BUBBLELESS FIBER AERATOR FOR SURFACE WATERS

The concept of bubbleless aeration with microporous hollow fiber membr anes is tested in a system that does not require external energy input , other than pressurizing oxygen, and is designed to add oxygen to sur face waters. Microporous hollow fiber membranes, potted at one end and connected to an oxygen supply, with the other end individually sealed , were installed vertically in a flume to simulate their performance i n rivers and lakes. The gas-filled fibers tend to rise vertically due to buoyancy, while bending downstream due to the drag force exerted by the flowing water. When operated at differential pressures of up to 3 atm during the experiments, this cross-flow configuration resulted in high rates of gas transfer with no supplemental energy input. Gas-tra nsfer coefficients were found to depend on cross-flow velocity and int ernal gas pressure for the tested fibers. Two possible applications fo r passive hollow fiber membrane aeration are considered, and contraste d with traditional methods of aeration.