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OCR for page 119
8
Parsons-AlliedSignal Technology Package
INTRODUCTION AND OVERVIEW
The Parsons-AlliedSignal team has submitted a pro-
posal under the acronym WHEAT (water hydrolysis of
explosives and agent technology). This technology
package is comprised of five basic technologies:
· The Army's baseline disassembly process, with
modifications including waterjet cutting for rock-
ets, is used to separate agent, energetics, and metal
parts.
· Hydrolysis is the primary process for detoxifying
the agent and deactivating energetics.
· Biological processing, supplemented by ultravio-
let/hydrogen peroxide treatment, is used to con-
vert the hydrolysis products to materials accept-
able for discharge to the environment.
· Metal parts and dunnage are decontaminated to
5X by heating in high-temperature steam.
· Gas discharges from the plant go through a cata-
lytic oxidation unit for treatment.
TABLE 8-1 Summary of the Parsons-AlliedSignal Technology Package
Table 8-1 lists how these technologies are used to
perform the six major demilitarization operations
listed in Chapter 2. A process flow diagram for the
Parsons-AlliedSignal package is presented in Fig-
ure 8-1, and a detailed description of the package is
given in the next section. The technology provider
addressed the processing of rockets, projectiles, and
mortars but did not consider the processing of land
mines.
DESCRIPTION OF THE TECHNOLOGY PACKAGE
Disassembly of Munitions and the Removal of
Agent/Energetics
The baseline disassembly process (see Appendix C)
is used to a large extent in this technology package.
However, some modifications to the baseline process
are proposed as described below.
Major Demilitarization Operation
Approach(es)
Disassembly of munitions Army baseline disassembly, augmented with water jet cutting
Treatment of chemical agent Base hydrolysis; biotreatment of hydrolysate
Treatment of energetics Waterjet wash-out; base hydrolysis; biotreatment of hydrolysate
Treatment of metal parts Heat in steam to SX conditions in metal parts treater; catalytic oxidation of gas
Treatment of dunnage Treatment in metal parts treater;catalytic oxidation of gas
Disposal of waste Solids. Dry salts and biotreatment product to appropriately permitted landfill; calcined grit to landfill
Liquids. None
Gases. Discharge to atmosphere after catalytic oxidation, caustic scrubbing (and possibly carbon
filtration)
119
OCR for page 120
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OCR for page 121
PARSONS-ALLIEDSIGNAL TECHNOLOGY PACKAGE
Projectile Disassemb/y
The fuze, booster (if present), and burster are re-
moved using the baseline process. The burster tubes
and supplementary charges are then placed in a special
fixture, and high-pressure hot water is used to dissolve
and/or physically remove energetics from the tubing.
The wash-out solution is fed to the energetics hydroly-
sis reactor as a batch. Boosters are washed out in the
same manner as bursters. The fuzes are sent to a rotary
metal parts treater, which will be described shortly.
The agent is drained from the projectile as in the
baseline process. The projectile body is then sent to
the metal parts treater, which is described later in
this chapter.
Mortar Disassemb/y
The fuze and burster are removed by the baseline
process; subsequent fuze and burster processing is the
same as for the projectile. The agent is drained from
the mortar as in the baseline process.
Rocket Disassemb/y
Rockets are disassembled with the rockets still in-
side their shipping and firing tube. Chemical agent is
removed using the baseline punch and drain approach
and is pumped to an agent storage tank prior to hy-
drolysis. Waterjet cutting with abrasive (garnet) is then
used to sever the fuze from the rocket, and the fuze is
sent to the rotary metal parts treater.
The rocket (with the fuze removed) advances to a
wash-out station, where high-pressure (4,500 psi), hot
water is used to remove the burster energetics (Par-
sons-AlliedSignals, 1998~. Abrasive waterjet cutting
is subsequently used to separate the warhead from the
motor section, and a high-pressure (15,000 psi) hot-
water jet washes the propellant from the motor section.
The burster energetics, propellant, and washout solu-
tion are fed to the energetics hydrolysis reactor. The
grit is separated from the cutting water; the cutting
water is sent to the agent hydrolysis reactor; and the
grit is sent to the rotary metal parts treater. Following
the removal of energetics, the warhead and motor sec-
tions are inspected and sent to the metal parts treater.
121
Treatment of Chemical Agents and Energetics
The chemical agents and the aqueous dispersion of
energetic materials derived from wash-out of the mu-
nitions are considered together in this section because
they follow the same processing sequence.
Hydro/ysis
The hydrolysis reaction conditions for agents are the
same as those outlined in Appendix D. Reaction times
will of this be specified to ensure very high conversion,
(e.g., 99.9999 percent destruction efficiency). Sched-
ule 2 compounds formed from the hydrolysis of each
agent will require further treatment by bioreaction.
Energetic material is fed to the hydrolysis reactor as
an aqueous slurry, having been reduced to a fairly small
particle size (e.g., less than a quarter inch). (An explo-
sives shredder may be used to reduce particles to this
size.) The reaction rate is expected to be controlled by
diffusion to the solid surface of the particle and is,
therefore, dependent on particle size. Reaction condi-
tions are the same as those outlined in Appendix E.
All hydrolysis products are transferred to storage
tanks before they are fed to the bioreactors. The hy-
drolysis reactors are operated as batch reactors; bio-
reactors are operated continuously. Tanks are sized to
accommodate the change between the batch and con-
tinuous operating modes.
Both VX and GB produce hydrolysates that contain
a small amount of an organic phase. The reactors and
storage tanks are constantly stirred to prevent the or-
ganic phases from separating from the bulk aqueous
phase. GB hydrolysate is more dilute than VX hydroly-
sate (i.e., 8 percent of the reaction products are from
GB compared to 30 percent from VX in their respec-
tive hydrolysates). The dilution prevents the formation
of a solid precipitate from GB hydrolysis, which is
probably sodium fluoride and some iron salt (see
Appendix D).
Bio/ogica/ Treatment
Aerobic bioreactors oxidize the hydrolysates (from
chemical agents and energetics) to the following
products:
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122
.
