370 sq m for human waste per person?

Discussion in 'Planting, growing, nurturing Plants' started by digging, Sep 21, 2010.

  1. digging

    digging Junior Member

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    I've been thinking about the amount of land needed to properly use composted human waste, and I've used
    animal numbers and compaired body weight and came up with this amount of land. So could someone even in on a town/city lot safely spread thier compost toilet waste? I think so! So we could become dynamic accumulators for our own land every time we ate food from afar as long as we only did our business back at home!

    Digging
     
  2. grassroots

    grassroots Junior Member

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    Digging, is this square meterage the area needed for composting, or is it the area needed to spread it over the garden without having any problems?
    Great thinking!
     
  3. digging

    digging Junior Member

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    No not for composting, that would be done in a small contained area just for the 'poo', after when it is finished , which takes 1-2 years, 370sqm would be for spreading it, even though animals drop where they want! However Joel Salaton from polyface farm does compost his cow manuer before adding it to his fields after winter housing so then there is no water pollution etc. Thus it is very good pratice to do so. However there is a limit as to how mcuh the earth and living plants can take up, so the question how much land to spread and use our own waste without over fertilizing.

    Here are some great links on composting urine diverting toilets.
    https://www.appropedia.org/WaterPod_Composting_Toilet
    https://www.youtube.com/user/peakmoment#p/u/8/tdN_3x8VNCY

    Digging
     
  4. Burra Maluca

    Burra Maluca Junior Member

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    We compost *everything* from four people, and, by the time we've added suitable cover material and allowed it to all rot down for a year, we end up with around a cubic metre of compost per year. If this was spread over 100 square metres, it would cover it to a depth of 1 cm. If this was from one person, spread over 370 square metres, it would only be about a milimetre thick - hardly 'over fertilising'...

    Another way of looking at it, using your own figures, is that your daily poop would provide for one square metre - dunno 'bout you but my soil needs more than that!!
     
  5. digging

    digging Junior Member

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    How do you handle the urine? If you save it and use it for fertilizer the urine alone can treat 275sqm, so the manuer part is the other 100sqm.

    Digging
     
  6. Burra Maluca

    Burra Maluca Junior Member

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    All the urine I can collect (the boys just tend to use trees...) gets poured on one or other of the compost heaps. I'm not actually arguing with anything you say - we're both pretty well in agreement that unless you have a seriously tiny garden, you aren't going to overload it with your own composted wastes. It's just that I have a seriously non-tiny garden, with seriously poor soil, and I like to add more. For me, the best use for the urine is to speed up the composting of stuff like sawdust that I fetch from a local sawmill. My soil needs nitrogen *and* humus - it's really thin as well as deficient in nitrogen, so I'm a bit of a composting freak. And a mulch freak for the forest part of the garden - I can't compost enough for all of it!!

    Actually, my other half is nagging me to break open last year's humanure heap as he wants it for the garden. Do you want a photo of it 'in the heap' and then a follow up one of the area it covers when it's spread? It might give you a better 'real world' view rather than just playing with numbers.
     
  7. digging

    digging Junior Member

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    Yes post it! I had a composting toilet for three years until we moved to a new piece of land so now we need to build a new one. Have you considered adding a hand full of biochar into your composting toilet with your shavings? I think I'm going to do that with this next one, it will help and more permanent carbon and compost the char at the same time! I think if you diluted the urine and watered over your areas it might be a way to increase your plant thus carbon growth on your property and then you could start a upwards climb of building humus faster!

    Digging
     
  8. Burra Maluca

    Burra Maluca Junior Member

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    Here's some photos of last year's heap.

    This one is what it looks like from just after pulling the front 'screen' away. Our climate is seriously dry over the summer so we try to keep the heaps enclosed on all four sides. We build the heap with a base of straw or sawdust, put all household waste and toilet buckets in the centre of the heap, then cover and surround with straw, sawdust or donkey poop. We do this roughly once a month and after twelve months we put a thick layer of straw on top to insulate the heap and attempt to keep rest of the pile relatively moist, then cover it all with a sheet. If you keep the moisture levels right, the centre of the heap reaches 65C, which is enough to kill any nasty bugs in the humanure. I'm not really sure how important it is to do that, but I feel much happier demonstrating the system to people when I can tell them that. My other half said that I probably shouldn't tell you but the best crops we had were grown when we used to just pour the contents of the old camping toilet in a trench, cover it with soil, and plant above it.

    The idea is to leave it for a full year after completing the pile. This one has only had ten months, but my other half wants it on the garden ready for autumn plantings. Over those ten months, the whole heap has shrunk considerably - it used to reach the top of the bricks!

    [​IMG]

    This is a close up - you can see that compost is well rotted down, almost black. The straw layer on top hasn't rotted down, but it's done it's job of insulating the main heap. This layer has now been pulled off and used as a base to start a new heap - I have six of these compost compounds in a row and only the first two are used for humanure.

    [​IMG]

    This is all that's left from twelve months of humanure and kitchen waste from four people, supplemented with cover materials, after I've removed the straw insulation. The infamous pink bucket is there to give you an idea of the scale. The heap measures five feet square, and very roughly I'd say that it would now contain a cubic metre of finished compost.

    [​IMG]

    More photos to follow when I've finished spreading it out on the garden!
     
