A system and process for disinfecting rooms such as health care facility rooms with an oxygen/ozone mixture is described, which is effective to combat “superbugs” such as Clostridium difficile (C. difficile); E. coli; Pseudomonas aeruginosa; methicillin-resistant Staphylococcus aureus (MRSA); and vancomycin-resistant Enterococcus (VRE). In preferred embodiments, hydrogen peroxide is additionally used. The system and process is effective to destroy bacteria deposited on surfaces as biofilm, and, accompanied by physical agitation such as jet nozzle outlets, is effective to disinfect carpet, drapery and similar absorbent and porous surfaces.