ALTERNATIVE TECHNOLOGIES FOR DEMILITARIZATION OF ASSEMBLED CHEMICAL WEAPONS
carbon dioxide, water, and biomass (solid prod-
ucts of the biological cell mass produced in the
reactions) (the technology provider estimates that
about 80 percent of the carbon in the process feed
is oxidized to CO2; the balance is in the organic
biomass (sludge), as well as a small amount of
organic matter remaining in solution)
other products, such as fluoride, sulfate, nitrite, ni-
trate, phosphate salts in solution, and ammonia
some low molecular weight, partially oxidized
species (e.g., acetic acid), as well as some organic
compounds that color the aqueous solution (color
bodies)
The biological reaction is relatively slow. The liquid
residence times in bioreactors (the so-called hydraulic
residence time) are typically five to 15 days, although
the technology provider believes that five days will be
sufficient. The average residence time of biomass can
be as long as two months.
The bioreactor design will include an AlliedSignal
development called an immobilized cell bioreactor,
which holds the biomass that develops in the reactor on
a porous screen (sponge). In other bioreactor designs,
the biomass floats freely in the liquid. Advantages
claimed by the technology provider for the immobi-
lized cell bioreactor are (1) more rapid reaction because
the biomass that accumulates on the screen is more
concentrated than in the free floating alternative; and
(2) lower production of biomass overall usually an
advantage because disposing of the biomass is a prob-
lem. The lower biomass production may not be an ad-
vantage in nerve agent disposal, however, because the
biomaterials use phosphorus primarily to produce bio-
mass, rather than for metabolism, and a bioreactor that
produces more biomass will more effectively eliminate
the phosphorus from the nerve agent hydrolysate.
Since the original proposal was made, the technol-
ogy provider has suggested using a combination of an
immobilized cell bioreactor and a "conventional"
bioreactor. The combined bioreactor would consist of
a long box, with its long side horizontal. The reactor
would be aerated to supply the oxygen for the bio-
reactions. The liquid in the reactor would be stirred by
the air, which would have the undesirable consequence
of keeping the entire process at the lowest reactant con-
centration (i.e., the exit concentration). To avoid this,
the reactor would be compartmentalized, with liquid
flowing horizontally from stage to stage within the re-
actor. The reactor would have two to four stages. The
first stages would use the immobilized cell bioreactor
design for rapid reaction. The last stage would have
free-floating biomass to promote the removal of phos-
phorus. Bioreactors used only for mustard and energet-
ics (that contain no phosphorus) are expected to use the
immobilized-cell technology for all stages.
The combination of a very large volume of feed (low
concentration of organics and salt in water), and a hy-
draulic residence time of five days, dictates the reactor
volume. The basic reactor module will be a 40,000-
gallon "box" the largest size that can be transported
by highway. Much larger reactor volumes will be
needed, however, and this requirement will be met by
adding more 40,000-gallon tanks.
The technology provider has suggested a basic mod-
ule of four 40,000-gallon tanks grouped around a cen-
tral "facilities" corridor (pumps, blowers, metering
equipment and controls, etc.~. The number of modules
will be determined in the final plant design by the re-
quired rate of munitions destruction, as well as on the
particular munitions. The technology provider has sug-
gested a configuration with three modules for the
Pueblo, Colorado, site and four modules for the Rich-
mond, Kentucky, site. Thus, there would be 12 or 16
40,000-gallon reactors at these sites (total bioreactor
volumes of 480,000 and 640,000 gallons).
The reactors are operated with very dilute solutions.
For example, experimental work has been done with
feed concentrations of less than 0.7 wt. percent; the
tentative plant design (for VX) calls for 1.2 wt percent.
This means the agent and energetics feed would repre-
sent 1.2 wt. percent of the material fed to the bioreactor.
The technology provider has suggested that salt con-
tents of up to 4 percent could be tolerated. Because the
hydrolysis products, which are the feed streams, are
typically in the range of 5 to 10 wt. percent, the hy-
drolysate feed stream must be diluted by a large factor,
as much as 10-fold, before entering the bioreactor.
Effective bioprocessing requires pH control. The
product from the hydrolysis reactors has a pH of 10 to
12, which is generally too high for the bioorganisms to
tolerate. The pH is adjusted by adding acid to lower the
pHto 8.5.
The microbial population responsible for the
OCR for page 123
PARSONS-ALLIEDSIGNAL TECHNOLOGY PACKAGE
bioreactions imposes additional requirements on the
feed to the reactor to keep the population alive. Three
important food elements are carbon, nitrogen, and
phosphorus. The optimum ratio for carbon to nitrogen
tophosphorusis 100:5:1 (Lupton, 1998~.Because none
of the hydrolysates meets this criterion, other materials
are added, such as dextrose. The amounts of these extra
materials vary depending on the particular hydrolysate
mixture being fed, but for hydrolysate from nerve
agents, the extra nutrients are a very large addition to
the feed to the plant. Mixing chemical agent hydroly-
sate, which is rich in phosphorus, with energetics hy-
drolysate, which is rich in nitrogen, can also help real-
ize the optimum feed.
The bioreactor cannot eliminate organic material
completely. Enough must remain in solution to sustain
microbial life. The solution leaving the bioreactor is
expected to have a dark color, due to organic color bod-
ies. The depth of color depends on the feed material.
The effluent from hydrolysate from munitions is par-
ticularly dark.
One product of the bioreaction is sludge, which is
flocculated, dewatered, dried on a drum evaporator, and
packaged for disposal in a landfill. The resultant solid
will probably contain most of the heavy metals from
the original feed and may be classified as toxic.
There are two other product streams from the
bioreactor: (1) the aeration air, mixed with product
gases from the big-organisms and volatile materials (in-
cluding low molecular weight chlorinated hydrocar-
bons from mustard) and some liquid "spray;" and (2) a
large stream of water containing dissolved salts and the
remaining organic material.
