Biodigesters – Got Gas?

“Each day when I awake I know I have one more day to make a difference in someone’s life.” ~ James Mann

June 16, 2014

I love my work with biodigesters. It’s fascinating stuff and for those of you non-sciency types who don’t like to read technical talk about poo I tried to keep it interesting so you’d enjoy too. Keep reading. It’ll be worth it, I promise.

I mentioned long ago that part of my work here is with anaerobic biodigesters, which decompose locally-available organic material (usually manure) and produce methane gas for cooking as well as a rich, very liquid compost that’s excellent for gardens, crops or use as a foliar spray to repel pests. I have a lot of interest in promoting these systems on farms here in PY and also because I wanted knowledge to maintain the seven biodigesters in my community, installed by the previous volunteer, I decided to be part of the Biodigester training group last year. We are a group of Peace Corps Volunteers (PCVs) with specialized training who travel throughout the country helping other volunteers teach about and install these systems in their communities. This alternative generally replaces a señora’s need to cook (and breathe) over an open fire on the ground and haul firewood. It better manages manure, smell and flies on the farm. It makes for healthier living conditions while helping abate nutrient loss into surface water and the massive deforestation that occurs in PY. Here’s the story of one such event I attended recently…

The trip to the volunteer’s community was about 11 hours by bus, including waiting in the bus terminals and alongside the road for my next rides (and missing a stop – oops). By the first bus station I was STARVING so during my ‘layover’ I went to the nearby supermarket for lunch and discovered to my delight that they had a hot buffet of prepared food. Whoa – I could hardly contain my excitement! Almost like a restaurant! After much deliberation, I’d just decided what I wanted and was about to get the señora’s attention and then I noticed it: a cockroach exploring the case and the edges of the food. My hopes sank and my excitement evaporated. I was bummed but not completely grossed out. This is PY and hygiene, sanitation and other expectations are, well, different than the US. It’s not drama, it’s just a fact. I walked away and started cruising the aisles the way teens troll the strip at Old Orchard Beach. I digress. After another tour of the store and my need for protein and carbs outweighing the underwhelming fruit and veggie options, I went back to the case. Yes, I did. Afterall, I reasoned, the insect was barely longer than my thumbnail and it was just one (that I saw) and I’ve probably eaten elsewhere with similar or worse conditions without knowing it and that roast loin with ham and melted cheese looked so deliciously inviting and I was SO hungry for something other than bus-station-empanadas. I bought my original choices and tried to push that scurrying visual out of my brain forever. My innerds remained cooperative and unaffected and I continued my journey to my friend’s community. By the time I arrived it was nearly 9pm. Two other volunteers had traveled to help as well and we sat down to prep for our morning workshop. When our travel-weary bodies called it a day, our host gave us a tour of her humble abode complete with instructions on how to use her cool, new homemade composting squat toilet (her version of an aerobic biodigester and she did a great job building it too!). This was a first for me. The composting and the squat. How I made it a year and a half in this country without an encounter with the squat toilet is beyond comprehension. I’ve been terribly sheltered it seems. The fact that the toilet was on a raised platform to allow easy management of the compost underneath combined with the outdoor spotlight that happened to shine down directly and brightly onto the squatting hole made me feel like a Rock Star Appearing On Stage every time I had business to do and stepped up onto that platform. The Leo in me saw the proximity of the neighbors’ homes and desperately wanted to do a princess wave during my inaugural visit to the throne, despite it being 10:30pm. Perhaps only Leos would understand and appreciate such an opportunity, I don’t know. Despite my Leonine leanings, I’m not especially proud of the fact that I LIKE being the center of attention and “being in the spotlight”, and this was one time I would prefer to do without either. When stepping onto the platform and standing upright, the tarp surrounding the structure came to my hips. Barely. Pun intended. I’m sure I half-mooned the neighbors on multiple occasions before getting down to business. Grateful to be no taller, I found myself hoping for a power outage when nature called after dark throughout this visit.

Sample squat toilet – basically a hole in the ground or cement platform (this is a stock image from the internet; the one described above is MUCH nicer)

At daybreak we headed to a local agriculture-themed high school of which there are many in PY. The day started with four of us teaching a workshop to 50 high school seniors about all aspects of the biodigester followed by hands-on application with the kids doing what they’d just learned. The kids were motivated and eager to see it come together, though we always have to convince new users that the gas does not make the cooked food smell like manure and the biodigesters themselves do not smell despite the hundreds of gallons of soupy manure inside because it is an enclosed, oxygen-free system. By 5pm we had started filling the plastic tube with water and were mostly done. All that was left was for the volunteer and kids to begin ‘charging’ it by adding manure the following day. They will add manure for the next three weeks before enough methane gas is produced for burning. This system was installed next to the pig barn for ease of collecting manure and putting into the system (as opposed to hauling buckets of manure across campus) and the fuel will be used to cook pig food. Pigs will provide fertilizer which produces gas and liquid compost. Compost will grow crops to feed the pigs and people. Gas will help cook the pig food (and in most cases, people food), which will result in more fertilizer for the biodidgester and meat for people. And a nice, closed-loop cycle continues!

Biodigester installation at a Paraguayan high school

The amazing volunteers who helped with this project (and the woman on the right is a volunteer’s community contact)

A completed biodigester after 2 years in use. The spout on top of the bag is where the gas exits into a hose that runs to the cooking area.

It was wonderful to participate in this installation, spend time with other volunteers, sharpen my technical and language skills, and see youth learning valuable new information and skills for their futures. And I can check “visit to a composting squat toilet” off my bucket list.