The Pueblo Chemical Agent-Destruction Pilot Plant (PCAPP) is preparing to use a process similar to that of an industrial wastewater treatment plant to treat the product of its chemical agent neutralization process.

“We remove the mustard agent from the munitions and neutralize it, resulting in a product called hydrolysate,” said Rick Holmes, Bechtel Pueblo Team project manager. “Once the agent destruction is confirmed, we store the hydrolysate in a storage tank and when enough is accumulated, biotreatment can begin.”

After munitions are robotically disassembled and the mustard agent is drained, the neutralized product will be treated in the plant’s biotreatment system. Utilizing Immobilized Cell Bioreactors (ICB), microbes will break down dissolved organic compounds such as thiodiglycol (TDG), said Dr. Yakup Nurdogan, a wastewater treatment expert at PCAPP.

“The ICB process is an aerobic fixed-film wastewater treatment process designed to oxidize TDG, the main ingredient in hydrolysate,” Dr. Nurdogan said

The goal of the biotreatment system is to break down TDG to simpler molecules such as carbon dioxide, water, sulfuric acid, and intermediate organic compounds. Biotreated effluent will be treated in the Brine Reduction System, which uses evaporation and crystallization processes to recover water for recycling and reuse in the plant, Dr. Nurdogan said.

The plant began processing munitions on Sept. 7 and it will take approximately two months before enough hydrolysate is produced to feed the microbes, said Dr. Pat Sullivan, environmental manager, PCAPP.