Catalytic Oxidation
A large volume of gas leaves the bioreactor. This
gas is then heated to 425 to 450°C (797 to 842°F) and
passed to a catalytic oxidation unit for the removal of
trace organics, oxidizable nitrogen, and chlorine com-
pounds. The gas is then cooled and scrubbed using ei-
ther a liquid or a solid soda scrubber. It may then be
passed through a carbon filter before release to the air.
A carbon filter has been installed on the Parsons-
AlliedSignal ACWA demonstration system. If analyti-
cal data show that the filter is necessary, it will be in-
cluded in the final plant design.
123
Salt Recovery and Water Management
Most of the water in the liquid bioproduct is re-
cycled. Salts are recovered by evaporation, and most of
the steam is condensed and recycled. A reverse osmo-
sis unit is included in the technology provider' s ACWA
demonstration system to reduce the volume of water
that must be evaporated. There is no plan to include the
reverse osmosis unit in a final plant design, however.
The salt content of the reactor liquid is affected by
the fraction of product liquid withdrawn and evapo-
rated. If the fraction is large (e.g., approaching 1), the
salt content can be maintained as low as 1 percent, but
at the expense of a large evaporation requirement. The
technology provider has suggested a salt content of 2
percent as a reasonable level, although the microbial
population can tolerate levels as high as 3 or 4 percent.
The organic matter remaining in the bioreactor liq-
uid from VX or GB disposal may contain low levels
(ppm) of Schedule 2 phosphonates. An ultraviolet /hy-
drogen peroxide treatment is used to reduce these ma-
terials to levels below detection limits.
Brine from the bioreactor unit is first concentrated
in an evaporator and then evaporated to dryness. The
salt is recovered with a rotary-drum dryer. The steam
from the evaporator is condensed and the water re-
cycled. The steam from the drum dryer is released to
the air. The salt, with a small residual organic compo-
nent' is packaged in drums for disposal.
Treatment of Metal Parts
Metal parts are heat treated to produce metal cleaned
to a 5X condition, which can be released from Army
control. The important difference from the baseline
approach is that the heating medium is superheated
steam instead of combustion gas.
A batch process is used to treat the parts to a 5X
condition. The metal parts treater is an autoclave with
induction heating. The metal parts are assembled in a
basket and placed in the metal parts treater, which is
then purged with nitrogen followed by low-pressure
steam. The metal parts treater and its contents are
quickly heated to about 650°C (1,202°F), and the sys-
tem is held at that temperature for 15 minutes. At the
end of the process, the steam is swept with air to a
condenser, and the gases are passed on to a reheater
and a catalytic oxidation unit. Organic materials driven
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124
ALTERNATIVE TECHNOLOGIES FOR DEMILITARIZATION OF ASSEMBLED CHEMICAL WEAPONS
off the metal parts and broken down by the heat are
oxidized to CO2, H2O, and possible acids, such as P2O5.
The gas from the catalytic oxidation unit is scrubbed
with lime or caustic solution, possibly passed through
a carbon filter, and exhausted to the environment.
Fuzes and associated small metal parts are also
heated in steam in a rotary metal parts treater where the
fuzes ignite or explode. The small metal parts are
treated to a 5X condition for disposal.
Treatment of Dunnage
Some contaminated dunnage is treated in the metal
parts treater. For example, DPE suits are shredded and
then vaporized in the metal parts treater, leaving be
hind a small ash residue. Some dunnage may be held
until the plant is closed. Some may be carefully exam
ined for contamination and reused (e.g., pentachlo
rophenol-treated wooden pallets). Grit from waterjet
cutting is heated to a 5X condition in the rotary metal Gas Streams
parts treater.
Process Instrumentation, Monitoring, and
Control
On-line chemical analysis during baseline disassem
bly and during operations unique to the Parsons
AlliedSignal process is limited to (1) a determination
of pH and specific gravity at critical control points; (2)
chemical oxygen demand and levels of all nutrients for
the immobilized cell bioreactor; (3) ACAMS monitor
ing of exhaust gases and of ventilated spaces and criti
cal operations, such as munition overpacks; and (4)
monitoring of sulfur and phosphorus content of the
catalytic oxidizer inlet stream. The bioreactor is instru
mented to monitor pH, temperature, and inlet and out
let chemical oxygen demand.
Feed Streams
The following materials will be required by the
plant:
· grit for waterjet cutting
· caustic for agent and energetics hydrolysis and for
gas scrubber solutions
· nitric acid for pH control
· nutrients for the bioreactor, with dextrose in the
largest amount
· a flocculating agent, probably a polymeric amine
· hydrogen peroxide for final polishing of the
bioliquid product
· carbon adsorbent for gas and ventilation air
cleanup
· fresh water (no wastewater leaves the plant, but
some water is lost as water of crystallization of
salts, water with the biosolids, humidity added to
the air, etc.)
· decontamination solution (sodium hypochlorite)
Waste Streams
There are three gaseous and four solid waste streams.
There is no liquid effluent from this process.
The largest gas stream is estimated to be 30,000 ac-
tual cubic feet per minute (ACFM) of slightly depleted
air, with oxygen content reduced from 21 percent to
about 19 percent. This stream is treated in a catalytic
oxidation unit. A second, much smaller stream, also
treated in a catalytic oxidation unit, is a product of the
metal parts treaters. A third gas stream is steam from
the drum dryers used to dry salts and biomass. This
stream is released to the atmosphere.
So/id Streams
Metal Parts. All of the metal parts from the original
munitions are cleaned to a 5X condition.
Biosludge. The dried biosludge, together with a
small amount of a flocculating agent, probably a poly-
meric amine, is expected to amount to 10 to 20 percent
of the mass of material fed to the reactor (agent plus
energetics plus added nutrients).
Sodium Salts of Various Acids. Sodium salts are pro-
duced from the heteroatoms (i.e., fluoride, chloride,
sulfate, nitrate and nitrite, and phosphate) and are a
solid waste. Chemical agents yield a large amount of
salt (e.g., VX yields salt equal to about 150 percent of
the mass of the original VX). The yield of solid salts
from the munitions varies with the munition but will
OCR for page 125
PARSONS-ALLIEDSIGNAL TECHNOLOGY PACKAGE
probably be roughly double the weight of the agent and
energetics in the munition. The salts may have a small
organic residue left from the biotreatment and the treat-
ment with ultraviolet light/peroxide. This remains to
be demonstrated.
