Biogas Digester Construction Method in Tamale , Ghana

Biogas Digester Construction Method in Tamale, Ghana:

  1. Site Selection: Choose a dry location without groundwater seepage. Consider using the toilet outlet and livestock manure outlet as the input ports for the biogas digester.
  2. Materials: Use concrete to cast the surrounding walls of the biogas digester. Use pre-made wooden molds and a vibrating rod to ensure a solid structure. Prepare the necessary materials and tools accordingly.
  3. Shaping: Begin by marking a circular shape with a radius of 1.4 meters at the selected location. Remove the soil from the center, ensuring the excavated soil is kept away from the marked circle for safety. Calculate the depth of the digester, which is 1.4 meters, with a fiberglass cover height of 0.8 meters and a floating soil layer of 0.2 meters. Therefore, excavate to a depth of 2.5 meters. Optionally, line the soil walls with plastic film as needed.
  4. Formwork Installation: Place a 3-meter vertical pole in the center of the excavated pit, with one end inserted into the center and the other end secured with three thin ropes. Use the pole as a reference and install wooden formwork with a radius of 1.2 meters. Make sure to position the inlet and outlet pipes as well.
  5. Concrete Casting: Check the stability of the installed formwork. Then, pour concrete quickly between the formwork and the soil walls, ensuring no soil blocks fall into the mixture. Use a vibrating rod to compact the concrete firmly. The bottom of the digester is poured after the cover is installed, and if there is groundwater present, drain it continuously. The holes shown in the image are for draining groundwater.
  6. Cover Installation: After approximately two days of curing, remove the wooden formwork and clean the area. Place a 2.8-meter diameter fiberglass cover on top of the digester walls and pour concrete around it, ensuring the cover remains in position. Pour 40 centimeters of concrete around the cover to secure it to the walls. Finally, pour the bottom of the digester.