Kizhisseri Mohamed Ibrahim, Sakr Marwa, Maraqa Munjed, Mohamed Mohamed M
Civil & Environmental Engineering Department, United Arab Emirates University, Al Ain, 15551, United Arab Emirates.
National Water and Energy Center, United Arab Emirates University, Al Ain, 15551, United Arab Emirates.
Heliyon. 2025 Jan 16;11(4):e41687. doi: 10.1016/j.heliyon.2025.e41687. eCollection 2025 Feb 28.
Aeration is widely employed in water and wastewater treatment systems. Aerobic wastewater treatment relies significantly on maintaining adequate levels of dissolved oxygen (DO) in water to ensure optimal quality of treated wastewater. Conventional aeration systems, however, require considerable energy usage due to the ineffectiveness of oxygen mass transfer to the treated water. Adopting micronanobubbles (MNB) can improve this limitation due to their high gas-liquid mass transfer rates. This study used micro-nano air bubbles to experimentally determine the volumetric oxygen transfer coefficient ( ), standard oxygen transfer rate (SOTR), and standard oxygen transfer efficiency (SOTE) of an MNB aeration system and compared them with those of a conventional aeration system. The MNB generation and bubble analysis results showed that the MNB concentration was 10^8-10^9 bubbles/mL, with an average diameter ranging from 100 nm to 2 μm. MNB aeration achieved a maximum of 0.4204 min at an airflow rate of 0.5 ± 0.1 LPM for a 25 L water volume, which was notably higher than the corresponding observed values for the conventional aeration system. Furthermore, MNB aeration demonstrated superior SOTR and SOTE values across all airflow rates tested, achieving a maximum of 139.78 mg/h and 54.33 %, respectively. The findings of this study suggest that MNB aeration, with its enhanced mass transfer characteristics, offers a more energy-efficient alternative to conventional aeration methods, with the potential for higher oxygen transfer rates and improved wastewater treatment performance. Results also indicate that optimal operation at specific airflow rates can increase oxygen transfer efficiency by two folds compared to conventional aeration systems.
曝气在水和废水处理系统中被广泛应用。好氧废水处理在很大程度上依赖于维持水中充足的溶解氧（DO）水平，以确保处理后废水的最佳质量。然而，由于氧气向处理水中的传质效率低下，传统曝气系统需要大量能源消耗。采用微米纳米气泡（MNB）可以改善这一局限性，因为它们具有高气液传质速率。本研究使用微纳米气泡通过实验确定MNB曝气系统的体积氧传递系数（ ）、标准氧传递速率（SOTR）和标准氧传递效率（SOTE），并将其与传统曝气系统的相应参数进行比较。MNB生成和气泡分析结果表明，MNB浓度为10^8 - 10^9个气泡/毫升，平均直径范围为100纳米至2微米。对于25升的水量，在气流速率为0.5±0.1升/分钟时，MNB曝气的最大 为0.4204分钟，这明显高于传统曝气系统的相应观测值。此外，在所有测试的气流速率下，MNB曝气都表现出优异的SOTR和SOTE值，分别达到最大值139.78毫克/小时和54.33%。本研究结果表明，具有增强传质特性的MNB曝气为传统曝气方法提供了一种更节能的替代方案，具有更高的氧传递速率和改善废水处理性能的潜力。结果还表明，与传统曝气系统相比，在特定气流速率下的优化运行可使氧传递效率提高两倍。
