Abstract:Aiming at the characteristics of poor biochemical properties and high chroma of citric acid biochemical tail water, in this study, MnOx-CeOx composite bimetal oxide was used as a catalyst, and adopts ozone catalytic oxidation-moving bed biofilm reactor (MBBR) combined process was used to deeply treat the citric acid biochemical tail water. The results showed that at the ozone dosage of 30 mg·L?1, the ozone intake of 1 m3·h?1, and the hydraulic retention time of 60 min, the removal rate of oxygen-consuming organic pollutants (calculated as COD) in the biochemical tail water of citric acid by the ozone catalytic system was 35.4%, the average COD decreased from 110 mg·L?1 to 70 mg·L?1, the average chromaticity decreased from 90 times to 15 times, and the chromaticity removal rate was 83.3%; the BOD5/COD of effluent increased from 0.08 to 0.23, and its biodegradability was significantly improved. In the MBBR system with a gas-water ratio of 4∶1 and a hydraulic retention time of 6 h, the effluent COD further decreased to 32~40 mg·L?1, and the chromaticity maintained at about 10 times. In addition, the combined process has good operating stability and low overall operating cost (0.79 yuan·t?1). The results of this study showed that the ozone catalytic oxidation-MBBR combined process had a good comprehensive treatment effect on the biochemical tail water of citric acid, which provides experimental basis and theoretical support for the upgrading and transformation of the sewage treatment system in the citric acid industry. Key words:ozone catalytic oxidation/ catalyst/ moving bed biofilm reactor/ citric acid biochemical tail water.
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College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China Received Date: 2021-04-01 Accepted Date: 2021-07-05 Available Online: 2021-09-15 Keywords:ozone catalytic oxidation/ catalyst/ moving bed biofilm reactor/ citric acid biochemical tail water Abstract:Aiming at the characteristics of poor biochemical properties and high chroma of citric acid biochemical tail water, in this study, MnOx-CeOx composite bimetal oxide was used as a catalyst, and adopts ozone catalytic oxidation-moving bed biofilm reactor (MBBR) combined process was used to deeply treat the citric acid biochemical tail water. The results showed that at the ozone dosage of 30 mg·L?1, the ozone intake of 1 m3·h?1, and the hydraulic retention time of 60 min, the removal rate of oxygen-consuming organic pollutants (calculated as COD) in the biochemical tail water of citric acid by the ozone catalytic system was 35.4%, the average COD decreased from 110 mg·L?1 to 70 mg·L?1, the average chromaticity decreased from 90 times to 15 times, and the chromaticity removal rate was 83.3%; the BOD5/COD of effluent increased from 0.08 to 0.23, and its biodegradability was significantly improved. In the MBBR system with a gas-water ratio of 4∶1 and a hydraulic retention time of 6 h, the effluent COD further decreased to 32~40 mg·L?1, and the chromaticity maintained at about 10 times. In addition, the combined process has good operating stability and low overall operating cost (0.79 yuan·t?1). The results of this study showed that the ozone catalytic oxidation-MBBR combined process had a good comprehensive treatment effect on the biochemical tail water of citric acid, which provides experimental basis and theoretical support for the upgrading and transformation of the sewage treatment system in the citric acid industry.