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I want to try turning human manure (humanure) into compost.

How much time does it take to become compost? Or how much time it takes the compost to become humus, ready to be used as a fertilizer? Maybe this is a better phrased question.

I live in Spain.

And what's the best carbon material to use? Straw (hay)? Sawdust? Autumn leaves?

Joe Jobs
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  • There are a lot of variables that can affect the rate. But why would you want to compost human manure? – That Idiot Oct 09 '14 at 17:17
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    possible duplicate of [Is it OK to use human waste or spent cat litter for fertilizing edibles?](http://gardening.stackexchange.com/questions/14249/is-it-ok-to-use-human-waste-or-spent-cat-litter-for-fertilizing-edibles) – The Flash Oct 09 '14 at 18:29

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The problem with composting crap is the possibility of contagion and parasite transfer.

Even if material is covered, it takes a lot of covering to block all the flies. Flies transfer bacteria at minimum, and smaller worm eggs aren't impossible.

However, if you want to do this, I would suggest doing it via a composting toilet. In your climate the Sunny John system should work quite well.

http://www.sunnyjohn.com/toiletpapers2.htm

This is a system of solar assisted composting, with the crap screened from flies, and maintained at a high enough temperature that you can actually kill most pathogens.

Despite this, I would not use human compost on a veggie garden, but rather use it on the flowers.

In passing: Much of the nitrogen is in urine. Urine, unless you have a bladder infection is sterile. Sterile enough that if you have an injury in the bush, it's an acceptable substitute for clean water. It has enough stuff in it that it will grow a bacteria culture fairly soon, but you won't transfer pathogens from one person to antoher through pee. Go pee on the compost pile.

Sherwood Botsford
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  • Parasite eggs and protozoa (such as toxoplasma gondii) can be found in urine. I suppose the chemicals in urine might kill some pathogens, though, but I wouldn't count on it being sterile. – Brōtsyorfuzthrāx Dec 20 '14 at 01:25
  • Urine is not sterile. – flowerbug Apr 27 '20 at 04:35
  • https://healthhearty.com/bacteria-in-urine claims that normal urine does not have a significant number of bacteria in it. Discussion & comment on medical.SE is split on it's efficacy for cleaning a wound. – Sherwood Botsford Apr 28 '20 at 12:31
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From Mother Earth News:

About a year with straw and comfrey as the carbon materials. This was in a climate cooler than that of Spain.

J. Musser
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Longdaysjourneyintocode
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    Read the article again: it was over two years from start to finish. – Niall C. Dec 02 '14 at 15:07
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    It actually says: "After 11 months, the 50 garbage cans were dumped into one large pile. After another year of composting with only comfrey and some old straw, Klehm delivered a fluffy compost" – J. Musser Dec 02 '14 at 15:08
  • Read the previous sentence @J.Musser, the one that starts with "For three months..." – Niall C. Dec 02 '14 at 15:10
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    Ah, there it is. I personally think the whole process described is rather unsanitary. – J. Musser Dec 02 '14 at 15:12
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The best description of the process and issues I have found so far is covered in The Humanure Handbook which is well worth the read.

flowerbug
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