A case study on the automatic ozone dose control system based on the ozone decay rate in a full-scale advanced water treatment plant

Abstract

Recently, a growing concern about algae-origin taste and odor in drinking water made it possible to introduce ozone and granular activated carbon (GAC) processes to large-capacity (more than 300,000 m3/d) water treatment plants in the Han River area in South Korea. Especially, concerning the ozone process, the ozone residual of ozone contactor effluent may affect on the biological destabilization, poor physical properties of the following GAC process and operators’ health due to high ozone gas concentration in GAC contactor. Therefore, maintaining an optimal ozone dose based on the ozone demand is essential to the operation of the ozone process. The Koyang Advanced Water Treatment Plant (KAWTP) has been utilizing a new type of ozone control method since July 2009, which automatically calculates required ozone dosed based on the instantaneous ozone demand (ID) and the ozone decay rate constant (Kc ). The ID and the first-order Kc values are calculated based on the measured dissolved-ozone concentrations fr...