Our Biogas Digester / The Septic Tank January, 2012 update
The Plan (Courtesy of David Fulford – Kingdom Biogas)
João local stone mason and general machine wielder. And Vitor, the local water and sanitation expert, lending his tractor to get rid of some earth and generally check out our endeavours.
João, with his digging toy... We dug to about 2.5m About one day’s digger time (and earth moving)
Kira inspecting the works And asking why we weren’t making a pool... Gravel laid before we poured the platform for the tank.
Everything in the round; The square bit is where sewage liquid is displaced to (and forced upwards under gas pressure) 15cm wide bricks offering a bit of insulation. Nice work by Anton (Romania!)
Father and son – discussing where we want the pipes to come in. Some concrete to be added around the edge of tank to avoid collapse when we back-fill with earth
Anton preparing holes for the pipe inlets – before the concrete is poured around the tank
Next we build a wooden platform on which to build the earth dome A rope has been attached to the legs of this wooden structure so when the concrete above has set we can pull out the legs, let the earth collapse and remove all the earth from the hole in the square bit – hopefully leaving the dome above intact!
Anton and Petrus do a lovely job making this perfectly symetrical dome from earth, then cover with 8mm iron to reinforce the concrete.
Anton and Petrus (also father and son) adding the final coat of concrete to the dome. Note pipe for gas already installed (50mm PVC, to connect to a 32mm gas pipe later).