Catalytic Oxidation for Treatment of ECLSS & PMMS Waste Streams, 1992

Catalytic oxidation has proven to be an effective addition to the baseline multifiltration (MF) water reclamation technology which will be used on Space Station Freedom (SSF). Low molecular weight, polar organics such as alcohols, aldehydes, ketones, amides, and thiocarbamides which are poorly removed by the baseline MF technology can be oxidized to carbon dioxide at low temperature (121 C). The catalytic oxidation process by itself can reduce the Total Organic Carbon (TOC) to below 500 ppb for solutions designed to model these waste waters. Individual challenges by selected contaminants have shown only moderate selectivity towards particular organic species. The combined technology is applicable to more complex waste water generated in the Environmental Control and Life Support System (ECLSS) aboard SSF. During the Phase III Core Module Integrated Facility (CMIF) water recovery tests at NASA Marshall Space Flight Center, real hygiene waste water and humidity condensate were processed to meet potable specifications by the combined technology. A kinetic study of catalytic oxidation demonstrates that the Langmuir-Hinshelwood rate equation for hetergeneous catalysts accurately represents the kinetic behavior. From this relationship, activation energy and rate constants for acetone oxidation were determined.