脱氮副球菌DYTN-1高效去除污水中的总氮

Efficient removal of total nitrogen from sewage by Paracoccus denitrificans DYTN-1

利用脱氮副球菌的异养硝化和好氧反硝化一体的特点,测定其去除污水中总氮(total nitrogen,TN)的效果。污水中TN在24 h内可被游离状态的脱氮副球菌DYTN-1由100 mg/L降低至20 mg/L以下。为了提高对TN的去除效率,对游离细胞进行了固定化,以不同的二价金属阳离子作为交联剂对脱氮副球菌细胞进行细胞固定化。结果表明:固定化的细胞DYTN-1可以在8 h内使得污水中TN的含量由100 mg/L降低至20 mg/L以下,达到了国家排放标准。正交试验优化后,12批次污水中大部分批次达标所用时间在3 h以内。固定化的最佳条件为:海藻酸钠(sodium alginate,SA)含量为3%,SA与菌种比例为1∶1,氯化钡浓度为0. 1 mol/L,固定化时间为5 h,固定化后的脱氮副球菌DYTN-1可以显著提高废水中的总氮的去除效率。

Biological method is an effective way to remove nitrogen pollutants from wastewater. The efficiency of Paracoccus denitrificans DYTN-1 to remove total nitrogen (TN) from sewage was determined using its characteristics of heterotrophic nitrification and aerobic denitrification. The TN in the sewage could be reduced from 100 mg/L to less thaN20 mg/L withiN24 h by free P. denitrificans DYTN-1 cells. To improve the removal rate of TN, P. denitrificans DYTN-1 was immobilized by different divalent metal ions as cross-linking agents. The results showed that immobilized DYTN-1 could reduce the TN content in wastewater from 100 mg/L to less thaN20 mg/L within 8 h, which met the national emission standard. After optimization, most of 12 batches of wastewater met the standard within 3 h. The optimal condition to immobilize P. denitrificans DYTN-1 was as follows: 3% sodium alginate (SA), the ratio of SA to strain was 1∶1, 0.1 mol/L barium chloride, and immobilized for 5 h. In conclusion, immobilized P. denitrificans DYTN-1 can significantly improve its efficiency to remove TN from wastewater.