Grit (Garnet). This material, used in waterjet cut-
ting, is treated at 1,000°F for at least 15 minutes in
steam.
Mass Balance
Mass balances for two munitions were provided by
Parsons-AlliedSignal: an 8-inch GB projectile and a
4.2-inch mortar with mustard (Tables 8-2 and 8-3~.
(Both tables show Fenton's solution being used, al-
though that is now considered unlikely.) These mass
balances cannot be considered exact because the prod-
ucts from the bioreactor are uncertain. The fraction of
the feed (C, H. and N) that will be oxidized to gaseous
products and the fraction oxidized to solid biomass are
not known with certainty.
Experience suggests that about 10 to 20 percent of
the feed (C, H. N) to the bioreactor, including added
nutrients, will end up as biomass; the rest will be oxi-
dized to gas products. The values shown in Table 8-3
demonstrate the large amounts of nutrients and dex-
trose required for bioprocessing nerve agent (GB)
hydrolysate.
TABLE 8-2 Mass Balance for Processing HD
4.2-inch Mortars (lb/lb HD)
Component
Amount (lb)
Input Streams
Flocculent + Fenton's reagent
Air
Nutrients
HD
Energetic materials
Sulfuric acid
NaOH
Water
Total input
Output Streams
Air
Sludge (wet)
Water (evaporated)
Salt
Total Output
0.2
278.0
0.3
1.0
0.1
o.o
1.0
9.4
290.0
280.0
0.6
7.8
1.6
290.0
Source: Parsons-AlliedSignal, 1999a.
125
TABLE 8-3 Mass Balance for Processing GB 8-inch
Projectiles (lb/lb GB)
Component
Amount (lb)
Input Streams
Flocculent + Fenton's reagent
Air
Nutrients
Dextrose
GB
Energetic materials
Sulfuric acid
NaOH
Water
Total input
Water (evaporated)
Salt
Total Output
7.8
2,897.0
6.3
44.4
1.0
0.5
2.8
2.7
50.1
3,012.6
2,930.0
53.0
24.3
4.9
3,012.2
Source: Parsons-Allied Signal, 1999a.
Start-up and Shutdown
The bioreactor is the largest volume unit in the Par-
sons-AlliedSignal technology package. This unit will
be run continuously but with some possible changes in
the feed. Experience suggests that the time required for
acclimation of the big-organism to a mustard hydroly-
sate feed is only a few hours. Acclimation to a nerve
agent hydrolysate that contains phosphorus in the form
of a phosphonate compound may take several weeks.
Disposal campaigns are planned accordingly.
In the event of a nonroutine shutdown, most pro-
cessing units, which are batch or semibatch operations,
can be shut down and held on stand-by status. The
bioreactor can withstand a shutdown of the air supply
for only a few hours, however. For a longer shutdown,
the bioreactor will require an auxiliary feed and air to
maintain the microbial population.
EVALUATION OF TH E TECH NOLOGY PACKAG E
Process Efficacy
Effectiveness of Munitions Disassembly
The technology provider claims that munitions han-
dling, disassembly, and plant safety design and practices
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126
ALTERNATIVE TECHNOLOGIES FOR DEMILITARIZATION OF ASSEMBLED CHEMICAL WEAPONS
will be modeled closely after the baseline system for
which significant operating experience is available.
These technologies have all been demonstrated and can
be considered to be mature.
Two new technologies will be introduced in the dis-
assembly process: waterjet cutting and waterjet clean-
out. Both have been used in the demilitarization of con-
ventional munitions. A brief overview of the state of
the art for demilitarizing ordnance using high-pressure
jet cutting and clean-out of the energetic materials is
given in Appendix G. In view of the significant devel-
opments in waterjet cutting technology and its tested
use for cutting high-explosive casings, the technique
can be considered suitable for application in disassem-
bly operations.
Explosive and propellant will be recovered from the
munitions by high- pressure waterjet clean-out, which
has been used on a substantial scale in conventional
demilitarization operations for many years. However,
it has only been used for removing energetic materials
from ordnance and not for minimizing the particle size
of the energetic material. The committee believes that
a small particle size (e.g., 0.25 inch) will be necessary
for the hydrolysis reaction. Therefore, the simultaneous
removal and size reduction of energetic materials will
have to be demonstrated.
Effectiveness of Hydrolysis
In the Parsons AlliedSignal Technology package,
hydrolysis will be the main technology for achieving a
99.9999 percent agent destruction. Subsequent treat-
ment in the bioreactor is expected to destroy the hydro-
lyzed materials, but the bioreactor should handle little
if any agent. The hydrolysis reactions of chemical
agents have been studied extensively (see Appendix
D), and hydrolysis for VX and HD should have accu-
mulated many hours of demonstration (at Aberdeen and
Newport) before an ACWA-based plant starts up. The
Army has already hydrolyzed several hundred pounds
of GB and VX to prepare hydrolysate for ACWA tech-
nology demonstrations of SCWO and biotreatment.
The hydrolysis of energetic materials is considered
a less mature technology than the hydrolysis of agent
(see Appendix E). The design will have to allow for
various reaction times and for various quantities, de-
pending on the type of munition being processed.
Effectiveness of Biotreatment
The use of natural microbial consortia for the degra-
dation and mineralization in a biotreatment system de-
pends mainly on providing organic food sources and
nutrients to the microorganisms. A sustainable food-
to-microorganism ratio must be maintained in the
bioreactor to ensure microbial viability. In theory, mi-
croorganisms can be made to mineralize almost any
organic contaminant, but in practice the toxicity of or-
ganic and inorganic constituents in the feed can be a
major problem that requires close monitoring and con-
trol. Furthermore, biotreatment alone cannot remove
all of the organics in the hydrolysate. A final polishing
step may be required to meet regulatory levels.
