降低负荷以提高反硝化颗粒污泥的稳定性

在上流式污泥床反应器（USB）内，接种好氧活性污泥，以甲醇为碳源，NO-3为电子受体，经过40多d培养，得到良好的反硝化颗粒污泥，粒径2～3 mm，MLSS为36 g/L，氮去除速率和COD去除速率分别在0.15 g NO₃-N/(g VSS·d)和0.8 g COD/(g VSS·d)。当负荷提高至6.44 g NO₃-N/(L·d)继续运行1周后，观察到反应器内颗粒污泥出现上浮，浓度降低，颗粒粒径多数在3～5 mm，外观呈乳白色。为恢复反应器稳定运行，当负荷降至3.86 g NO₃-N/(L·d)时，上浮现象减轻，当负荷降至2.57 g NO₃-N/(L·d)时，上浮现象消失，颗粒污泥密度由不稳定时的1.0018 g/cm³提高到1.0126 g/cm³，颗粒粘连现象基本消失，污泥氮去除速率在0.19 g NO₃-N/(g VSS·d)，连续运行30 d，系统保持稳定。分析认为，颗粒污泥表面微生物生长速度过快是导致不稳定的主要因素，较长的泥龄有利于系统稳定。

Enhancing stability of denitrifying granular sludge by decreasing loading

Well-formed denitrifying granular sludge was obtained within 40 days,when aerobic activated sludge was inoculated with methanol as a carbon source in upflow sludge bed reactor(USB).The diameter of the mature sludge was 2 to 3 mm.MLSS of the USB was 36 g/L.It had a high sludge removal loading of N and sludge.At this time,granular sludge was white and had a diameter of 3～5 mm.Then reduced the volume loadcreased from 1.0018 g/cm3,which was measured under unstable condition,to 1.0126 g/cm3.Single granules'settleability was enhanced,adhesion of granules disappeared,N sludge removal loading was 0.19 g N03-N/(gthe surface of granule is the main factor of instability,long solid retention time contributes to the system stability.