School of Water Conservancy & Environmental Engineering, Zhengzhou University, Zhengzhou, 450001, China.
Environ Sci Pollut Res Int. 2021 May;28(18):23386-23394. doi: 10.1007/s11356-020-12297-4. Epub 2021 Jan 14.
Nitrite accumulation usually occurred when domesticating the idle aerobic activated sludge. A sequencing batch reactor (SBR) was used to investigate whether the short-cut nitrification sludge could be cultivated using the idle sludge as inoculated sludge. The results showed that the nitrification process consisted of three stages. In the first stage, the activity of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) were very low with almost no nitrification performance. In the second stage, the activity of AOB started to recover with the effluent NH-N gradually decreased to 0.29 mg L, while NOB was alternately inhibited by free ammonia (FA), free nitrous acid (FNA), and nitrite. The effluent NO-N was mainly NO-N with an average nitrite accumulation ratio of 74.00%. In the third stage, the nitrification altered from short-cut nitrification to complete nitrification, and the nitrification kinetics of AOB and NOB were both well-fitted to the Monod equation (R > 0.92). The variations of effluent pH and ORP between cycles could indicate the recovery stage of the nitrifying ability. Through monitoring the curves of effluent pH and ORP, when the domestication process is between the pH peak and ORP plateau, the short-cut nitrification sludge could be cultivated. This study revealed the mechanism of nitrite accumulation during the domestication of long-term idle aerobic activated sludge, and established a control strategy to accelerate the domestication.
亚硝酸盐积累通常发生在闲置好氧活性污泥驯化过程中。采用序批式反应器（SBR）研究了能否利用闲置污泥作为接种污泥来培养短程硝化污泥。结果表明，硝化过程分为三个阶段。在第一阶段，氨氧化菌（AOB）和亚硝酸盐氧化菌（NOB）的活性很低，几乎没有硝化性能。在第二阶段，AOB 的活性开始恢复，出水 NH-N 逐渐降至 0.29mg/L，而 NOB 则被游离氨（FA）、游离亚硝酸（FNA）和亚硝酸盐交替抑制。出水中的 NO-N 主要是 NO-N，平均亚硝酸盐积累率为 74.00%。在第三阶段，硝化作用从短程硝化转变为完全硝化，AOB 和 NOB 的硝化动力学均很好地符合 Monod 方程（R>0.92）。循环过程中进出水 pH 和 ORP 的变化可以指示硝化能力的恢复阶段。通过监测进出水 pH 和 ORP 的曲线，当驯化过程处于 pH 峰值和 ORP 平台之间时，可以培养短程硝化污泥。本研究揭示了长期闲置好氧活性污泥驯化过程中亚硝酸盐积累的机制，并建立了一种加速驯化的控制策略。
