The development of an ozone contact tank simulation model

Anglian Water (AW) operates ozone facilities as a treatment stage at all its surface water sources. The main ozone treatment stage takes place after filtration in multi-compartment concrete ozone contactors. These have two stages of ozone gas injection via ceramic bubble diffusers and two decay stages. To enable AW to gain a better understanding of the contact tank performance, a computer simulation model incorporating Computational Fluid Dynamics and ozone process modeling was developed in conjunction with AEA Harwell. The model was calibrated using site data from Alton WTW. The results were used to improve the tank design and to optimize the ozone dose; this resulted in improved performance and a significant reduction in ozone dose.