NASA is interested in alternative biocides for disinfecting process water. During the proposed project, a resin will be developed for the slow-release of chlorine or bromine. 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. A halogen residual of 0.5 to 1.0 mg/L will be delivered to the water. Chlorine and bromine have a long history of use within this range for land-based and marine potable water treatments, respectively. As a result of their widespread use, much data is available concerning their long term health effects, antimicrobial efficacy and materials compatibility. This concentration range is generally accepted as being safe and therefore removal is not required prior to crew consumption. The residual concentration will remain within this range over a wide range of flows. This Halogen Binding Resin (HBR) will be entirely analogous to the original MCV resin but will release chlorine or bromine instead of iodine. The next generation Microbial Check Valve (MCV2) made with this resin can be used as a direct replacement for the currently used MCV. The resin will be developed by modifying the structure of existing halogen binding materials. Currently, existing materials that bind chlorine and bromine provide good contact kill antimicrobial properties but fall short of meeting NASA’s biocide residual needs. 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. 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.
The NASA application will be as Flight Hardware for deployment in support of future manned missions. The production and storage of safe potable water is a requirement for all manned operations in space. MCV2 technology will be microgravity compatible, reliable (>3-year life), and will remain functional with system pressures exceeding 30 psig. The MCV2 will find application in various deep space manned exploration mission phases including Mars transit.
This technology is applicable towards water disinfection in locations where access to safe drinking water is unavailable. In 2017, 2.1 billion people lacked access to safe, readily available water. The occurrence of diseases such as typhoid and cholera could be prevented by adequately treating drinking water. MCV2 will provide a more economical and effective solution than existing technologies.