Tarlac HBS Project

Brgy. San Isidro, Tarlac City, Philippines

October, 2007

 

EditorŐs NOTEs:

 

  1. This HBS was built under extreme & difficult conditions.
  2. Learn what to avoid, how to solve problems, etc.
  3. Our thanks go to the owners of this HBS for allowing us to photograph.

 

 

 

The unit was built to capture biogas produced and seen as bubbles in the manure pit.
Gas that simply escapes into the atmosphere causing pollution.
The biogas will be used for cooking to save money from buying firewood, charcoal,
kerosene, LPG, etc. It will also help prevent Global Warming.

 

 

 

As building was done during the rainy season, water started seeping in at 1.5 meters
deep. It is probable, some of this water was seeping from the manure pit that was less
than 10 meters away. (Sometimes you have no choice but to build near the manure pit.
If so, learn what to do to ensure water tight floor & walls for the digester.)

 

 

 

A pump was used to remove water while the foundation footings were being installed.
Since water seepage was too strong, the builders decided to continue installing the walls
and worry about the seepage later. (They decided to finish the project even with the
seepage, try the digester & work on re-sealing it in the summer if necessary)

 

 

 

The inlet & outlet pipes and the expansion tank.

 

 

 

The manhole to be used in entering the HBS after the cover slab is installed – to remove
form works and to seal the ceiling & inside walls. The inlet & outlet pipes as seen inside
the HBS.

 

 

 

Inlet pipe fitted with a basin. Note short piece of pipe that can be inserted in & out of
basin drain hole for use as a plug (to allow pre-mixing of manure.)

 

 

 

Outlet pipe as it appears in the expansion tank. Notice again, how a short piece of pipe
can be inserted in & out of the outlet hole – to control the in & out flow of digestate
(i.e: to trap solids & sediments in the expansion tank and keep them from re-entering
the digester.)

 

 

 

The pivoting exit pipe: Note how it can be re-positioned (horizontally) to drain the
contents of the expansion tank or at a selected angle so that sediments can exit the
expansion tank.

 

 

 

Biogas Piping: They are installed at a inclined angle to allow condensation & moisture to
flow back into the digester. Position-wise, they should have been higher (or closer to the
ceiling.) Only one pipe is needed. The second pipe is a spare.

 

 

 

Final piping, Burner connection & Burner with biogas flame (below)