After so many weeks skimming the world like a flat stone across deep water, I needed to do something.
I knew that biogas is a thing in Nepal from some Engineers without Borders work I had looked into back in college. So I emailed some NGOs I found on the internet and within a few days I was having tea at my local Indian spot with Kalyan Bastola from the Nepal Biogas Promotion Association.
Kalyan told me about some work his group was funding in the provinces of Kaski, Syangja, and Myagdi. The first two were maintenance projects and the third was a new installation. I decided I would join for the maintenance first, to get a concept of the running system and common failure mechanisms.
Quick Rundown on Biogas
“Biogas” is what comes out of the top of a reactor called an Anaerobic Digester. Its good to think about this reactor as a “digester” because this is just a pressure vessel that “digests” food- extracting nutrients and farting out the waste gas.
The food for the digester can be anything organic- from actual food, to cow shit, and many things in between.
The gas is mostly methane and carbon dioxide with trace hydrogen sulfide and water vapor, and some other miscellaneous volatile organic compounds. Good for burning.
And then… there’s that good stuff. The Digestate. Think of the Digestate as the nutrients an Anaerobic Digester would absorb if it were a sentient being and not an inert pressure vessel buried in the dirt. The Digestate is that nutrient-rich, carbon-sequestering, water-absorbing compost which replenishes the soil.
So you put shit in one end, and out the other ends you get 1.) highly calorific gas and 2.) inert carbon based compost.
And so the corn grows and buffalo eat the corn husks and then shit in a big heap in their pen. And that shit (sorry, feedstock) is gently placed down into the Anaerobic Digestor buried next to the buffalo pen. And in the Digester the feedstock decomposes into fuel gas and compost fertilizer. And humans cook their food with the biogas fuel, and grow more food with the fertilizer, and the cycle continues, as it always has, with humans nicely replenishing the carbon and nutrients in the soil and getting some energy out to boot.
The Anaerobic Digestion process for waste biomass is generally good for the planet. It definitely beats putting your banana peels into landfills, where trash is buried under heaps and thus decomposes without exposure to oxygen. When this happens, the carbon molecules have no oxygen to bind to, and thus form methane CH4. Methane is a horrible, horrible greenhouse gas.
It is much better to promote decomposition of biomass with exposure to oxygen such that the molecule CO2 can form instead, because CO2 is a less potent greenhouse gas. This is what happens when you compost.
So Anaerobic Digestion is about comparable to composting in terms of carbon emissions (assuming biogas is fully oxidized). However in contrast to composting, Digestion produces usable chemical energy for the user.
This is the idea to help rural farmers in Nepal. Its particularly potent for Nepali farmers who rely so heavily on firewood for fuel. Firewood which has been cut from the hillsides in droves, leading to landslides which cripple the nation every monsoon season. Firewood which belches ash particulate in the low-ceilinged mud-brick hut with the baby sleeping in the next room.
De-centralized, renewable energy accessible to a remote farmer in the mountains. That’s the idea.
Let’s Do It
Kalyan hooked me up with two Nepali guys, Rajan & Devendra, and soon enough we were loading our equipment onto a bus in the early morning in downtown Pokhara. I would take the bus with the equipment and the other two would ride a motorcycle down to Syangja. I stood on the busy street of downtown Pokhara with Kalyan, Rajan, and Devendra. The morning air was still cool and fresh and the sun peeked out from the hills. Taxi hawks pestered me about where I was going, trying to offer rides. The haggling abruptly ended and the bus started to move. It was packed with Nepalis brimming out the door. Kalyan and the others shouted, “Go!” and a few words in Nepali. The bus was packed and I hesitated to get on but grabbed onto the sidebar lining the doorway and pushed my onto the bus as it peeled out into the street.
The bus was packed with people standing in the aisle, and small children stacked up on the seats. I had my full “house-level” backpack on. Immediately, a man from the second to last row waved at me to come forward and gestured to the seat next to him. I shuffled through the crowd, dropped my pack in the middle of the aisle, and squeezed in next to the Nepali man.
I had a vague idea of where I was going. I knew for sure we were going to the district of Syangja, one of the 77 districts of Nepal. Kalyan had said we’d be going to the town of Mirmi. However while we were in the street I thought I heard something else… My seatmate asked me where I was headed and I had to admit I was not sure, to his total confusion and amusement. Anyway I had the equipment with me so I knew I would see those guys again.
