Development of a Community Water Security Filtration System Using Composite Cartridges

Under a Cooperative Research and Development Agreement (CRADA) established between the U.S. Environmental Protection Agency (EPA) and Harmsco, Inc., a prototype Community Water Security Filtration System for drinking water treatment using composite cartridges is being developed and tested at the EPA's Test & Evaluation (T&E) Facility in Cincinnati, Ohio. The filtration system incorporates a composite cartridge that combines physical pre-filtration with carbon adsorption and a cyst-rated final filter for removal of turbidity, specific chemical compounds, and some biological oocysts. The composite cartridge is then followed by ultraviolet (UV) light to provide short wave UV disinfection. The housing is constructed with a tangential inlet that induces a centrifugal motion to the water which aids filtratiom. The research has focused on optimizing the filtration media and housing configuration by testing the system using various biological surrogates and chemical compounds as contaminants. The current system configuration consists of a housing with two chambers; the upper chamber contains 8 (eight) composite cartridges for filtration, while the lower chamber contains six UV lamps for disinfection. Electrodes have been installed between the internal cartridge basket and the housing wall to provide an experimental electroseparation process to enhance particulate and pathogen removal and to determine if there is any pathogen cell disruption. Results of developmental tests conducted on single cartridges to optimize the composite cartridge media configuration show complete removal of Polystyrene Latex (PSL) beads (used as a non-biological surrogate for Cryptosporidium) which satisfies the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) requirement of >3.0 log reduction of Cryptosporidium. Results of tests conducted on the 8-chamber full-scale unit show almost complete removal of MS2 bacteriophage as a surrogate for enteric virus satisfying the LT2ESWTR requirement of a 4-log reduction for viruses.