Waste Systems Blog
The first community we visited after landing in Cuiaba was the Nazare orphanage outside the town of Pocone. Both the kids and adults who live there were excited and a little confused at our arrival, but were very welcoming. After a few days to gather basic supplies and get settled, we traveled to our first homestay with a teacher in the nearby community of Cangas. For the rest of the week we taught high school age kids the theory behind our biodigester design, as well as the basics of why they should practice sustainability and environmental conservation. It was exciting to meet so many new people, both students and teachers, as well as sampling local foods and exploring our surroundings. For one afternoon we traveled to another nearby village, even smaller than Cangas, called Chumbo. The schools had been closed due to a teacher strike, but we were still able to gather a group of around 30 students and go through our entire lesson plan. The students invited us to play soccer with them after the lesson, and we finished off the week by heading back to Cangas. We had planned to build a small scale biodigester and store it at the school for one week until it started to produce gas, then we return to Cangas to demonstrate how it worked. However, so many kids rushed outside when they saw us building the sample product that we were able to turn its construction into another lesson. It was very cool to see them become genuinely interested and continue to ask more questions even outside of the classroom setting. We look forward to visiting more communities this upcoming month to teach and simultaneously learn more about the culture and lifestyle here in Brazil.
Today we arrived in Pocone after almost three weeks at PCER. During out time in the Pantanal we worked on Adrienne´s biodigester, our own telescoping biodigester and an assessment of solid waste generated at PCER and the Jaguar Ecological Reserve.
We began with Adrienne´s biodigester. Because it was dismantled after Adrienne´s team left PCER in 2010, we tried to reconstruct it to Adrienne´s specifications. Unfortunately one of the three PVC pipes was broken so we could only use two of them. We built supports using brick and cement to create a meter grade from one end to the other. We filled the biodigester 75% of the way with slurry (1 part cow manure, two parts water). We observed leaks at the bottom of the biodigester and one small one at the elbow. We allowed the leaks to clog themselves with sediment from the manure. We checked for gas production every day for six days using a pressure guage on one of the valves. After not observing any change in pressure in the biodigester, we decided to empty it and start over. We emptied the biodigester and reconstructed it this time without the elbow to minimize possible locations for leaks. After resealing the biodigester and letting the seals dry, we refilled the bidigester, this time filling it all the way to the valve. When we checked for pressure 24 hours after filling the biodigester. the guage read 3psi. We do not know if the guage is reading air pressure or water pressure inside the biodigester.
Testing the telescoping biodigester proved to be much less labor intensive. In order to install the valves and PVC pipes, we punctured holes in our buckets using a hot metal rod, which necessitated liberal sealing. We filled the upright bucket with enough slurry to cover the top of the inside bucket to ensure an anaerobic environment. Within 48 hours, the inside bucket had risen above the slurry line indicating gas in the biodigester. Due to pig traffic in the back porch of PCER, the gas escaped from the bucket when a pig ran into it. We took this opportunity to reseal the valves and holes in the bucket before refilling it with slurry. We put a brick on the inside bucket to make sure it stayed below the slurry line. Now we are waiting to confirm if it has produced gas.
While staying at PCER we also assessed the solid waste generated and the waste management systems in place at PCER and Jaguar Ecological Reserve. First, we observed several piles of trash located on the grounds of both facilities. These included a pit that was originally intended to be the septic tank for the house next to PCER, an approximately 25 foot deep well that is full with solid waste, and several smaller piles on the grounds of the Jaguar Ecological Reserve. The types of solid waste that was most prevalent in these piles were plastic bottles, aluminum cans, cardboard, organic waste, ceramics, and palm fronds. We performed a quantifying assessment of the trash in the well by measuring the volumes of each type of trash in a 17.3 feet cubed sample, finding that about 30% was plastic bottles and about 20% was paper/cardboard. Lastly, we talked to an employee at Jaguar Ecological Reserve named Leonardo and he told us that all solid waste except for some plastic bottles is burned in various pits on the grounds of Jaguar Ecological Reserve on frequencies of every other day during the dry season and once a week during the wet season. Leonardo also told us that plastic bottles can be recycled in Pocone for R$3 per kilo. This price makes it worth the Jaguar Ecological Reserve~s effort to bring the bottles to Pocone, but the 15 centavos per kilo of cardboard and 20-25 centavos per kilo of other plastics does not make it worth the Jaguar Ecological Reserve´s effort to recycle these materials.
The three of us arrived together early Wednesday afternoon. After a brief trip to the Brazilian equivalent
of Sam’s Club, we drove to the Nazaré Orphanage where we have been staying since. On Thursday we
went into Poconé to buy materials for our biodigester. Yesterday we taught an English class to the kids
at the orphanage. We covered introductions, numbers, key phrases such as “What is that?” and “How
do you say… in English?” in addition to a few simple nouns like cat, dog, and bird. The kids were very
excited to learn and we ended up teaching them more material than what was on the initial lesson plan.
After the class we spent a few hours speaking a mixture of English and Portuguese with the kids. We
talked about music, shared popular dances, and listened to them play guitar.
Tomorrow we are going to PCER to assemble the telescoping biodigester and fill it with manure. We
plan to stay at PCER for about ten days to construct the biodigester and conduct initial measurements
of methane production. We will also revisit the biodigester designed by former student Adrienne
Lemberger. Adrienne’s biodigester leaked and had no system in place to store gas. It was disassembled
for parts in the years following since no one was using it. We would like to reconstruct Adrienne’s
biodigester and address these issues of leakage and gas collection. After we build the two biodigesters,
we will devise a system for organic waste collection and analyze feasibility of maintenance. Our end
goal is to build two different biodigesters and compare their efficiencies. Based on these results we
will decide which design is better suited to supply cooking gas to the stove. These biodigesters we are
building this week are test versions, the data from which we will use to scale a future, larger biodigester
that can produce enough methane gas to power the PCER stove.