Halogen Binding Resins for Potable Water Disinfection

NASA is interested in alternative biocides for disinfecting process water.nbsp; During the proposed project, a resin will be developed for the slow-release of chlorine or bromine.nbsp; This resin will be used in a simple flow-through cartridge that will act as both a contact kill biocide device and as a source of free chlorine or bromine.nbsp; A halogen residual of 0.5 to 1.0 mg/L will be delivered to the water.nbsp; Chlorine and bromine have a long history of use within this range for land-based and marine potable water treatments, respectively.nbsp; As a result of their widespread use, much data is available concerning their long term health effects, antimicrobial efficacy and materials compatibility.nbsp; This concentration range is generally accepted as being safe and therefore removal is not required prior to crew consumption.nbsp; The residual concentration will remain within this range over a wide range of flows.nbsp; This Halogen Binding Resin (HBR) will be entirely analogous to the original MCV resin but will release chlorine or bromine instead of iodine.nbsp; The next generation Microbial Check Valve (MCV2) made with this resin can be used as a direct replacement for the currently used MCV.nbsp; The resin will be developed by modifying the structure of existing halogen binding materials.nbsp; Currently, existing materials that bind chlorine and bromine provide good contact kill antimicrobial properties but fall short of meeting NASArsquo;s biocide residual needs.nbsp; Either the halogen is held too tight, resulting in an insufficient water residual, or the halogen is not held tight enough, resulting in an excessively high residual that requires dilution.nbsp; The proposed research will result in a resin with a high chlorine or bromine loading capacity and slow-release kinetics suitable for disinfecting NASA process water.