That bus ride was tough, though saved by the majesty of the Nepalese countryside. The bus was certainly designed for the average Nepali, whose height may be about 8″ shorter than me. I was either straight backed with my knees pressed hard into the seat in front of me, or else slouched with my knees lifted against my chest. My huge bag was my right armrest, and people clambered over my bag to reach the last row. I talked at length with the guy next to me until he got off with his family. Then I slept in fits as our bus bumped along the dirt mountain roads. A varying set of people came to sit next to me, including an old women and her sleeping child who sprawled out on us both.
After a few hours, I opened my eyes for a moment and spied Rajan out my window, gesturing to me. They were pulling the equipment off the roof. I gathered my pack and scampered off the bus just before it pulled away. We moved the equipment out of the street and loaded it onto a van by the curb. Rajan told me that the van would leave at 2:30 (to go… somewhere), and then they ran off to stash some of the cargo at their buddies place.
Its important to mention that all of the communication here is in somewhat broken English. I am ruing my total ineptness in Nepali and simultaneously vowing to study and get better. I am only like 90% sure of the plan at any given moment, and spending a lot of focus trying to decipher what Rajan is saying. Devendra speaks very little English. However, once again I was left with the valves, fittings, tubing, steel mixers, and bags of tools so I knew I would find Rajan once again. I had an hour to kill so I ambled down the hot dusty street of Mirdi in search of some food.
It was a one-horse town as they say so I walked into a small dirty Khaja Ghar to find veg momos. They had no veg momos, but a young child was rolling chicken momos at the counter. I grabbed a cold coke from the icebox and sat down at the singular table with two guys. They asked me all sorts of questions about where I was from and what I was doing in Mirdi by myself. They were drinking Raksi so I ordered a Raksi. The Raksi was quite hot and had flakes of dirt in it. We exchanged facebook information and took a few pictures and then I was on my way by 2:25. The van set off with an assortment of people headed southeast through Syangja over the hill-pass towards the Kali Gandaki river valley.
Fortunately this van wasn’t so packed as the bus, and I had a wide open window to drape my arm out of and feel the cool breeze. The van wound up mountain roads, alternating between pavement and dirt. There were dozens of landslides, some fresh, some old with the road carved through the fallen rocks. We forded many streams where the water gushed down from the mountain and overflowed the road.
Our van finally descended into a big valley through which ran the Kali Gandaki. This is the river whose source is in Mustang, the same one I had biked alongside for 65 miles in the mountains. Here in the foothills, it was wide, lazy, and filled with silt.
The hotel owner showed me my room. It was a big room on the roof with a terrace that looked over alternating corn fields and jungle, which squeezed into the valley between the foothills.
View from the hotel in Chapakot
I heaved my big bag off and onto the floor with a sigh of exhaustion. I looked at the small hard bed and swept a little roach off of my sheets and out the door. Then I went down and the three of us headed into the jungle with a long list of anaerobic digesters to repair.
The Chapakot district is comprised of lots of rural farmhouses interspersing fields of maize, rice, and a variety of other crops. Humid jungle fills in the rest of the space with lots of fruit & palm trees and dense ground vegetation. The bugs here are insane- the biggest ants, the biggest spiders, the biggest hornets, the biggest you-name-a-bug I’ve ever seen.
The well-off families had a pen with buffalo/oxen, goats, and chickens. The homes were mainly constructed of brick and concrete with sheet metal roofs. They had scant electricity, and running water came from a tank on the roof which they filled with small water pumps. Their fuel came from lumber and LPG tanks brought in from the town market. These families are likely in the middle to upper income bracket in Nepal.
In each house lived a big family with three or four generations; however, in many of the houses the only adults of working age were women, as some men had probably gone to labor in the Persian Gulf.
We were a lean operation, for sure. We carried all of our stuff, as we only had one motorcycle between the three of us. I slung 30 ft of half inch coiled plastic tubing around my shoulders and held a bag of concrete in my arms as we picked our way from house to house along the dirt jungle road.
The operation was pretty much the same at every home. The valves were the primary failure point. A close second was external corrosion. Nothing surprised the crew and we moved through the repairs methodically and quickly.
We worked hard through the heat of the day. Thread in a new valve on the reactor gas outlet. Replace the tap and pressure gauge manifold in the kitchen. Smash up the concrete on the feedstock inlet trough to install a new steel mixer. Dig a trough, run line to a new location, dig the water drain, bury the new line, bore the wall through to the kitchen and hook in the new gas tap and pressure gauge. Stuff like that.
