Appendix C
Composition of Liquid Waste Streams from Destruction of Sarin in the EDS
The destruction of sarin (GB) in the EDS using aqueous MEA (45 percent) as the treatment chemical produces an organic-rich neutralent stream, as described in Chapter 2. The posttreatment of this neutralent stream is the focus of this report, but there are also other liquid waste streams that must be dealt with. The other streams result from the rinsing of the EDS chamber with water after each use to remove residual MEA and solid residues and the cleaning to remove other solid and liquid residues. These waste streams must also be prepared for ultimate disposal unless their compositions meet the feed requirements for an on-site treatment works. The diverse nature of these waste streams is illustrated in Table C-1.
The data in Table C-1 indicate that there are two main types of liquid waste streams from the EDS treatment of GB as produced in the bomblet campaign at Rocky Mountain Arsenal: (1) organic-rich neutralent derived from the MEA treatment and from the MEA rinse step used with the first two bomblets and (2) aqueous streams resulting from water rinses of the EDS chamber and from aqueous acetic acid cleaning of the chamber.
Most of the MEA reagent and most of the GB and energetic degradation products appear in the organic-rich neutralent stream. The concentration of isopropyl methylphosphonic acid (IMPA), the major product of GB decomposition, approximates that expected from 70 to 90 percent hydrolysis of the 1.3 pounds of GB contained in each bomblet (Lucille Forrest, Office of the Product Manager, Non-Stockpile Chemical Materiel, communication to the committee, February 2001). It is clear that the neutralents are far too organic-rich for direct treatment in a water treatment works. Some further treatment such as oxidation is needed to mineralize the organic components for disposal through a treatment works or by deposition in a hazardous waste landfill. A further complication is the high concentrations of some metal ions such as aluminum, copper, and zinc. These metals presumably were present as materials of construction for the bomblets and were washed or extracted from the bomblet fragments by the MEA solutions.
The water rinsates contain small quantities of MEA and GB degradation products that clung to the bomblet fragments and to the interior surfaces of the EDS apparatus. The metal ion concentrations are generally much lower than in the neutralents. The rinsates may be suitable for disposal through FOTW or POTW, depending on the regulations and permit requirements applying to the particular treatment facility.
The spent cleaning solutions are primarily water-based and acidic. The acidity appears to have played a major role in extracting metal ions, of which mercury may be the most problematic. The protocol for cleaning liquid flow lines on the EDS appears to have been a work in progress during the RMA campaign. The concentrations of chloroform and dichloromethane in this waste stream appear to arise from a commercial lubricant used as a sealant on the EDS (Lucille Forrest, Office of the Product Manager, Non-Stockpile Chemical Materiel, memorandum to the committee, May 10, 2001). The appropriate disposal of the spent cleaning solutions requires careful analysis. It may be possible to combine them with the aqueous rinsates, but care must be taken to be sure that the mixture can be handled in accordance with regulatory standards for the treatment works.
There are no established treatment standards (e.g., RCRA land disposal restrictions) for the agent or degradation/hydrolysis products that may be of concern. Whether to establish numerical treatment standards for agents and degradation products has been the subject of intense discussions between the Army and the states.
