A Slurry-Based Photocatalytic Reactor with Slurry Separation for Water Recovery

Currently, proposed water recovery systems for baseline space missions consist of integrated technologies to remove contaminants from graywater for reuse. Lacking in these mission scenarios and in current research efforts is a solid understanding of how photocatalysis might perform as a primary and/or secondary processor. However, one of the major hurdles for slurry-based photocatalysis is the ability to separate the catalyst from solution after mineralization of pollutants is complete. Purifics, a Canadian engineering company, has solved this problem with a patented separation device utilizing a backpressure cycled membrane and automated system (Photo-Cat®). Purifics specifically designed a pilot unit to be used to solve the water recovery problem for long-term space missions. Operating Purifics’ Photo-Cat® as a secondary processor, with and without ammonium bicarbonate demonstrated that the TOC concentration could be reduced to below 0.5 ppm. Preliminary studies treating gray water, hence serving as a primary processor, have been promising.