A decontamination system includes a spraying system in an enclosed chamber for application of a decontamination fluid having a liquid carrier, such as water, and an enzyme-based decontaminating chemical additive. The additive contains an organophosphorus compound-degrading enzyme. The decontamination system also includes a fluid flow control system that ensures delivery of decontamination fluid to spray nozzles. The fluid flow control system features a recirculation system that collects runoff from the chamber and transports the collected runoff to a decontamination reactor. The decontamination reactor removes contaminants from the collected runoff liquid and permits the collected runoff liquid to be reused for further decontamination, thus taking advantage of the catalytic characteristic of the enzyme.
