Zhang Yu-Jun, Li Dong, Li Shuai, Zhang Jie
Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, China.
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
Huan Jing Ke Xue. 2020 Aug 8;41(8):3707-3714. doi: 10.13227/j.hjkx.202001032.
In this study, three SBR reactors R1, R2, and R3 were set up and operated using (A/O)-SBR gradient aeration, (A/O)-SBR constant aeration, and the conventional (A/O)-SBR mode, respectively. The nutrient removal performance and aerobic granular sludge characteristics under these aeration modes were explored using real municipal wastewater as the influent matrix. The experimental results revealed that for the R1, R2, and R3 particles during the stable period, the average removal rate of COD was 88.68%, 89.05%, and 88.96%, respectively, the average removal rate of TN was 76.97%, 71.99%, and 64.92%, respectively, the average removal rate of TP was 96.28%, 85.05%, and 78.97%, respectively, and the proportion of denitrifying phosphorus accumulating bacteria to phosphorus accumulating bacteria was 25.52%, 19.60%, and 12.77%, respectively. The results showed that the operation mode of anaerobic, aerobic, and anoxic was more conducive to the enrichment of denitrifying phosphorus accumulating bacteria (DPAOs), and that the gradient aeration was more enriched than the constant aeration mode, which is of great significance to low-intensity municipal domestic sewage treatment with an insufficient carbon source. At the same time, the dissolved oxygen in the aeration section of R1 was reduced step-by-step, which improved the simultaneous nitrification and denitrification rates of particles and the utilization rate of the internal carbon source, which was beneficial for the efficient removal of TN. The particle size of the three groups of reactors was 727.368, 815.072, and 895.041 μm respectively. As the transfer rate of the matrix decreased with particle size, the microorganisms in R2 and R3 may have caused anaerobic respiration to release harmful gas, thus damaging the particle structure, such that the particles in R2 and R3 were less dense than those in R1. In addition, the PN/PS values of R1, R2, and R3 were 6.31, 5.63, and 4.83, respectively, and the EPS content (in terms of VSS) was 103.97, 92.22, and 76.98 mg·g, respectively, at the time of particle stabilization, which revealed that the mode of intermittent gradient aeration was beneficial to stimulate the secretion of EPS. This was especially the case for the secretion of PN, which increased the PN/PS value, enhanced the cell hydrophobicity, and made the particles dense and stable.
在本研究中，设置了三个序批式反应器R1、R2和R3，分别采用（A/O）-SBR梯度曝气、（A/O）-SBR恒曝气和传统（A/O）-SBR模式运行。以实际城市污水作为进水基质，探究了这些曝气模式下的脱氮除磷性能及好氧颗粒污泥特性。实验结果表明，在稳定期，R1、R2和R3颗粒的COD平均去除率分别为88.68%、89.05%和88.96%，TN平均去除率分别为76.97%、71.99%和64.92%，TP平均去除率分别为96.28%、85.05%和78.97%，反硝化聚磷菌占聚磷菌的比例分别为25.52%、19.60%和12.77%。结果表明，厌氧、好氧、缺氧的运行方式更有利于反硝化聚磷菌（DPAOs）的富集，且梯度曝气比恒曝气模式更易富集，这对于碳源不足的低强度城市生活污水处理具有重要意义。同时，R1曝气段的溶解氧逐步降低，提高了颗粒的同步硝化反硝化速率和内碳源利用率，有利于TN的高效去除。三组反应器的颗粒粒径分别为727.368、815.072和895.041μm。由于基质的传质速率随粒径减小而降低，R2和R3中的微生物可能发生厌氧呼吸释放有害气体，从而破坏颗粒结构，使得R2和R3中的颗粒比R1中的颗粒密度小。此外，R1、R2和R3的PN/PS值分别为6.31、5.63和4.83，颗粒稳定时EPS含量（以VSS计）分别为103.97、92.22和76.98mg·g，这表明间歇梯度曝气模式有利于刺激EPS的分泌。对于PN的分泌尤其如此，其增加了PN/PS值，增强了细胞疏水性，使颗粒致密且稳定。
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