Kan Eunsung, Deshusses Marc A
Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, USA.
Biotechnol Bioeng. 2005 Nov 5;92(3):364-71. doi: 10.1002/bit.20619.
Continuous operation of a new bioreactor for air pollution control called the foamed emulsion bioreactor (FEBR) has been investigated. The effect of several liquid feeding strategies was explored. The FEBR exhibited high and steady toluene removal performance (removal efficiency of 89%-94%, elimination capacity of 214-226 g/m3h at toluene inlet concentration of 1 g/m3) for up to 360 h, when 20% of the culture was replaced every 24 h by a nutrient solution containing 4 g/L of potassium nitrate as a nitrogen source. This feeding mode supported a high cell activity measured as INT reduction potential and active cell growth without being subject to nitrogen limitation. In comparison, operating the FEBR with the liquid in a closed loop (i.e., batch) resulted in a significant decrease of both the removal efficiency of toluene and INT reduction activity. Operation with feeding active cells resulted in stable and effective treatment, but would require a significant effort for mass culture preparation. Therefore, the continuous process with periodically feeding nutrients was found to be the most practical and effective operating mode. It also allows for stable operation, as was shown during removal of low concentration of toluene or after pollutant starvation. Throughout the study, INT reduction measurements provided insight into the process. INT reduction activity data proved that under normal operating conditions, the FEBR performance was limited by both the kinetics and by mass transfer. Overall, the results illustrate that engineered gas-phase bioreactors can potentially be more effective than conventional biofilters and biotrickling filters for the treatment of air pollutants such as toluene.
对一种名为泡沫乳液生物反应器（FEBR）的用于空气污染控制的新型生物反应器的连续运行进行了研究。探索了几种液体进料策略的效果。当每24小时用含有4 g/L硝酸钾作为氮源的营养液替换20%的培养物时，FEBR在长达360小时内表现出高且稳定的甲苯去除性能（在甲苯入口浓度为1 g/m³时，去除效率为89%-94%，去除容量为214-226 g/m³·h）。这种进料模式支持以INT还原电位衡量的高细胞活性和活跃的细胞生长，且不受氮限制。相比之下，在闭环（即间歇）模式下运行FEBR会导致甲苯去除效率和INT还原活性显著下降。进料活性细胞的操作可实现稳定有效的处理，但大规模培养制备需要付出巨大努力。因此，发现定期进料营养物的连续过程是最实用有效的操作模式。它还能实现稳定运行，如在去除低浓度甲苯期间或污染物饥饿后所示。在整个研究过程中，INT还原测量为该过程提供了深入了解。INT还原活性数据证明，在正常操作条件下，FEBR的性能受动力学和传质的限制。总体而言，结果表明，工程气相生物反应器在处理甲苯等空气污染物方面可能比传统生物滤池和生物滴滤池更有效。
