Determination of the water quality correction factor α using a tracer gas method

The purpose of this work is to evaluate, in a bubble column pilot using different wastewaters, the water quality correction factor α, defined as the ratio between the volumetric mass transfer coefficient klaO2 in the wastewater and klaO2 in clean water. The characteristic of this paper is that the volumetric mass transfer coefficient klaO2 is determined using propane as a tracer gas as it is neither produced nor consumed in biological reactors. Three types of water were tested in a bubble column pilot: raw wastewater, the supernatant of mixed liquor from an aeration tank and treated water after the secondary settler. The first results show that the alpha factor depends on water quality and seems to be linked to organic carbon and surface tension. The separation of the parameters kl and a allowed us to understand the variations of the alpha factor.