Impacts of nanobubbles on fouling control in phosphorus water distribution systems: Performance and mechanism investigation

Phosphorus water distribution system (PWDS) serves as an efficient carrier for phosphorus utilization across various fields. However, fouling formation commonly occurs in PWDS, leading to a range of technical and economic issues. This study evaluates the potential of nanobubbles (NBs) for controlling fouling, particularly phosphorus fouling, in PWDS. The results indicate that NBs inhibited fouling accumulation, resulting in an overall reduction of 8.7–42.9 %. Specifically, NBs appeared to adsorb cations (e.g., calcium ions) in the water due to their negative charged, resulting in a reduction of hydroxyapatite precipitation in fouling by 35.7–84.0 %. Meanwhile, NBs facilitated the transformation of calcite into loosely structured aragonite, which reduced the calcium precipitation content by 7.3–54.7 %. NBs can also induce particle aggregation and settling through enhanced coagulation, leading to a reduction in humic acid phosphate content by 31.5–40.7 % and silicate particle content by 10.8–47.9 %, respectively. In summary, this study elucidates how NBs influence and control phosphorus fouling as well as other types of fouling, providing valuable insights for the development of environmentally friendly and effective fouling control strategies.