Evaluation of Cascade Air Stripping Pilot—Scale and Prototype Studies

A simple modification of the conventional countercurrent air‐stripping process, introduced as cascade air stripping, is proposed for cost‐effective removal of semi‐ and low‐volatile organic contaminants from water. This paper summarizes the results of a pilot‐scale demonstration study and a prototype‐scale feasibility study undertaken to demonstrate the concept of cascade air‐stripping system, and to evaluate its performance against that of the conventional air‐stripping (AS) system. Pressure drops and energy requirements of the two systems were compared under a range of water and air loading conditions in the pilot‐ and prototype‐scale versions. Removal capabilities of the two systems were compared over a wide range of volatilities. When compared on the basis of air‐side energy input, the proposed cascade AS system offers some advantages over the conventional AS process: accommodating 35–50% more air flow; achieving comparable removals at 40–50% of the packing depth; and attaining considerably lower effluent concentrations.