Rajan and Devendra were a smooth operation, and I tried best I could to make myself useful even though I was ten times slower than Rajan and Devendra at any given task. I usually jumped on replacing the biogas valve off the reactor, since that was an easy task that had to be done pretty much every time. I’d close the valve and unthread the coupling on the outlet side and pull out that O-ring. Then I’d unthread the inlet side on the valve as quick as I could and block the pipe-end with my thumb. The reactor was usually pressurized so I tried to hold my breath during this part. One time, I felt my sense of smell go away so I knew that I was unfortunately exposed to hydrogen sulfide. Somebody file a report. I imagined the paperwork we would need at my old job for this sort of single block isolation against methane via thumb.
I also enjoyed smashing up the concrete when we had to replace the inlet mixer, though Devendra and Rajan would laugh at my form with the hammer. To be honest, this was a nice and uncomfortable experience being very bad at something. Rajan and Devendra were truly experts in their crafts, and they were very kind in showing me the little things- like how to roll teflon tape on the threads of a fitting in the clockwise direction so that the threading process doesn’t undo the tape, how to join tubing with linkages, or how to cut tubing with the Nepali curved blade. But there was definitely a learning curve to figuring out how to work with the crew effectively, especially considering the language barrier. Often, the other two would finish before me and politely take my tools from me to finish my task more smoothly and quickly. It was a little frustrating/demoralizing but hey we were there to repair reactors and drink milk tea and Rajan did both at record speed.
I enjoyed trying to apply my knowledge from the refinery to an application like this. After the first house, we stopped creating low point loops of tubing at the pressure gauge connection to prevent pocketing water as it condensed out from the biogas. Also- some of the families were draining water from their kitchen into the biogas reactor. I asked Rajan to explain to them that they were flushing the manure through the reactor prematurely by doing this and that they should re-route their wastewater elsewhere.
In good Nepali working fashion, we spent a fair amount of time hanging out with the locals, drinking chai, eating fruit and corn, and chatting. All of the neighbors knew each other, so once word got round that we were out and about, there was a contingent of neighbors and kids who would find their way to the job to watch us, hang out, and ask questions. People were very appreciative of what we were doing. It was rewarding to turn on the gas after each job and watch the family’s reaction. We’d walk into the kitchen and flip it on and they had a new stove with free power. People were stoked!
The people always offered plastic chairs and milk tea from the buffalo in the backyard, which was just fine with me. The tea was delicious- thick with fresh milk and loaded with sugar and spice. I was often pretty confused to see ants swirling around in my tea, but I just drank it along with everybody else and appreciated it, ants notwithstanding. I’m not sure if the ants were purposeful or if they were just in the sugar.
The last place we went was a farmhouse close to the Kali Gandaki, a few miles from our hotel. We had to leave the motorcycle behind since the roads were too wild. So we carried our dwindling equipment in the shade under mango, banana, and bodhi trees as the sun sank lower in the sky and turned the jungle from green to golden.
When we arrived at the farm, there was a big family and lots of neighbors all hanging out in the coolness of the twilight. They were lounging on straw mats in a gazebo-like structure in the center of the yard. There was an elderly woman in a beautiful sari, who smiled that tight-lipped, eyes-twinkling smile of an old person with no teeth. Her husband bounded up to us and extended his hand. His arms were bulging with veiny muscles, and his upper spine curved sharply from many years of laboring in the Nepali fashion. But he had the energy of a excited child and he was very happy to see us. A beautiful married couple of around 18-22 years old passed a baby back and forth. They were trying to get the baby to say “Namaste!”
We had a big scope of work at this farm; the family wanted to re-route the gas piping to their new kitchen. I was always happy when there was a big scope, since that meant I would definitely have something to do. Rajan went into the kitchen to disconnect the tap and I started replacing the reactor gas outlet valve. Devendra and the ripped 70 year old guy started excavating the old line, tearing a jagged line across the mud brick yard.
As we worked, everyone chatted in Nepali. We were great entertainment to the people. People were curious about my presence there. I can’t understand Nepali, but you know when people are talking about you. They wondered where was I from? why I was there? who was paying me? Rajan explained to them, as he had 20 times before, that I was a volunteer from America. The family really appreciated this, though they scolded me for knowing none of the language and made me promise to learn, and come back. The old man offered for me to stay with the family for a few days, if I wanted.
We laid the new line and bored a hole in the wall to connect the new kitchen tap to the reactor. The family gathered around as we switched on the hot blue biogas flame. The family oooh-ed and ahh-ed and the children squealed with excitement. Fresh buffalo milk was brought out and put over the flame for tea. The family brought out wicker stools and we sat in the yard in the fading light sipping the milk tea and chewing tobacco. Everyone had that nice, tired feeling after a day of honest, productive labor. The darkness was rising and nobody felt much like moving, except we stood up and started the long walk back in twilight. We were much lighter than before.