生物转鼓过滤器反硝化净化NO的效率研究

Study on removal efficiency of nitric oxide in rotating-drum biofilter

采用自行研制的生物转鼓过滤器(RDB)反硝化净化NO。结果表明,在实验温度为25～30℃、pH为7.0～7.5、转鼓转速为1.0r/min、空床停留时间(EBRT)为86.40s、营养液用量为5.0L、营养液更换频率为0.2L/d的条件下,RDB在30d内完成挂膜;RDB稳定运行期间,当NO进气质量浓度为90～433mg/m3时,NO去除率维持在42.9%～85.2%,平均去除负荷为10.40g/(m3.h);转鼓转速决定了生物膜表面的更新速率和液膜厚度,当转速为0.5r/min时,NO去除率达到最大值(75.0%);将营养液用量控制在1.3～3.0L较为合理;EBRT是决定反硝化效率的重要因素,当EBRT为345.60s时,NO去除率不受其进气浓度的影响,且去除率高达95%以上,当EBRT为43.20s、NO进气质量浓度从98mg/m3增加到1095mg/m3时,NO去除率从62.5%下降到30.7%,当进气负荷为50.00g/(m3.h)时,NO去除负荷达到最大值(27.50g/(m3.h))。

Self made rotating-drum biofilter （RDB） was employed for purification of NO contained waste gas. Under the conditions of 25-30 ℃, pH of 7.0-7.5, rotating speed of 1.0 r/min, Empty Bed Residence Time（EBRD） of 86.40 s, nutrient solution of 5.0 L and fresh nutrient solution replacement ratio of 0.2 L/d, the process of biofilm training was finished after 30 days of running. RDB presented high denitrificaion capability in stable operation, when the inlet NO concentration was 90-433 mg/m^3 , NO removal efficiency ranged from 42.9% to 85.2% and average removal capacity was 10.40 g/（m^3 ·h）. The optimum operating conditions were drum rotating speed of 0.5 r/min and nutrient solution of 1.3-3.0 L. EBRT was the key factor in determining the denitrification efficiency of RDB, when the EBRT was 345.60 s, the NO removal rate of RDB was stable at 95% with varying of inlet NO concentration. However, when the EBRT was changed to 43.20 s, NO removal rate decreased from 62.5 % to 30.7 % with NO inlet concentration increasing from 98 mg/m^3 to 1 095 mg/m^3. In this experiment, the maximum elimination capacities of RDB reached 27.50 g/（m^3 · h） and it was a rather high value in comparison with the previous reported results, while the higher capacities could be achieved by optimizing the reactor configuration and operational parameters.