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Finish reading the article. >According to Simha’s estimates, humans produce enough urine to replace about one-quarter of current nitrogen and phosphorus fertil

Finish reading the article. >According to Simha’s estimates, humans produce enough urine to replace about one-quarter of current nitrogen and phosphorus fertilizers worldwide; it also contains potassium and many micronutrients (see ‘What’s in urine’). On top of that, not flushing urine down the drain could save vast amounts of water and reduce some of the strain on ageing and overloaded sewer systems. >In a study[1] that modelled wastewater-management systems in three US states, she and her colleagues compared conventional wastewater systems with hypothetical ones that divert urine and use the recovered nutrients to replace synthetic fertilizers*. They projected that communities with urine diversion could lower their overall greenhouse-gas emissions by up to 47%, energy consumption by up to 41%, freshwater use by about half, and nutrient pollution from the wastewater by up to 64%, depending on the technologies used. [1] http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=33319997 http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&d...

mschuster91 5y ago
> to replace synthetic fertilizers That synthetic is the key. Replacing it makes sense - but why replace current wastewater systems at an enormous price tag with "tech magic" when we could simply use existing supplies of animal dung? > and reduce some of the strain on ageing and overloaded sewer systems. ETA: Actually, sewer systems are more strained by not enough wastewater flowing through them - they were designed to the load of many decades ago, prior to the invention of water-saving toilets, showers and other appliances. Now, there is not enough water let in, and the sewage doesn't get swept away - the result is smelly [1]. [1]: https://taz.de/Wasserverbrauch-in-Deutschland/!5032936/ https://taz.de/Wasserverbrauch-in-Deutschland/!5032936/
scythe 5y ago
I don't see how that addresses the GP's key point about the cost of replacing wastewater systems in literally every household. If I imagine, say, replacing all the walls in every house with modern insulated walls, windows with double-pane glass, roofs with solar panels, etc, a variety of environmental and economic objectives can be achieved. With regard to the very shiny "up to 47%" reduction in GHGE, this appears to be relative to the wastewater system, not the economy as a whole: >Urine diversion consistently provides improved environmental performance relative to the conventional system for each scenario for all impact categories, except AP, as shown in Figure 2 (see Table S17 for data plotted in this figure). Both diversion alternatives reduced the GWP, CED, freshwater use, and EP categories from anywhere between 24 and 63%. As a reality check, there are still tens of thousands of homes in the United States using lead pipes for drinking water. The current regulatory and economic climate has made it infeasible to replace infrastructure that literally poisons people. Any reform that proposes to alter the physical structure of the vast majority of existing residential buildings must necessarily be situated in the context of laws, costs and politics that define what is possible for those buildings, and compared in terms of realistic costs and impact to the scores of other proposals to do similar things. This is a painful and depressing reality that anyone who has studied American urban development for more than a few months comes to understand.
i_am_proteus 5y ago
Yeah this here's a good post by j cranberry. At the end of the day, humans and animals are both part of a cycle of nutrient use and recycling those nutrients from waste, be that human waste or animal waste, is a way to cut down on synthetic fertilizer use. Some bits from the USA [0] [1] [2] that y'all might find informative. Important part is that manure comes in different varieties and it's not all a 1:1 replacement for synthetics in the way farmers use them today. Also of note is that, just like in Germany, parts of the USA that concentrate livestock have too much bull shit and that's bad for runoff from the livestock operations. But that's the expected result, ain't it? Concentrating feed from fields all over means you're concentrating what comes out of the animal also, which means you need to truck it off somewhere or end up with a local pollution problem. One other upside of pursuing human waste streams is that we already have a lot of infrastructure in place to process human sewage. Have a look at [3] right here and you'll see the potential— but that's still less than half the phosphorous that Europe uses in the present day. Good news is that cutting back on fertilizer input doesn't result in a 1:1 linear reduction in cereal yields so a reduction in fertilizer availability (after the phosphates get mined out) doesn't necessarily lead to a bad famine. These are complex systems here and there's no one-size-to-fit-them-all type solution. [0] https://www.ers.usda.gov/webdocs/publications/42731/16741_ap037b_1_.pdf https://www.ers.usda.gov/webdocs/publications/42731/16741_ap... [1] https://www.ers.usda.gov/webdocs/publications/42731/16744_ap037e_1_.pdf https://www.ers.usda.gov/webdocs/publications/42731/16744_ap... [2] https://www.epa.gov/sites/production/files/2015-07/documents/2006_8_25_msbasin_symposia_ia_session8.pdf https://www.epa.gov/sites/production/files/2015-07/documents... [3] https://www.nweurope.eu/projects/project-search/phos4you-phosphorus-recovery-from-waste-water-for-your-life/ https://www.nweurope.eu/projects/project-search/phos4you-pho...
causi 5y ago
Are they seriously arguing that fifty percent of a household's water usage goes into flushing urine? That sounds like bullshit.
- mschuster91 5y ago
  According to [1], toilet usage accounts for ~24% of household water usage. The missing 26% to "about half" likely comes from removing the water usage caused by the production of synthetic fertilizer. [1]: https://www.epa.gov/watersense/how-we-use-water https://www.epa.gov/watersense/how-we-use-water
  - causi 5y ago
    I'm having difficulty finding concrete numbers but I'm doubtful 26% of the world's freshwater use is making synthetic fertilizer.

