低温投加短程硝化污泥下城市污水SPN/A工艺运行特性

Operation characteristics of the SPN/A process for municipal wastewater under low temperature shortcut nitrification sludge

以城市污水为研究对象,考察低温条件下通过生物添加强化氨氧化菌(AOB)活性,并进一步提高短程硝化-厌氧氨氧化一体化(SPN/A)工艺脱氮效果的可行性.平行运行2个序批式反应器(SBR)SBR1与SBR2,在间歇曝气条件下运行,控制温度由30℃梯度下降至15℃(30,27,24,21,18,15℃),随后逐步回升至30℃.在降温与升温过程中,向SBR2中定期投加短程硝化污泥强化AOB活性,SBR1作为空白试验不进行投加.结果表明,30℃时SBR1与SBR2在不外加短程硝化污泥的条件下均可成功启动并稳定运行,脱氮效果均良好;温度降至15℃时,SBR1与SBR2出水NH_4^+-N分别为36.38,33.10mg/L,总氮去除率分别为30.72%与35.76%,2个反应器脱氮效果均变差,SBR2较SBR1抗低温能力较强;梯度升温至30℃时,SBR1与SBR2总氮去除率分别升至52.43%与63.60%.通过考察SBR1与SBR2菌群活性可知,2个反应器的菌群活性均随着温度降低而降低,但SBR2的AOB丰度活性均高于SBR1;温度回升阶段,2个反应器的菌群活性有所升高,其中SBR2亚硝酸盐氧化细菌(NOB)活性受到抑制持续降低,推测这是因为SBR2中的AOB活性得到强化后,产生更多的亚硝酸盐,厌氧氨氧化菌(Anammox)可获得基质增多,造成Anammox活性丰度较高,所以SBR2脱氮效果相对较好.因此,在低温条件下通过生物添加强化SPN/A系统中AOB活性,可提高系统抗温度冲击能力,利于系统脱氮效果的恢复.

In this study, feasibility of enhancing ammonia-oxidizing bacteria (AOB) activity by biological addition under the condition of temperature fluctuation and further improving the denitrification effect of Single-stage Partial Nitrification and Anammox (SPN/A) process in municipal wastewater treatment was investigated. Two sequencing batch reactors (SBR) SBR1 and SBR2 were operated in intermittent aeration. The controlled temperature was reduced from 30 gradient to 15 (30, 27, 24, 21, 18 ℃℃, 15 ), and then gradually increased to 30 .Shortcut nitrification sludge was regularly added to SBR2 ℃℃ to enhance AOB activity during the cooling and heating process, and SBR1was used as the control process. The results showed that SBR1 and SBR2 started successfully and run stably without shortcut nitrification sludge, and the nitrogen removal efficiency of SBR1 and SBR2 was good at 30. When t ℃ he temperature was dropped to 15℃, the concentration of the ammonia nitrogen in effluents of of SBR1 and SBR2 were 36.38mg/L and 33.10mg/L, and the total nitrogen removal efficiency was 30.72% and 35.76%, respectively. Both rectors' efficiency become worse in low temperature settings, SBR2 shown a better cold resistance performance. When temperature were increased gradient back to 30℃,the total nitrogen removal rates of SBR1 and SBR2 increased back to 52.43% and 63.60% respectively. The activity of bacteria in SBR1 and SBR2 decreased with the decrease of temperature, but the AOB activity of SBR2 was higher than that of SBR1. During the temperature rising stage, the activity of bacteria in SBR1 and SBR2 both increased, and the inhibition of nitrite-oxidizing bacteria (NOB) activity in SBR2 was continuously decreasing. The better denitrification performance of SBR2 was suspected because when the AOB activity of SBR2 was enhanced, more nitrite was produced, and the substrate of Anammox was increased, which resulted in the higher activity abundance of Anammox. Therefore, it was conclude that the AOB activity in SPN/A system can be enhanced by biological addition at low temperature, which can improve the resistance performance of the system to the temperature shocks and facilitate the recovery of denitrification capacity.