The Pueblo Chemical Agent-Destruction Pilot Plant is preparing to increase its processing capacity by activating a third Immobilized Cell Bioreactor module.

“We have started to approach the maximum capacity of two ICBs when the plant is running really well,” said Dr. Patrick Sullivan, physical scientist and environmental manager, PCAPP.

Michael Abaie, Program Executive Officer, Assembled Chemical Weapons Alternatives, made the decision this fall to prepare PCAPP’s third Immobilized Cell Bioreactor module for operation in the next month to handle an expected increase in throughput at the plant. Nicholas Stamatakis III, deputy PEO, made the announcement Oct. 30 to the Colorado Chemical Demilitarization Citizens’ Advisory Commission.

Dr. James Earley, chief scientist, PCAPP, said seeding of the ICB module with microbes will begin in December and take approximately four to six weeks to acclimate the biomass to the hydrolysate feed.

“This provides for additional hydrolysate treatment capacity and reduces risk associated with hydrolysate storage, allowing for much-needed maintenance work to be performed on the other two modules to maintain and improve system performance over the long term,” Earley said.

Hydrolysate is the caustic wastewater resulting from the plant’s process of chemical neutralization used to destroy mustard agent in aging Army munitions.

Following confirmation of agent destruction, hydrolysate is treated in the reaction tanks – aerobic, fixed-film bioreactors packed with 2-inch polyurethane foam cubes where biological organisms reside. Biomass to feed the reactors is sourced from local sewage plants, although Sullivan said the reactors would eventually propagate with bacteria from the air inside them.