134 Building Toilets
Urine fertilizer
Some farmers use urine mixed with water as a fertilizer because urine carries
valuable nutrients such as nitrogen and phosphorous that can help plants
grow. Urine is much safer to handle than feces. However, the same nutrients
that make it a good fertilizer can pollute water sources. Also, urine can carry
blood flukes (see page 56). Because of this, it is important not to put urine into
water sources, or near where people drink or bathe.
To make simple urine fertilizer
Store urine for a few days in a closed container. This will kill any germs the
urine contains, and will also prevent nutrients from escaping into the air.
To make fertilizer, mix 3 containers of water for every 1 of urine. You can
fertilize plants with watered down urine as often as 3 times a week.
Plants fertilized with urine can
grow as well as plants grown with
chemical fertilizers, and need less
water. Plants that have leaves you
can eat, like spinach or other dark
green leafy vegetables, grow best.
Always wash your hands after
handling urine.
water water water
urine
3 jugs of water plus 1 jug of urine = safe fertilizer
To make fermented urine fertilizer
Adding compost to urine, and letting this mixture rot and turn sour (ferment),
can create new soil for planting.
1. Collect urine from dry toilets. For each liter of urine, add 1 tablespoon of
rich soil or compost.
2. Let the mix sit uncovered for 4 weeks. This will smell bad, so do it in a
place away from people. The urine mixture will ferment and turn brown.
3. Fill a large container with dry leaves, straw, or other dry plant matter.
Line the container with thick plastic to prevent water leakage through
the hole in the bottom.
4. Add fermented urine. The best mix is 7 parts plant matter to 1 part urine
(about 3 liters of urine for every 30 cubic centimeters of plant matter).
5. Cover with a thin layer of soil (no more than 10 cm). Plant seeds or
seedlings.
6. Water every 2 days with a mix of 1 part urine to 10 parts water. (This
is a weaker mix than we suggest above, because it will be used in closed
containers rather than in open gardens or fields.) The dry plant matter
will turn to rich soil in 10 to 12 months.
The new soil can be used for planting.
A Community Guide to Environmental Health 2012