5 ms·

> "For every ton of phosphoric acid produced, the fertilizer industry creates 5 tons of radioactive phosphogypsum waste..." Is that correct? That sounds unsust

> "For every ton of phosphoric acid produced, the fertilizer industry creates 5 tons of radioactive phosphogypsum waste..." Is that correct? That sounds unsustainable, as well as unprofitable. Also, is it safe to presume that if the cost of proper disposal was reflected in the price of food, food would be significantly more expensive? Finally, are there particular foods this is used for?

pfdietz 6y ago
Phosphate is the most limiting long term global mineral resource. Eventually we're going to have to mine it from average rocks (at 0.1% concentration). There is no substitute if you want agriculture.
- deleted 6y ago
  [deleted]
ta988 6y ago
Almost every crop. The problem is also that those phosphorous fertilizer are horribly inefficient , plants dont absorb much and most of it gets leached. So out of this 1 ton not a lot gets absorbed by the plants. To this, we need to add the fact that phosphorous reserves are limited, some estimate that we will reach the peak P in 2030. Maybe then we will be forced to think about more sustainable approaches?
samus 6y ago
In the past, people used their own manure and that of animals to fertilize fields. Manure contains lots of phosphorus as animals actually absorb only a small percentage from nutrition. Urbanization broke this cycle. Sewer systems got established and the phosphorus doesn't end up on the fields anymore. It eventually reaches the rivers and seas and passes into the sediment. What a waste (pun intended). Instead, people started to mine graveyards (for bones) and guano on remote pacific islands... Edit: Urine might work even better because reprocessing it is way simpler than dealing with manure. The nitrate and sodium levels have to be adjusted. Also, excreted pharmaceuticals have to be neutralized. Meanwhile, with manure one has to deal with pathogens, eggs of parasitic worms and a host of other ingredients, which might be difficult to predict in urban settings.
- nitrogen 6y ago
  The processed sludge from sewer plants is still sometimes used as a fertilizer.

pfdietz 6y ago

Phosphate is the most limiting long term global mineral resource. Eventually we're going to have to mine it from average rocks (at 0.1% concentration). There is no substitute if you want agriculture.

deleted 6y ago
[deleted]

ta988 6y ago

Almost every crop. The problem is also that those phosphorous fertilizer are horribly inefficient , plants dont absorb much and most of it gets leached. So out of this 1 ton not a lot gets absorbed by the plants. To this, we need to add the fact that phosphorous reserves are limited, some estimate that we will reach the peak P in 2030. Maybe then we will be forced to think about more sustainable approaches?

samus 6y ago

In the past, people used their own manure and that of animals to fertilize fields. Manure contains lots of phosphorus as animals actually absorb only a small percentage from nutrition. Urbanization broke this cycle. Sewer systems got established and the phosphorus doesn't end up on the fields anymore. It eventually reaches the rivers and seas and passes into the sediment. What a waste (pun intended). Instead, people started to mine graveyards (for bones) and guano on remote pacific islands... Edit: Urine might work even better because reprocessing it is way simpler than dealing with manure. The nitrate and sodium levels have to be adjusted. Also, excreted pharmaceuticals have to be neutralized. Meanwhile, with manure one has to deal with pathogens, eggs of parasitic worms and a host of other ingredients, which might be difficult to predict in urban settings.

nitrogen 6y ago
The processed sludge from sewer plants is still sometimes used as a fertilizer.