微孔曝气系统氧传质规律及能耗模型研究

Fine-pore diffuser system has become the most commonly used aeration technology in municipal wastewater treatment plants for its high efficiency and low energy consumption. However, oxygen transfer of fine-pore diffuser is affected by wastewater quality and sludge properties, therefore the actual oxygen transfer efficiency (OTE) is lower than the theoretical value (quantified by wastewater effect coefficient alpha factor). During long-term operation, diffuser pores are easily clogged by the attachment and growth of biofilm and precipitation of inorganic salts, both effects reduce OTE (quantified by OTE loss coefficient F). This project will focus on predicting OTE and fouling tendency of diffuser in continuous flow reactor and sequencing batch reactor. Pilot-scale process will be established on-site and fine-pore diffuser aeration performance test device will be developed. Through on-site tests in local wastewater treatment plant, factors affecting oxygen transfer of the fine-pore diffuser system will be determined. Fouling mechanism of the fine-pore diffuser in the long-term operation is analyzed. Effects of wastewater quality, sludge properties, and microbial community on OTE and diffuser fouling are systematically studied. Prediction models of alpha and F are constructed, and combined with activated sludge model and theoretical OTE curve, to establish a complete OTE and energy consumption prediction model for fine-pore aeration systems. The key factor affecting oxygen transfer is identified. Solutions for aeration performance improvement are proposed. The results of this project will provide useful information for performance evaluation, precise control and operation optimization of fine-pore aeration process.

微孔曝气因其高效低耗成为当前污水处理厂中最常用的曝气技术。但微孔曝气器的氧传质受污水水质、污泥性质的影响，导致实际氧利用率低于理论氧利用率（用影响系数alpha量化）。在长期运行过程中，微孔曝气器表面的气孔很容易因为生物膜附着生长或者无机盐沉积而堵塞，导致氧利用率下降（用损失系数F量化）。本申请项目将针对连续流和序批式反应器两种工艺面临的氧利用率与曝气器污染趋势预测问题，构建现场中试实验装置，并开发微孔曝气器充氧性能测试系统。通过污水厂实地实验探明微孔曝气系统氧传质的影响因素，分析长期运行中曝气器的污染机制，污水水质、污泥性质、微生物种群对氧利用率与曝气器污染影响的系统研究并量化，构建alpha和F的预测模型，与活性污泥模型、理论氧利用率关系曲线耦合，建立完善的氧利用率和能耗预测模型，识别影响氧传质的关键因子，提出改善曝气性能的解决方案，以指导微孔曝气工艺的性能评价、精确控制和运行优化。

微孔曝气因其高效低耗成为当前污水处理厂中最常用的曝气技术。本项目针对连续流和序批式活性污泥两种工艺中应用的微孔曝气系统面临的氧传质效率与污染趋势预测问题，构建现场中试实验装置，通过污水处理厂实地实验探明微孔曝气系统氧传质的影响因素；分析了长期运行中微孔曝气器的污染物累积的动态变化；系统研究了污水水质、污泥性质、微生物种群、运行模式、运行时长对氧传质效率与曝气器污染的影响，建立了完善的曝气系统氧传质效率和能耗预测模型；对微孔曝气器上的污染物进行了提取和分析表征，评估了清洗对曝气性能恢复和能耗的影响，提出了改善曝气性能的解决方案。研究结果表明，氧亲和菌、丝状菌和胞外聚合物分泌菌倾向于在微孔曝气器表面聚集；综合的能耗模型提高了曝气系统氧传质效率、供气量、能耗的预测准确度，可作为微孔曝气系统性能监测和定期评价的工具，对精确控制、优化运行、节能起到重要指导作用；在本项目研究结果的基础上制定有针对性的预处理策略和必要的清洗方案，可确保微孔曝气系统的长期可持续运行。