In an earlier thread (detailed here: http://www.altenergy...and-aeroponics/), I asked whether it was possible to turn toilet water into nutrient suitable for use in an aeroponics system as part of an underground, self-sustaining home I'm designing. After further review, I scrapped the idea of being self-sufficient on food due to space limitations of the design, which simplified things. Now, while doing research on ways to recycle waste, I believe I've hit upon a novel solution. There are lots of kinks to work out and a good deal of uncertainty, but I wanted to see if any of you green folks who are wiser than I am have any thoughts on the idea.
I propose the following design: a plexiglass tank is filled with water and kept well-lit from above by LEDs. Waste from the toilet and any organic waste from the kitchen composter is shredded and pumped into the bottom of the tank. A culture of algae is kept in the tank, feeding off of the waste materials, producing oxygen. This allows aerobic bacteria to thrive, breaking down the waste more quickly and killing any harmful pathogens. The algae can be harvested periodically, dried, and used as a high-nutrient fertilizer. In my current home design, this setup is additionally used as part of the air scrubbing system: incoming and recycled air, once filtered of any particulates and chemicals, is bubbled through the algae tank, allowing CO2 to be scrubbed from the air and releasing O2 into the ventilation system.
The part that bothers me with this design is the fact that most species of algae are sensitive to chemicals. While this can be partly solved by lifestyle modifications, I worry that even basic soaps like castille soap or pharmaceutical metabolites could damage the algae culture. Also, I'm unsure if aerobic breakdown would be possible in this scenario because the algae may outcompete the aerobes. Additionally, while urine may prove an excellent food source for algae due to its phosphorous content, fecal matter might kill it if it contains pathogens to which it is susceptible. A solution to this would be to use a composting toilet type setup and then feed the algae with the finished compost. Does anyone know if any of this is feasible?
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2
Human waste into fertilizer, oxygen
Started by TheArchitect, Jun 18 2014 10:33 PM
13 replies to this topic
#4
Posted 19 June 2014 - 03:35 PM
TheArchitect, on 19 June 2014 - 01:39 PM, said:
Yes, but is it entirely safe to use untreated toilet waste to feed algae? and what of filtrates from the graywater system? Would it be better to compost the waste first, r could it be fed straight to the algae?
first somehow. (Hint-not all posters commenting may know this)
Some idea's here-
http://inhabitat.com...nd-human-waste/
http://en.wikipedia....ewage_treatment
http://www.algaeindu...ofuel-cal-poly/
http://e360.yale.edu...f_biofuel/2167/
Hope that helps.
And it's good to know that a few universities are working on the issue.
#5
Posted 19 June 2014 - 07:25 PM
TheArchitect, on 18 June 2014 - 10:33 PM, said:
I propose the following design:...... a Does anyone know if any of this is feasible?
#6
Posted 20 June 2014 - 08:31 AM
A painstakingly developed living room septic jungle system is in the Global Model Earthship from Earthship Biotecture.
http://www.earthship.com
I was just at a lecture by Mike Reynolds where he described it. It has three rubber lined tanks with vegetation of different kinds on top.
Apparently it works fine and doesn't stink. Overflow goes to a black water system.
Rainwater catchment>gray water>filters or planters>hot water or drinking water>drains divided between gray and black water.
Gray water overflow to black water septic system. Gray water for flushing / used water from dishes or clothes washing> indoor septic/gardens>graywater. Shower drain>graywater. Rinse cycles to graywater.
The black water leach field is bio type with trees/berry bushes above. No water leaves the house lot area.
The vertical scrap made wind generators for when the sun doesn't shine enough on the PV panels.
In my Earthship, the toilet is a Biolet NE compost, which works fine. The gardens also contain red and earth worms, nematoies of three kinds, fungi, and other organisms which make them composters, too. Two large composters outside are for scrap food etc. and a target for a stupid bear that eats rotting crap. Now I have a pile to put back in with my busted back. If I catch the bear, I will beat the _____ out of him with my fists or wound him with my sword cane. However, I am usually sound asleep at 2 AM or so when he is around. Deer ate all my out side zucchini before they had a chance to grow much past the transplant to outdoor stage. Now I have repellent, but it is too late this season for outdoors.
