Amalgamation of Mercury-Contaminated Waste using NFS DeHgSM Process, Applied Technology Laboratories, Erwin, TX

Site Name:

Idaho National Engineering and Environmental Laboratory

Location:

Idaho and Tennessee

Period of
Operation:

1998

Cleanup
Type:

Field demonstration

Vendor:

Nuclear Fuel Services, Inc.
Erwin, Tennessee

Technology:
Amalgamation using the NFS DeHgSM Process
- Prior to amalgamation, waste is sorted, shredded, and slurried to create a homogeneous mixture
- The first step in the process is to stabilize elemental mercury using one or more amalgamation agents (agents not specified)
- A possible second step is a chemical stabilization process using a proprietary reagent to break mercury complexes and allow removal of mercury as a precipitant; this step is required if the waste fails the cleanup criteria after the first step
- Treated material is produced as a presscake; filtrate is either recycled to the reactor or discharged
- Processing was conducted at ambient conditions in a ventilated hood

Cleanup Authority:
Not identified

Contacts:
Thomas B. Conley
Oak Ridge National Laboratory
Telephone: (423) 241-1839
Fax: (423) 241-2973
E-mail: tbc@ornl.gov

William Owca
DOE Idaho Operations Office
Telephone: (208) 526-1983
Fax: (208) 526-5964
E-mail: owcawa@inel.gov

Contaminants:
Heavy metals
- Mercury

Waste Source:
Nuclear processing operations

Type/Quantity of Media Treated:
Liquid mercury
- 51 kg from East Tennessee Technology Park, formerly the K-25 Site; characterized as RCRA Waste Code U151
- 23 kg from INEEL; contained oil at 17% by volume; characterized as RCRA Waste Code D009
- 1 kg from Diversified Scientific Services (DSSI); this material had been recovered from a thermal desorption treatability study; also D009

Purpose/Significance of Application:
Demonstrate amalgamation of elemental mercury

Regulatory Requirements/Cleanup Goals:
- Envirocare of Utah Waste Acceptance Criteria
- For mercury - TCLP leachate concentration of 0.20 mg/L; also considered UTS of 0.025 mg/L

Results:
- Wastes from INEEL (DSSI wastes were combined with those from INEEL) were treated with two step process; for mercury - TCLP leachate in presscake from second step averaged 0.05 mg/L (range 0.02 to 0.12 mg/L); TCLP leachate in oil phase was 0.03 mg/L; total of 15 amalgams weighed 114 kg
- Wastes from ETTP were treated with two step process; for mercury - TCLP leachate in presscake from second step averaged 0.05 mg/L (range 0.01 to 0.17 mg/L); total of 20 amalgams weighed 238 kg

Cost Factors:
- Projected costs for treating more than 1,500 kg were $300/kg, assuming waste is elemental mercury, and does not include disposal costs of the treated waste

Description:
Nuclear Fuel Services (NFS) conducted a demonstration of an amalgamation technology on wastes containing elemental mercury. The NFS process consists of a two step process, where mercury is first treated using amalgamation agents and then with proprietary chemical stabilization agents, and is conducted in a hood at ambient conditions.

Wastes from ETTP, INEEL, and DSSI were tested using this process. Results showed that the process reduced the concentration of mercury to 0.05 mg/L (on average) for each of 35 batches tested, and that the product met the Envirocare Waste Acceptance Criteria. Projected costs for use of the technology were $300/kg and costs for treating smaller amounts of wastes, such as at a specific site, were projected to be prohibitive. The report discusses the possibility of a national procurement contract to lower the cost of the technology on a unit mass basis.