Biotreatment of the hydrolysate from mustard will
be used at the Aberdeen Proving Ground facility. Tests
using a "sequencing batch reactor" system have been
quite successful. The liquid product from this process
will go to the sewage treatment plant of the Aberdeen
Army base before final release to the environment.
Similar testing of a batch reactor was conducted for
biotreatment of VX hydrolysate for possible use at the
Newport, Indiana, bulk storage site. However, difficul-
ties were encountered that were not completely re-
solved (DeFrank et al., 1996~. VX hydrolysate contains
phosphorus in the form of phosphonate (i.e., with a C-
P bond), which appears to be difficult to metabolize.
Recent tests by the technology provider, however, have
been successful in removing the phosphorus to very
low levels (more than 95 percent removal) (Parsons-
AlliedSignal, l999b). Removal of phosphonate appears
to depend on the following factors:
.
.
.
The bacteria will use phosphonate as long as no
other form of phosphorus is available. Therefore,
other materials, such as phosphates must be rigor-
ously excluded.
The optimum ratio of major nutrients for the bio-
mass is in the approximate ratio C:N:P = 100:5:1.
Therefore, relatively large amounts of nutrients
containing C and N have to be added to make use
of the phosphorus in the feed. For example, dex-
trose was added in a ratio of 44 lb per lb of origi-
nal agent in the hydrolysate.
Phosphorus is used to produce biomass, rather
than for metabolism. Therefore, a combination of
reactor types must be used for optimum results
OCR for page 127
PARSONS-ALLIEDSIGNAL TECHNOLOGY PACKAGE
(e.g., an immobilized-cell reactor followed by a
free-floating biomass reactor).
In contrast to the difficulties experienced with the
bioreaction of nerve agent hydrolysates, the bioreaction
of mustard hydrolysate has worked well, although food
supplements are required. Mustard does contain low
molecular weight chlorinated hydrocarbons that are
difficult to biodegrade, and they will be sent to the cata-
lytic oxidizer, either in the effluent air from the bioplant
or in gases leaving the evaporator. The catalytic oxida-
tion unit is expected to be effective in destroying them,
but this will have to be demonstrated.
The committee anticipates that the ACWA demon-
stration tests being conducted during the preparation of
this report will address a number of questions concern-
ing the bioprocess. First, the pH of GB hydrolysate will
be adjusted to 8.5 before it goes to the bioreactor. This
pH is low enough for GB to re-form (see Appendix E).
This possibility will be monitored during the demon-
stration. Second, the biosludge, amounting to 10 to 20
percent of the carbon in the feed, will have to be tested
for toxicity.
Third, the technology provider has indicated that the
final effluent from the bioreactor after post-treatment,
should have a biological oxygen demand of < 100 mg/L,
a chemical oxygen demand of < 1,000 mg/L, and a
total organic carbon of < 100 mglL. This chemical oxy-
gen demand is somewhat lower than reported in the
technology provider's proposal and will have to be
demonstrated. (The biological oxygen demand and to-
tal organic carbon are usually much lower than the
chemical oxygen demand, though exceptions can oc-
cur.) A "polishing" step (hydrogen peroxide with ultra-
violet light ~ to reduce them further is provided for the
nerve agent hydrolysates.
Fourth, the airflow rate through the bioreactors is far
above the stoichiometric requirement for mineralizing
the feed. In early laboratory tests reported by the tech-
nology provider, the air flow was 25 to 50 times the
stoichiometric requirement. In more recent larger scale
work, however, the technology provider has demon-
strated satisfactory operation with 12-fold stoichiomet-
ric requirements (i.e., about 8 percent of the oxygen in
the inlet air was used). Operations should require as
small an air supply as feasible for the bioreactors be-
cause the product air must be treated further (i.e.,
127
heated to 425°C t797°F] for the catalytic oxidation unit,
cooled for acid gas scrubbing, and possibly reduced in
relative humidity for activated carbon adsorption).
Fifth, material vaporized or entrained in the air from
the bioreactor may affect the performance of the cata-
lytic oxidation unit. For example, entrained phospho-
rus could deactivate the catalyst. The gas stream from
the bioreactors will have to be characterized. Also, tests
will have to show whether entrained material will be a
problem.
Sixth, the salt content of the feed to the bioreactor
must be kept low for the microbial population. The
technology provider has stated that it will be main-
tained at less than 3 percent. It appears that a salt con-
tent of about 1 percent is being used in the ACWA
demonstrations. The level will affect the requirements
for the salt-recovery evaporator. A low salt content of
about 1 percent (which will be demonstrated) appears
to be a conservative choice for operation.
Effectiveness of Evaporation for the Production of
Sa/ts and Bioso/ids
The evaporation processes for recovering biosolids
and salts are well established. The products will prob-
ably be considered toxic, however, because most heavy
metals in the feed will end up in the biosolids. Polysac-
charides formed in the big-operation are known to be
good sequestering agents for heavy metals. (See Tables
D-3 and D-9 in Appendix D for a list of heavy metals
found in some samples of VX and HD.) Some metals
will also appear in the salts from the evaporation
process.
Heavy metals in the biosludge will probably prove
to be nonleachable as defined by EPA's TCLP test be-
cause they are usually tightly bound to the polysaccha-
rides. Heavy metals in the salts from nerve agent pro-
cessing will probably also be relatively nonleachable
because phosphates are present. However, heavy met-
als in the salt product from mustard may be more
soluble.
Effectiveness of Cata/ytic Oxidation
Two separate catalytic oxidation units, with subse-
quent alkaline scrubbing and carbon filtration, are pro-
posed. One treats gas from the metal parts treaters, the
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128
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ALTERNATIVE TECHNOLOGIES FOR DEMILITARIZATION OF ASSEMBLED CHEMICAL WEAPONS
other treats gas from the bioreactors. The catalytic oxi-
dat~on units resemble automobile catalytic converters
and use proprietary AlliedSignal technology. They
must handle a large gas flow, estimated at 30,000
ACFM, from the bioreactors, and the oxidizable mate-
rial will be very dilute. The proposed catalyst has been
shown to be effective at residence times as low as 0.1
seconds and should oxidize most of the chlorinated
materials in the gas stream (arising from mustard).
