厌氧/缺氧并联的AAO工艺生物脱氮除磷试验研究

Removal efficiency of nitrogen and phosphorus by an anaerobic/anoxic parallel AAO process

针对传统AAO工艺因生物环境矛盾及碳源竞争而导致脱氮除磷效率不高的现象,提出将厌氧段与缺氧段并联设置、后接好氧段形成“厌氧/缺氧并联的AAO工艺”思路.采用小型实验装置,分别以人工配水和实际污水为原水进行连续运行实验,探讨了厌氧池污泥回流比、缺氧池污泥回流比、混合液回流比等操作条件对该工艺脱氮除磷效果的影响,研究了该工艺脱氮除磷特征及微生物群落变化特征.结果表明:在实验最佳操作条件下,该工艺对TN、NH4^+-N、TP的平均去除率分别达到94.1%、96.4%、96.2%;厌氧段与缺氧段并联设置后,各反应区的微生物群落发生明显变化,与传统AAO工艺相比,活性污泥中反硝化及除磷相关微生物群落的占比明显增大,并联设置有效缓解了脱氮菌群与除磷菌群互相竞争的问题,有利于功能菌群的积累和脱氮除磷效率的提高.

AAO is a traditional process for the removal of nitrogen and phosphorus from wastewater.However,the nitrogen and phosphorus removal efficiency of this technology is insufficient because of the biological environment conflicts and carbon source competition.Herein,a new anaerobic/anoxia parallel AAO process(P-AAO),the anaerobic stage is arranged in parallel with the anoxic stage and followed by the aerobic stage,was proposed for improving the removal efficiency of the nitrogen and phosphorus.The effect of anaerobic tank sludge reflux ratio,anoxic tank sludge reflux ratio,and mixture reflux ratio on the treatment efficiency was investigated using artificial and actual sewage as raw water,and the results showed that the average removal rate of TN,NH4^+-N and TP was 94.1%,96.4% and 96.1%,respectively,under the optimal operating conditions.High-throughout sequencing analysis revealed that the proportion of denitrifying and phosphorus-removing microbial communities was significantly increased both in the anaerobic and anoxic stage,compared with that in a traditional AAO process.In addition,the competition between the denitrifying and phosphorus-removing bacteria would be alleviated in the P-AAO process,which is beneficial to the accumulation of functional flora and the improvement of nitrogen and phosphorus removal efficiency.