After 17 days of total curing time the raw material can be put into the Biogas plant.
Initial production of Biogas will take about 6 days. After that, it will be a regular daily production.
To check whether Biogas has been produced, do the following -** Ensure that both the safety valves are in open position, for the gas to be conveyed.
** Light the burner and check the flame for production of the Biogas.
Pls watch the Spoken Tutorial - Assembly of the Biogas plant.
Answer to your question has been well explained with graphics.