Laying the Foundation

March 20, 2010

It was easy enough to decide where we plan to place the biogas digester, but it is a quite a different story making a solid foundation in the clay filled hill that we had selected. Brigitte and I decided to locate the biogas digester just outside the kitchen for easy access and use. The land surrounding the building slopes quickly downwards so the first order of business was to create a level and solid foundation for the 1130 gallon tank and all the degrading food that it will hold.

After debating a multitude of options for supporting the big lug, it was decided to dig a hole in the hill to level the ground, set the foundation in cement, and build a cylindrical wall to set the digester on top. Sounds basic enough, right? Well, let me tell you about the Amazonian soil: it is much less dirt and more like clay. Digging four feet into is trouble since it sticks to the shovel, so it is work to get it out of the soil and work to get it off the shovel...and don't get me started about the heat that we did all this digging in! Once that grueling work was done, we lay our sand to level the ground, drove some rebar into the ground to fortify the wall, set the first layer of bricks for the wall, and poured the cement for the floor. Foundation complete! Now let dry and onto building the wall!

Piping

March 13, 2010

Since the tank was made for storing potable water rather than for use as a biogas digester, the tank needed to be fit for its piping before it could even be taken outside to be set in place. The lid needed two holes drilled into it and the tank itself had two extra holes already in place that needed to be filled.

The two extra holes that needed filling proposed a bit of an initial problem since we had not anticipated pre manufactured holes in our tank. The problem was soon resolved with the rubber seals that came with the tank along with a few extra supplies we had on hand such as polymer glue and two-inch lids, we were able to devise a way to seal the holes.

The two holes in the lid are for the effluent for the decomposed material to come out. The first is a small hole for a one inch pipe to glide smoothly through without having discharge around the seal. This pipe will be releasing enriched liquid from the top of the tank to prevent it from getting too full. In order to make this happen, an ''L'' shaped pipe was constructed for the extra liquid at the top of the tank to flow through. Then a a hole was drilled in the lid and lined with natural rubber tubing and the long pipe was pushed through the hole. There was some guess work here to make the hole big enough for the pipe to slide freely, but not too big that the seal is no longer effective.

After doing this first hole, the second hole was a bit easier since we only had to get a two inch pipe to fit snugly with a rubber seal. The problem camewhen we went to attatch the valve that will release the decomposed food sludge. The ball valve we had purchased would not budge! So really, we now have a heavy pipe with a handle on it. We will need to go back to Iquitos to find a better valve.