内置缺氧区的改良型Pasveer氧化沟工艺脱氮除磷性能研究

Research on improving biological nutrient removal by a modified Pasveer oxidation ditch with additional internal anoxic zones

针对传统Pasveer氧化沟内缺氧段碳源难以被反硝化菌充分利用的问题,采用内置缺氧区的改良型Pasveer氧化沟工艺,并进行中试规模实验研究,考察了不同内回流比条件下系统的脱氮除磷效果。研究结果表明,在内回流比为200%的情况下,系统的脱氮除磷效果最好,出水TN和TP的浓度分别降至12.7 mg/L和0.34 mg/L,去除率分别达到61.9%和89.2%。内置缺氧区的设置一方面能使有限的碳源充分用于反硝化,另一方面,促使了反硝化吸磷现象的发生,这使得系统在进水碳源较低的情况下仍能够获得上佳的脱氮除磷效果。但是,过高的内回流比会导致好氧区亚硝酸盐的积累,这对生物除磷是不利的。

In order to solve the problem that carbon source could not be fully utilized by denitrifiers in anoxic zones of the Pasveer oxidation ditch （OI）） , a pilot-scale Pasveer OD modified with presence of additional internal anoxic zones was adopted to investigate the nutrient removal process through varying the internal recycle ratio in this study. The results showed that when the internal recycle ratio was 200% , the system obtained the highest nutrient removal efficiency. The effluent TN and TP contents were 12.7 mg/L and 0. 34 mg/L, respec- tively, with the removal efficiencies remarkably improving to 61.9% and 89.2%. The results indicated that addi- tional internal anoxic zones could optimize the utilization of avail carbon source from the anaerobic outflow for denitrification and stimulate denitrifying phosphorus removal process, which were both beneficial for biological nitrogen and phosphorus removal when treating wastewater with carbon source limited. However, the excess internal recycle would cause nitrite to accumulate in the aerobic zone, which seems to be harmful to biological phosphorus removal.