Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
Earth Technology

Researchers Try To "Close the Nutrient Cycle" Through Better Waste Recycling 112

An anonymous reader writes "Converting human waste into usable fertilizer may become the next important development in sustainable living. 'Most conventional farms invest in synthetic fertilizer, which requires energy to produce and is associated with many environmental problems of its own. But by separating out human urine before it gets to the wastewater plant, Rich Earth cofounder Kim Nace says they can turn it into a robust fertilizer alternative: a "local, accessible, free, sanitary source of nitrogen and phosphorous."'"
This discussion has been archived. No new comments can be posted.

Researchers Try To "Close the Nutrient Cycle" Through Better Waste Recycling

Comments Filter:
  • Night Soil (Score:5, Informative)

    I believe "nightsoil men" used to sell the human waste they carried away to tanners and farmers. In any case, the idea of using human waste as fertiliser is very a very old one. The massive wastage of human sewage is probably a modern phenomenon.

  • by mellon ( 7048 ) on Monday February 03, 2014 @09:16AM (#46139679) Homepage

    From the FAQ:

    What about pharmaceutical residues in the urine? When we take prescription or over-the-counter drugs, a portion of the dose passes through us unchanged and is excreted in our urine. When we use flush toilets that are connected to sewers, these residual drugs pass largely unchanged through the treatment plant in about twenty-four hours and then go directly into rivers, lakes, or the ocean, where they can harm sensitive aquatic life and end up in our drinking water. If we spread the urine on agricultural land instead, the robust soil ecosystem has a chance to break down the drugs and biodegrade them over a much longer period of time, greatly reducing or eliminating their levels before they ever reach a body of water. In this way, soil application is a great improvement over current practice. On the other hand, plants have the ability to absorb some pharmeceuticals, which could potentially affect people eating crops grown with urine. We plan to investigate pharmaceutical levels in crop plants and, if necessary, test methods of removing pharmaceuticals from urine before using it as a fertilizer.

  • Re:Ick is right (Score:5, Informative)

    by SirGarlon ( 845873 ) on Monday February 03, 2014 @09:22AM (#46139719)
    Not just illegal drugs, either. Antidepressants have been found [salon.com] in urban drinking water supplies.
  • Re:Night Soil (Score:5, Informative)

    by Savage-Rabbit ( 308260 ) on Monday February 03, 2014 @09:27AM (#46139739)

    I believe "nightsoil men" used to sell the human waste they carried away to tanners and farmers. In any case, the idea of using human waste as fertiliser is very a very old one. The massive wastage of human sewage is probably a modern phenomenon.

    Not entirely but the extent to which we fail to recycle human excrement and urine is quite new. Many ancient societies used human waste for fertiliser although that can be a health hazard. In Roman times tanners, people who dyed cloth and other such businesses actually had pissoires [wikipedia.org] outside their shops and big signs inviting customers to please come over and relieve themselves. Apparently tanners and dyers processed the urine to get Ammonia rich solutions which they used to prepare their products. I remember a QI episode where Stephen Fry dropped this fact-bit about how the House of Lords in London used to reek of stale piss on rainy days because of the quantities of urine used to in the production of tweed fabric which was popular with the upper classes in the late 19th and early 20th centuries

  • Re:Night Soil (Score:5, Informative)

    by K. S. Kyosuke ( 729550 ) on Monday February 03, 2014 @09:31AM (#46139773)
    The night soil was untreated, though, and therefore extremely dangerous for public health. Also, they were dealing with feces, and urine is less dangerous even when untreated.
  • Re:Ick is right (Score:2, Informative)

    by Anonymous Coward on Monday February 03, 2014 @09:52AM (#46139861)

    Your bottled water is tap water run through a charcoal filter. So, you are drinking tap water everyday.

  • by Noe-Hays ( 3523525 ) on Monday February 03, 2014 @10:10AM (#46139981)

    Here's an analysis we did [richearthinstitute.org] on how many pounds of wheat (and loaves of bread) could be grown using only the fertilizer contained in one person's yearly urine output. This figure didn't make it into the National Geographic article, but it's really important for understanding the potential for urine recycling to replace synthetic fertilizers at a large scale. Of course urine-derived fertilizer could be applied to any other food or non-food crops, but we thought the huge pile of bread was the more accessible measure.

    And if you look closely at the numbers, you'll see one of the most surprising things of all: that nearly 90% of the nitrogen (and 2/3 or better of the potassium and phosphorus) in human waste is in the urine!

    Abe Noe-Hays, Research Director, Rich Earth Institute [richearthinstitute.org]

  • Re:Night Soil (Score:5, Informative)

    by retroworks ( 652802 ) on Monday February 03, 2014 @10:58AM (#46140331) Homepage Journal

    The nightsoilmen (toshers) processes, while imperfect, were much less toxic than what they were replaced by - Whitehead's flush toilet (which drove them out of business). The outflow from flush toilets in London were directed into the same dry pits as the toshers worked from, making the pits impossible to manage. With no downstream plan for the new flush toilet technology, "The Great Stink of London" came from the stormwater runoff into the Thames, which caused thousands of death in cholera epidemics.

