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).

And a close up..

75mm pipe for kitchen or organic waste to coming from near the future kitchen. Gas

return to come back in same channel.

The latest: Petrus and Anton installing the pipes linking the toilets to the digester.