  9. digging

    digging Junior Member

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    Wow I LOVE your stone fence!!!!! I wonder if you were to add biochar to your toilet perhaps you cou;d get more carbon volume?

    Digging
     
  10. Burra Maluca

    Burra Maluca Junior Member

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    Hehehe - yeah, we love that stone wall too! As for biochar, for now we add any ash from the fire and we'll also add any from the brick-oven when the boys finally finish building it, but no money to buy and we're too rushed off our feet to make it specially. For bulk, we can fetch a trailer-load of sawdust every now and then from the mill (he gives it to us 'for the donkey') and also cut the grass in neighbours' unused fields and use that for compost and mulch. Donkey produces a fair bit herself - *much* more than the 'two humans' she weighs the same as, 'cos she eats so much bulk of grass or straw. Properly composted sawdust apparently produces a really stable, long-lasting humus so hopefully all the compost we make in the other compounds will start to really add to the carbon in the soil.

    I'm hoping to get out today and finish spreading the humanure heap,if the old man behaves himself... We've made a strip 3 metres wide and I'm working my way along it putting down the amount we like to use and then we'll measure how far we get along the strip. The soil is gradually improving in the veggie garden area. When we first moved here we'd just throw kitchen waste down in loose heaps but they would never rot down until we started putting it in compounds and trying to keep them damp. If we buried kitchen waste, it would just come out the next year looking exactly the same as the soil was so 'dead'. But gradually, with the addition (and digging in - our soil was too far gone for it to work just putting it on top!) of compost, it's starting to come to life. These days, if we put half-finished compost on top the soil 'eats' it within a few months, so when we can we put compost down and then some kind of mulch on top. Ultimately, we're hoping to be able to keep the whole lot fertile with just the compost from the humanure and some mulch with no digging, but it's taking a lot longer than we thought it would to get to that stage. More later, with photos hopefully!
     
  11. Burra Maluca

    Burra Maluca Junior Member

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    OK, here's the photos...

    The strip was 2 metres wide, not 3 like I said before. I barrowed out the entire batch of humanure compost and tipped it in heaps along the strip. Then when I ran out, I parked the barrow at the end of the heaps and took a photo while my other half got busy with the hose pipe damping it all down before I started to bash the heaps apart and spread them out.

    [​IMG]

    After I'd finished playing with it, it looked like this. I think this is a reasonable amount of compost for this area of land - not too skimpy but not too extravagant either. The compost covered 15 metres along the 2 metre wide strip, so 30 square metres in all. I think most veg gardens, even small suburban ones, could easily take that amount of compost in a year.

    [​IMG]

    And here's one more piccie of my other half looking totally content and serene playing with his newly prepared veg bed and dreaming of planting cabbages to share with the donkey.

    [​IMG]
     
  12. sweetpea

    sweetpea Junior Member

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    Burra, very nice! That is a great example of composting. Because people are so focused on the contents, they forget that composting will break down all of that stuff they don't want to deal with, it just takes time. I love that wall, too! Did you build it? That is definitely a labor of love.


    Digging, by the time it's composted, it shrinks a lot, as you can see from Burra's pics. I have two acres of orchard and berries, and I barely have enough urine to feed to everything once diluted. You can also control how much compostable "stuff" you get by the amount of carbohydrates you eat. They really come flying through and contribute greatly to the pile :)
     
  13. digging

    digging Junior Member

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    Yes thank-you for sharing the pictures, I noticed it is very dry where you are! Will you mix the compost in or leave as a top dressing? I bet things will grow GREAT there, you will need to post pictures of the spot 6mnths from now when the jungle is growing!

    digging
     
  14. Burra Maluca

    Burra Maluca Junior Member

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    Digging - we are in Portugal, with it's typical Mediterranean 'summer dry' climate. This time of year, which is just at the end of summer when the nights have cooled off a little but there's still not been any rain worth speaking of, the place is as dry as a bone. But when the rain arrives, it tends to do so big time and we often end up with completely waterlogged soil for a few weeks. My other half (who is in charge of the veg garden as I'm confined to quarters most of the time) likes to get the beds ready now and the cabbages and things planted so they are established by the time the rain comes and the place turns to mush. He *did* mix the compost in, but later in the year, when the soil is moister and more 'alive', he doesn't bother and just spreads it on the surface. We'd like to mulch the surface too, so we'll have to go find some straw, or maybe go raid the forest for pine needles. More photos to follow when the cabbages (or whatever ends up in that bed) are planted and grown.

    Sweetpea - that wall was there when we arrived! The place was built over a hundred years ago by the father of the old man we bought it from, who was born and raised there. We had to promise him faithfully that we would take good care of the land and have at least one donkey on the place. The Portuguese are very very attached to their land, far more so than Brits, and he only sold it to us because his daughter died and the place would have become government property after his death if he hadn't found a new owner, so he was determined to 're-family' his old home to ensure its long-term care. Of course, when he was a lad, there were no toilets on the property at all. Everything went 'back to the land' directly! And there are still houses in the village that use the same system. Humanure composting is quite a modern addition to the place! I still think we need another donkey or two though...

    Aslo - about carbohydrates, in my case they don't 'come flying through', they stick. Horrendously! Low carb for me, and lots of hi-carbon straw/hay/sawdust for the compost! ;-)
     

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