How to build the new compact biogas plant

The apparatus itself consists of:

-Two plastic water tanks sold in sanitary and plumbing ware shops. One should be bigger than the other so that once the top of each tank is cut open, the smaller one can fit in the bigger one and move like a "telescope“. The bigger tank (or drum) serves as a digester, and the smaller, placed upside down in the bigger one serves as the gas holder.

-The inlet pipe: a 3cm diameter flexible pipe, a bit longer than the height of the tank, is fitted at the bottom side of the bigger tank. At the free extremity of the pipe , a funnel is fixed to facilitate the pouring of the quite fluid feedstock material. The pipe with the funnel are to be fixed loosely to the top of the tank, in upright position. This pipe will also serve as a purge in case of necessity.

-The effluent outlet is fitted to the upper part of the bigger tank and determines the maximum level of matter in the tank.

-The gas outlet is fitted to the smaller inner tank and directed toward a gas stove.

-a frame structure is build above the tanks to stop the gas tank to fall open when too filled. It is possible to put a weight on the upper tank to increase gas pressure in the tank.

Methane burns with a blue flame, without producing any smoke or soot. It is therefore an environmentally friendly cooking system. Thus, introduction of the new efficient, compact biogas system would not only help urban households in utilizing their domestic wet waste, but also help prevent millions of premature deaths of women and children in rural households due to indoor air pollution caused by smoke and soot from burning fuelwood in traditional chulhas. This markedly impacts the health of the people in the kitchen (mainly women) positively. Further reductions in pollution and energy use arise from not having to transport LPG cylinders to be re-filled. The small amount of solid residue produced by the biogas plant makes a good fertiliser. Methan, on the contrary of propane, is lighter than air, there is therefore little risk of an accumulation and explosion in case of a leak. In hot regions, the system could be placed in a garden or on an accessible roof terrasse, for it needs a relatively warm temperature.

Adjust the air input to the burner so that the flamme is blue and not yellow.