The sparging of aerobic biological processes with air canresult in the emission of odors and volatile organic compounds (VOCs)that exceed acceptable rates. Because emission rates for many VOCs fromsparged bioreactors are equilibrium limited and not mass transferlimited, VOC emission rates are directly proportional to the volumetricrate at which air bubbles are added to the bioreactor. A means ofreducing the volumetric gas flow rates is to supply a portion or all ofthe required oxygen in a bubbleless manner. That portion of the oxygensupplied in a bubbless manner would be emission-free, because no bubblesare added to the bioreactor.While is can be demonstrated that the use of bubbleless in-pipe membraneoxygenators provide significant operating cost savings by reducing VOCemissions, the in-pipe module are not suited for large scaleapplications, have high energy requirements, and may be fouled with theflocculent and filamentous materials found in activated sludge systems.The overall goal of the proposed work is to develop a low-cost means ofdissolving oxygen without bubbles into aeration basin to reduce VOCemissions. In particular, the study will collect data needed for therational design of a bubbleless oxygen dissolution technology that usedunconfined membranes in a mixed tank reactor.
