2.1. Materials
Three (3) identical 25 Litre-biogas digester tanks each of height
0.5 m and diameter 0.25 m were fabricated from Galvanized steel
which is strong enough to withstand the weight and pressures of
the contained slurry. The cylindrical shape was adopted to enhance
better mixing. The tank is air tight and is clearly placed above the
ground level and outside the shed where it is exposed to the sunlight
for partial heating. The three identical 12.1 L gas holder tanks
each of height 0.25 m and diameter 0.25 m were fabricated from
thin sheet metal and used to temporarily store the biogas until it
was used to produce heat or used to replace or supplement the
supply of cooking gas. Plastic hose was used to connect each digester
to its gas collection system and the biogas stove burner while
plastic valves were installed to control the gas flow.