Comprehensive physicochemical treatment can also be adopted for fluorescent penetrant inspection wastewater. Processes including pH adjustment, coagulation and flocculation, air flotation sedimentation, filtration and adsorption are applied to remove penetrants, emulsifiers, oil contaminants and suspended solids from the wastewater, as well as degrade organic matter. The treated effluent can meet Class 1, Class 2 and Class 3 discharge standards specified in the national standard GB 8978-2005, steadily complying with environmental pollution discharge regulatory requirements.