ABSTRACT:
Air stripping for the efficient removal of volatile organic chemicals (VOCs) from contaminated groundwater is used in drinking water purification and hazardous waste site remediation. As air quality regulations become more stringent, emission controls such as granular activated carbon (GAC) will be required on the air stripper offgases. Often air stripper‐GAC adsorber interactions are neglected with the air stripper design optimized and the GAC adsorber designed for the resulting offgases, leading to unrealistically high operating costs.
This paper presents a multicomponent offgas adsorption model which is used to calculate the carbon breakthrough curves. Due to its generality and ease of application, the Polanyi equilibrium potential theory is used to describe the equilibrium sorption isotherms. These are combined with the hydraulics and mass‐transfer kinetics to calculate chemical breakthrough curves. The model is calibrated using data from a pilot‐scale unit treating a contaminated groundwater containing seven chlorinated VOCs. Application of the model to temperature effects on GAC adsorber design and the impact of regeneration frequency on carcinogenic risk are presented.