碳源变化对降解2,4-D的好氧颗粒污泥性能及形态的影响

Effects of Carbon Sources Changes on the Property and Morphology of 2,4-D Degrading Aerobic Sludge Granules

在长期运行的序批式生物反应器(SBR)中,考察了以葡萄糖和2,4-二氯苯氧乙酸(2,4-D)为混合碳源培养的好氧颗粒污泥在转换为2,4-D唯一碳源废水后,其形态、结构及对目标污染物去除功能的变化.结果表明,基质转换为2,4-D单一碳源后,好氧颗粒污泥仍保持了对目标污染物高效的去除能力.当进水2,4-D浓度为361～564mg/L,其去除率为99.2%～100%,COD平均去除率达到85.6%.混合碳源向2,4-D单一碳源转换对原好氧颗粒结构产生一定破坏作用,使其发生部分解体,粒径由513μm下降到302μm.但好氧颗粒污泥良好的耐负荷冲击使其保持了颗粒主体,通过一段时间适应调整后能够重新聚集生长,最终获得能够利用2,4-D为唯一碳源生长并具有良好沉降性(SVI20～40mL/g)的好氧颗粒污泥,粒径为489μm.扫描电子显微镜(SEM)观察结果表明,混合碳源转向单一碳源使好氧颗粒生物相丰富度降低.

This study investigated the changes of the morphology,structure,and capability of removing the target contamination of the aerobic granules pre-cultured with mixed substrates of glucose and 2,4-dichlorophenoxyacetic acid（2,4-D） in a long-time running sequence batch reactor（SBR）,when the carbon source transformed into the sole carbon source of 2,4-D.Results showed that when the substrate turned to the sole carbon source of 2,4-D,the aerobic granules still maintained a strong degradation ability to the target contamination;a 2,4-D removal percentage of 99.2%-100% and an average COD removal rate of 85.6% were achieved at the initial 2,4-D concentration of 361-564 mg /L.Carbon source transformation caused certain damages to the original aerobic granule structure,made some parts of granules disintegrated,and led to granule size decline from 513 μm to 302 μm.However,those granules maintained the main body,re-aggregated and grew after a period of adaptation due to their strong resistance to toxicity.Aerobic granules capable of utilizing 2,4-D as the sole carbon source with a good settling ability（SVI 20-40 mL /g） and a mean diameter of 489μm were finally obtained in this study.Scanning electron microscope（SEM） observation showed that the diversity of granule microbial species was declined when turned to the sole carbon source.