Use pyrosis-alkali solution-oxidization process as previous treatment

and use hydrolysis acidification-BIOFOR as succeed treatment of isocyanate wastewater. The experiment prove that the COD concertration of wastewater can be degraded by 80% after the previous treatment

and can be degraded by 93% after the succeed treatment. The water quality of the final effluent in this system meet the first grade of integrate wastewater discharge standard（GB 8978-1996）.