Research
| Title： | Study on the breakage mechanism of algal floc in coagulation flow field |
|---|---|
| First author： | Ding, Wenting; Lin, Zhe; Wu, Xingqiang; Zhang, Xuezhi; Zhang, Haiyang |
| Journal： | SEPARATION AND PURIFICATION TECHNOLOGY |
| Years： | 2025 |
| DOI： | 10.1016/j.seppur.2025.132655 |
| Abstract： | Coagulation is a widely adopted pretreatment technique for enhancing algae-water separation efficiency. However, the breakage behavior of algal flocs during the algae-water separation process has not been understood clearly, which hinders the development of strategies to prevent floc breakage during separation. This study investigates the breakage behavior of algal flocs in vortex flow fields. By employing high-speed imaging to track the breakage of algal flocs and integrating CFD simulations of the flow field, the relationship between floc breakage behavior and the characteristics of both floc structure and vortex flow fields is established to elucidate the mechanisms behind floc breakage in hydraulic flow fields. The results indicate that algal floc breakage is proportional to vortex intensity, when the vortex intensity increases from 3.7 to 78.5 cm(2).s(-1), the ratio of the mean size of flocs after to before breakage decreases from 0.966 to 0.500. Floc breakage is not merely proportional to floc size; generally, larger flocs are more prone to breakage. Interestingly, within flocs of size 0 1500 mu m, the greatest breakage occurs when the floc size approximates the vortex size, often resulting in even more breakage than in larger flocs. This is because when the floc and vortex sizes are similar, flocs are more likely to enter the vortex center, where significant energy differences between the center and periphery subject the flocs to multidirectional tearing, leading to greater breakage. This study enhances the understanding of algal floc breakage behavior in separation flow fields and provides theoretical guidance for the design of algae-water separation equipment. |
