Abstract:The identical three sequencing batch reactors (SBRs) were set up in order to illuminate the effects of Fe3O4@SiO2 on the performances and kinetics of nitrogen and phosphorus removal in the sequencing batch reactor (SBR). 0.5 g·L?1 nano-Fe3O4 and 0.5 g·L?1 nano-Fe3O4@SiO2 were added to SBR 2 and SBR 3, respectively, and compared with the control group of SBR 1 without addition of magnetic material. The results showed that nano-Fe3O4@SiO2 had significant influence on the sludge property in SBR. After 20 d running, the sludge in SBR 3 presented complete structure, fullness and compactness, and its particle size was mainly distributed in 0.3~1.0 mm, obvious granulation phenomenon occurred. However, no obvious granular sludge appeared in SBR 1, a few sludge granules with non-uniform distribution formed in SBR 2. Moreover, Fe3O4@SiO2 could promote the secretion of exopolysaccharides(EPS) and improve sludge sedimentation performance. On the 70th day, the contents of PN and PS in SBR 3 were 318.89 mg·g?1 and 28.51 mg·g?1, respectively, and sludge volume index(SVI) was 35.22 mL·g?1, and the sludge performance was better than that of SBR 1 and SBR 2. In the aspect of pollutants removal, compared with reactor 1, the removal efficiencies of total nitrogen(TN) and total phosphorus(TP) in SBR 2 and SBR 3 increased by 10.80% and 15.20%, 9.40% and 12.40%, respectively, and SBR 3 showed the highest performance on nitrogen and phosphorus removal. In addition, the removal rates of nitrogen and phosphorus in SBR 3 were significantly higher than those in SBR during the typical circle; during 240 min, the TN removal rates in SBR 1 and SBR 3 were 4.56 mg·(L·h)?1 and 5.84 mg·(L·h)?1, respectively, the TP removal rates in SBR 1 and SBR 3 were 0.44 mg·(L·h)?1,0.51 mg·(L·h)?1, respectively. Therefore, the silica-based magnetic particles (nano-Fe3O4@SiO2) could improve its dispersion in water and contact with sludge, then significantly promoted the formation of granular sludge through enrichment on the sludge surface by magnetic aggregation, adsorption functions, and was conducive to the interception and adsorption of the microbes of nitrogen and phosphorus removal. The removal efficiency and rate of nitrogen and phosphorus were improved. This study provides a theoretical basis for further exploring the effect of magnetic nanomaterials on the denitrification and phosphorus removal performance of SBR activated sludge. Key words:silica-based magnetic particles/ sequencing batch activated sludge process/ sludge sedimentation performance/ nitrogen and phosphorous removal.
图1SBR实验装置流程示意图 Figure1.Schematic diagram of experiment device
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College of Resources and Environment, Chengdu University of Information Technology, Chengdu 610225, China Received Date: 2019-06-09 Accepted Date: 2019-11-14 Available Online: 2020-03-25 Keywords:silica-based magnetic particles/ sequencing batch activated sludge process/ sludge sedimentation performance/ nitrogen and phosphorous removal Abstract:The identical three sequencing batch reactors (SBRs) were set up in order to illuminate the effects of Fe3O4@SiO2 on the performances and kinetics of nitrogen and phosphorus removal in the sequencing batch reactor (SBR). 0.5 g·L?1 nano-Fe3O4 and 0.5 g·L?1 nano-Fe3O4@SiO2 were added to SBR 2 and SBR 3, respectively, and compared with the control group of SBR 1 without addition of magnetic material. The results showed that nano-Fe3O4@SiO2 had significant influence on the sludge property in SBR. After 20 d running, the sludge in SBR 3 presented complete structure, fullness and compactness, and its particle size was mainly distributed in 0.3~1.0 mm, obvious granulation phenomenon occurred. However, no obvious granular sludge appeared in SBR 1, a few sludge granules with non-uniform distribution formed in SBR 2. Moreover, Fe3O4@SiO2 could promote the secretion of exopolysaccharides(EPS) and improve sludge sedimentation performance. On the 70th day, the contents of PN and PS in SBR 3 were 318.89 mg·g?1 and 28.51 mg·g?1, respectively, and sludge volume index(SVI) was 35.22 mL·g?1, and the sludge performance was better than that of SBR 1 and SBR 2. In the aspect of pollutants removal, compared with reactor 1, the removal efficiencies of total nitrogen(TN) and total phosphorus(TP) in SBR 2 and SBR 3 increased by 10.80% and 15.20%, 9.40% and 12.40%, respectively, and SBR 3 showed the highest performance on nitrogen and phosphorus removal. In addition, the removal rates of nitrogen and phosphorus in SBR 3 were significantly higher than those in SBR during the typical circle; during 240 min, the TN removal rates in SBR 1 and SBR 3 were 4.56 mg·(L·h)?1 and 5.84 mg·(L·h)?1, respectively, the TP removal rates in SBR 1 and SBR 3 were 0.44 mg·(L·h)?1,0.51 mg·(L·h)?1, respectively. Therefore, the silica-based magnetic particles (nano-Fe3O4@SiO2) could improve its dispersion in water and contact with sludge, then significantly promoted the formation of granular sludge through enrichment on the sludge surface by magnetic aggregation, adsorption functions, and was conducive to the interception and adsorption of the microbes of nitrogen and phosphorus removal. The removal efficiency and rate of nitrogen and phosphorus were improved. This study provides a theoretical basis for further exploring the effect of magnetic nanomaterials on the denitrification and phosphorus removal performance of SBR activated sludge.