Where Does the Sawdust Go? Inside the Baño Seco

A lot of people have been asking us how composting toilets work. Now that we have two (one on-site in Tecuanipan, the other a portable toilet), they will be the primary bathrooms for future visiting groups and the after-school program. Below you’ll find some facts about composting toilets and why it makes sense to promote their use in Mexico.

What Is a Dry Composting Toilet?

  • A dry compost toilet bowl separates urine from excrement.
  • Urine (clean waste) passes through a tube directly out to the lawn or garden to irrigate plants.
  • When excrement passes into the chamber below the toilet, a cup of carbon (hay, ashes, sawdust, straw or shredded paper) is sprinkled over the waste in the chamber. This is critical for various aspects of the composting process:
  1. Compost needs carbon to help it break down into soil.
  2. The carbon neutralizes nitrogen found in human waste. This balance prevents excess nitrogen from creating ammonia, which causes foul smells.
  3. Carbon allows oxygen to circulate, permitting the compost to process aerobically. (Anaerobic decomposition creates methane, ammonia and hydrogen sulphide.)
  • Once the chamber fills with excrement it decomposes for 6 months to one year.
  • The end product is an oxidized, humus-like soil that can be used as fertilizer. 
  • Nearly all pathogens die during the decomposition process.

The Benefits of a Dry Composting Toilet in Tecuanípan

  • Because there is no sewage treatment system in Tecuanípan, human waste from the community is piped directly into the rivers. Our project works to inhibit further pollution of the waterways in this region.
  • There are no chemicals or power consumption involved in the dry composting process.
  • Composting in Tecuanípan helps sustain the local ecosystem by producing fertilizer; returning organic waste to the earth renews soil structure.
  • Composting toilets save water in dry areas like Tecuanípan.
  • Our composting toilet is made from all natural and recycled materials, minimizing costs and our environmental footprint.


This slideshow requires JavaScript.

Our after-school program in Tecuanipan inaugurated the baño seco and it is now being used by the class. Here is what one student had to say about it:

El baño seco está formado como por tierra. Por dentro tiene una figura que parece iguana o una lagartija el cual contiene vidrios en algunas partes de su cuerpo. La taza del baño está dividida en dos partes. En la parte de atrás el espacio está un poquito más grande que el de adelante porque el parte de atrás está hecho para hacer popo. Ese retrete no utiliza agua solo le echas aserrín. Todo eso serviría para algunas cosas como para las plantas.

The composting toilet was created from the land. Inside there is a figure that looks like an iguana or a lizard that has glass pieces all over its body. The toilet bowl is divided into two parts. The part in the back is a little bit bigger than the part in front because the back part is for excrement. For this you don’t use water, you just throw sawdust on top. All of this is very beneficial for many reasons, like for feeding the plants.

-Cecilia Morales Coatl. (15 years old)


“Water Efficiency Technology Fact Sheet.” EPA. September, 1999. http://www.epa.gov/owm/mtb/comp.pdf

Low Impact Living Initiative. “Composting Toilets Fact Sheet.” http://www.lowimpact.org/factsheetcomposttoilets.pdf

Hornsby Shire Council. “Sewage Management: Composting Toilet.” http://www.hornsby.nsw.gov.au/media/documents/services/sewerage-management/Composting-Toilet-Information-Sheet.pdf


About Community Links International

Community Links is an environmental, service-learning, immersion, volunteer, and international educational organization.
This entry was posted in After School Program, Construction Projects & Natural Building, Dry Composting Toilet, Service-Learning Trips. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s