A Dense-Phase Latex Rubber Tube and a Polyporous Propylene Hollow-Fiber Membrane Module (HFMM) Were Investigated for Control of Benzene-Contaminated Gas Streams. the Abiotic Mass Flux Observed through the Latex Tube Was 3.9-13 Mg/(Min·m2) for 150 Ppm of Benzene at Various Gas and Liquid Flow Rates, While a 100-Fold Lower Mass Flux Was Observed in the HFMM. after Seeding with an Aromatic-Degrading Culture Enriched from Activated Sludge, the Observed Removal Was 80% of 150 Ppm, Corresponding to a Mass Flux of 45 Mg/(Min·m2). the Observed Mass Flux through the HFMM during Biofiltration Also Rose, to 0.4 Mg/(Min·m2). Because the HFMM Had a 50-Fold Higher Surface Area Than the Latex Tube, the Observed Benzene Removal Was 99.8%. Compared to Conventional Biofilters, the Two Reactors Had Modest Elimination Capacities, 2.5-18 G/(M3·h) in the Latex Tube Membrane Bioreactor and 4.8-58 G/(M3·h) in the HFMM. Although the HFMM Had a Higher Elimination Capacity, the Gas-Phase Pressure Drop Was Much Greater.