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#1 2019-08-09 07:49:35

Terraformer
Member
From: Lancashire
Registered: 2007-08-27
Posts: 3,295
Website

Composting Toilets

Particularly urine diverting ones.

I know RobertDyck has posted before about using water to clean yourself instead of toilet paper, but the downside is that you produce a lot of blackwater which needs to be recycled. If the toilets themselves are flush toilets, then this just adds to the problem.

On the other hand, if we use composting toilets, and keep the excrement and urine separate, they will be a lot easier to treat. In a small colony especially, we can little afford the complexity that modern sewage systems would require. It should be noted they were never designed as they are now (originally the waste was just dumped, then that caused problems so they had to treat it - damn path dependency). The downside is that it's slightly less convenient. The upside, in low (but non-zero) gravity, is that we won't have to worry about splashback...


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#2 2019-08-09 08:37:33

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,854

Re: Composting Toilets

This is an interesting subject area! Here are some thoughts:

1. Water preservation might be important for a small colony, but if it is conveniently located next to a water ice glacier, that might not be an issue.

2. A modern version of the Roman sponge might be an alternative...perhaps personalised and made hi tech with microwave cleansing.

3. Dumping waste on Mars should not be a real problem for a colony as long as it is not dumped too close. Maybe find a convenient quite deep crater and start filling that up.

4. That said, faeces is going to be pretty precious stuff on Mars if we want to grow food. Throwing away that natural fertiliser makes no sense. If a person produces 0.5kg of faeces per day and there are 100 people in your colony, that's over 36 tons of fertiliser that would otherwise have to be shipped from Earth to Mars or manufactured on Mars.


Terraformer wrote:

Particularly urine diverting ones.

I know RobertDyck has posted before about using water to clean yourself instead of toilet paper, but the downside is that you produce a lot of blackwater which needs to be recycled. If the toilets themselves are flush toilets, then this just adds to the problem.

On the other hand, if we use composting toilets, and keep the excrement and urine separate, they will be a lot easier to treat. In a small colony especially, we can little afford the complexity that modern sewage systems would require. It should be noted they were never designed as they are now (originally the waste was just dumped, then that caused problems so they had to treat it - damn path dependency). The downside is that it's slightly less convenient. The upside, in low (but non-zero) gravity, is that we won't have to worry about splashback...


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#3 2019-08-09 08:39:19

IanM
Moderator
From: Chicago
Registered: 2015-12-14
Posts: 276

Re: Composting Toilets

This seems like a good and energy-efficient idea. Two thoughts:

-Usually human excrement is too "hot" (i.e., Carbon-rich) to use directly as fertilizer, so we would need to add Nitrogen (usually with fiber, etc.). Given that the early Martians will be vegan this will be less of an issue, and composting would probably improve it even further (especially if we use toilet paper, if I'm not mistaken).

-Would toilet paper be used or water? Either has its downsides; paper requires trees or plants, while water needs to be filtered before reuse to avoid the spread of diseases. (EDIT: Louis's idea of a Roman sponge sounds like a good idea.)


The Earth is the cradle of the mind, but one cannot live in a cradle forever. -Paraphrased from Tsiolkovsky

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#4 2019-08-09 08:39:51

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,035
Website

Re: Composting Toilets

Terry Kok argued strongly for composting toilets. Issue is the toilet has 2 parts, one for urine and the other for feces. You have to be careful to use it that way. Urine will still have to be processed, so there's still black water just a lot less and easier to process. And you'll need toilet paper. That can be made with hemp or bamboo, both of which grow faster and produce more fibre per year per acre of land than trees. What is the total system cost? Grey water sewage processing with a low flow flush toilet and washlet (toilet seat that washes your bum) vs composting toilet with urine processing and toilet paper with separate greenhouse to grow fibre and manufacturing for toilet paper? I've heard strong advocates for both sides.

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#5 2019-08-09 08:52:13

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,035
Website

Re: Composting Toilets

IanM,
I've heard human urine called "hot" because it contains too much nitrogen. It will "burn" a lawn.

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#6 2019-08-09 17:59:01

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,235

Re: Composting Toilets

Sure geared at the use on the surface looking at resource reuse but that could also be applied for the long trip legs as well and for a destination mars send it down to the surface for reuse.

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#7 2019-08-10 07:45:22

tahanson43206
Member
Registered: 2018-04-27
Posts: 3,101

Re: Composting Toilets

For Terraformer re #1 ...

In another topic you have proposed raising bamboo as a useful economic activity for Mars.

in this topic, you have stimulated discussion which includes the need/desire for toilet paper.

