溶解氧对长距离输水管道水质影响

为保证长距离输水管道输送水水质，采用管道模拟反应器考察了溶解氧（DO）对输水管道水质影响以及曝气充氧后水质恢复情况。结果表明：DO降低影响氨氮（NH₄⁺-N）的去除，DO浓度越低越不利于NH₄⁺-N的去除，且曝气充氧后恢复越缓慢，DO=0.5 mg·L^-1和DO=1.5 mg·L^-1的反应器在运行95 h后，NH₄⁺-N去除率分别由90%降到21%和85%，曝气充氧54 h和3 h后恢复；DO浓度降低导致亚硝酸氮（NO₂^--N）积累明显增加，DO浓度越低，NO₂^--N的积累越严重，且曝气充氧后恢复越缓慢，DO=0.5 mg·L^-1的反应器在运行95 h后，出水NO₂^--N由0.02 mg·L^-1增加到0.354 mg·L^-1，曝气充氧54 h后恢复，DO=1.5 mg·L^-1的反应器在运行32 h后，出水NO₂^--N达到最大值0.112 mg·L^-1，曝气充氧4 h后恢复；DO浓度降低使水中UV₂₅₄升高，DO=0.5 mg·L^-1和DO=1.5 mg·L^-1的反应器在运行2 h后，出水UV₂₅₄分别增加了70.8%和20.8%，均在运行32 h后恢复，且曝气充氧后保持稳定。因此，DO对长距离输水管道水质具有重要影响，可采用DO实现对水质的调控。

Effect of dissolved oxygen on water quality in long distance pipeline transportation

To ensure the water quality in long distance pipeline transportation, the influence of dissolved oxygen (DO) on water quality and recovery process after aeration oxygenation were studied in a pipeline reactor that could simulate this long distance pipeline transportation. The results showed that the decrease of DO could reduce the removal of ammonia nitrogen (NH₄⁺-N), and the lower DO concentration was the more unfavorable removal of NH₄⁺-N, the slower recovery after aeration oxygenation was. The removal rate of NH₄⁺-N declined from 90% to 21% and 85% after reactor run 95 h at DO=0.5 mg·L^-1 and 1.5 mg·L^-1, and the recovery after aeration oxygenation took 54 h and 3 h respectively. The accumulation of nitrite nitrogen (NO₂^--N) increased significantly as DO reduced, and the lower DO concentration was the more favorable accumulation of NO₂^--N, the slower recovery after aeration oxygenation was. At DO=0.5 mg·L^-1 nitrite nitrogen increased from 0.02 mg·L^-1 to 0.354 mg·L^-1 after reactor run 95 h, and the recovery after aeration oxygenation took 54 h. While the maximum value of nitrite nitrogen was 0.112 mg·L^-1 after reactor run 32 h at DO=1.5 mg·L^-1, and the recovery after aeration oxygenation took only 4 h. The decrease of DO concentration could lead to rise of UV₂₅₄. UV₂₅₄ increased by 70.8% and 20.8% after reactor run 2 h at DO=0.5 mg·L^-1 and 1.5 mg·L^-1, respectively, and both recovery took 32 h, and then it was relatively stable after aeration oxygenation. Therefore, DO is of important impact on water quality in long distance pipeline transportation, and could used for the regulation of water quality.