控制ORP实现连续流反应器部分亚硝化稳定运行

利用ORP在线监控设备,研究了控制ORP值实现连续流部分亚硝化反应器稳定运行的可行性,并使出水水质满足厌氧氨氧化需求.结果表明,在亚硝氮与氨氮比值、温度和pH值恒定的条件下,反应器内ORP值波动主要由于DO浓度波动引起.在稳定的亚硝化系统中,当ORP值大于250mV左右时,反应器出水亚硝氮与氨氮比值大于2.1;当ORP值控制在150mV左右时,反应器出水亚硝氮与氨氮比值稳定在1.2~1.3之间.ORP值控制在120mV时,反应器出水亚硝氮与氨氮浓度比值为0.9~1.06.将ORP值控制在150mV时,随着进水氨氮浓度由300mg/L提高至813mg/L,反应器出水亚硝氮与氨氮比值基本维持在1.1~1.3之间.但随之增加的游离氨浓度易导致亚硝化菌活性抑制.因此,在低氧环境下ORP作为连续流部分亚硝化反应器亚硝化程度的控制指标,其灵敏度和精度明显优于DO监测设备.

Stable operation of partial nitritation by controlling ORP in continuous flow reactor

Stable operation of partial nitritation reactor by using ORP online monitoring equipment and the effluent satisfied the anammox process were studied in continuous flow reactor. The results showed that fluctuation of ORP value was mainly caused by the fluctuation of DO concentration, when the ratio of nitrite and ammonia, pH and temperature were constant in the reactor. In partial nitritation system, the ratio of nitrite and ammonia was greater than 2.1when the ORP value was greater than 250mV, which didn’t satisfy the ANAMMOX process demanded. The ratio of nitrite and ammonia was oscillating between 1.2 and 1.3when ORP value was controlled at 150mV. The ratio of nitrite and ammonia was oscillating between 0.9 and 1.06when ORP value was controlled at 120mV. The results also showed that the ratio of effluent nitrite and ammonia was oscillating between 1.1 and 1.3 with the influent ammonia concentration increased from 300mg/L to 813mg/L when ORP value was controlled at 150mV. However, increased free ammonium (FA) concentration inhibited ammonia-oxidizing bacteria activity. Sensitivity and accuracy of ORP were better than DO monitoring equipment as indicators to controlling partial nitritation reactor in low oxygen environment.