Biodigester Workshop
At last, the workshop we’ve been preparing for months took place, and it was so rewarding! A big shout out to Margarita, without whose guidance, good ideas, steady support and organizing skill this could not have taken place. And deep thanks to Jakob for designing a wonderful poster.
The slogan, “Convert your wastes into new resources,” is appropriate; the inputs are manure (including human) and the products after anaerobic digestion are methane gas for cooking and a high quality liquid fertilizer.
Visiting nonworking digesters
On Tuesday, Lylian and Ricardo from Redbiocol (Network of biomass in Colombia) drove here from their farm in Guapota. After I made breakfast for everyone, six of us (including Rafa, Margarita, Somara, and me) squeezed into their car and we set off to visit four different farms with non-working biodigesters. The roads are dauntingly rough and steep. A few times I was amazed that Ricardo and Lylian’s heavily loaded car could manage to get up the hills.
The problem at Sandra’s: the distance from her digester (and pigs) to the house, around 2 km, a long way to run a hose or a ½ inch PVC pipe! The solution: she’ll receive 4 meters of greenhouse plastic for a reservoir bag, to capture gas that can then be brought up to the house and kitchen.
Two farms we visited had a simple problem — condensed water vapor clogging up the pipes to the kitchen. For one of these, we installed a simple T with a valve to allow drainage of any water before the tube reached the house. For another, a farm with at least 50 goats, we gave the PVC pipe a good shaking out and the water fell into the safety valve bottle; then re-positioned the pipe a bit.
One other farm, inhabited by two elderly people (the man used a walker), had a digester in a state of total collapse. A few months ago, a hole had been chewed in the greenhouse plastic. Perhaps a mouse had accidentally fallen into an intake port, then chewed its way out?
Although we weren’t prepared to fix it, the elderly couple nevertheless fed us a traditional soup for lunch. And after we got the water out of the tubes at the big goat farm, the smiling couple offered us large glasses full of thick, delicious goat yogurt with fruit mixed in. Margarita bought some yogurt, and I bought a creamy goat cheese. Another farmer offered us coffee.
It was so satisfying to know that two more biodigesters are back to working again, with just a bit of maintenance and improvement!
Installation Day
Wednesday morning, after a flurry of last-minute registrations and cancellations, about 17 people besides us organizers arrived for the installation workshop. Lylian and Ricardo brought a new roll of greenhouse plastic, and Paúl had purchased all other parts.
What made the day so outstanding for me?
- Lylian’s skill in drawing out the participants
- Playfulness
- Good turn-out, variety of people
- Clear shared purpose and desire to learn
- Learning the benefits (see below!)
- Hands-on construction and assembly
- Teams working together with dedication, excitement, collaborative problem-solving
- Sharing delicious hearty food together, chatting about everything from liquid fertilizer to angel wings
- Laughing with Emerita, as we got tugged around by Ricardo’s wrapping of tubes
- The small, dedicated group that stayed past dark to complete the process
- Rafa grinning as he wrapped the last wires holding the methane pipe to a support structure
- Finally seeing all the pieces put together, and a digester ready to load with manure and water!
- The enthusiastic posting of photos that ensued, as everyone strove to document this process, along with expressions of gratitude
- As Martin Prechtel might say, “The sort of smiley togetherness that keeps a village strong.”
- The fulfillment of my vision and fundraising last year!
Economic & environmental benefits
The gas expected to be produced by this digester would be worth about $233 US/year…and the expected biol (liquid fertilizer) has an impressive value of $7,450 US/year in production of crops and animals, and some sales of the fertilizer. Total cost of building a digester: $1,000–2,000 US.
CO2 avoided: a whopping 4,848.4 tons a year.
Methane emissions avoided from undigested manure: 0.373 ton. Over 13,000 kg of manure will be treated yearly.
The family’s greywater (sinks, showers, washing machine) and blackwater (toilets), currently flowing to a septic tank, will ultimately go into the digester.
Connections
I was pleased to see Serafin and Jose both there, since I’d invited them personally. Serafin is a friend of Rafa’s who lives nearby. Last year I was struck by his depth of philosophy and spirituality, despite having grown up in poverty. Jose is the musician who also co-facilitates meetings of the Territorial Foundation. He’d brought his drum with its colorfully painted deer face, and played a little riff while some assembly was going on. Other people I already knew included Somara, Sandra, and Joep, and of course Margarita and Rafa.
Teamwork
Lylian immediately involved participants, asking their goals and expectations. She gave a basic presentation on how a biodigester works. Tossing a tangerine in a playful way, she drew out people’s fears about biodigesters. “Food might taste like poop.” “The bad odor.” “Too much hard work.” “Too expensive.” (Hydrogen sulfide can be scrubbed out — no smell to the gas; digesters smell far less than the unmanaged manure; digesters pay for themselves in a year or less and last up to 14 years with good maintenance.)
In four teams, we then sawed PVC tubes, cut motorcycle innertubes into strips for binding the plastic to the intake and outlet pipes, created safety valves out of 3-liter recycled plastic bottles and ½ inch tubing, cut out rigid plastic discs and rubber discs to make the exit fittings for the biogas, dug trenches in which to lay the intake and output pipes, measured and cut lengths of greenhouse plastic. Paúl’s funny little dogs chased each other around and generally got underfoot, and a rooster occasionally crowed.
Sharing
Meanwhile, a wood fire sent wafts of smoke our way as a friend of Paúl’s cooked a sancocho (traditional festive stew of squash, potatoes, yucca, carrots, and meat). He kindly kept apart a portion for me without the meat. There was also rice, guacamole, cheese, pineapple, watermelon, and limonada. During lunch, I sat awhile with Serafin and remarked on his name; he told me that the seraphim have 6 wings, 4 of which are for protection (from the intense heat of divine light) and 2 for flying. I also received an invitation from Luis, who said he wants to learn more English.
All together!
We began assembling the digester. First, the group dance of positioning one 8-meter tube of plastic inside another (for added strength). Pairs created a ½ inch hole and snugly inserted the fittings for the methane biogas to exit. A long rope fitted with two large plastic discs was inserted; pulling the rope back and forth breaks up any crust that may form. A length of 4-inch pipe was inserted at each end for the intake and outlet; we folded layers of the plastic and secured them tightly with rubber strips and plastic tape. The same process was completed with the second bag, to be a reservoir for the liquid. As the day got later, a few participants left, a few spouses and children arrived.
A triumphant procession carried the huge bags out to the field and carefully placed each in its trench. Paul dug post holes, which took amazing strength, for a wooden support structure. After the first bag was inflated with a blower, Rafa balanced on boards above it to glue tubing in place for the methane and safety valve. As darkness fell, the few who had stayed till completion converged on the kitchen to devour some snacks.
What’s next?
In three weeks, our teachers will come back to assess, make improvements and offer guidance.
Of the initial plastic, 19 meters were used for Paúl’s digester, 15 meters for the liquid reservoir, and 4 for the gas reservoir. That left enough for three extra gas reservoirs. Sandra and Somara each received 4 meters of plastic to take home. The small entrance fees collected (total about $150 US) will go towards the purchase of more parts and plastic to help other farmers with digesters. There are around 20 in our region.