As is shown in the table below). Another

 

 

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