I am not actually a trained biodigester technician, but I did help organize a one-day workshop at my neighbor's house last month, and invited four trained and fantastic Peace Corps volunteers to my site to show us how it's done. I presented on the nutrient cycle of a farm with my amazing friend Lydia (her website Pedal and Plow, I recommend checking out!) and coordinated logistics of the workshop. Thanks to the help, know-how, and skills of these volunteers, we successfully carried out a 30+ participant workshop, and installed the first (hopefully not last!) biodigester in my community, La Novia.
The need and utility of a biodigester is very important, especially in the developing world where cooking fuel is a major priority. Most people in my community still cook "tata yvype" - over a wood-fire on the ground. Some families have a cook-stove that uses a chimney to funnel out the smoke, but not many. The process for collecting firewood can take up hours of the day since people must go farther and farther away for usable wood. There are many other issues here, too - it is mainly a woman's job, it increases deforestation on already disappearing forests in PY, and the smoke created from the fires is a serious respiratory and health problem. Needless to say, an alternative to collecting firewood can be a huge change to the way a family prepares their food.
There are also families who use a gas stove, but the propane is super expensive and those who have them use them selectively and never to cook main meals or anything takes a long time to prepare. An alternative to buying expensive gas tanks is using charcoal, which is also widely used. The charcoal is pretty cheap, but this still has the same health and environmental risks as firewood. Making gas from a resource that is abundant, smoke-less, and free (ANIMAL POOP!) can have a significant impact.
I thought I'd show some photos of the finished product, and hopefully this sheds some light on what it is, and how it's used!
You start with a mix of fresh cow manure and mix it with water in a 20-liter bucket. The ratio is about 1/4 poop to 3/4 water.
Note: it can be pig manure too, it's actually better, but because families who own pigs generally kill them to sell the meat, it's not a consistent source of manure. Cow manure is more of a sure-thing, since cows are kept for milking.
You stir this mixture very well, and then add it to the 'entrance' of the biodigester.
This is the other side of the biodigester, the 'exit', which has a bio-product of organic liquid fertilizer! You collect this liquid in a bucket, as shown, and then dilute it and apply it to the garden to help crops grow!
The view of the back of the house, the biodigester is right behind it, which it's own fancy roof and fence to keep out animals and protect it from the sun.
Side angle of the biodigester, with plenty of room to walk around inside.
The security valve, which connects the tube from the biodigester, to the tube that will connect to the stove-top.
The biodigester! To understand better, those are two 200-liter barrels at each end, with both ends cut out. The plastic tube is made up of 3 layers of heavy-duty plastic, and is connected by that green hosing to the security valve on the wall.
Hope that explains things better! At the end of August we will try and see if the gas is sufficient enough to light a flame. It makes about a month for the microorganisms to full decompose the organic matter that is there, and create enough biogas to start a fire. I'll keep you updated on the progress :)
All my love,
Meagan
