The AroBIOS bioscrubber system removes odors and gaseous contaminants such as ammonia, hydrogen sulfide and other reduced sulfur compounds without using expensive chemicals or costly incineration methods. It provides low gas retention times; an easy access, low-profile design; nondegradable AroPAC biomedia; easy installation, factory preassembly with mixed flow exhauster; no expensive chemical costs; and environmentally safe byproducts.