The thing is, I harvest compost from the year before in spring and add it to all my gardens.
http://www.earthship.com
I was just at a lecture by Mike Reynolds where he described it. It has three rubber lined tanks with vegetation of different kinds on top.
Apparently it works fine and doesn't stink. Overflow goes to a black water system.
Rainwater catchment>gray water>filters or planters>hot water or drinking water>drains divided between gray and black water.
Gray water overflow to black water septic system. Gray water for flushing / used water from dishes or clothes washing> indoor septic/gardens>graywater. Shower drain>graywater. Rinse cycles to graywater.
The black water leach field is bio type with trees/berry bushes above. No water leaves the house lot area.
The vertical scrap made wind generators for when the sun doesn't shine enough on the PV panels.
In my Earthship, the toilet is a Biolet NE compost, which works fine. The gardens also contain red and earth worms, nematoies of three kinds, fungi, and other organisms which make them composters, too. Two large composters outside are for scrap food etc. and a target for a stupid bear that eats rotting crap. Now I have a pile to put back in with my busted back. If I catch the bear, I will beat the _____ out of him with my fists or wound him with my sword cane. However, I am usually sound asleep at 2 AM or so when he is around. Deer ate all my out side zucchini before they had a chance to grow much past the transplant to outdoor stage. Now I have repellent, but it is too late this season for outdoors.
The thing is, I harvest compost from the year before in spring and add it to all my gardens.
#7
Posted 20 June 2014 - 03:15 PM
Not laughing at you but I can just here the bear saying the line that
Donkey said to the dragon in the first Shrek-
"And do I detect a hint of minty freshness?"
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Lot's of veggies=no odor, so the bear likes it. (Kind of like rabbit pellets)
Hope your back is better; you know we love you.
Donkey said to the dragon in the first Shrek-
"And do I detect a hint of minty freshness?"
donkey.jpg 5.24K
0 downloadsLot's of veggies=no odor, so the bear likes it. (Kind of like rabbit pellets)
Hope your back is better; you know we love you.
#8
Posted 25 June 2014 - 08:30 PM
I was pretty sure that you can't feed raw sewage to aglae, but a man can hope... it would make the design simpler, though not all that efficient. Maybe you could feed raw urine to it, but solids would be toxic. My problem now is figuring out a way to create a continuous-composting system to feed the algae with, which is more or less the same problem I had in the last thread... hmm. Just to be clear, I'm not using a standard composting setup: all water, including urine, is diverted to be filtered into pure using a very interesting molecule seive design I came across. This means that only the solids filtered out of urine, food scraps, and solid waste matter would go to the digester/composter/bio-reactor thing. I don't know if that's relevant, but I thought I'd mention it.
As for why I want to use algae, I'm still working that out. I came across the idea as a nifty way of recycling waste into useful things, not necessarily out of a need for it. However, the idea of having a self-sustaining oxygen supply appeals to me, and since I'm not growing any food on-site due to space constraints, the recycled nutrients have to go somewhere. You might as well turn them into nice, breathable air. It might even be possible to sustain an airtight environment that way with no external ventilation, there was an article years ago on a guy who built a hut on the bottom of the ocean and breathed from a vat of algae... I think it was in Popular Science. Don't quote me on that.
I'm having trouble working out a compact, continuous, waste-breakdown method. Ideally I'd like it to be a single-tank design... I'm also not sure how frequently algae needs to be fed. Based on what little I've come across, it doesn't require an insane amount of nutrients to flourish, and three people putting out NPK-rich urine and solid waste would more than fill the need of a giant vat of algae. But I'm not sure. Perhaps it could be fed off of a purely anaerobic process? either way, there needs to be a way to continuously break down waste into useful nutrients -- for a number of reasons, batch methods won't work well here. I need a slow, continuous trickle of nutrients into the algae tank.