mschuster91 5y ago

> to replace synthetic fertilizers That synthetic is the key. Replacing it makes sense - but why replace current wastewater systems at an enormous price tag with "tech magic" when we could simply use existing supplies of animal dung? > and reduce some of the strain on ageing and overloaded sewer systems. ETA: Actually, sewer systems are more strained by not enough wastewater flowing through them - they were designed to the load of many decades ago, prior to the invention of water-saving toilets, showers and other appliances. Now, there is not enough water let in, and the sewage doesn't get swept away - the result is smelly [1]. [1]: https://taz.de/Wasserverbrauch-in-Deutschland/!5032936/ https://taz.de/Wasserverbrauch-in-Deutschland/!5032936/

scythe 5y ago

I don't see how that addresses the GP's key point about the cost of replacing wastewater systems in literally every household. If I imagine, say, replacing all the walls in every house with modern insulated walls, windows with double-pane glass, roofs with solar panels, etc, a variety of environmental and economic objectives can be achieved. With regard to the very shiny "up to 47%" reduction in GHGE, this appears to be relative to the wastewater system, not the economy as a whole: >Urine diversion consistently provides improved environmental performance relative to the conventional system for each scenario for all impact categories, except AP, as shown in Figure 2 (see Table S17 for data plotted in this figure). Both diversion alternatives reduced the GWP, CED, freshwater use, and EP categories from anywhere between 24 and 63%. As a reality check, there are still tens of thousands of homes in the United States using lead pipes for drinking water. The current regulatory and economic climate has made it infeasible to replace infrastructure that literally poisons people. Any reform that proposes to alter the physical structure of the vast majority of existing residential buildings must necessarily be situated in the context of laws, costs and politics that define what is possible for those buildings, and compared in terms of realistic costs and impact to the scores of other proposals to do similar things. This is a painful and depressing reality that anyone who has studied American urban development for more than a few months comes to understand.

i_am_proteus 5y ago

Yeah this here's a good post by j cranberry. At the end of the day, humans and animals are both part of a cycle of nutrient use and recycling those nutrients from waste, be that human waste or animal waste, is a way to cut down on synthetic fertilizer use. Some bits from the USA [0] [1] [2] that y'all might find informative. Important part is that manure comes in different varieties and it's not all a 1:1 replacement for synthetics in the way farmers use them today. Also of note is that, just like in Germany, parts of the USA that concentrate livestock have too much bull shit and that's bad for runoff from the livestock operations. But that's the expected result, ain't it? Concentrating feed from fields all over means you're concentrating what comes out of the animal also, which means you need to truck it off somewhere or end up with a local pollution problem. One other upside of pursuing human waste streams is that we already have a lot of infrastructure in place to process human sewage. Have a look at [3] right here and you'll see the potential— but that's still less than half the phosphorous that Europe uses in the present day. Good news is that cutting back on fertilizer input doesn't result in a 1:1 linear reduction in cereal yields so a reduction in fertilizer availability (after the phosphates get mined out) doesn't necessarily lead to a bad famine. These are complex systems here and there's no one-size-to-fit-them-all type solution. [0] https://www.ers.usda.gov/webdocs/publications/42731/16741_ap037b_1_.pdf https://www.ers.usda.gov/webdocs/publications/42731/16741_ap... [1] https://www.ers.usda.gov/webdocs/publications/42731/16744_ap037e_1_.pdf https://www.ers.usda.gov/webdocs/publications/42731/16744_ap... [2] https://www.epa.gov/sites/production/files/2015-07/documents/2006_8_25_msbasin_symposia_ia_session8.pdf https://www.epa.gov/sites/production/files/2015-07/documents... [3] https://www.nweurope.eu/projects/project-search/phos4you-phosphorus-recovery-from-waste-water-for-your-life/ https://www.nweurope.eu/projects/project-search/phos4you-pho...

causi 5y ago

Are they seriously arguing that fifty percent of a household's water usage goes into flushing urine? That sounds like bullshit.

mschuster91 5y ago
According to [1], toilet usage accounts for ~24% of household water usage. The missing 26% to "about half" likely comes from removing the water usage caused by the production of synthetic fertilizer. [1]: https://www.epa.gov/watersense/how-we-use-water https://www.epa.gov/watersense/how-we-use-water
- causi 5y ago
  I'm having difficulty finding concrete numbers but I'm doubtful 26% of the world's freshwater use is making synthetic fertilizer.