In the discussion above, a contributor pointed out that toilet paper can be made from bamboo.

Plot0004 Teraformer Bamboo

You have a plot reserved in My Hacienda on Mars.  I think the number of that plot is 0004.

I'm going to try to encourage you in this post, to plant a stake in the plot reserved for you, and to begin to assemble the knowledge that will be needed on Mars to grow bamboo (a) and (b) to make the equivalent of the American brand of toilet paper, "Charmin" (www.charmin.com)

I am presuming there is a brand in the UK that is comparable or superior.  My invitation to you is to approach them to sponsor your bamboo growing operation on Mars, by assigning an individual or a small team to help you with technical details of their requirements.  There may well be resident experts on how to grow bamboo in a greenhouse in the UK as well. It would be a challenge for you to find them, and to persuade them to help you with technical details, but you don't have to be an expert yourself to build a team which collectively can address whatever difficulties may become visible.

Regarding the larger issues raised by your topic ....

This is an opportunity (right here in the NewMars forum) for individuals who are experts in the field of waste management to help to assemble the knowledge required for a full scale community on Mars (or anywhere, for that matter).

(th)

Last edited by tahanson43206 (2019-08-10 07:47:14)

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#8 2019-08-10 08:44:55

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,235

Re: Composting Toilets

Here is a treasure trove of Mars Homestead documents http://marshome.org/documents.php
Waste Recycling System Concept Presentation  http://www.marshome.org/files2/MarsHomestead-WRS.ppt

Bamboo topic

edit
Here is another topic Bamboo shoots up the chart

James.png
http://www.marsfoundation.org/ James Burk

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#9 2019-08-10 09:09:56

tahanson43206
Member
Registered: 2018-04-27
Posts: 3,101

Re: Composting Toilets

For SpaceNut re #8 and specifically the PowerPoint ...

Gary C. Fisher
Treasurer – The Mars Foundation
Steering Committee – The Mars Society

Impressive! Thanks!  I was glad to see the trapdoor pulled up at the bottom of the last slide.

I would like to see some Artificial Intelligence built into the system at the point of scraping with a squirt of water.  That process cannot be expected to complete properly with nothing more than a mechanical action which is not monitored for failure.  Failure is certain, in a process which combines biological processes with mechanical activity. 

(th)

Last edited by tahanson43206 (2019-08-10 09:10:28)

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#10 2019-08-10 12:07:58

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,235

Re: Composting Toilets

So early mars would construct a toilet or will it bring it for mars use?

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#11 2019-08-10 14:45:33

tahanson43206
Member
Registered: 2018-04-27
Posts: 3,101

Re: Composting Toilets

For SpaceNut re #8 ...

I followed the link from James Burk's picture, and found this:

Robert Dyck B.S. (Software Engineer)
Science Study Contributor
is a computer software developer with a B.S. in Computer Science from the University of Manitoba and 24 years commercial experience. Currently a contractor forMicroPilot, he develops systems for calibration and quality control of miniature Unmanned Arial Vehicles. Robert has been an active member of the Mars Society, founding a chapter in Winnipeg, Canada. As a Mars Society project leader, he has worked on spacesuit designs, wrote a paper on extraction of aluminum from a mineral identified in Mars soil, and is developing a high accuracy Mars regolith simulant with the principal investigators of NASA Mars missions. He has also studied ion engines, life support, asteroid mining, and in-situ resource utilization. Robert brought his diverse experiences with minerals and gases to the Program Study team.

© Copyright 2019 - The Mars Foundation - The Mars Homestead Project

(th)

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#12 2019-08-10 15:02:09

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,235

Re: Composting Toilets

A little carrot will sometimes lead to one exploring.. Robert Dyck has been quite a valued Mars enthusiast as you have already found in the vast number of topics that we have here.
So early mars is mass constrained while later visits will build on not duplicating what has gone on before that current mission planning.
Some would say we are going to jump right aways to Mars with a BFR launcher while others here have been planning for something that is more of an assembly task in LEO to make mars possible.

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#13 2019-08-11 06:01:43

Terraformer
Member
From: Lancashire
Registered: 2007-08-27
Posts: 3,295
Website

Re: Composting Toilets

What is the total system cost? Grey water sewage processing with a low flow flush toilet and washlet (toilet seat that washes your bum) vs composting toilet with urine processing and toilet paper with separate greenhouse to grow fibre and manufacturing for toilet paper?

