AWWA WQTC58933

CT-values of ozone bubble columns are often underestimated. By modelling the processes in an ozone bubble column, the ozone concentration profile can be determined and the CT-value can be calculated. Most of the processes inside a bubble column are well known, except for the rapid decay of ozone in water. It is found that the rapid decay can be modelled in relation to the decrease of ultraviolet (UV) absorbance (254 nm) and plays an important role in the prediction of the ozone profile in the bubble column. At Amsterdam Water Supply the contribution of the bubble column to the total CT-value is between 50 and 75% and can thus not be neglected. Includes 16 references, table, figures.