氯酸钾对两段式PN/A工艺处理低氨氮废水的影响

Effect of Potassium Chlorate on Two‑stage Partial Nitritation/Anammox for Treating Low Ammonia Nitrogen Wastewater

为考察添加氯酸钾对两段式部分亚硝化/厌氧氨氧化(PN/A)生物膜反应器处理低氨氮废水的影响,首先在低氨氮浓度下建立并采取不同措施维持部分亚硝化,然后在添加氯酸钾条件下降低温度并将PN段出水作为A段进水耦合运行。结果发现,在进水NH_(4)^(+)-N为60 mg/L、氮负荷为1.44 kgN/(m^(3)·d)、温度为20℃、曝气量为90 mL/min的条件下,连续添加1 mmol/L氯酸钾可成功实现PN反应器的稳定运行,NO_(2)^(-)-N积累率高达88.72%,出水NO_(2)^(-)-N/NH_(4)^(+)-N值在1.0~1.32之间,满足A段反应器进水氮基质要求,其原因在于PN反应器主要功能区生物膜和活性污泥中AOB主导菌丰度分别为7.70%和9.60%,NOB主导菌丰度分别为1.07%和0.79%,因而使氨氧化速率(AUR)与亚硝酸盐氧化速率(NUR)的比值分别为4.52和8.61。PN段出水进入A段反应器后,氮去除负荷由初始的0.85 kgN/(m^(3)·d)降至0.07 kgN/(m^(3)·d),表明添加氯酸钾的部分亚硝化出水对后续厌氧氨氧化产生了破坏性影响。因此,氯酸钾并不适宜作为PN/A工艺中NOB的抑制剂。

In order to investigate the effect of potassium chlorate(KClO_(3))addition on the treatment of low ammonia nitrogen wastewater in a two‑stage partial nitritation/anammox(PN/A)biofilm reactor,the PN at low ammonia nitrogen concentration was firstly established and maintained under different conditions.Finally,the temperature was lowered under the condition of KClO_(3) addition and the PN effluent was coupled as anammox influent.The results showed that the stable operation of PN reactor could be achieved successfully by adding 1 mmol/L KClO_(3) continuously under the conditions of influent NH_(4)^(+)-N of 60 mg/L,nitrogen load of 1.44 kgN/(m^(3)·d),temperature of 20℃and aeration rate of 90 mL/min.The nitrite accumulation rate was as high as 88.72%,and the ratio of NO_(2)^(-)-N to NH_(4)^(+)-N in effluent was kept between 1.0 and 1.32,which could meet the influent nitrogen substrate requirements of the anammox reactor.This could be ascribed to that the abundance of AOB‑dominant bacteria in biofilm and activated sludge in the main functional area of the PN reactor were 7.70%and 9.60%respectively,while the abundance of NOB‑dominant bacteria were 1.07%and 0.79%respectively,leading the ratios of AUR to NUR were 4.52 and 8.61 respectively.After the PN effluent entered the anammox reactor,the nitrogen removal load decreased from 0.85 kgN/(m^(3)·d)to 0.07 kgN/(m^(3)·d),which indicated that the PN effluent with KClO_(3) addition had a destructive effect on the subsequent anammox reaction.Therefore,KClO_(3) is not suitable to inhibit NOB in PN/A process.