We're going to need that greenhouse anyway (we need cellulose fibres, especially if it's an actual colony so it's not just males there - even if it was, we still need bandage, paper, wipes...). The question is then about the cost of making it bigger so we can produce toilet paper - again, we need to ability to manufacture toilet paper even if we don't use it.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#14 2019-08-11 09:35:10

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,235

Re: Composting Toilets

This shows the start to finished product for any paper products.
toilet-paper-making-machine.jpg

https://bestonpapermachine.com/toilet-p … g-machine/

hybrid product
https://cabooproducts.com/how-its-made/

Bamboo harvesting takes place within two years of initial sprouting. Bamboo produces 35% more oxygen than trees and absorbs huge quantities of carbon dioxide. And—unlike trees—cutting bamboo actually promotes its growth.

http://www.toiletpaperhistory.net/toile … aper-made/

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#15 2019-08-11 11:46:50

tahanson43206
Member
Registered: 2018-04-27
Posts: 3,101

Re: Composting Toilets

For SpaceNut re #14

Thanks for showing this summary of the paper making process, and for the reinforcement of the value of bamboo.

I would like to see someone take on the stretch goal of assembling all of the knowledge that would be needed to re-create that graphic on Mars, and document that knowledge in one of the Plots in the My Hacienda topic.  The knowledge assembled would (if well constructed) assist planners for expedition planners, as well as someone who might want to try their hand at this on Earth.

(th)

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#16 2019-08-11 12:32:25

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,035
Website

Re: Composting Toilets

Terraformer wrote:

What is the total system cost? Grey water sewage processing with a low flow flush toilet and washlet (toilet seat that washes your bum) vs composting toilet with urine processing and toilet paper with separate greenhouse to grow fibre and manufacturing for toilet paper?

We're going to need that greenhouse anyway (we need cellulose fibres, especially if it's an actual colony so it's not just males there - even if it was, we still need bandage, paper, wipes...). The question is then about the cost of making it bigger so we can produce toilet paper - again, we need to ability to manufacture toilet paper even if we don't use it.

Nope. A greenhouse to grow fibre for clothing, etc, will be needed for that purpose. There won't be fibre required for toilet paper. If you use a composting toilet, you need toilet paper and that requires fibre over and above anything needed for any other purpose. You did say the question was the cost of making bigger, and I guess I'm saying the same thing. But you went on to claim we need toilet paper anyway. The answer is no we don't. With a washlet, you don't use toilet paper.

This is fundamental. A lot of people in North America often respond: this is how I've always gone to the toilet, so I will continue anyway. If that's your attitude, then you don't belong in space. Not on Mars, not on ISS. Remember the toilet on ISS has a hose you urinate into, and a separate toilet with an air stream to collect feces. If you claim you'll just piss into the toilet and ignore the hose, then you're kicked out of the astronaut corp.

Toilets are different around the world. What we use in North America is not what other countries use. When you travel, you have to learn to use what's there. If you can't adjust, again that means you don't belong on Mars.

Tokyo had a problem. That vast majority of houses are not connected to any sort of sewer system, they have septic tanks. A truck called a "honey wagon" uses a hose with suction to empty the septic tank, take the contents to be disposed. Toilet paper clogs septic tanks, it has to be emptied several times more often. So an inventor in Tokyo developed the washlet. France invented the bidet in the 17th century. But the French bidet is a separate fixture:
170px-Bidet_side.jpg

The inventor in Tokyo developed a seat for a convention flush toilet in 1980, the seat acts as a bidet. So this combines the fixtures into a single practical unit.
toilets_tile_1.jpg images?q=tbn:ANd9GcTqCDKKBWEmmuUiagDaO_X4JXYJgSornyFJhYvVafr2YBTR0d02

Other countries have greater differences. Squat tiolet

Squat toilets are used all over the world, but are particularly common in many Asian and African countries, including those with a large proportion of Muslim or Hindu faith.

170px-Squat-toilet-with-tank.jpg 170px-Pedestal-squat-toilet.jpg 480px-Public_toilet_in_Japan.jpg

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#17 2019-08-11 14:20:37

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,235

Re: Composting Toilets

Which means we are sending the toilet and system to make it work which makes it not a composting type as posted in #16...as Robert Dyck indicates we are somewhat unable to change our ways....

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#18 2019-08-11 20:12:04

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,235

Re: Composting Toilets

Found it Toilet Systems

As time passes we forget or the search engine fails to find the topics and some may even be under the wrong location in the forum...

edit
we also take about bamboo here as well
http://newmars.com/forums/viewtopic.php?id=8918

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