BIODIGESTORES. Materials. 1 PVC macho adaptor ½” 2 five gallon buckets with the bottoms removed 1 PVC hembra adaptor ½” 2 non-corrosive washers (4-6 inch diameter) with a ½” hole 2 rubber spacers 1 inch of equal or greater diameter than the washer 6. 1 PVC Tee conjunction ½”
A ditch 8m x 1m x 60cm with an approximate
difference of 5cm from entrance to exit
(ditch dimensions will vary according to plastic)
1. Provisional, well secured posts need to also be installed at both ends of the ditch (approx. 2ft. behind the stairs).
Once the two bags are aligned, extend a rope (approximately 15m) through the double bag and tie it off at the secured posts on both ends of the ditch so as to leave the bag hanging, however, touching the ground.
Once the bag is in place the gas outlet can be installed. You’ll need two non-corrosive palm size washers, and two rubber spacers of equal or greater size.
Insert a ½ inch PVC hembra adaptor with the rubber spacer on top of the non-corrosive washer, and likewise with the ½ inch PVC macho adaptor.
The location of the gas outlet will depend largely on the general surroundings of the ditch. The hole does not need to be in the middle of the bag, it can be placed towards one end or another so as to take advantage of hanging branches for the outlet’s support. If there are no surrounding branches to support the outlet tubing, a post may be installed to serve the same purpose.
Once the location has been chosen, make a small cut, no bigger than a ½ inch, through the double bag.
Once the gas outlet is in position, the bag is filled with unchlorinated water to approximately 4 inches below the stairs on both ends of the ditch.
As the bag fills with water, the rope sustaining it is removed and the outlet tubing is glued into place, taking into consideration the direction of the kitchen and the height of any supporting branches.
Note: take special care that no glue touches the bag.
After cutting a ½ inch size hole in a 2 liter bottle, a tee conjunction is placed at a distance determined by the supporting branch. The 2 liter is then filled approximately half full with water to submerge the PVC extension. The submersion allows for excess gas to escape while preventing air from entering the system.
A small metal screen is inserted into the tee conjunction to prevent the flame from passing into the system.
Two stakes are hammered securely in place at a distance the width of the bucket on both ends of the ditch. The plastic is then pulled through the bucket, folded over, and tied to both bucket and the stakes with a long 2 inch wide strip of rubber (any rope will do).
It is essential that each bucket be submerged in at least 3-4 inches of water to prevent gas from escaping. The entrance bucket rest in an up-right position while the exit bucket is tilted at a 45 degree angle to allow the passage of excess liquids.
The suggested initial input to bring the biodigestor up to a functional level is 20 buckets of two shovels of cow manure (one shovel of pig manure) mixed with five gallons of water. The same mixture is added once a day for at least eight consecutive days following the original mixture; after which point the input may continue as such or decrease to every other day. One can expect a period of at least 30-60 days until the biodigestor is operating at full capacity.
Note: all mixtures should be well liquefied, any incorporated fruit should also be well shredded.
Two valves are secured to the stove, then depending upon the placement of the stove and the direction of the incoming tubing, a 90 degree and tee conjunction are placed accordingly.