Breathing new life into old technology

Filed Under: EARTH Stories
Date: February 14th, 2014

Raul Botero, professor of Integrated Farm Production Systems and Environmentally Friendly Animal Production and Health.

Since joining the faculty at EARTH University in 1994, Raul Botero has answered to many names, including “Doctor” while performing surgery on a sick animal, “Botero” from friends and colleagues, and most often, simply “Profe” (short for professor) by the hundreds of students he has guided throughout his 20 years at EARTH. As a teacher of Integrated Farm Production Systems and Environmentally Friendly Animal Production and Health, Raul has dedicated his career to demonstrating that raising livestock can be done in harmony with the environment, in sharp contrast to the industry’s reputation. One of the ways he has proved this to EARTH students and the global community is through his dedication to promoting biodigester technology not only within the University, but also in countries across Latin America, the Caribbean and Africa. Biodigesters treat and contain animal waste (among many other materials) and convert it into biogas which can be used as a fuel source to cook and heat, making it a versatile and environmentally friendly solution for waste management and sustainable renewable energy.

A veterinarian by trade, Raul earned his degree in veterinary medicine and animal science from Caldas University in his native Colombia, and in 1986 started a master’s degree in Tropical Animal Production from the Tropical Agricultural Center for Teaching and Research (CATIE) in Costa Rica. It was at CATIE that he met Dr. Thomas Preston, an Englishman who had spent years researching in Asia to become an expert on biogas and the Taiwanese style biodigester, which had already been used for centuries to collect biomass and “digest” the matter while simultaneously collecting the natural gases.

Professor Raul Botero and colleague Dr. Thomas Preston installing a biodigester as part of a learning module at a prison in Colombia, circa 2004.

Raul credits Dr. Preston as being “the father of the modern biodigester, the one who taught us all about what sustainability really means,” and states that, “Before I started working with him, I had an idea about what the technology was but really, I didn’t know much. I helped him to adapt the technology to be very affordable, environmentally friendly, and to fit with the available materials and climate in the tropics. For example, the original model has a concrete base and costs around $4,000, which is an almost impossible investment for a small producer in Latin America. Our revised model uses a polyurethane bag and many repurposed materials and costs just $200, making it infinitely more accessible.”

The duo jointly published the first comprehensive installation manual and began installing biodigesters in Colombia that same year. They later founded the Center for Research in Sustainable Systems of Agricultural Production (CIPAV) where Raul served as executive director and co-founder before coming to EARTH.

After witnessing firsthand the positive effects that biodigesters had created in communities in Colombia. Raul was eager to share his knowledge with EARTH. “I put the first [biodigester] right next to the pigpen at EARTH. It lasted 11 years, and would have lasted longer but there was a cat who liked to sharpen his nails on the bag in there because it was always nice and warm,” he laughs.

EARTH now has eight biodigesters spread throughout the grounds that treat much of the animal and human waste produced on campus. Some of the biogas is being piped directly into the cafeteria to cook the thousands of meals it serves every week. They vary in size and design, but five of the models are the same Taiwanese style that Raul has perfected over the years.

Most of the students at EARTH arrive knowing nothing or very little about biodigesters, and show great enthusiasm and interest in learning exactly how to install, repair and fine tune the systems. “Every student that takes my class will leave the University knowing how to install a basic biodigester, without a doubt. Right now, we are installing biodigesters in the Las Lomas community near EARTH’s campus and we go in groups of 25 students, that way they all get real hands on experience.”

A Taiwan style biodigester installed in February 2014 by EARTH students and faculty in the Las Lomas community.

When the class goes out into the community, they learn that the real impact of a biodigester isn’t measured just by the money saved on cooking gas; it’s about initiating a change in the way people interact and care for the world around them.

Raul explains, “Installing a biodigester means less dependence on firewood, which obviously leads to less deforestation. Traditionally, the job of collecting firewood falls on women and children, and using biogas means that they can stop getting wet while they walk for miles looking for wood and they don’t have to breathe in the noxious wood fire smoke. They can have more time to study or the mother can have a garden or some chickens because she doesn’t have to worry about looking for a fuel source. Even the effluent that comes out of the biodigester can be put back into the garden as a natural fertilizer.”

Even after installing more than 3,000 biodigesters in Colombia, Costa Rica, Mexico, Ecuador, Venezuela and several countries in Africa in his 28 years of working in the field, Raul is still as passionate as ever about the impact they have on communities and on the students he teaches.

“I still get calls all the time from graduates who ask me questions or advice about a project they are working on, and even though it takes up a lot of my time I feel I have a moral obligation to assist them because I know they are trying to help a farmer or a family or an entire community. To me, biodigesters are worth putting in to practice because reading it in a book is not the same as digging into it with your own two hands and seeing the changes you can make.”


  1. Alex Kyeyune says:

    Thanks alot Dr. Raul And Dr. Thomas, this article inspires me to join EARTH UNIVERSITY, if such knowledge is brought to Uganda after my 4years study at EARTH UNIVERSITY, we shall indeed clean environment in our cities and villages but mostly to our pigfarmers through their lead group PIG PRODUCTION AND MARKETING UGANDA LIMITED, We have visited several farms with smelly environment due to poor waste management, with such cost effective way of waste management alot of farmers will benefit and many youths and women will have access to jobs hence living a safe and healthy life in a healthy environment.


  2. Helen Martínez says:

    El Profe Botero, excelente profesor! Excelente calidad de persona! Se lo extraña mucho! Una inspiración!

  3. Grethel Diaz says:

    Definitivamente Don Raul es uno de los mejores profesores que puede tener la Universidad!!! excelente persona, excelente academico!!!

  4. juan carlos says:

    gracias MAESTRO

  5. Fabian Castillo Pinos says:

    Don Raúl, que gusto saber de usted y que gratos recuerdos de mi paso por EARTH. Sin duda el biodigestor es una excelente herramienta para contribuir con el cuidado ambiental. Ahora más que nunca entiendo su pasión por enseñarnos su utilidad e implantación. Le envío un gran abrazo y mi más profundo respeto, principalmente por reforzar mis conocimientos con la famosa matemática de “noturna”.

    Fabián Castillo (promo 2000, Ecuador).

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