消除内回流液中溶解氧对反硝化过程影响的对策

Countermeasures for Eliminating Influence of Dissolved Oxygen in Internal Reflux Liquid on Denitrification Process

内回流液中的溶解氧浓度偏高是活性污泥法中普遍存在的问题,为了简单有效地消除内回流液中溶解氧对反硝化过程的影响,针对典型的传统A/O工艺和多段进水A/O工艺,考察了有限提升进水C/N值、导入内源耗氧过程以及调整进水碳源组分等策略的可行性。结果表明,在传统A/O工艺中,有限提高进水C/N值对消除内回流液中的溶解氧有一定作用,但在多段进水A/O工艺中此消除作用受到削弱;在两种工艺中,导入内源耗氧过程均对内回流液中溶解氧有明显的消除作用,能确保缺氧段进水碳源不被溶解氧消耗,使反硝化正常进行;进水碳源组分对内回流液中溶解氧的消除有一定影响,慢速可生物降解有机物含量过高,在传统A/O工艺中对内回流液中溶解氧的消除不利,对TN的去除有负面影响,但在多段进水A/O工艺中,由于慢速可生物降解有机物在好氧条件下不会被完全降解,而且会跟随内回流液转移到缺氧段,这对消除内回流液中的溶解氧是有利的。

The high concentration dissolved oxygen in the internal reflux liquid is a common problem in the activated sludge process.In order to eliminate the influence of dissolved oxygen in internal reflux liquid on denitrification process simply and effectively,the feasibility of strategies such as limited increase of C/N ratio of the influent,introduction of endogenous oxygen consumption process and adjustment of influent carbon source components were investigated in typical traditional A/0 process and step-feeding A/0 process.The limited increase of C/N ratio had a certain effect on eliminating the dissolved oxygen in the internal reflux liquid of the traditional A/0 process,but the effect was weakened in the step-feeding A/0 process.The introduction of endogenous oxygen consumption process had an obvious effect on elimination of the dissolved oxygen in the internal reflux liquid of the two processes.The strategy could ensure that the carbon source in the anoxic section was not consumed by the dissolved oxygen,so that the denitrification could proceed normally.The carbon source components in the influent had a certain effect on the elimination of dissolved oxygen in the internal reflux liquid.Excessively high content of slowly biodegradable organic matter was detrimental to the elimination of dissolved oxygen in the internal reflux liquid of the traditional A/0 process and had a negative impact on the removal of TN.However,the slowly biodegradable organic matter would not be completely degraded under aerobic conditions and would be transferred to the anoxic section along with the reflux in the step-feeding A/O process,which was beneficial to eliminate dissolved oxygen in the internal reflux liquid.