The Brine Reduction System (BRS) at the Pueblo Chemical Agent-Destruction Pilot Plant is working as designed, recovering water and recycling it back into the facility.

“The Brine Reduction System is doing what it was intended to do, which is recycling water and producing salt cakes,” said Paul Usinowicz, technical advisor, PCAPP.

After hydrolysate, the product of the mustard agent neutralization process, is treated by Immobilized Cell Bioreactors (ICB), biotreated effluent is pumped to the BRS for further processing and water recovery.

“Effluent from the biotreatment process consists of a high concentration of inorganic salt, residual thiodiglycol (TDG) and biomass,” said Usinowicz.

An 86-foot tall evaporator is used to boil water from the effluent and recover the water through condensation. The water is filtered and then recycled back into the plant.

“Approximately 85 to 90 percent of water is recovered and used in the ICBs and other areas of the plant,” Usinowicz said.

After evaporation, the concentrated brine is pumped to a crystallizer to further reduce the brine volume and to prepare the salt slurry for filtration. Salt crystals and other solids are filtered out and compressed, resulting in a filtered salt cake. The salt cakes are sampled for TDG and trace minerals and must pass a paint filter test for free water before being sent to a hazardous waste disposal facility, said Usinowicz.

“We have been able to show the Colorado Department of Public Health and Environment that we are meeting standards necessary for the recovered water to be used in the plant. This is a big accomplishment,” Usinowicz said.