Urine

A suprisingly useful aqueous mixture of several compounds.

Production

Production of urine is a natural process for most animals.

Components

The major products of interest derived from human urine are:

• Water
• Urea, approximately 9.3g (0.66 mol) per liter.
• Salt 3g per liter
• Phosphorus, 0.4 to 1.0 grams (0.013-0.032 mol) per liter.

Other animals' urine may also include:

• Ammonia
• Uric acid

Character

• 85% phosphoric acid is 15.2 molar, so between 500L and 1200L (130-320 gal) of urine would be required to make 1L of that acid.
• 25% ammonia is 13.4 molar, so about 20L (~5 gal) of urine would be required to make 1L of that solution.

Maximizing urea content

In the ammonia production from urine process, it is of value to maximize the urea content of urine. Simple ways to do this include:

1. Collect urine first thing in the morning - urea is produced during the night, but is not diluted by additional water (not) consumed while you sleep.
2. Collect urine within 36 hours of heavy exercise
3. Collect urine from humans eating large amounts of protein rather than carbohydrates.

Obviously all of these could be done simultaneously, given the right diet, exercise, and sleeping schedule.