As for why I want to use algae, I'm still working that out. I came across the idea as a nifty way of recycling waste into useful things, not necessarily out of a need for it. However, the idea of having a self-sustaining oxygen supply appeals to me, and since I'm not growing any food on-site due to space constraints, the recycled nutrients have to go somewhere. You might as well turn them into nice, breathable air. It might even be possible to sustain an airtight environment that way with no external ventilation, there was an article years ago on a guy who built a hut on the bottom of the ocean and breathed from a vat of algae... I think it was in Popular Science. Don't quote me on that.
I'm having trouble working out a compact, continuous, waste-breakdown method. Ideally I'd like it to be a single-tank design... I'm also not sure how frequently algae needs to be fed. Based on what little I've come across, it doesn't require an insane amount of nutrients to flourish, and three people putting out NPK-rich urine and solid waste would more than fill the need of a giant vat of algae. But I'm not sure. Perhaps it could be fed off of a purely anaerobic process? either way, there needs to be a way to continuously break down waste into useful nutrients -- for a number of reasons, batch methods won't work well here. I need a slow, continuous trickle of nutrients into the algae tank.
#9
Posted 26 June 2014 - 08:11 AM
Mike Reynold's design has the three tanks and vegetation which may even include algae. However, it requires sunlight for the plants and algae to live, lots of it. Only then will the plant life produce O2.
Another thing is excessive humidity buildup unless vented or condensed at an energy penalty.
The added regular septic black water system is for overflow and clean-out, with drains for gray and black water, and faucets for clean hot and cold water or gray water.
The black water is an anaerobic system, continuous flow, with bio type leach field and an orchard above.
You might check with NASA on space ship/station systems.
Another thing is excessive humidity buildup unless vented or condensed at an energy penalty.
The added regular septic black water system is for overflow and clean-out, with drains for gray and black water, and faucets for clean hot and cold water or gray water.
The black water is an anaerobic system, continuous flow, with bio type leach field and an orchard above.
You might check with NASA on space ship/station systems.
#10
Posted 01 July 2014 - 12:49 PM
From what I've read, I could do a septic-type system similar to those used by sewage treatment plants, and feed the clear effluent to algae. However, space is an issue, as the home is built entirely underground. As far as light goes, I've looked into superluminescent LED lamps. Energy isn't a massive problem, despite being off-grid, because I've worked out several designs to recover energy from waste heat, human occupants, the water filtration system, etc. Most electricity is produced by a combination of solar heating and high-efficiency plastic-based photovoltaic arrays I found browsing through research articles from MIT. Additionally, a septic system would allow for the use of geobacter to break down oils and produce electricity in the process.
As I mentioned, space is a huge concern. Is there a space-efficient method of anaerobic breakdown? My only major criteria for the system are: 1) space efficiency 2) continuous-flow breakdown and 3) variable capacity handling. I've been doing some research on MELISSA and the BioSphere systems, and I've found a few things that look promising, but so far none of them seem to meet #1 or #2.
As I mentioned, space is a huge concern. Is there a space-efficient method of anaerobic breakdown? My only major criteria for the system are: 1) space efficiency 2) continuous-flow breakdown and 3) variable capacity handling. I've been doing some research on MELISSA and the BioSphere systems, and I've found a few things that look promising, but so far none of them seem to meet #1 or #2.
#11
Posted 01 July 2014 - 06:02 PM
TheArchitect, on 01 July 2014 - 12:49 PM, said:
From what I've read, I could do a septic-type system similar to those used by sewage treatment plants, and feed the clear effluent to algae. However, space is an issue, as the home is built entirely underground. As far as light goes, I've looked into superluminescent LED lamps. Energy isn't a massive problem, despite being off-grid, because I've worked out several designs to recover energy from waste heat, human occupants, the water filtration system, etc. Most electricity is produced by a combination of solar heating and high-efficiency plastic-based photovoltaic arrays I found browsing through research articles from MIT. Additionally, a septic system would allow for the use of geobacter to break down oils and produce electricity in the process.
As I mentioned, space is a huge concern. Is there a space-efficient method of anaerobic breakdown? My only major criteria for the system are: 1) space efficiency 2) continuous-flow breakdown and 3) variable capacity handling. I've been doing some research on MELISSA and the BioSphere systems, and I've found a few things that look promising, but so far none of them seem to meet #1 or #2.
