复合人工湿地中反硝化除磷作用的发生及其稳定性

将2套潮汐流人工湿地(T-A和T-B)构建为复合人工湿地(HCW),研究了HCW中反硝化除磷作用的发生及其稳定性.结果表明,当HCW按照两段进水潮汐流方式连续运行时,T-A的反硝化除磷性能和T-B的硝化性能均可得以强化,HCW随之具有理想的同步脱氮除磷效果;周期性补充碳源的磷移除操作可缓解T-A中磷素的过量积累,同时可提高反硝化聚磷菌(DPAOs)胞内聚β-羟基丁酸(PHB)的合成量,有助于HCW反硝化除磷效果的高效与稳定;当磷移除周期为30 d时,T-A在反硝化除磷过程中对TP与NOx--N的去除率分别为(97. 86±0. 70)%和(98. 29±2. 62)%,在磷移除过程中的磷素释放量、PHB合成量(以C/填料计)及补充碳源利用率分别为(1 486. 29±123. 25) mg、(4. 43±0. 57) mmol·g~(-1)和(94. 65±2. 66)%,HCW的磷素回收效率则为63. 97%.本研究为人工湿地同步脱氮除磷提供了新的思路,又进一步拓展了磷回收技术的研发和应用范围.

Occurrence of Denitrifying Dephosphatation in a Hybrid Constructed Wetland System and Its Stability

This study was conducted to explore the startup characteristics and stability of a hybrid constructed wetland (HCW) system with a denitrifying dephosphatation process, which was composed of two tidal flow-constructed wetlands (termed T-A and T-B). As the system was operated according to the two-time feeding tidal flow operation mode, denitrifying dephosphatation and nitrification could be respectively enhanced in T-A and T-B, and the HCW achieved ideal simultaneous denitrification and phosphorus removal effects when treating domestic sewage. The introduction of periodical carbon source supplements for phosphorus harvesting alleviated excessive phosphorus accumulation in T-A and increased the storage of PHB within denitrifying phosphate-accumulating organisms (DPAOs). Subsequently, a stable and efficient denitrifying phosphorus removal effect could be guaranteed to some extent as the HCW system was operated during the test. As the phosphorus harvesting cycle length was 30 d, the mean phosphorus recovery efficiency of the HCW system was 63.97% throughout the experiment. Regarding the typical cycle, the mean TP and NO_x^--N removal efficiencies of T-A could respectively achieve (97.86±0.70)% and (98.29±2.62)% during the denitrifying dephosphatation process, and the amounts of phosphorus release and PHB synthesis in T-A could also reach up to (1486.29±123.25) mg and (4.43±0.57) mmol·g^-1, respectively, during the phosphorus harvesting process. Meanwhile, the utilization rate of the supplementary carbon in the system was (94.65±2.66)%. To summarize, this study offers a new method for simultaneous denitrification and phosphorus removal in constructed wetlands, and expands the development and application range of phosphorus recovery processes.