SBR工艺交替硝化反硝化运行方式的可行性研究

将交替好氧、缺氧运行方式应用于间歇式污水处理系统(SBR工艺),分别在原水碱度充足和碱度不足情况下考察该运行方式的可行性．结果表明：原水碱度充足时,交替硝化反硝化的运行方式在处理效率上并没有体现出优势;原水碱度不足时,交替硝化反硝化与传统硝化反硝化相比,处理效率与出水水质明显提高,出水氨氮可以达到检测水平．当原水碱度的不足量低于所需碱度理论值的1／3时,采取交替硝化反硝化,无需额外补充碱度就可以达到原水碱度充足情况下的处理效率．如果原水碱度的不足量已超过1／3,采取交替硝化反硝化可最大限度节省额外投加碱度的量,降低处理成本,是一种理想的运行方式．

Process evaluation of alternating aerobic-anoxic process applied in SBR for nitrogen removal

Feasibility of alternating aerobic-anoxic process (AAA process) applied in SBR system for nitrogen removal was investigated. Under the sufficient influent alkalinity, AAA process did not have an advantage over one aerobic-anoxic (OAA) cycle on treatment efficiency because microorganism had an adaptive stage at alternating aerobic-anoxic transition, which would prolong the total cycling time. On the contrary, AAA process made system control more complicated. Under the deficient influent alkalinity, when compared to OAA, AAA process improved treatment efficiency and effluent quality, and NH₄⁺-N in effluent reached the detection limitation. In the nitrification, the average stoichiometry between alkalinity consumption and ammonia oxidation is calculated to be 7.07mg CaCO³/mg NH₄⁺-N. In the denitrification, the average stoichiometry between alkalinity production and NO₃^--N reduction is about 3.57mg CaCO³/mg NO-N. As a result, half of the alkalinity previously consumed during the aerobic nitrification can be recovered during the subsequent anoxic denitrification period. That was why the higher treatment efficiency in AAA process was obtained without the supplement of bicarbonate alkalinity. If the lack of alkalinity in influent was less than 1/3 of that needed, there is no need for external alkalinity addition and treatment efficiency was same as that under the sufficient influent alkalinity. Even if the lack of alkalinity in influent was more than 1/3 of that needed, AAA process was an optimal strategy because it reduced the external alkalinity addition and saved the operational cost.