Destruction of Ozone Off–Gas by Thermal Catalytic Method

In the operation ofozone treatment plants, one will have to deal with ozone inthe off–gas exhaust air. In higher concentrations in the exhuast air, ozone has the unpleasant property of being detrimental to plant, animal and man. The normal ozone concentration inambient air should not be more than 1/10of the MAK–value. Insmall treatment plants inEurope the small amount of ozone off–gas can be diluted with atmospheric airso that itis permitted to be discharged into the outside air. For larper plants there isthe choice between a thermal and catalytic ozone destruction, or a process that combines both. In the Lengg Waterworks the exhaust air of the reaction chamber was passed through a thermal destruction systen. From the granular activated carbon (GAC) filters theair was passed into the atmosphere untreated. It was ascertained that during GAC back–washing 1200 PPtl ozone were in the exhaust air. This ozone concentration was much too high.