水性聚氨酯(WPU)包埋活性污泥的亚硝化反应

Nitritation with immobilized active sludge by waterborne polyurethane(WPU)

以水性聚氨酯(WPU)为载体利用活性污泥制作成包埋固定化颗粒,置于序批式反应器(SBR)中在22.5~25.5℃、DO=2.0 mg·L^(-1)条件下,逐步提高进水氨氮浓度(100~200 mg·L^(-1))驯化13 d后包埋颗粒亚硝化率(NAR)成功实现至90.98%。运行30 d后NAR保持在95%以上,小试分析表明NOB活性受抑制,亚硝化处于稳定状态。然后调节曝气量,研究不同DO对亚硝化稳定性的影响。提高DO至4.5 mg·L^(-1),NAR仍保持在83.99%,说明活性污泥经包埋固定后对DO有较好的耐受性。通过扫描电镜(SEM)对反应器内包埋颗粒进行了微观分析。结果表明,包埋颗粒内接种污泥中细菌形态多样,含长杆、短杆及球状菌,随着运行的延续,细菌形态呈现了向短杆状球状转变的态势。

Active sludge was immobilized on a waterborne polyurethane（ WPU） gel and subsequently used to inoculate a sequencing batch reactor（ SBR）. After 13 days,the nitrite accumulation rate（ NAR） was 90. 98%when the operating dissolved oxygen（ DO） was at 2. 0 mg·L-1,increasing the influx of ammonia（ from 100 to200 mg·L-1） and maintaining temperature at 22. 5 to 25. 5 ℃. Batch tests showed that the growth of nitrite-oxidizing bacteria（ NOB） was inhibited and NAR stayed above 95% over 30 days,thus a rapid and stable nitritation was achieved. The effect of different concentrations of DO on the stability of nitritation was investigated by adjusting aeration. NAR remained at 83. 99% when increasing DO to 4. 5 mg · L-1,indicating a good tolerance of changes in DO by immobilized active sludge. Scanning electron microscope（ SEM） photographs of the immobilized cells indicated that the bacteria within the immobilized sludge shifted from a diverse morphology towards spherical and small rod-shaped clusters.