A 3 L biogas digester receives cow dung and produces biogas at a constant rate of $0.25$ L per hour. If the digester operates continuously for 15 days, calculate: (a) the total volume of biogas produced in cubic metres, (b) the volume of methane produced, given methane is $55$ of the biogas.

Step-by-step solution

1. Compute the hourly production: $0.25$ L/h.
2. Convert hourly rate to daily production: $0.25\times 24=6$ L/day.
3. Multiply by 15 days: $6\times 15=90$ L total biogas.
4. Convert to cubic metres: $90/1000=0.09$ m³.
5. Calculate methane volume: $90\times 0.55=49.5$ L.
6. Convert to cubic metres: $49.5/1000=0.0495$ m³.

Concept tested: Biogas production and unit conversion

Published 23 September 2026 · How this solution was prepared and checked