Investigation of DMSD Trend in the ISS Water Processor Assembly

Abstract

The ISS Water Recovery System (WRS) is responsible for providing potable water to the crew, to the Oxygen Generation System (OGS) for oxygen production via electrolysis, to the Waste & Hygiene Compartment (WHC) for flush water, and for experiments on ISS. The WRS includes the Water Processor Assembly (WPA) and the Urine Processor Assembly (UPA). The WPA processes condensate from the cabin air and distillate produced by the UPA. In 2010, an increasing trend in the Total Organic Carbon (TOC) in the potable water was ultimately identified as dimethylsilanediol (DMSD). The increasing trend was ultimately reversed after replacing the WPA's two multifiltration beds. However, the reason for the TOC trend and the subsequent recovery was not understood. A subsequent trend occurred in 2012. This paper summarizes the current understanding of the fate of DMSD in the WPA, how the increasing TOC trend occurred, and the plan for modifying the WPA to prevent recurrence.

Measurement of CO2 in Water from an Ultraviolet Oxidizer for a Space-Worthy Wastewater Recovery System Using Raman Spectroscopy

“…Such improvements might be obtained by using an internally coated mirror sample cell, a higher power laser, and/or a lower noise detector. Finally, the Raman system could serve multiple duties when not being used to measure TOC, such as identifying chemicals and their source, when high TOC is detected, 6 analysis of crew member biofluids, such as urine and saliva, to monitor anti-weightlessness drugs, bone loss biomarkers, 35 or degradation of medications. 36 We believe that a Raman analysis system will ultimately be the method of choice for long duration space craft.…”

“…1 The latter mission will take approximately three years and will require ∼20 000 kg of food and ∼80 000 kg of water for a crew of six. [2][3][4][5][6] While methods to recycle food are under development, 2 NASA has been developing and testing a wastewater recovery system (WRS), both on earth and on the International Space Station (ISS) for more than two decades. [5][6][7][8] The current WRS recovers ∼90% of the wastewater, which could reduce the water requirement to ∼5000 kg, but the system components are considered too large and massive.…”

“…[2][3][4][5][6] While methods to recycle food are under development, 2 NASA has been developing and testing a wastewater recovery system (WRS), both on earth and on the International Space Station (ISS) for more than two decades. [5][6][7][8] The current WRS recovers ∼90% of the wastewater, which could reduce the water requirement to ∼5000 kg, but the system components are considered too large and massive. The WRS is comprised of the urine processor assembly (UPA) and the water processor assembly (WPA).…”

Superior single- and multi-component siloxane removal from water using a faulted silica DON zeolite adsorbent

“…Linear siloxanes that have been detected in water and that are products of the hydrolysis of larger siloxanes include monomethylsilanetriol (MMST), 17 dimethylsilanediol (DMSD), and trimethylsilanol (TMS). 18,19 DMSD is toxic to humans if ingested for long periods, even at low concentrations ( i.e. , mg L −1 ), 20 while TMS has been associated with causing central nervous system problems.…”

“…For instance, MMST, TMS, and DMSD have been detected in reclaimed water from closed-volume environments, such as the International Space Station (ISS); low molecular weight siloxane concentrations up to 10 mg L −1 have been reported downstream in the ISS. 19,23,24…”