Role of urine in Permaculturally based toilets

I've got questions about the use of urine as a fertilizer and how it impacts all the other Permaculture Principles I'm trying to wrap my head around. Any input welcome!!

Permaculture Principle that artificial fertilizer is bad as it kills the natural balance between the soil organisms and plants. It makes plants grow artificially fast so that they're weaker and have fewer of the important micronutrients needed for good health.
So..... how is urine different? If you fertilize with this "liquid gold" aren't you going to have the same effect on the plants and soil, although at least you're not using fossil fuels to get that effect?

Permaculture Principle that plants should be grown using water-conserving systems such as swales/hugelculture/good design rather than relying on irrigation. Once plants become used to irrigation, they can't cope without it.
So..... how can you dilute the urine to the 1:20 ratio with water and not be essentially irrigating your plants?

If my concerns above are valid, what are the alternatives? At the moment, those in the household with "Y" chromosomes pee in jugs which can be poured onto a mulch pile. This breaks Paul's principle of not using a noisy, fossil-fuel dependent machine to turn larger bits of wood into smaller bits, but where we live, wood is plentiful and becomes a fire hazard in the dry summers, and the wood chips are hugely useful on paths. Life's a compromise.

Is the focus on "urine diversion" all about keeping the poop down to a smaller mass, and *not* having to add as much low-nitrogen material such as sawdust to the composting process? If so, how do we set up a system that makes the diverted urine into a really useful, Permaculturally beneficial raw material? I suspect that part of this whole issue is knowing the right density. We're very forested, so I believe light is the more limiting factor in growing things than nitrogen. That being said, I often find that when I'm confused about seeming contradictions in principles being raised in the literature and at Permies.com {sorry Paul, but you say composting is bad, but you also seem to say that Humanure (a form of composting) is good and that heating your shower water with animal poop (also a method of "hot" composting) is also good, so my sad brain gets confused} that other people may be wondering the same thing and feeling like it's a bit like the old saying about an Elephant in the room! How much urine can be added to an eco-system and stay beneficial? Please enlighten me!

A toilet is first and foremost a tool to prevent human waste from contaminating water and perpetuating cycles of disease and parasites. Most of the pathogens in human waste are not tolerant of dessication, so separating the urine and keeping the material dry for 6-24 months depending on climate can greatly reduce risk. Hot composting afterwards reduces risk even further. Once we have achieved the goal of treating human waste so that it can't hurt us, we are left with a bunch of fresh urine (produced daily) and a pile of humanure every 6 months or so. The idea of putting it on plants is a way to turn a waste into a resource. It might not be 100% in line with ideals of making plants provide all the nutrients for each other, but its far better than having a giant vat of urine and nothing to do with it. Plus, we are removing nutrients when we harvest food, and it is good to return that to the land.

My general rule of thumb is to look at the area required to provide food for an animal. If waste is returned to that same area, it is unlikely to cause any nutrient excesses resulting in runoff or leaching to water. For example, if your pasture can produce forage for 6 goats, doing spread the manure and urine of more than six goats on it. Same goes for people and their food base.

Hi Izzy,

I agree that most pathogens don't tolerate desiccation, but I'm told that "composting" only happens if the material being composted has the moisture content of "a wet sponge" which will not cause death by desiccation. That is why some people recommend that animal manures be dried *after* composting - to kill pathogens that might remain. Having read the book, "Teaming with Microbes" the goal in soil building is to have the good guys out compete the bad guys and I would expect desiccation will kill both. What I've read about Humanure composting suggests that time is the main factor used to reduce the dangerous microbes, and possibly air as well, as many of the bad guys are anaerobic.

That aside, your approach of balancing the distribution of urine to the square footage of land producing the food makes good sense to me.

Thanks

The advantage of dessication of human waste before composting rather than after is that a dry, cool pile can be stored near or in the toilet. An actively composting pile will attract insects and produce at least some smell, even if its just of ammonium. This is better done away from the toilet, and I would rather not move fresh, wet waste. Much more pleasant to let it age a bit in a multi chambered design. It will be lighter to move that way too.

I'd rather reduce the pathogen load before composting also because it's hard to control leaching from compost piles and I have no tolerance for fresh human waste leaching into ground or surface water.

