废水回用已成为应对全球水资源短缺的重要手段。然而，复合污垢对废水供水系统构成了重大挑战。本研究探索了利用纳米气泡（NBs）控制复合污垢的新方法，研究了三种类型NBs（氧气、氮气和氦气）、六种氧气NBs浓度以及两种模式（预防和去除）对复合污垢的控制效应。结果显示，与未采用NBs组相比，NBs有效地减轻了复合污垢，包括生物污垢、无机结垢和颗粒污垢。具体而言，NBs的自坍缩产生了羟基自由基，它可氧化废水中的有机物并灭杀微生物。NBs的负电荷表面将CaCO₃的结晶形态从方解石转变为较疏松的文石，减少了离子沉淀的可能性。此外，NBs可充当污水中颗粒之间的气体“桥梁”，增强了将颗粒从废水中去除的能力。尽管氧气NBs具有比氮气和氦气NBs更强的防污能力，但低浓度（约5%）的氧气NBs增加了污垢总量。此外，虽然NBs抑制了污垢的生长，但它难以去除已经附着的污垢。本研究结果表明NBs的应用将解决各种废水供水系统的污垢问题，以应对全球水资源短缺的挑战。

The increasing demand for wastewater treatment has become a notable trend for addressing global water scarcity. However, fouling is a significant challenge for wastewater distribution engineering systems. This study provides an approach using nanobubbles (NBs) to control fouling. The antifouling capacities of three types of NBs, six oxygen concentrations, and two application procedures (prevention and removal) are investigated. The results show that NBs effectively mitigate composite fouling—including biofouling, inorganic scaling, and particulate fouling—in comparison with the non-NBs group. More specifically, hydroxyl radicals generated by the self-collapse of NBs oxidize organics and kill microorganisms in wastewater. The negatively charged surfaces of the NBs transform the crystalline form of CaCO₃ from calcite to looser aragonite, which reduces the likelihood of ion precipitation. Furthermore, the NBs gas-liquid interfaces act as gas “bridges” between colloidal particles, enhancing the removal of particles from wastewater. Lastly, although the NBs inhibit the growth of fouling, they do not significantly remove the already adhered fouling in non-NBs treated groups. This study anticipates that the application of NBs will address the significant fouling issue for various wastewater distribution engineering systems in order to meet the global challenge of sustainable water supplies.

・Nanobubbles (NBs) effectively mitigated biofouling, scaling, and particulate fouling.

・The control mechanisms of NBs for various foulants were revealed.

・The NBs antifouling were investigated using different gas types, doses and strategies.

・Practical measures for the successful engineering application of NBs were proposed.