Small molecules are difficult to oxidize, however, and
the efficiency of the catalyst in oxidizing materials such
as methylene chloride (which might be in the gas) must
be demonstrated.
The possible presence of chlorinated dioxins and
furans in the product gas should be checked. If they are
present, the proposed carbon filters could effectively
remove them.
A small amount of liquid mist in the gas leaving the
bioreactors should be expected. Phosphorus and sulfur
(derived from nerve agents and mustard, respectively)
in this mist may negatively affect the catalyst. The cata-
lyst has been shown to destroy nerve agents and mus-
tard in short-term tests, but the technology provider
recognizes that long-term data are limited, and durabil-
ity has yet to be demonstrated. This is one area being
investigated during the ACWA demonstration tests. A
caustic scrubber and an activated carbon filter to treat
the effluent from the catalytic oxidizer are included as
an extra safeguard. (The presence of agent in the gas
stream from the bioreactors appears to be highly un-
likely. Much smaller gas streams Efrom the metal parts
treaters or venting of feed tanks] might contain some
agent.)
The technology provider's proposal states that sul-
fur and phosphorus concentrations in the gases flowing
to the catalytic oxidation units will be monitored. Con-
tinuous monitoring of the exhaust-gas stream is used in
place of a hold-test-release monitoring process.
Effectiveness of Peroxide/U/travio/et Oxidation
The hydrogen peroxide/ultraviolet light treatment
process must be tested to demonstrate its effectiveness.
The solution to be treated is colored (brown) and un-
doubtedly contains finely divided solids in suspension.
Ultraviolet radiation is directed into the solution
through quartz windows, and it may be difficult to keep
the window clean during VX processing. The technol-
ogy provider's goal is to reduce the total organic car-
bon to less than 50 ppm and to reduce residual phospho-
nate to 3 ppm.
Effectiveness of the Meta/ Parts Treater
The metal parts treater and rotary metal parts treater
will heat the metal parts (as in the baseline system) but
will use steam (at 650°C t1,202°F]), rather than com-
bustion gas. The process will qualify as a 5X treatment.
Sampling and Analysis
The proposed sampling and analysis methods are
generally well established and straightforward and
should not pose significant difficulties.
Maturity
The overall process is a combination of many (at
least 10) different technologies, all of which have sub-
stantial operational backgrounds, although some will
require demonstration for their application to chemical
weapons destruction. Hydrolysis of mustard and VX
are planned at Aberdeen, Maryland, and Newport, In-
diana, respectively. Extensive testing and development
of the hydrolysis processes has been done for the de-
sign of these two facilities. Biotreatment of mustard
hydrolysate is planned for the Aberdeen facility, and a
similar level of testing and development has taken
place, albeit on a different type of bioreactor than the
immobilized cell bioreactor. Tests of the biological
treatment test work on mustard hydrolysate have been
quite successful. Biotreatment of energetic hydroly-
sates has also been successful, though the full range of
materials has not been demonstrated. Ultraviolet/per-
oxide treatment of the mustard hydrolysate to remove
low molecular weight chlorinated hydrocarbons is also
being investigated at Aberdeen, but this process differs
from the treatment proposed by Parsons-AlliedSignal
for ACWA. The concentration of chlorinated hydro-
carbons at Aberdeen should be much lower than the
concentration of organics to be treated in this applica-
tion. The bioreaction of a feed with high phosphorus
content, particularly with the phosphorus present as a
"phosphonate" (i.e., C-P bond), has not been proven.
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PARSONS-ALLIEDSIGNAL TECHNOLOGY PACKAGE
Individually, all unit operations can be considered
mature technologies, and some have been applied to
the treatment of assembled chemical weapons materi-
als. Nevertheless, past industrial experience has shown
that starting up a process with many steps in series can-
not be accomplished without significant difficulties.
Robustness
All of the technologies appear to be reasonably op-
erable and robust in that they can be readily controlled
to desired set points and can accommodate modest fluc-
tuations in feed composition. Munitions disassembly,
energetics wash-out, hydrolysis, and biotreatment will
already have been applied to chemical weapons dis-
posal at Aberdeen and Newport. The sensitivity of the
bioreactor to fluctuations in feed or contamination is
being addressed in the demonstration. Biological con-
versions bring their own special problems, however,
particularly in dealing with living materials. Problems
with feed toxicity or predators for the microorganisms
may develop. The problems previously mentioned all
appear to be solvable. However, one aspect of robust-
ness that cannot be determined at this time is the ability
of the integrated process to handle feed variations
through the entire set of technologies.
Monitoring and Contro/
Overall, the proposed monitoring, control, and in-
strumentation system appears to be modern in design
and well thought out. Parsons-AlliedSignal proposes
using as much of the design as possible of the Army's
current baseline technology, taking advantage of the
design and lessons learned from that experience. The
following monitoring and control technologies are new
to chemical weapons destruction:
· the design of monitoring, control, and instrumen-
tation of waterjet cutting and wash-out systems
· the demonstration of a biomass accumulation
in the reactor that can achieve the necessary
conversions
· control of foaming in the evaporator (a small
amount of organic material from the bioreactor in
the brine would affect the liquid surface property
and could lead to foaming in the evaporator, a
129
common problem that can probably be handled by
additives)
· demonstration of the steady-state ultraviolet/per-
oxide oxidation step
Applicability
Many of the technologies in this technology pack-
age will have been applied to chemical weapons before
the start up of an ACWA plant based on this overall
process. Catalytic oxidation (on a large scale), metal
decontamination (to 5X) with steam, and waterjet cut-
ting applied to rockets will be new. In the committee's
opinion, the technology package is conceptually appli-
cable to the treatment of all assembled chemical weap-
ons. However, mine processing was not addressed by
the technology provider, and successful biotreatment
of nerve agent hydrolysate must still be demonstrated.