I don't see it as adding urine to a system, I see it as cycling nutrients within a system. If the land is feeding you, then you are most certainly part of that system and returning urine to the system is as natural as a cow peeing on her pasture.

At my place, the boys pee outside wherever seems appropriate. Mine generally gets collected in a bucket. Sometimes I pour that on the humanure heap, sometimes I pour it along a strip of ground I'm starting to prepare for planting - it enriches the soil but tends to kill off any grass if I apply it liberally, so the soil is ready for planting in. Sometimes I pour it on top of hay mulch to keep critters from nibbling my plants. Every system is different and part of the fun is in finding the best solutions for you, even if they don't seem 'perfect' by anyone else's definition. For instance, I use bark chips on my garden paths because there's a heap of bark that has fallen off the pine logs that the boys sawed up for last winter's firewood. I treat it almost like a game to figure the best ways for me and my system.

Hi Burra,
Thanks for the good ideas. I just happen to have a grassy patch that I really want to get planted and have been avoiding dealing with. Using some urine to knock the grass back sounds like a great way to start.
Do you water it down at all when you pour it on hay mulch?

Hi Izzy,
I get your point - if the urine is separate, getting the poop to dry would be possible even in this climate, although I expect it would require the addition of something like sawdust. Then when one wants it to decompose, one might have to add some urine back in to balance the "brown" sawdust that was used to dry it. What I recall is that human poop on its own is already at the right balance of brown/green to compost well. (Sorry, can't remember the reference.) If we add more brown to reduce its microbial load, does it become out of balance? How exactly are you getting yours "dry"? How do you then compost it? In my shady, cool environment, it takes a large pile to get a hot compost and that's hard work. One group on this Island that do have a humanure composting system that I know of, have a fairly complicated purpose built system which isn't practical on my property, and the second uses a batch composting system, but I don't know if they separate the urine or add a lot of brown to balance it. I do know they are in a much sunnier location. I will try to find out more information on their system. As Burra wrote, fitting the system to the environment is part of the fun, and perfection is certainly not what Mother Nature's all about!

If I had to choose between the two, I would much rather recycle the urine onto the land than the humanure. The majority of the nitrogen, at least, ends up in the urine. I have grown many a crop of nitrogen-hungry stuff like corn, wheat, nightshades, and brassicas for which urine, diluted or not, was the only soil amendment. These and others will really show a yield difference with one or more dilute-urine topdressings at crucial growth stages.

Sawdust seems to be the most readily available material that works well. Wood shavings or dry leaves can work too, but they tend to hold more air and don't cover over the feces quite as well, meaning more access to flies, smell, etc.

You're right - adding a carbonaceous material to human feces will raise the carbon level too high to compost. After dry storage, there are two possibilities. If the material has been kept dry, the pathogen load should be as minimal as from city sewer treatment plants, so you could just apply the dry mix (which will look like aged sawdust, starting to turn grey) on the soil surface as mulch around large plants. It will break down and slowly release the nutrients. But more importantly, you have treated human waste so it won't make anyone sick.

To be extra safe, the material can be hot composted, which would require the addition of high nitrogen materials, as you said. Urine works, but as Alder pointed out, it seems a waste to have much of the nitrogen off gas in the composting process instead of being drawn down into the soil with water and immediately used by plants.

In your original post, you mentioned two ideals - minimize work (don't make compost piles), and be water-efficient. In many places, it's very difficult to grow food without using ANY irrigation. The ideals of permaculture are meant to give you a destination for your journey. It's ok if you don't make it there in your first step, or ever. The important thing is to walk in the right direction.

I garden in a region with 8" natural precipitation each year. I don't feel bad at all about mixing my urine with 10 parts water and adding that to the garden. It's the best way I can think of to turn a waste into resource.

Jay, I agree with your questions about urine as fertilizer. Yes, it's much like soluble fast acting fertilizers which we avoid by building up our humus and soil nutrients. For those purposes, it's better to have a fully composting toilet with a carbonaceous cover material, making nice humus for you to add to the soil much later. But sometimes one has to collect urine for one reason or another (eg if your outhouse seems far away on winter nights), so then you can use it, diluted with water, on places that would like the quick nutrients.

