Evaluation of an Air Stripping-Ozone Contactor System

The latest generation of modular shelter, power, and health care equipment for Army field hospitals is termed the MUST: Medical Unit, Self-Contained, Transportable. Supporting the MUST-equipped hospital is a Water Processing Element (WPE) designed to treat non-sanitary hospital wastewater for reuse. Treatment train processes of the WPE are hydraulic equalization, ultrafiltration, reverse osmosis (RO), ultraviolet (UV) activated ozone oxidation, and hypochlorination. A nominal one-quarter scale UV-ozone contactor was evaluated at the US Army Medical Bioengineering Research and Development Laboratory. The contactor, built by Life Systems, Inc., of Cleveland, OH, consisted of six sparged columns in series preceded by an ozone scrubber or precontactor. The contactor was evaluated using a synthetic clinical hospital RO permeate. Evaluation included defining the fluid regime inside the columns, investigating the effectiveness of pre-stripping, and monitoring the oxidation of selected laboratory wastewater components throughout the oxidation process as well as measuring TOC and COD. A correlation between the TOC stripping rate constant and oxygen mass transfer coefficient was developed in cooperation with the University of Illinois. Effects of ozone concentration and UV light on the kinetics and mechanisms of organic carbon oxidation were explored.