Process Safety
The unique equipment proposed by the Parsons-
AlliedSignal team is associated with the following
technologies:
· waterjet cutting
· wash-out of agent and energetics
· shredding of energetics
· base hydrolysis
· biological treatment
· ultraviolet/peroxide oxidation
· catalytic oxidation
· decontamination of metal parts with high-tem-
perature steam in the metal parts treaters
· decontamination of grit and munition fuzes in
high-temperature steam in the rotary metal parts
treater
Waterjet cutting, wash-out, and energetics hydroly-
sis will be done in explosion-containment areas. The
hydrolysis process operates at temperatures up to 90°C
(194°F); the bioreactor processes operate at ambient
temperature. Both processes operate at ambient pres-
sure. The catalytic oxidizer and the metal parts treaters
operate at elevated temperatures, 425°C (797°F) and
649°C (1,200°F), respectively. The hydrolysis reactors
and the 5X treaters, which represent the primary detoxi-
fying processes, operate in a batch mode; thus, the
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ALTERNATIVE TECHNOLOGIES FOR DEMILITARIZATION OF ASSEMBLED CHEMICAL WEAPONS
effectiveness of treatment can be ascertained prior to
release of the processed material to the next step.
The remaining systems are routine chemical pro-
cesses, and in this application, they occur down-
stream of the primary (hydrolysis) and secondary
(biotreatment) detoxifying processes. These systems
should pose no unique hazards. The equipment con-
sists of caustic scrubbers, carbon filters, evapora-
tors, and dryers.
Worker Health and Safety
If a process upset occurs, the primary destruction
components (the hydrolysis reactors and bioreactors)
cannot be shut down quickly because incomplete hy-
drolysis products, are extremely hazardous. Procedures
are expected to be established for safe shutdown and
restarting of the system. The air effluent during an up-
set will continue to be treated, first in the catalytic oxi-
dizer, then in the caustic scrubbers, and, potentially, in
activated carbon filters.
The low-speed shredder for energetics poses a po-
tential worker safety issue. Friction, shear, or heat may
result from the inadvertent introduction of metal, an
excessive feed rate, or some other cause and could ini-
tiate the energetic material. Workers are not expected
to be present, however, during normal operations.
The rotary metal parts treater can be designed to ac-
commodate detonations of fuzes (fuze detonation
chambers are not unique). Workers are not expected to
be present during normal operations.
Only trace amounts of energetics will be present in
the metal parts treater under expected operating condi-
tions. Scenarios for the introduction of energetics be-
yond design conditions will be evaluated to ensure that
they are extremely unlikely before the design is com-
pleted. Potentially flammable dunnage pyrolysis prod-
ucts are being characterized during ACWA demonstra-
tion testing, and the impact of these and other effluents
should be considered as the design develops.
The technology provider plans to hydrolyze differ-
ent types of energetic materials simultaneously in the
same reactors. As discussed in Appendix E, the com-
mittee is concerned that this could lead to the forma-
tion of compounds that are both energetic and sensi-
tive. Therefore, different energetic materials should
be processed in separate reactors unless tests shows
that the formation of sensitive compounds does not
occur.
Small amounts of aluminum particulates created
during waterjet cutting of the rocket warhead sections
will generate hydrogen during the hydrolysis step. The
hydrogen and hydrolysis gases will be vented to the
bioreactor off-gas stream and then heated to 425°C
(797°F) for treatment in the catalytic oxidizer. The
large bioreactor off-gas flow rate will dilute the hydro-
gen to well below the flammability limit before heating
in the oxidizer. Standard operational procedures and
designs for flammable gas systems, (e.g., maintaining
a negative pressure to avoid release to air spaces)
should be adequate to minimize explosion hazards.
The biosludge produced in the bioreactor could con-
tain some pathogenic microorganisms. The potential
for worker exposure to these microorganisms is ex-
pected to be minimized by appropriate protective gear.
Waterjet technology is commonly used in the de-
militarization of conventional munitions and should not
pose unique safety issues. The ACWA demonstration
includes tests of the capability of this technology to
separate the fuze and the rocket motor from the war-
head. Even if an ignition occurs, there will be little risk
to workers because the cutting is performed remotely
in an explosion-containment area.
The energetics hydrolyzer incorporates an external
circulation and cooling loop. Pumping an aqueous
slurry of energetic materials can be done safely under
the proper conditions. If an accident occurs during nor-
mal operations, there would be little risk to workers
~. ~
. . . .
because the loop is in an explosion-containment area.
The loop will have to be designed to ensure that ener-
getic material does not precipitate and accumulate in
the piping, which could result in an accident during
maintenance procedures.
The primary hazardous materials used are sodium
hydroxide, nitric acid, sodium hypochlorite, and hy-
drogen peroxide. These chemicals are used routinely at
many industrial facilities and are not unique to the Par-
sons-AlliedSignal process for demilitarization.
Public Safety
The release of agent and other regulated substances
in plant effluents is judged to be extremely unlikely.
The destruction of agent and energetics will be verified
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PARSONS-ALLIEDSIGNAL TECHNOLOGY PACKAGE
by hold-test-release operations before the transfer of
hydrolysate from the hydrolysis reactors to the bio-
reactors and before the transfer of bioreactor sludge to
the sludge containerization step. The gaseous effluent
from the bioreactors will be continuously released
through activated carbon filters, if the demonstration
test results indicate that this is desirable or necessary.
No hold-test-release operation is provided for the gas-
eous effluent stream from the bioreactors. Because this
stream will be continuously monitored for hazardous
materials, the release of hazardous materials is consid-
ered extremely unlikely.
There is a low probability of agent release in case of
a failure of the rotary metal parts treater. This hazard
can be mitigated by good design and operational pro-
cedures that are confirmed by risk analyses.
GB reformation in the bioreactor because of low pH
(see Appendix D) is being investigated during demon-
stration testing. Any GB vented from the feed tank or
the bioreactor is expected to be destroyed in the cata-
lytic oxidizer or captured in the backup activated
carbon filters.