As I mentioned, space is a huge concern. Is there a space-efficient method of anaerobic breakdown? My only major criteria for the system are: 1) space efficiency 2) continuous-flow breakdown and 3) variable capacity handling. I've been doing some research on MELISSA and the BioSphere systems, and I've found a few things that look promising, but so far none of them seem to meet #1 or #2.
#12
Posted 02 July 2014 - 01:50 AM
As it stands, I'm considering integrating the various subsystems into the structure - i.e. into the walls, etc. instead of having a central processing space.
A lot of the organics recycling deals with greywater and wastewater, so I've decided to integrate that into the bathroom space. Geobacter-seeded greasetraps and a few other microbes break down soap, grease, hair and dead skin in the washbasin and shower drains, cranking out electricity and CO2. A septic tank breaks down blackwater. The problem I'm having is what to do with the algae part of things. There are a number of ways I could integrate it into the building or various other spaces within, but how do I feed it CO2? Perhaps I could take a page out of mother nature's book, and just run gas-permeable tubing through the whole house and fill it with sewage water and algae culture? CO2 leaches straight out of the air, O2 leaches out of the tubes... heck, I could probably couple it with a strain of bioluminescent bacteria and use them as nightlights. Hmm.
A lot of the organics recycling deals with greywater and wastewater, so I've decided to integrate that into the bathroom space. Geobacter-seeded greasetraps and a few other microbes break down soap, grease, hair and dead skin in the washbasin and shower drains, cranking out electricity and CO2. A septic tank breaks down blackwater. The problem I'm having is what to do with the algae part of things. There are a number of ways I could integrate it into the building or various other spaces within, but how do I feed it CO2? Perhaps I could take a page out of mother nature's book, and just run gas-permeable tubing through the whole house and fill it with sewage water and algae culture? CO2 leaches straight out of the air, O2 leaches out of the tubes... heck, I could probably couple it with a strain of bioluminescent bacteria and use them as nightlights. Hmm.
#13
Posted 02 July 2014 - 04:52 AM
TheArchitect, on 02 July 2014 - 01:50 AM, said:
As it stands, I'm considering integrating the various subsystems into the structure - i.e. into the walls, etc. instead of having a central processing space.
A lot of the organics recycling deals with greywater and wastewater, so I've decided to integrate that into the bathroom space. Geobacter-seeded greasetraps and a few other microbes break down soap, grease, hair and dead skin in the washbasin and shower drains, cranking out electricity and CO2. A septic tank breaks down blackwater. The problem I'm having is what to do with the algae part of things. There are a number of ways I could integrate it into the building or various other spaces within, but how do I feed it CO2? Perhaps I could take a page out of mother nature's book, and just run gas-permeable tubing through the whole house and fill it with sewage water and algae culture? CO2 leaches straight out of the air, O2 leaches out of the tubes... heck, I could probably couple it with a strain of bioluminescent bacteria and use them as nightlights. Hmm.
A lot of the organics recycling deals with greywater and wastewater, so I've decided to integrate that into the bathroom space. Geobacter-seeded greasetraps and a few other microbes break down soap, grease, hair and dead skin in the washbasin and shower drains, cranking out electricity and CO2. A septic tank breaks down blackwater. The problem I'm having is what to do with the algae part of things. There are a number of ways I could integrate it into the building or various other spaces within, but how do I feed it CO2? Perhaps I could take a page out of mother nature's book, and just run gas-permeable tubing through the whole house and fill it with sewage water and algae culture? CO2 leaches straight out of the air, O2 leaches out of the tubes... heck, I could probably couple it with a strain of bioluminescent bacteria and use them as nightlights. Hmm.
Sounds like all your neurons are firing.
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#14
Posted 09 July 2014 - 12:17 PM
according to my research, the average human needs 8 meters cubed of algae under cultivation to produce oxygen sufficient to breathe without external aid. Currently I'm considering a biocoil design, which would require 1795 meters of 4cm-diameter transparent tubing to sustain one person. I'll need at least three times that, if I'm going to sustain multiple people, so this might not be practical. Still, it's a nifty idea. Better than leaching usable nutrients into the ground, anyways.
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