Microbiological water purification without the use of chemical disinfection

Objectives.-Point-of-use (POU) water treatment systems are self-contained units that can be used by recreational enthusiasts who normally obtain drinking water from untreated sources (ie, rivers, lakes, etc). Microbiological water purifier units are capable of removing all waterborne pathogens. The purpose of this study was to evaluate a new technology (Structured Matrix) capable of microbiologically purifying the water without the use of chemical disinfectants or an external power requirement. Methods.-Each of 3 identical portable water filtration units were evaluated for their ability to remove Klebsiella terrigena, poliovirus type 1, rotavirus SA-11, and Cryptosporidium parvum oocysts. Units were operated according to the manufacturer's instructions to process 378 L of water. Each unit was challenged with test organisms after 0, 94, 190, 227, 284, 340, and 378 L had passed through it. For the 227-L and 284-L challenges, a "worst-case" water quality (4 degrees C, pH 9, and turbidity 30 NTU) was used that contained 1500 mg/L dissolved solids and 10 mg/L humid acid. At 340-L and 378-L challenges, worst-case water quality was adjusted to pH 5.0. Units were tested after stagnation for 48 hours following passage of 190, 340, and 378 L of water. Results.-The geometric average removal exceeded 99.9999% for bacteria, 99.99% for viruses, and 99.9% for Cryptosporidium parvum oocysts. Conclusion.-These units comply with the criteria guidelines for microbial removal under the United States Environmental Protection Agency's "Guide Standard and Protocol for Testing Microbiological Water Purifiers."