Hello!
Saebe, Gretty, and I (Monica) will be working together to find the best design for a biodigestor in the coming weeks. The Women of Totogalpa are looking to improve their existing biodigestor, and we will be communicating with them, along with doing extensive research, to figure out how we can best contribute.
Here is some background on the Women of Totogalpa, and the project in general.
Here's an article that describes the Women of Totogalpa, who belong to the second poorest municipality (Totogalpa) in the second poorest nation of the Western hemisphere (Nicaragua).[1] Grupo Fenix was founded in 1996 by university students and their professor at the U of Managua, and is focused on researching and delivering sustainable technologies to Nicaragua. So far, they have " install[ed] solar pumps, solar drip irrigation systems, micro-hydroelectric systems, PV battery charging centers and hundreds of photovoltaic systems in rural communities. They also built solar dryers, solar water heating systems, biogas digesters, dozens of solar ovens, hundreds of photovoltaic panels and a hand full of miniature solar cars." [2] Many new organizations also arose because of their efforts. The Women of Totogalpa is one of these organizations, that was developed after solar cookers were brought to the area.
The Women of Totogalpa built a solar center, a solar restaurant, host visitors from Grupo Fenix and improve their homes through a microloan program, improve solar cookers, are working on many other solar projects, established a scholarship fund for secondary education, have access to electricity (mostly solar). Details about their solar cooker: "The cooker design is based on a model originally promoted by Bill Lankford throughout Central America. It’s a box cooker on a stand with wheels so it can be moved easily. It has one reflector in the front of the cooker for easy accessibility. Throughout the years the women have been adapting the cooker to their specific needs, and constantly improving it and updating the design. The cookers, which have been used to roast coffee and cook rice, vegetables, chicken, cakes and cookies, don’t replace wood 100%, but definitely help reduce the amount of wood used for cooking, and the amount of smoke the women breathe throughout their day." [1]
Image [1]:
[1] http://ases.conference-services.net/resources/252/2859/pdf/SOLAR2012_0230_full%20paper.pdf
[2] http://grupofenix.org/about-us/our-story/
Each of us did some research on the topic, and our observations are recorded here!
Saebe:
Biodigestor
"Currently there are two examples of biodigestors in the community of Sabana Grande. One that is located at the Green Energy Restaurant “La Casita Solar” which runs on a combination of human waste and cow manure and another that uses the tunnel design run on cow manure. We would like to come up for a design that could be used in the households of Sabana Grande. Few people have access to large quantities of either cow or pig manure. We would like the design to be an affordable alternative to cooking with firewood. The initial installation of the system should cost no more than US$200 and should use materials locally available. Fuel to be added to the biodiogester should be on a par of what is spent weekly in firewood consumption (approximately US$3) so that this can be a viable alternative."
Unfamiliar with biodigestors, I first had to research their basic definition. A biodigestor essentially takes in manure and produces usable cooking gas and organic fertilizer. According to one blogger, "It's basically a huge plastic bag laying on top of straw, insulated between adobe walls and covered with a roof." It serves as a cheap and reliable source of energy. It has great social and environmental benefits. This project is geared towards the same community as the solar cookers, where cooking with firewood is common but dangerous to the women's health.
Existing designs:
This image from the Grupo Fenix website shows a man putting well-mixed cow manure into the biodigestor for the restaurant's use.
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Another example of biodigestors.
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Questions:
Will this be installed in the home, or outside of it?
If few people have access to pig or cow manure, is it going to be processing mostly human waste?
How complex must the design be in order to ensure sanitary outputs?
--
Gretchen:
1.) Develop a bio-digester that is suitable for household use in the community (see attachment).
The Organization
Solar Center in Sabana Grande of Puerto Rico or Venezuela
The local community
Sabana Grande is a municipality of Puerto Rico
Existing Solutions to the problem
ARTI (Appropriate Rural Technology Institute), in India: Biogas from food waste, not manure
Biodigesters: At the bottom of the tank is the fermentor, and then at the top is the gas holder. At the bottom is the manure with water, that ferments and produces methane. Apparently the tank in this particular model is separated in two-- the top part, which fills with gas, raised as the bag within the tank fills with methane. It lowers when it is empty. A cap at the top lets the methane out for use. It is good to use manure/food waste that can be totally digested by the bacteria. Bacteria feed on the food waste-- they themselves exist in the manure. They produce more methane when there is more raw food material present.
