Seriously though, I wish the article had more information about material strength, time and cost. Eco-centric tech like this is great in my opinion, but is it something that's actually practical?
A kiln fired brick is a 5 to 7 depending on its constituent parts.
"When urea is hydrolysed by the urease enzyme from the microorganism, ammonia is released and becomes accumulated in the medium which then increases the pH, making it alkaline (Zoheir et al 2013)
(PDF) Integrating Biotechnology into Geotechnical Engineering: A Laboratory Exercise. Available from: https://www.researchgate.net/publication/326113096_Integrati... [accessed Oct 25 2018]."
> Is large amounts of ammonia easier to dispose of than urea?
Ammonia's boiling point is -33 C, so pure urea is a gas a room temperature.
When dissolved in water, ammonia is in equilibrium with ammonium hydroxide. So the stuff can stick around until consumed by microorganism or it evaporates.
Both urea and ammonia can be used as fertilizers.
Maybe there are even earlier ones, but this is from 2010: https://www.treehugger.com/green-architecture/architect-grow...
Edit: Ahh, I guess the nuance is that the first effort used extracted urea versus actually using urine.
Here are some ins and outs on the hows and whys:
https://www.earthmagazine.org/article/p-phosphate-could-urin...