Evaluation of Surfactant-modified Zeolite for Control of Cryptosporidium and Giardia Species in Drinking Water

Gastrointestinal infection due to biological contamination of drinking water supplies is a major health issue worldwide. Naturally occurring and inexpensive modified materials such as surfactant-modified zeolites (SMZ) have net positive surface charge, which may prove useful for adsorption of pathogens such as Cryptosporidium parvum and Giardia intestinales (lamblia). SMZ is engineered by modifying the concentration of surfactant hexadecyltrimethylammonium (HDTMA) on the surface of zeolite media. Two different SMZ formulations (cationic SMZ and hydrophobic SMZ) were engineered to develop the most effective media for pathogen removal from drinking water. In the laboratory, batch experiments of SMZ, raw zeolite, and sand were conducted to determine pathogen sorption to the media. Then, vertical columns packed with SMZ or zeolite material were used to evaluate pathogen transport. Tritium tracer tests were used to determine hydraulic properties of the materials. Synthetic microspheres 1 Department of Earth and Environmental Science, New Mexico Tech, Socorro, NM 87801. 2 Department of Earth and Environmental Science, New Mexico Tech, Socorro, NM 87801(corresponding author). E-mail: [email protected] 3 Department of Geological Science, University of Texas at El Paso, TX, 79968.