基于低频振动强化物质传递过程的污水处理效能提升机制

考察了在低溶解氧(DO)条件下，低频机械振动(LFMVs)的加入对AO工艺脱氮效果的影响，从氧在气—液—固三相之间的传质效率、污泥絮体结构变化以及理化特性等方面进行了机理探究。结果表明：在(1.5±0.3) mg·L⁻¹的低DO浓度下，随着振动频率的增加，系统 COD和TN的去除率有所提高，在40 Hz时达到最高，平均去除率分别为94.86%和76.88%，相比于对照组R0分别提升了5.42%和23.46%，此时，气-液间氧传递系数增加约140.46%，液-固间氧扩散系数增加了255.26%;理化特性分析结果表明，气-液间氧传递系数的增加是由于LFMVs强化了液相的湍流流态造成的，而液-固间氧扩散系数的提升主要是因为LFMVs的引入降低了污泥粒径，增大了絮体间孔隙和刺激了胞外聚合物(EPS)的分泌。此外，经济性评估结果表明，荷载 LFMVs的AO反应器比传统模式AO反应器的综合用电量低0.12 kW·(m³·h)⁻¹。

The mechanism of strengthening sewage treatment efficiency based on the enhancement of substrate transfer efficiency: Low frequency mechanical vibrations application

In this study, the effect of low frequency mechanical vibrations (LFMVs) on the denitrification of AO process under the condition of low dissolved oxygen (DO) was investigated. Furthermore, the mechanism was explored from the aspects of oxygen mass transfer efficiency between “gas-liquid-solid” phases, sludge floc structure and physicochemical properties. The results showed that the removal rates of COD and TN in the system increased with the increase of the vibration frequency under the low DO concentration of (1.5±0.3) mg·L−1, they reached the highest values at the LFMVs of 40 Hz, and the corresponding average removal rates were 94.86% and 76.88%, respectively. Compared with the control group R0, the average removal rates increased by 5.42% and 23.46%, respectively. Meanwhile, the oxygen transfer coefficient between gas-liquid phases increased by approximately 140.46%, and the diffusion coefficient between liquid-solid phases increased by approximately 255.26%. The analyses of physical-chemical properties implied that the increment of oxygen transfer coefficient was attributed to LFMVs, which strengthened the turbulent flow pattern of liquid phase; while the increased diffusion coefficient was mainly caused by the introduction of LFMVs which reduced the sludge particle size, increased the pores between flocs, and stimulated the secretion of extracellular polymeric substance (EPS). In addition, the preliminary economic efficiency evaluation indicated that the comprehensive power consumption of AO reactor loaded with LFMVs was 0.12 kw·(m3 h)−1 lower than that of traditional AO reactor.