| The core ALS-driven requirements of these missions
must address the nutritional and environmental needs of a crew member
group (i.e., 4-6), whereby extended (e.g., 1000 day) space survival demands
near-100% closed-loop recycle of water, near 100% in-situ oxygen generation,
and at least partial dietary supplementation drawn from in-situ plant
products. Based on current NASA-BVAD figures, the specific daily ?consumable?
(input) and ?waste? (output) masses will comprise approximately
30 kg per crew-day (kg/cd), of which the majority of mass transferred
each day will include both grey water (e.g., hygiene-related oral and
body cleansing, clothes washing, kitchen and utensil cleanup, etc.), condensate,
urine, and plant residue processing. Extending beyond the largely non-recyclable
system inputs (i.e., energy, prepackaged food, expendable tapes, paper,
wipes, etc.) and outputs (i.e., heat, leftover packaging, salt brine,
and non-biodegradables), the expected characteristics of the prospectively
recycled streams (e.g., fecal, urine, grey water streams, plant biomass,
etc.) and their integrated passage through essential bioregenerative systems
bear chemical, physical, and biological attributes which are not only
unique to these systems, but which also complicate their necessary handling
and processing schemes, as follows:
Solid wastes (i.e., collectively including fecal matter,
food scraps and waste, plus uneaten, waste plant biomass)
-
The expected solids content of this material will
range from ~6 to 20%, at which point processing complications will
arise with mixing, aeration, post-processing dewatering, disinfection,
etc.,
-
These higher solids densities, as well as the associated
energetic content of the waste, will also impose an abnormally high-level
specific oxygen demand (i.e., mass O2 per waste volume) for its aerobic
degradation,
-
Given its fecal fraction, and the related potential
for pathogen dissemination, this waste stream must be suitably processed
(e.g., ranging from simple drying and freezing to full degradation
and pasteurization or sterilization) to negate disease concerns,
-
Solid waste degradation will not likely be warranted,
or even desired, during transit, given that it would increase the
vehicle?s already problematic carbon dioxide loading,
Urine wastes
- As with the fecal matter, urine could well be collected in its raw,
undiluted form (albeit with limited additional flush water), and as
such its original contaminant (e.g., nitrogen, salt) concentrations
will also be considerably higher than normal municipal wastewaters,
- Urine processing for water recovery will almost certainly be necessary
during transit, given the magnitude of demand in comparison to cumulative
available mass. A related concern with this urine stream is that of
its high-level sodium content which then warrants isolation and removal
efforts in a fashion which avoids downstream sodium-related impacts
on plant growth
Significant Project Issues
STAR Solid Waste Processing (Jim Alleman - Purdue University)
STAR Off-Gas Processing (Charles Glass - Howard University)
STAR Residuals Processing via Tilapia (Paul Brown - Purdue University)
STAR Residuals Water Recovery and Post-Processing via Reed Beds (Jeff
Volenec and Brad Joern - Purdue University)
Waste Group Leader
James Alleman
Professor of Civil Engineering
Purdue University
Phone: 765.494.7705
e -Mail: alleman@ecn.purdue.edu
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