The numerical pretreatment standards listed in EPA’s Clean Water Act (CWA) are a minimum requirement. The sewerage agency must make a case-by-case determination to ensure that (1) the POTWs permit limits are not exceeded by the influent, (2) the water quality standards are not exceeded as a result of the discharge, (3) the toxic pollutants entering the POTW are adequately treated, and (4) the influent does not cause the POTW’s sludge to exceed any applicable
TABLE C-1 Composition of Liquid Waste Streams from the EDS Treatment of Sarin (GB) Bomblets at RMA
Waste Component from EDS Treatment of Sarin Bomblets at RMA |
Water Rinseb |
Cleaning Solutionc |
POTW Feed Limit for Organic Chemical Industry |
LDR Treatment Standards Goal of Treatment Prior to Disposal in Landfill |
|
Monoethanolamine (MEA) (%) |
43.8–48.3 |
0–4.7 |
0.8–1.1 |
None |
None |
Water (%) |
51.7–56.2 |
95.3–100 |
98.9–99.2 |
NA |
NA |
Isopropyl methylphosphonic acid (IMPA) (ppm) |
3,400–5,000 |
24–78 |
|
NA |
|
Diisopropyl methylphosphonate (DIMP) (μg/L) |
18,000–27,400 |
291–480 |
ND |
|
NA |
Explosives in liquids (μg/L) |
<1,000 |
<1,000 |
<1,000 |
|
NA |
Benzene (μg/L) |
1,330–2,850 |
28.6–40.7 |
<100 |
137 |
140 |
Chloroform (μg/L) |
ND-21.6 |
ND-4,380 |
8,360–10,500 |
325 |
46 |
Dichloromethane (μg/L) |
ND-97.1 |
ND-71 |
377–968 |
|
NA |
Toluene (μg/L) |
369–810 |
ND-23.7 |
<2 |
74 |
80 |
Mercury (-μg/L) |
0.1–1 |
0.1–2.65 |
17.9–25 |
|
150 |
Aluminum (μg/L) |
8,720 to 11,100 |
876 to 11,800 |
<876 |
|
|
Arsenic (μg/L) |
<200 |
<20 |
<20 |
|
1,400 |
Cadmium (μg/L) |
6.81–10 |
<0.68 |
2.2–46 |
|
690 |
Chromium (μg/L) |
445–770 |
11.5–485 |
1,070–1,870 |
|
2,770 |
Copper (μg/L) |
9,030–18,200 |
486–5,470 |
3,850–6,200 |
|
|
Lead (μg/L) |
63–237 |
3.82–603 |
128–168 |
690 |
690 |
Zinc (μg/L) |
23,100–38,300 |
72.5–308 |
4,920–5,680 |
2,610 |
NA |
pH |
12 |
10.4–11.5 |
6.5–7.8 |
|
|
NOTE: NA, not applicable; ND, none detected. The expected source and collection regime for these wastes are presented in Table 2–1. The term “treatment” is used to describe steps involving addition of reagent or water to the EDS and oscillating for some time period prior to opening the chamber. Note that water treatment and rinse water wastes can be combined. To date, the Army has chosen to segregate the three categories of wastes, so as not to foreclose on the options for treating the waste streams that are primarily water. aNeutralent consisting of the initial treatment of agent with active reagent (e.g., MEA) and any subsequent chamber washes with chemical reagent (if used). bRinsate consisting of additional agent treatment with water and chamber washes with water after opening the EDS. cCleaning solution consisting of washes (water and detergent) made between processing of each munition and final washes (e.g., water and acetic acid), made after completing a munitions campaign. SOURCE: Lucille Forrest, Office of the Product Manager, Non-Stockpile Chemical Materiel, “Interpretation of Waste Results from EDS GB Bomblet Destruction, Rocky Mountain Arsenal,” communication to the committee, February 2001. |
sludge limits. Clearly, a site-specific determination must be made to ensure that MEA, arsenic, and other significant constituents do not require pretreatment.
Table C-1 also compares the concentration of the nonstockpile chemical constituents in neutralent and rinsate with federal LDR treatment standards. There are no applicable federal LDRs for constituents of state-listed agent waste. But if the neutralent exhibits a RCRA hazardous waste characteristic, the federal LDRs apply. If the neutralent is not hazardous waste, the Army would have broad discretion to determine what constitutes acceptable treatment.
If the neutralent is a RCRA characteristic hazardous waste, it must be treated in accordance with LDRs before being disposed of in a hazardous waste landfill. Thus, constituent levels must be reduced from those shown in Table C-1 to the treatment technology-based limits before disposal in a landfill. Again, nonstockpile agent is not a listed hazardous waste (except for phosgene), and neither EPA nor the states have specified a treatment technology or treatment limits for the disposal of stockpile or nonstockpile agents.
Assuming the waste is determined to meet a RCRA characteristic, there are treatment standards that apply to several constituents of the EDS neutralent. The LDR treatment standards were developed based on the ability of existing technologies to reduce the concentrations of these constituents, which are typical commercial wastes. They are not based on the alternative treatment technologies being studied by the Army. The LDR treatment standard for a given constituent is generally the same regardless of the other constituents in the waste. One would expect the concentration of constituents in the neutralent to at least periodically exceed these treatment standards. Table C-1 suggests that some treatment might be necessary before disposal in a hazardous waste landfill, assuming that the waste is a RCRA characteristic waste. The average percent reduction in the constituent provides a general sense of the order of magnitude of treatment required if regulatory agencies use a treatment technology-based method to set the treatment goals for the alternative treatment technologies being considered by the Army.