ACWAFS_PUEBLO1/20030414

FOR MORE INFORMATION CONTACT: Program Manager Assembled Chemical Weapons Alternatives Public Affairs at 410-436-3398. Pueblo Chemical Depot Public Affairs can be reached at 

719-549-4135. Additional information is available at the Pueblo Chemical Depot Community Outreach Office, 301 N. Main Street, Suite 306B, Pueblo, Colorado, 81003, 719-546-0400.

The Neutralization / Biotreatment 

Process at Pueblo

The Pueblo Chemical Depot community 

has worked together to select a safe 

technology to destroy the chemical weapons 

stored there. This coordination led to the 

identification of “neutralization followed 

by biotreatment” as the preferred disposal 

technology.

On July 16, 2002, Department of Defense 

officials made this technology selection 

official. A Request for Proposal was 

released on July 26, 2002, to seek bids from 

contractors to design, build and operate the 

Pueblo chemical agent destruction facility.

Neutralization followed by biotreatment 

uses hot water to neutralize the chemical 

agent, effectively destroying the mustard 

agent molecules. The resulting hydrolysate 

is mostly water and thiodiglycol, a 

common industrial chemical that is readily 

biodegradable. Ordinary sewage treatment 

bacteria, or microbes, consume the organics 

in the hydrolysate. Besides being a common 

phenomenon in nature, the science of using 

microbes to help dispose of hazardous waste 

has existed for decades. Sewage treatment 

facilities across the country use microbes 

every day to help break down raw sewage.

In addition, extensively trained, skilled 

workers and state-of-the-art robotic systems 

will ensure the safe destruction of Pueblo’s 

chemical weapons stockpile.

Step One: Removing the Energetics

Robotic equipment will remove the weapon’s 

energetic components, including the fuze 

and the burster. Removing these parts first 

makes the remaining processes safer. The 

energetics in the burster will be removed 

by soaking in a bath of caustic solution. This 

energetics mixture will be further processed 

in Step Three. Metal parts, including 

fuzes that contain very small amounts of 

energetics, will be disposed of in Step Five.

Step Two: Removing the Mustard Agent

Once the energetic components are 

removed, the weapon body containing 

chemical agent will be processed. To remove 

the agent, the body is robotically accessed 

and then the agent is washed out with 

pressurized water. 

Step Three: Neutralizing the Energetics 

and Mustard Agent

After the energetics and agent have been 

separated from the metal parts, they 

will be treated in separate tanks with a 

caustic solution and water respectively. 

The by-product from this process is called 

hydrolysate. The energetic hydrolysate and 

agent hydrolysate are then combined and 

further processed in Step Four.

Step Four: Biotreatment

The hydrolysates generated in Step Three 

will go through the biotreatment process, 

which consists of large tanks containing 

microbes that digest and further break down 

the solution. Water released from the process 

will be recycled, leaving various salts and 

biosludge. Biosludge, which is made up of 

microbe waste products and other bacterial 

matter, will be filtered to remove water and 

shipped off-site to a permitted treatment, 

storage and disposal facility.

Step Five: Disposing of the Metal Parts

The final step of the destruction process is 

treating the weapon’s metal parts. Although 

the metal parts were cleansed of energetics 

and agent in Step One and Step Two, they 

still may contain energetics and agent and 

need to be decontaminated to a higher level. 

This level is called “5X,” a military standard 

of decontamination that ensures the metal is 

clean and safe for disposal. To reach this level 

of decontamination, the metal parts will be 

heated to 1,000 degrees Fahrenheit for 15 

minutes. The metal can then be recycled.