Aly Hassan Ashraf, Sorial George
Department of Civil and Environmental Engineering, University of Cincinnati, 765 Baldwin Hall, 2624 Clifton Avenue, Cincinnati, OH 45221-0071, United States.
Chemosphere. 2009 Jun;75(10):1315-21. doi: 10.1016/j.chemosphere.2009.03.008. Epub 2009 Apr 3.
Trickle bed air biofilters (TBABs) are suitable for treatment of relatively high volumes of volatile organic compounds due to their controlled environment. A laboratory-scale TBAB was used for the treatment of an air stream contaminated with benzene under different loading rates (LRs) ranging from 7.2 to 76.8 gm(-3)h(-1). The TBAB was operated at pH 7 and 25 degrees C. Consistent long-term performance of the benzene TBAB depends on various factors one of which is the excess amount of biomass accumulated within the bed. Three experimental strategies for biomass control were employed in the study: weekly backwashing for 1h, starvation (no benzene feed for a period of 2d/week) and stagnation (no benzene, air and nutrient flow for a period of 2d/week). The experimental plan was designed to investigate the long-term performance of the TBAB with emphasis on the empty bed resident time (EBRT), different benzene LRs, removal efficiency with TBAB depth, volatile suspended solids and carbon mass balance closure. For benzene loading up to 34.1gm(-3)h(-1), removal efficiency consistently over 98% was achieved. At the maximum LR 76.8 gm(-3)h(-1) the removal efficiency was still above 80% by utilizing stagnation strategy for 2d and gas flow switching once per week as means of biomass control. Backwashing once per week provided less efficient performance as compared to stagnation while starvation showed the worst performance. EBRT at 120 s provided the best performance while EBRT at 90 s showed slightly lower performance.
滴流床空气生物滤池（TBABs）由于其可控的环境，适用于处理相对大量的挥发性有机化合物。使用一个实验室规模的滴流床空气生物滤池来处理含有苯的气流，该气流的负荷率（LRs）范围为7.2至76.8克/立方米·小时。滴流床空气生物滤池在pH值为7和25摄氏度的条件下运行。苯滴流床空气生物滤池的长期稳定性能取决于多种因素，其中之一是滤床内积累的过量生物质。本研究采用了三种控制生物质的实验策略：每周反冲洗1小时、饥饿法（每周2天不进料苯）和停滞法（每周2天不进料苯、不进空气和营养物）。实验方案旨在研究滴流床空气生物滤池的长期性能，重点关注空床停留时间（EBRT）、不同的苯负荷率、随滴流床深度的去除效率、挥发性悬浮固体和碳质量平衡闭合情况。对于高达34.1克/立方米·小时的苯负荷，去除效率始终达到98%以上。在最大负荷率76.8克/立方米·小时时，通过采用每周2天的停滞法和每周切换一次气流作为生物质控制手段，去除效率仍高于80%。与停滞法相比，每周反冲洗一次的性能较差，而饥饿法的性能最差。120秒的空床停留时间表现最佳，而90秒的空床停留时间表现略低。
