IMPACT OF RELATIVE HUMIDITY AND AIRBORNE BENZENE CONCENTRATIONS ON CONDENSATION WATER FROM AIR TECHNOLOGY PRODUCT WATER

Finding sources of safe drinking water poses a challenge in remote areas without access to a reliable natural water source. Condensation Water From Air (CWFA) technology can help alleviate the worldwide water crisis by producing potable water in diverse environments. This technology produces water by passing air over a surface cooled below the dew point of the ambient air, similar to a home dehumidifier. Previous studies have shown that water produced by CWFA systems is within drinking water standards for basic parameters such as metals, turbidity, pH, conductivity, alkalinity, total hardness, and total dissolved solids. However, a recent study evaluating the impact of air temperature and ambient benzene vapor concentrations on the CWFA product water found that benzene vapor concentrations representing an indoor industrial environment resulted in benzene product water concentrations up to twice the EPA drinking water standard of 5 μg/L.

The purpose of this research is to understand the effects of humidity on the transfer of benzene from ambient air to the CWFA product water. A CWFA machine was placed inside a 1 m³ volume exposure chamber with a low airflow rate (11 air changes per hour). A pressure vessel generated and maintained six different benzene vapor concentrations at steady state representing a range of polluted environments from 50 to 800 µg/m³. The conditions of the experiment consisted of two relative humidity conditions: 45% and 65%, and an air temperature of 25˚C. Both CWFA product and control water were analyzed for benzene using U.S. EPA Method 524.2. Preliminary results of this study suggest that the amount of benzene in the CWFA product water increases when relative humidity and coil’s temperature decreases; they are also indicative of the potential health risks of drinking CWFA product water in a highly polluted environments without using the appropriate water treatment technology.