiment 1. Waste samples were subjected to a sulfuric acid extraction, at acid concentrations between 5 and 20%, followed by analysis of the residue by TCLP. The level of Cd and Cr was found to decrease, while the level of Ph increased.
- Experiment 2. Waste media samples were subjected to 5% sulfuric acid extraction, followed by a N2OH rinse. TCLP of the residue showed the level of Pb to increase.
- Experiment 3. Waste media samples were subjected to 5% sulfuric acid extraction followed by a series of distilled water rinses until the desired pH was obtained. TCLP of the residue showed the level of Pb to increase.
Experiment 4. From a review of the literature, it was proposed that an organic acid would successfully leach out the heavy metal contamination. Samples were subjected to a citric acid (0.02M) extraction, followed by a series of distilled water rinses. Although an analysis of the rinse water indicated the extraction of all three metal ions, the residue when tested by TCLP, showed little or no decrease in the level of leachable Pb.
- The level of Cd and Cr in blast media waste can be decreased by acid extraction. However, the level of Pb detected by TCLP can actually increase after some acid extractions. Additional laboratory work is required to establish a workable extraction process. The advantage of acid extraction would be that it should work for a wide variety of blast media types.
- Aug 94 Processes were not acceptable. This project is closed.
Initial Submission Date: 1994-01-28
Update Submission Date: 1994-08-09
Lead Service: Army
Key Words: Remediation, PMB
Point of Contact - Name: Dennis Reed
Point of Contact - Organization: HQ DESCOM
Point of Contact - Phone: DSN 570-9427
Last Updated: 10/29/96