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The sorption and ion exchange water reclamation technologies used to treat the waste streams in the Environmental Control and Life Support System (ECLSS) and Process Materials Management System (PMMS) are ineffective for removal of low molecular weight, polar organic contaminants which do not have ionized forms. These include likely waste stream constituents such as methanol, ethanol, isopropanol, and acetone. Catalytic oxidation of these compounds in oxygen saturated water at moderate temperatures (125 to 160 C) provides a reliable, simple, and inexpensive way to eliminate these contaminants. By the suitable choice of catalysts, these species can be converted to carbon dioxide and water or to species which can be removed effectively by sorbents and ion exchange resins. The operation requirements of the baseline system are oxygen and heat. Since much of the heat is recovered, the energy use of the technology is very low.

A new technology for controlling the partial pressure of CO2 (pCO2) in a plant growth chamber (PGC) has been demonstrated. CO2 is gathered from the source atmosphere across a membrane gas exchanger and stored in an alkanolamine solution. The CO2 loading of the alkanolamine reservoir is monitored using specific conductance and controlled by the exposure time and temperature. The PGC pCO2 is maintained using a second membrane exchanger through which the alkanolamine circulates, absorbing or releasing CO2 to maintain equilibrium. The equilibrium pCO2 is determined by the CO2 loading and the temperature. Constant PGC feed pCO2 levels of roughly 1000 ppm have been maintained using sources with pCO2 both above and below this value.

The Microbial Check Valve (MCV) is used on the Space Shuttle to impart an iodine residual to the drinking water to maintain microbial control. Approximately twenty MCV locations have been identified in the Space Station Freedom design, each with a 90 day life. This translates to 2400 replacement units in 30 years of operation. An in situ regeneration concept has been demonstrated that will reduce this replacement requirement to less than 300 units based on data to date and potentially fewer as further regenerations are accomplished. A totally automated system will result in significant savings in crew time, resupply requirements and replacement costs. An additional feature of the device is the ability to provide a concentrated biocide source (200 mg/liter of I2) that can be used to superiodinate systems routinely or after a microbial upset. This program was accomplished under NASA Contract Number NAS9-18113.

The baseline hygiene water reclamation system for Space Station Freedom has been changed from Reverse Osmosis with Multifiltration post-treatment to stand-alone Multifiltration. The Multifiltration concept offers increased system reliability, a decrease in power consumption, and essentially 100% water recovery. Multifiltration is based on well documented sorption technology for removal of contaminant species. System complexity is minimal. Moving parts are limited to one pump and simple valving. Reliable microbial control is obtained by heat sterilization and by the use of iodine as a bactericide. Iodine addition is accomplished in the Unibeds with an iodinated resin which is also used in the Microbial Check Valve (MCV). Microbial Check Valves have proven reliable and effective on board the Space Shuttle since the beginning of the Shuttle program. Power consumption is primarily attributed to heat sterilization. The energy required for the pump and controls is relatively low.

A breadboard Electrochemical Water Recovery System (EWRS) that is designed to produce potable water from a composite waste stream without the use of expendables is described in this paper. Umpqua Research Company working together with NASA/JSC developed a sequential three-step process to accomplish this task. Electrolysis removes approximately 60% of the organic contaminants from ersatz composite waste water containing a total organic carbon (TOC) concentration of 707 mg/L. The contaminants in this solution consist of organic and inorganic impurities common to laundry, shower, handwash, and urine waste water. Useful gases and organic acids are the chief by-products of the first step. The partially oxidized electrolysis solution is then transferred to the electrodialysis process where ionized organic and inorganic species are concentrated into a brine. The deionized solution of recovered water contains ∼6% of the original organic contaminants and >90% of the original water.

The Microbial Check Valve (MCV) is a reloadable flow-through canister containing iodinated ion exchange resin, which is used aboard the Shuttle Orbiter as a disinfectant to maintain water potability. The MCV exhibits a significant contact kill and imparts a biocidal residual I2 concentration to the effluent. MCVs in current use have nominal 30 day lives. MCVs baselined for Space Station Freedom will have 90 day lives, and will require replacement 120 times over 30 years. Means to extend MCV life are desirable to minimize resupply penalties. New technology has been developed for fully autonomous in situ regeneration of an expended MCV canister. The Regenerative Microbial Check Valve (RMCV) consists of an MCV, a packed bed of crystalline I2, a flow diverter valve, an in-line iodine monitor and a microcontroller. During regeneration, flow is directed first through the packed I2 bed and then into the MCV where the resin is replenished.

This paper describes a newly designed, 2.7 Kg (6 pound) capacity, laundry machine called the Single Phase Space Laundry (SPSL). The machine was designed to wash and dry crew clothing in a micro-gravity environment. A prototype unit was fabricated for NASA-JSC under a Small Business Innovative Research (SBIR) contract extending from September 1990 to January 1993. The unit employs liquid jet agitation, microwave vacuum drying, and air jet tumbling, which was perfected by KC-135 zero-g flight testing. Operation is completely automated except for loading and unloading clothes. The unit uses about 20 percent less power than a conventional household appliance.

The Microbial Check Valve (MCV) is a canister containing an iodinated ion exchange resin and is used on the Shuttle Orbiter to provide microbial control of potable water. The MCV provides a significant contact kill, and imparts a biocidal iodine residual to the water. The Orbiter MCV has a design life of 30 days. For longer duration applications, such as Space Station Freedom, an extended life is desirable to avoid resupply penalties. A method of in situ MCV regeneration with elemental iodine is being developed. During regeneration water en route to the MCV first passes through a crystalline iodine bed where a concentration between 200 - 300 mg/L I2 is attained. When introduced into the MCV, this high concentration causes an equilibrium shift towards iodine loading, effecting regeneration of the resin. After regeneration normal flow is re-established. Life cycle regeneration testing is currently in progress.

The ability to aseptically remove samples and products, and the capability for addition of materials to sterile or otherwise microbially susceptible systems have always been compromised by the lack of a reliable means of sterilizing the mating fixtures. Cultures of mammalian cells are particularly vulnerable to microbial contamination due to the complexity of nutrient media and the lengthy periods required for cell growth. The Microwave Sterilizable Access Port has been developed to overcome this limitation. The system consists of three primary components: a microwave power source, a combined sterilization chamber/in-line valve port assembly, and a specimen transfer interface. Microwave energy is transmitted via coaxial cable to a small pressurized chamber that serves as a sterile transition between the surrounding environment and the system during transfer of materials.