Human Health and the Environment
Eff/uent Characterization and Impact on Human
Health and Environment
In the absence of health risk and environmental as-
sessments, a precise statement on the impact of the ef-
fluents on human health and the environment cannot
be made at this time. However, the gas flow leaving the
plant should be free of hazardous material. It will have
been exposed to a very high temperature (about 425°C
[797°F] in the catalytic oxidation unit), and it will have
been through extensive cleanup processes to remove
traces of organic materials (including any agent).
Two of the solid materials leaving the plant will be
treated as hazardous waste: salts with traces of organic
material; and biomass with small amounts of salts.
Completeness of Eff/uent Characterization
The very large gas flow, primarily from the bio-
reactor, will have gone through catalytic oxidation and
... . . .
131
then be tested routinely for chemical agent, oxygen,
carbon dioxide, and carbon monoxide on a real-time
basis. It should also be characterized for low concen-
trations of hazardous materials, such as dioxins.
Biomass will be tested periodically for leachability
and for toxicity. Salt residue will also be tested for
leachability. Other effluents that have been treated to a
5X condition will not require further characterization.
Eff/uent Management Strategy
Salts. Dried salt, probably containing some organic
materials, will contain sodium salts of fluoride, chlo-
ride, sulfate, nitrate, and nitrite. The technology pro-
vider expects this waste stream to be hazardous. Sta-
bilization, either at the plant or at a commercial
hazardous-waste treatment facility, may be required.
Experimental studies will be necessary to determine
the leaching levels of hazardous constituents in the salt
and then, if required, determine the additives needed to
stabilize the salt. Stabilization and burial in a hazard-
ous-waste landfill should provide adequate protection
to human health and the environment.
Biosludge. The composition of the biosludge pro-
duced in the bioreactor is unknown at this point, al-
though the technology provider expects it to be hazard-
ous because it will be the sink for most heavy metals
from the process. The sludge will also contain micro-
organisms, some of which might be pathogenic. Test-
ing will be necessary to determine whether or not the
waste is hazardous as defined by the EPA. If so, dis-
posal in a hazardous-waste landfill may not be possible
because of the biological activity. Incineration of the
waste is an alternative. If it is not hazardous, it can
most likely be sent to a municipal solid-waste landfill
without threat to human health or the environment.
Gas. Exhaust gas from the catalytic oxidizer will
pass through an acid gas scrubber (and possibly through
an activated carbon adsorber). Whether or not any con-
stituents of concern will be present in this stream is not
known at this point. Analyses will be necessary to con-
firm the presence or absence of low molecular weight
hydrocarbons and chlorinated hydrocarbons, oxides of
nitrogen, and chlorinated dioxins and furans.
acid gas scrubbing. The composition will have to beMetal Parts and Garnet Grit. Metal parts and grit
determined in detail during initial trials. The gas shouldare cleaned and deactivated to the 5X condition in the
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ALTERNATIVE TECHNOLOGIES FOR DEMILITARIZATION OF ASSEMBLED CHEMICAL WEAPONS
metal parts treaters. The cleaned parts are not expected
to pose any threat to human health or the environment.
Resource Requirements
The Parsons-AlliedSignal technology package has
three steps that will consume large amounts of energy:
(1) producing 650°C (1,202°F) steam for the metal
parts treater; (2) heating the vent gas from the bio-
reactor to about 425°C (797°F) for the catalytic oxi-
dizer; and (3) evaporating the salt solution from the
bioreactor. The power requirement has been estimated
to be a few megawatts. None of the resource require-
ments appears to be excessive.
Environmenta/ Compliance and Permitting
There are no apparent reasons that the combination
of technologies selected by the technology provider
should lead to unusual permitting or compliance prob-
lems. The absence of liquid emissions is an important
advantage of the process. However, the catalytic oxi-
dation operations are close enough to incineration in
concept that regulatory (and public) concerns could be
raised.
STEPS REQUIRED FOR IMPLEMENTATION
The following steps would have to be taken to imple-
ment this technology package:
1. demonstration of the effectiveness of the bio-
treatment of various combinations of agent and
energetics hydrolysates of sufficient length to
give reasonable assurance of long-term perfor-
mance
operation of the bioreactor at the planned salt-
content
a. characterization of the off-gas from the bioreactor
to evaluate the extent of air-stripping from the re-
actor and the possible poisoning of the catalyst in
the catalytic oxidation unit
4. demonstration of the effectiveness and long-term
performance of the catalytic oxidation system in
destroying organic constituents in the bioreactor
off-gas
5. quantification and characterization of the sludge
from the biological process to ascertain if Sched-
ule 2 compounds or other hazardous constituents
are present
6. demonstration of unproven steps in the proposed
process, including ultraviolet/peroxide oxidation
and evaporation operations
7. quantification and characterization of the salts
from the evaporation operations to ascertain what
organic compounds are present
FINDINGS
Finding PA-1. The biological treatment operation will
require further demonstration to prove its ability (1) to
handle a variety of feed stocks with reasonable accli-
mation times between changes, and (2) to achieve high
levels of conversion of the Schedule 2 compounds in
the hydrolysate. The demonstration will have to last
long enough to give confidence in the long-term opera-
tion ability of the process.
Finding PA-2. The relative effects of biological treat-
ment and air-stripping on the destruction of organic
materials in the bioreactor have not been established.
This will affect the composition of the off-gas from the
bioreactor.
Finding PA-3. The effectiveness of ultraviolet/
hydrogen peroxide oxidation in reducing Schedule 2
compounds to an acceptably low level has not been
demonstrated.
Finding PA-4. The bioreactor has been operated only
at very low salt concentrations. Operation at design
concentrations has not been demonstrated.
Finding PA-5. Additional data should be gathered on
the effectiveness of the catalytic oxidation system in
destroying organic materials in the biotreatment off-gas.
Finding PA-6. The sludge from the biological process
has not been completely characterized.
Finding PA-7. Even though the evaporation operations
involve conventional technologies, they have not been
tested for this application.
Finding PA-X. The dried salts from the evaporation
operations have not been characterized for leachability
and toxicity.
Representative terms from entire chapter:
technology provider