    You are right, the work should not perhaps be romanticized, but was not given any incentive to improve... it was flushed away by the new million dollar flushable toilet technology industry. The fact is that the toshers/nightsoil industry created better than average pay in London, certainly much better than blackleg coal mining. But the marketers of "flush toilet technology" stigmatized them, and the sewage treatment plants of today are seen by many in the environmental community as a "correction" to a technological advance. http://retroworks.blogspot.com... [blogspot.com]

    During the mid 1800s another "technological advance" was the sale of mercury as a laxative. I guess it gives great bowel movements (Lewis and Clark's expedition can be tracked today by the mercury laxative residue - they ate a lot of elk and not much fiber). What I find fascinating are the parallels between the toshers and the past decade of private sector electronic waste management. Most of the "export market" buyers of used CRTs turned out to be not primitive wire burners but factories formerly licensed by Proview, BenQ, Wistron, Foxconn etc., which were purchasing very specific models of CRT for refurbishment and sale to markets like Cairo, Lagos, Jakarta and New Dehli. Like the nightsoil workers, they were flooded with product and then denigrated as "primitive recycling". The CRTs were diverted to a shredding industry designed for scrap metal. Leaded glass cullet doesn't shred well, and the glass diverted from reuse private markets still lies around. At one of the largest sites, in Hallstead PA, floodwaters engulfed the CRT cullet piles twice in the past decade, leading to the closure of the recycling facility last summer. http://resource-recycling.com/... [resource-recycling.com]

  • Re:Is It Safe? (Score:4, Informative)

    by RedBear ( 207369 ) <`moc.tenraebder' `ta' `raebder'> on Monday February 03, 2014 @04:55PM (#46144167) Homepage

    Since epidemiology is well outside my area of expertise, I have to ask: would this be safe?

    With artificial fertilizers we don't have to be concerned about the purity of the material, whereas if we were to use natural fertilizers (animal or otherwise) it introduces all of the impurities and other undesirable byproducts that come with waste. And if we're talking about human waste in particular, does that mean this would create a new cycle for pathogens? Or is there a way to process waste to remove pathogens?

    Having recently become much more educated than I used to be on this subject, I now find it hilarious (and a bit frightening) how disconnected modern society has become from good old Mother Nature. If you'll stop and think a moment you'll realize that we live on the surface of a planet where quadrillions of living organisms have been living, dying, urinating and defecating for billions of years, and until a veritable blink-of-an-eye ago there were no "waste treatment facilities" anywhere to be found. The very fact that our civilization requires artificial "waste treatment facilities" in order to survive is a symptom of just how totally disconnected we are from the natural cycles of life. Every living thing that has ever existed here for billions of years has lived by recycling nutrients from the bodily decay or waste products of other living things.

    So, asking "if there is a way" to process waste to remove pathogens is a question that should answer itself now that we are all in the correct mindset. The answer of course is that nature _is_ a gigantic and unbelievably effective and efficient waste reprocessing facility. Step out of the door of your artificial housing construct and walk to any nearby location where you might be able to grow a plant and look down. That stuff underneath your feet is called "dirt". It's composed of minerals extracted from the air by plants, leeched out of rocks by water, and more rock bits ground up by glaciers. But most importantly it's composed of lots of chemicals and compounds that either used to be part of the body of some animal or plant, or was a waste product of a living organism. If dirt, the infinitely reprocessed waste product of billions of previous excreting organisms, was going to hurt us we'd already all be long dead.

    The bacteria and other organisms that live in dirt evolved to live on the kinds of things we refer to as "waste". They reprocess it into yummy fertilized soil that plants love to grow in, and in the process kill off all the things we call "pathogens" that evolved to live inside us and are excreted in our waste. The worms and soil bacteria and the eventual heat of the full composting process creates a perfectly safe fertilizer from any kind of animal "manure", including human. They even have a name for the manure that comes from us: Humanure.

    Using this purifying ability of nature, we can even make cheap and highly effective water filters [wikipedia.org] that work by letting the soil bacteria in a column of sand kill off the "pathogens" in contaminated water as it trickles through the filter. The soil bacteria just gobbles up and destroys everything that we would refer to as a pathogen. Chemical toxins of course are a different matter. Many of those are unnatural to the environment and have to be dealt with in other ways, unfortunately. But animal waste? No problem. Nature takes care of that quite easily.

    Now, the issue of urine separation turns out to be interesting for multiple reasons. Using urine separating toilets not only makes it immensely easier to separately process and use the urine for fertilizer, it also allows one to have a composting toilet that doesn't smell bad and holds a surprising amount of waste before it needs to be emptied. Apparently that horrible latrine, RV/boat holding tank smell is caused not by the solid waste itself but by mixing the urine and solids. Separating the urine and throwing a layer of something organic like peat moss

Things are not as simple as they seems at first. - Edward Thorp