Pilot Plant Study on High Concentration Food Additives Wastewater Treatment

According to the characteristics of food additives wastewater with great variety of quality, complicated composition, the processes of hydrolysis acidification-contacting oxidation-catalytic ozonization-biological aerated filter(BAF) is applied. Through this processes, the COD of effluent can fall below 100 mg/L from about 2000 to 7000 mg/L of influent. The minimum COD of effluent is 33 mg/L. Quality of effluent is up to the integrated wastewater discharge standard. After treatment of hydrolysis acidification process, the COD of wastewater is from 5290 mg/L to 2323 mg/L. Besides, it can change the molecular structure of compounds rupture them into smaller molecules, and improve their biodegradability, so making the wastewater more easily treated by contacting oxidation process. The average COD of contacting oxidation process´s effluent is 268 mg/L. The catalytic ozonization preoxidation process could improve the biodegradability of wastewater, whose BOD5/COD ratio was from 0.3 up to 0.44 when the COD was removed 45%. The pilot plant study showed that the hydrolysis acidification processes and catalytic ozonization (using ceramsite enwraped by MnO₂ as catalysts)-biological aerated filter processes are the key elements of the processes treating with high concentration food additives wastewater stably meeting water quality of discharging limit.