Waste is pumped into an anaerobic digester where naturally occurring microbes digest the waste and make gas. That biogas (methane and CO2 is taken to a generator).
A list of questions about the project
-is the local community in Puerto Rico or Venezuela? I could not find more information on the organization or the individuals involved
-are there food wastes in the community? Is there an existing system of food waste disposal?
--
Monica
Project: develop a bio-digester that is suitable for household use in the community.
Estado de Proyecto
Este breve resumen sirve para reclutar nuevos voluntarios adecuados para el proyecto.
Nombre de Proyecto: Biodiogestor
Colaboradores de proyecto: Solar Center
Descripción de proyecto: To design a biodigestor that will work in the reality of Sabana Grande
Estado actual: Currently there are two examples of biodigestors in the community of Sabana Grande. One that is located at the Green Energy Restaurant “La Casita Solar” which runs on a combination of human waste and cow manure and another that uses the tunnel design run on cow manure. We would like to come up for a design that could be used in the households of Sabana Grande. Few people have access to large quantities of either cow or pig manure. We would like the design to be an affordable alternative to cooking with firewood. The initial installation of the system should cost no more than US$200 and should use materials locally available. Fuel to be added to the biodiogester should be on a par of what is spent weekly in firewood consumption (approximately US$3) so that this can be a viable alternative.
Próximos pasos: To determine if this is a viable project.
--
My research:
Here is a picture of the biodigestor, located in the Casita Solar, which is the restaurant built by the Women of Totogalpa (see above description). He is loading cow manure into it, and I assume it's the brick on the group. Look, you can see the solar panels in the background! Here is a website, where they also describe the new project of generating portable solar cookers, which also seem to rely on wood. Note that the solar cookers have to be sturdy enough to cook coffee, jams, and other restaurant foods... (pic also comes from the above link)
Biodigestors can be very simple systems; essentially, you put the excrement (animal or human) into a tank, which does not have much airflow and is warm. You'll get methane gas (you can take it out of a pipe for cooking) and fertilizer due to the anaerobic bacteria digestion. If placed underground, it can be used year round, and the more complicated systems store the gas for when it needs to be used. They can be built with less than $100 with a tank and some inner tubes, and are being used increasingly in developing countries. [4]
[4] http://www.slideshare.net/raddieman/an-introduction-to-biodigestors
My questions: this sounds wonderful. I'd like to learn more about how to construct a biodigestor, what kind of scale they can be operated on, what are their drawbacks, and what are the women currently using in their restaurant.
--
On our first day, we established our goals for this group. We will not be trying to construct a biodigestor from scratch, because that would take much longer than the few weeks we have (additionally, it’s too cold outside). Thus, our plans are to communicate with the Solar Women, and research to come up with existing biodigestor solutions.
We each planned to do some research on the topic, and create a sketch for a possible design based on our research. Gredy already did a post on her research, and uploaded the three designs!
We also came up with questions to ask Lyndsey, who is at GrupoFenix and is our coordinator with the Solar Women.
Do you have any documentations/pictures of the biodigester that you can share?
Why and how did the community start using the biodigester? (Could you specify the what the goals were for the project? ex reduce reliance on trees, take care of extra animal waste)
How much gas is it producing so far?
What are the challenges that arose while designing the biodigester?
What are the current challenges of using the biodigester?
How familiar are people with the design and are they willing to install biodigesters in their households?
Could you connect us to potential users?
The current biodigester:
-who operates it? Can we talk?
-where does the waste (manure) come from? Does everybody contribute? Are there pipes involved? etc
-do some people in the community have problem with the system?
-are you primarily looking for more biodigesters or better ones?
-What is the community structure? Do people live in homes that are close to one another-- (perhaps answer this question by google maps)
Additionally, we came up with group roles:
Goal Minder- Gretty: is what we are doing getting us closer to goal?
Timeline Minder- Monica: are we hitting our dates? What can we do right now?
Community Partner liaison- Saebe: communicating with Lyndsey.
Finally, we found most of our information on practicalaction.org.
Until then,
Monica
Ps, we will alternate on who has responsibility for posting every week :)
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