On Thursday, December 1, 2016 at 1:58:27 PM UTC+13, William Mook wrote:
Carbon dioxide is plentiful on Mars.

On Thursday, December 1, 2016 at 12:32:00 AM UTC+13, Fred J. McCall wrote:
Alain Fournier wrote:

On Nov/29/2016 at 9:47 AM, Fred J. McCall wrote :
Alain Fournier wrote:

Le Nov/28/2016 Ã* 9:53 PM, Fred J. McCall a écrit :
Alain Fournier wrote:

On Nov/27/2016 at 10:26 PM, Fred J. McCall wrote :
Alain Fournier wrote:

On Nov/27/2016 at 1:17 AM, Fred J. McCall wrote :
JF Mezei wrote:


100pax over 3-4 months will consume large amounts of food. That is a lot
of mass that you have to lift and accelerate out of earth's orbit
towards mars most of which will become waste. Not doing anything with it
means wasting that mass which you spent much fuel accelerating.


I know it's hard for you, but think about it. Most of the mass of
food (and feces) is water. You're going to get the water back for
recycling on the back side of the process. That means each person
will generate 1-2 ounces of solid waste per day once the water has
been recovered (and you'll get 3-6 ounces of water out of the same
waste stream). Let's use the larger number as more 'favorable' to
your case; 100 people (not sure what 'pax' are when they're up and
dressed) will generate around 12.5 pounds of solid waste per day. That
waste is a mix of dead bacteria, indigestible food elements like
cellulose, minerals, and indigestible fats. You're not going to turn
it into methane without giving up a lot of the recovered water and
even then most of it isn't going to 'convert'. Recovering the water
is more valuable, since you can make things like breathing air out of
that stuff. So you're going to accumulate a little over half a ton of
such cruft during the course of the trip.

It's not one or the other. You can very well recover the methane and the
water and grow food. Plants don't need the methane from human waste to
grow. So after extracting methane, the waste isn't any less fertile than
it was before extraction.


What 'methane' is there to recover? To get methane from ****e, you
have to process the ****e, removing carbohydrates. That makes it less
fertile because you've removed all the carbon and hydrogen.


Plants don't need carbon in soil, removing carbohydrates is not a
problem. Plants get their carbon from CO2 in the air.


Try growing plants in soil with no carbon in it and see how that works
for you (it mostly will work very poorly, if at all).

Do you have a site to support that claim.
https://en.wikipedia.org/wiki/Plant_nutrition#Carbon
Doesn't seem to agree with you.


While carbon isn't used directly by plants, it seems to be very
important in enabling soil chemistry that is essential to plant
growth.

http://www.unep.org/yearbook/2012/pd..._2012_CH_2.pdf

Maybe I missed something in there. But here is what I saw.
1) Soil organic matter is important because it slows down water run off
which is important not only because plants need the water but also
because this reduces erosion and loss of soil and nutrients.
2) The large amounts of carbon in soil world wide is important because
if all that carbon was released in the atmosphere that would exacerbate
global warming.
3) The biota, mainly bacteria, in the soil decomposes soil organic
matter, releasing the carbon into the atmosphere, which leaves behind
important nutrients.

Point 1) There shouldn't be any large sudden rain fall in the spaceship
carrying colonist to Mars. So this is irrelevant here.
Point 2) I think we will both agree that spacecraft greenhouse warming
is a non-issue.
Point 3) Basically says that to provide nutrients to plants, the carbon
must be removed.


The proof is in the pudding. Go grow some plants of various types in
sand with no carbon content. Fertilize at will, but nothing with
carbon as a component. Let us know how that goes.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

Supercritical Water Oxidation is a well established treatment process for closed cycle systems and is 99.99% efficient.

Supercritical water oxidation defined as oxidation pro- cess which occurs in water above its critical point (Tc=374°C and Pc=22.1 MPa). It uses supercritical water as a reaction medium and exploits the unique solvat- ing properties to provide enhanced solubility of organic reactants and permanent gases (like oxygen and carbon dioxide), a single-phase environment free of inter-phase mass transfer limitations, faster reaction kinetics, and an increased selectivity to complete oxidation products (Tester et al., 1993; Savage et al., 1995; Schimeider and Abeln, 1999).

So, all the carbon in the waste becomes carbon dioxide whilst the ashes and other products (primarily phosphates) are easily removed by low pressure water distillation. Hydrogen is then used to reduce carbon dioxide to methane, and the methane is pyrolysed to form elemental carbon with recovery of the hydrogen which is recycled in the process. The carbon black is used to absorb odours from the air.

128 grams per day per person translates to 12.8 kg per day for 100 persons. Watering this down for processing, from as excreted, translates to 80 litres per day for a crew of 100. 800 millilitres per day per person of urine translates to 80 litres per day for 100 persons. A total of 240 litres of dark water per day from four aircraft style toilets. Each unit processes 3 litres per hour - and any three can support the crew in the event of one unit failing. Each unit expends 870 kJ/hour - or a 242 Watt heater - with a typical heat exchanger. The reduction of solids is 99.99% and occurs very quickly - done continuously. All four toilets operating at full capacity consume 1 kW which is easily supplied by the solar power system.

The carbon dioxide produced by the SCWO process is processed by the atmospheric processor, which is part of the toilets as well. Gallies and showers are attached to the units that make use of the recycled water. Packaging and toiletries are also reducible through SCWO to elemental carbon and oxygen as well.

Beta-glucan molecules assembled into a polysaccharide using a micro-scale chemical processor is a handy renewable resource to produce fibres on demand for reconstituting tissues, toilet papers, packaging, disposable plastic dishes, utensils, bandages, clothing, blankets, pillows, and the like using 3D print technology in combination with the compact micro-scale chemical proccessor.

http://inhabitat.com/joshua-harris-3...e-new-apparel/