water is defined as water fit for human consumption. There are several
standards for potable water that need to be defined:
turbidity, color, taste, odor, and temperature
- Minerals: dissolved
and insoluble, hardness
acidity, alkalinity, dissolved gases
alpha, beta, gamma contamination
are several classes of microorganisms that are present in the human intesitine
and feces, the most common of which is the pathogen E. coli. Potable
water is rendered safe and kept free from microbiological contamination
by various disinfectants - most commonly chlorine. However, chlorine
is unacceptable in a space mission due to its tendency to form chlorine
gas, which is toxic. For this reason, iodine or silver may be used
for disinfection or ozone bubbled through the water may be used as well.
It is also possible to use ultraviolet light or hydrogen peroxide.
Ultrafilteration is another possibility, employing filters with the
capacity of filtering out all bacteria any many viruses.
water should be pleasant to the eye, free of coloration or solids, and
without any odor. Particulate removal is accomplished by multiple
filteration techniques while activation carbon filteration serves best
for odor removal. Mechanical water treatment processes:
a) Multifiltration: a system consisting of beds of sorbents and ion
b) Reverse Osmosis: a system consisting of a semi-permeable membrane
through which water is forced under high pressure.
c) Evaportion: water is heated and vapor is collected as pure water
crew member will require at least 26.2 kg of water per day. Of that
5.26 kg/day will be used for potable uses and 29.3 kg/person/day for hygiene.
In order to overcome the need of water in this long-term mission in space,
we will have to recycle water from showers, laundry and urine. Our
goal is to recycle all air, water, and solid wastes using mechanical and
chemical processes as well as plants. A biological bioreactor, a
vacuum cleaner-sized device that relies on bacteria to remove organic waste
from urine, laundry and shower water will be used. Urine, however,
will be processed separately through a more stringent filtration process
than the waste water. All the liquids will be run through a similar
final purification step that will produce a water of high quality. Iodine
will be added as a final bacteria killer, giving the recycled water a distinctive