Developing a method to measure actualCTdistribution in an ozone contactor with a reactive tracer test

Abstract

AbstractCT (i.e. concentration × contact time) is one of the critical design and operational parameters to manage pathogen inactivation in ozone treatment. Ozone concentration and contact time are measured using an ozone sensor and a non-reactive tracer test, respectively. The actual CT value, however, might be different from this because of non-ideal flow in an ozone contactor. Hence, there is a need to investigate the spatial actual CT distribution. We developed a method to quantify CT distribution in an ozone contactor using a microsphere and three-dimensional laser-induced fluorescence technology. The dyed carboxylate microsphere, 50 nm in diameter, was used since its fluorescence decreased gradually according to CT without turbidity issues. The microsphere was fed continuously into an ozone contactor and reacted with ozone. After reaching steady state, planar laser sheets scanned a model ozone contactor and induced fluorescence light, which was captured with a high-speed video camera. The image was c...