As collect water from Mars(the chemical composition is shown

 

 

As mentioned in the “Resources” section, the resources-bringing spacecrafts
collect water from Mars(the chemical composition is shown in the table below).
Another water supply is Europa(which is also mentioned in the “Resources”
section). In order to determine the amount of water which should be collected
from the locations, we calculated the number of liters needed per day on Ibis(the
calculations are only approximated, so the real amount of water needed per day
may change from one day to another, depending on the spacecraft’s necessities).
Therefore, the estimated numbers are:

·Industry(35%):
437 500 liters;

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·Agriculture(35%):437
500 liters;

·Drinking
Preparation(10%): 125 000 liters;

·Corporal
Hygene Machines(20%): 250 000 liters.

    Estimated amount of water that is daily
needed on the spacecraft: 1250000 liters.

    The used
water goes through a treatment system, so that it can be reused; the purging
system is not able to purify the water in a proportion of 100%, so after every
treatment process, there is a 1%-water loss(highly contaminated water).

  

 

 

Water purification stages

 

 

The table shows the (generalized!)chemical compounds
of the water that needs purification. It is important to know what chemical
compounds the water has, in order to decide what treatment techniques must be
applied.

 

 

 

Type
1

Type
2

Type
3

Origin
of water

Greywater
Toilet flushing

Industry
Public places
Agriculture

Water procured from  
space

 
Chemical
Compounds
(generally)

·  
Bacteria
· 
Pyrogenes
· 
Toxic agents

· 
Heavy metals
· 
Bacteria(might be)
· 
Salts
· 
Dissolved minerals
· 
VOCs
· 
Some contaminants

·
Hydrated salts
· Carbon-based compounds(such as frozen CO2)
· Other compounds that could come from the soil, like
oxides, different types of dust etc

 

 

 

 

 

 

 

 

            The process of water purging must
be efficient(as simple as possible), 
environmentally friendly and should not consume many resources(such as
energy and chemical compounds).

     

1.Ultrafiltration 

          Prior to
all other water treatment stages, water will be filtered. The main scope of
ultrafiltration is to eliminate the macromolecules(algae, organic molecules,
germs, bacteria, viruses), that could cumber the Reverse Osmosis process. This
action doesn’t require a high amount of energy and the water becomes clear at
the end.

          This stage can not, however, get rid
of dissolved salts, nor of ionized contaminants and solvents, so that’s why the
other stages are still very important.

 

2.Reverse
Osmosis

           In this stage, dissolved minerals, metals, salts, fluoride and even
pyrogens are eliminated. At low pressure, the process generates a relatively
big amount of waste water; However, the water loss can be minimized by using
high pressure instead of a lower one.

           Reverse Osmosis is efficient when
the entering water is clear and free of microorganisms(these two aspects are
achieved in the Ultrafiltration).

           After this stage, water loses almost
all its minerals and it has acid pH.

 

 

3.UV Light Action

 

 This stage is also known as photooxidation and it requires
a small amount of energy. It separates electrons from the molecules and it is
creating free radicals that alter the structure of toxic agents.

After stage 1 and 2 of water treatment, water is
clear, so the UV light can reach every corner of the water tank. If there is
still some bacteria left in the water, it is deactivated by this process.

 

4.Electrodeionization

This water treatment technic is used as a polishing
process after Reversed Osmosis. Electric current is applied in order for the
ions to move toward the electrodes(cathode and anode). The ions don’t arrive to
the specific electodes because they can’t get through the ion-selective
membrane that is fixed in their way. They concentrate on one side of the
membrane and they are eliminated from the system.

 The water
becomes ions-free and it splits into OH- and H+ and the water treatment process
continues.

 

 

5.Activated
Carbon Filters

 

This process eliminates organic chemicals(and
carbon-based substances) and even VOCs. It also gives the water a natural good
taste and odors are removed.

The AC beds might be able to shelter bacteria, that’s
why the microorganisms were killed before reaching this module (the
deactivation of the bacteria was done in the ultrafiltration and UV light
modules).

 

      

 

 

 

 

Distribution
of water

        

 

1.Distilled water

          At the end of the purging process,
the water is purified(distilled). 45% goes through mineralization stage(as
shown in the diagram) and the other part is sent to other sectors, where
needed(for example in industry and into homes).

2.Mineralized water

        If there
were only one source of mineralized water on the whole spacecraft, people would
have had to store the water in plastic bottles(plastic being one of the most
economical and practical materials for producing bottles), so water might have
slightly modified its chemical composition. Besides this, there would have been
an increased plastic usage. Getting mineralized water directly at home/work/school/greenhouse/farm
etc. through a specific faucet is more environmental friendly and more
efficient. Therefore, there exists two types of faucets: one that brings
distilled water and one that brings mineralized water. These two types of
faucets involve, obviously, different types of pipes.

      The water
is enriched with minerals and vitamins in proportion of 25% of the Reference
Daily Intake; this way, we make sure that all the nutrients needed for a
balanced life are provided. Details about the necessary nutrients are given in
the Biosphere&Alimentation part.

3.Pipes: types and structure

      Different
types of faucets(mineralized and non-mineralized water) involve, obviously,
different pipes. Furthermore, different quantities of minerals and vitamins in
the water involve different pipes as well(because the water for people doesn’t
have the same amount of nutrients as the water for plants). Beside those,
certain pipes have to the conduct grey/black water back at the purification
system for recycling.

       The pipes
have a is silicate structure. This structure made with silicates is very
resistant and eco-friendly(it does not contain VOCs); it helps in avoiding
pipes’ penetration.

 

4.Peak use of water

 

         The
water system has an excess of 10% of water to cope with a presumed peak use.

 

What happens if a problem occurs in the water system

 

         Apart from the water that is constantly used and
recycled, on Ibis there full backup reservoirs. In case any problem occurs and
the water system doesn’t work properly, there is a 4 million–liter
water reserve, that should supply enough water for a couple of days(mentioning
that the water consumption would be strongly minimized in such a case). A very
important aspect is that the water is stored in special reservoirs: they don’t
let water and air interact. If the two interacted, CO2 would dissolve and it
would change water’s pH.

          There is also a backup method of
cleaning water, used only in special cases: Polymeric Nanoadsorbents. If a leak
of toxic substances occurs accidentally(what could happen in the industry, for
example) and the water needs advanced treatment, the purging process will be
modified: in the Ultrafiltration stage, there will be used Polymeric
Nanoadsorbents in order to eliminate organics and heavy metals from water. They
are engineered nanoparticles that “trap” inside of them toxic substances; they
are biodegradable and they aren’t a toxic adsorbent. However, the production of
polymeric nanoadsorbents involves multistages that are complex, so this water
treatment method is not meant for everyday use.

           A backup method of producing water
is using chemical reactions, like these given as examples below:

·     
CO+2H? C(solid)+ 2HO

·     
2HO+2HO? 2HO+ 3O

·     
2H+O? 2HO