Izzy Bickford wrote:Sawdust seems to be the most readily available material that works well.

Hey guys. I was wondering if anyone had any suggestions for making sawdust if you don't have a source?

You could try for smaller sources instead of an actual sawmill. I am producing quite a bit myself this year by cutting my winter wood supply in one small area with a chainsaw. Most firewood producers consider sawdust a waste and haul it away to be dumped so I am hoping that I can come up with a good local supply. You could also consider a local alternative such as leaf mulch, coffee grounds or almost any plant based material that is or can be mulched easily. In the fall I am going to try leaf mulch myself as an experiment and I would also like to try coffee grounds. Good luck with your hunt Michael.

We used leaf mulch for a bit but found it didn't get the surface contact that sawdust gives, allowing a little more smell to escape and more flies around. Try to get bone dry leaves and crush them to maximize surface area. Ash could also work if that is more plentiful and if the soil where you will be applying the material is not already alkaline.

Where are you located that sawdust is hard to find?

Ash, the leftover from burning not the wood, can't be used for cover material if you want to compost. Cover material for a toilet receptacle that is going to be added to a compost pile needs to be a fairly fine plant based material. Sawdust, rice hulls, leaf mould, coffee grounds or any other available former plant matter that is the right consistency should work.

How about finely shredded paper? I have a cross-cut shredder and my line of work generates tons of paper.

I have been told that paper can work, not sure of the type etc. Some people mix cover ingredients to produce something workable. So far I have only experimented with varying types and coarseness of sawdust so I have no practical experience with anything else but I do want to experiment.

From what I have read the key is experimentation, if the material doesn't work try changing the coarseness or shift the base material slightly and try again. In paper you are going to have the choice of thicknesses, gloss and type. Newspaper vs legal documents vs computer printouts etc.

Have you read the back threads on the http://humanurehandbook.com/ forum. I just reviewed a thread where two users said they used paper successfully but they didn't state the form that it took. I will ask.

If you are planning to use the dry material for urine in a watertight tank, I warn you that it takes really huge amounts, more than you imagine. Ask me how I know... I've tried leaves (last winter), and rough sawdust and shaving (this winter). Just a barrel, and only for those winter nights when the outhouse seemed too far away, but a single barrel of dry material is not enough at all. Liquid accumulates at the bottom, goes anaerobic and makes stinky methane.

I'm planning on separating the urine from the rest.... Does this make the question easier to answer?

For many years I used dry clay soil as a cover material in my humanure bucket. I was separating the urine, and using it for direct burial, mostly under permanent plantings. I figured that if clay based kitty litter was a good deodorant, then it should work for me too, especially since this bucket was indoors. I kept that bucket in a small apartment for ten years, and nobody whom I didn't want to find out about it (such as the landlord) ever discovered it......

Rebecca I am surprised you don't do an indoor sawdust toilet as well as the composting outhouses if you have the cover material available. You could add each pail to the compost chamber instead of having a compost pile.

Michael I am curious why you want to separate the urine?

Wyatt Barnes wrote:Rebecca I am surprised you don't do an indoor sawdust toilet as well as the composting outhouses if you have the cover material available. You could add each pail to the compost chamber instead of having a compost pile.

Yeah, I'm surprised at myself too. Social issues... Maybe I'll get it together eventually.

Wow that sounded just like me when I wonder why I have put up with something fixable for years. I tell people I have a high tolerance for crap. No pun intended.

Wyatt Barnes wrote:Michael I am curious why you want to separate the urine?

Because I want to use the waste for fertilizer and I've read that mixing urine and fecal matter allows the urine to evaporate, loosing a great deal of the nitrogen, plus separating them helps with the smell.

A couple of thoughts, if you are using a compost pile to create food grade compost I am not sure how much nitrogen is lost but I expect it is minimal, and separating the urine from feces does not solve the odour problem, it gives you odour in two different containers.

Cover material will stop an odour problem and it also balances the material in the compost pile while increasing the volume of usable compost at the end of the cycle. If the cover material is well chosen then you are probably also taking an otherwise unused resource and introducing it into your food cycle rather than buying man made alternatives.