The use of pure oxygen for aeration in aerobic wastewater treatment: a review of its potential and limitations


The use of pure oxygen for aeration in aerobic wastewater treatment: a review of its potential and limitations

Skouteris, G.; Rodriguez Garcia, G.; Reinecke, S.; Hampel, U.

In aerobic wastewater treatment, aeration is the most critical element of the treatment system. It supplies microorganisms with the required amount of dissolved oxygen, maintains solids in suspension and controls membrane fouling, where needed. However, conventional activated sludge, where air is used, is limited to low-strength wastewaters as higher loadings or more intense feeds require both higher biomass and dissolved oxygen concentrations. In membrane bioreactors, despite being able to operate at higher biomass concentrations, their operation at high biomass concentrations and high organic loadings has not been tested. By replacing air with pure oxygen, oxygen transfer rates increase at lower flowrates. In this work, the potential and limitations of pure oxygen systems over conventional ones are reviewed. Also, the effect of the operational parameters or the mixed liquor characteristics on oxygen transfer is determined. Pure oxygen affects bacterial structure, controls foam formation, improves bacterial enzymatic activity and, in membrane bioreactors, leads to a better recovery of permeability after cleanings. It treats much higher loadings without compromising final effluent quality. Fine bubbles are more efficient in oxygen transfer due to their increased contact area. Nevertheless, pure oxygen aeration at times is not essential or it may generate effluent organic matter of a higher refractory character. We then recommend that it be used to applications where conventional aeration is not adequate.

Keywords: aerobic treatment; activated sludge; membrane bioreactor; pure oxygen; fine bubbles

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Publ.-Id: 30162