Liu Xiemin, Jin Jin, Gao Yu, Zhou Zheng, Zhang Feng, Geng Jiao
Key Laboratory of Mesoscopic Chemistry of Ministry of Education (MOE), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
Key Laboratory of Mesoscopic Chemistry of Ministry of Education (MOE), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
Water Res. 2025 Feb 15;270:122852. doi: 10.1016/j.watres.2024.122852. Epub 2024 Nov 24.
Efforts have been made to enhance ozone utilization efficiency and reduce energy costs in ozone-aerated wastewater treatment. Microbubbles, characterized by their large interfacial area and efficient gas-liquid mass transfer, are extensively used to boost ozone utilization. However, generating microbubbles demands significant energy, and their actual efficiency requires careful evaluation due to the absence of universal strategies for designing microbubbles with optimal performance. This study established an integrated mathematical model for ozone oxidation in wastewater treatment, based on comprehensive ozone reaction kinetics, microbubble mass transfer control theory, and mass conservation equations for gas-liquid phase components. Simulation results showed a pollutant removal rate with a prediction error of less than 20 %, confirming the model's reliability. Further analysis revealed that although the initial mass transfer rate of 0.5 mm bubbles is lower than that of 0.1 mm bubbles, the total mass transfer quantity is reduced by only 8.7 %. This suggests that an optimal bubble diameter can balance mass transfer efficiency and energy consumption. Based on this finding, we integrated ozone production and bubble generation energy consumption to develop a regulation mechanism for optimizing bubble diameter, minimizing total energy consumption while meeting target removal rates. Results indicate that the optimal bubble diameter is closely related to water depth: as depth increases, the optimal bubble diameter also increases. At a depth of 2.1 meters, the optimized bubble diameter reduces energy consumption by 33.5 % and 16.2 % compared to millimeter-sized and 100-micron bubbles, respectively. Sensitivity analysis shows that total energy consumption is more sensitive to changes in specific ozone energy consumption, while variations in bubble generation energy remain relatively stable. These results underscore the feasibility of using the proposed model to guide energy-efficient bubble size selection.
人们已做出努力来提高臭氧利用效率，并降低臭氧曝气废水处理中的能源成本。微气泡具有较大的界面面积和高效的气液传质特性，被广泛用于提高臭氧利用率。然而，产生微气泡需要大量能量，并且由于缺乏设计具有最佳性能微气泡的通用策略，其实际效率需要仔细评估。本研究基于综合的臭氧反应动力学、微气泡传质控制理论和气液相组分的质量守恒方程，建立了废水处理中臭氧氧化的综合数学模型。模拟结果表明，污染物去除率的预测误差小于20%，证实了该模型的可靠性。进一步分析表明，虽然0.5毫米气泡的初始传质速率低于0.1毫米气泡，但总传质量仅减少了8.7%。这表明存在一个最佳气泡直径，可以平衡传质效率和能源消耗。基于这一发现，我们综合了臭氧产生和气泡产生的能源消耗，开发了一种调节机制来优化气泡直径，在满足目标去除率的同时将总能耗降至最低。结果表明，最佳气泡直径与水深密切相关：随着深度增加，最佳气泡直径也会增加。在2.1米的深度下，与毫米级气泡和100微米气泡相比，优化后的气泡直径分别降低了33.5%和16.2%的能耗。敏感性分析表明，总能耗对特定臭氧能耗的变化更为敏感，而气泡产生能耗的变化相对稳定。这些结果强调了使用所提出的模型指导节能气泡尺寸选择的可行性。
