4.4.3 Sizing of gasholder

The purpose of this chapter is to offer guidance on how to size the gas holder and what information is required.

Biogas consumption
of the lamp
Operation of biogas lamp8hoursDefined by the project
Number of biogas lamps9piecesCalculated in the previous exercise
Inflow quantity
per person
6.2L/user/dayWater usage survey:
5L/cap/day for cleansing and flushing.

Estimated excreta generation rate:
(Urine 0.9L/cap/day, Faeces: 0.3L/cap/day)
TS13,000mg/LCharacterisation study
VS9,200mg/LCharacterisation study
COD21,200mg/LCharacterisation study
C:N5:1 Literature values
Specific biogas production
0.23m3/kgVSCharacterisation study
Organic Loading rate0.75kgVS/m3/dayLiterature values
Assumptions for Case Study

The size of the gasholder is determined by the biogas generation and consumption rates. It must be designed to ensure adequate coverage during peak consumption and to retain the gas generated during long periods of no consumption.

The required volume of the gasholder to cover the peak biogas consumption over the day is calculated by multiplying the maximum biogas consumption rate by the duration of the longest zero-consumption period.


VPBiogas Volume to cover during the peak consumptionm3
C MAXMaximum biogas consumption rate per hourm3/h
tMAXDuration of the longest zero-consumption periodh


C MAXMaximum biogas consumption rate per hourm3/h
NEDNumber of end devices
CEDBiogas consumption rate for end devicem3/h

In addition, it is necessary to determine the amount of biogas that needs to be stored for the longest period of zero usage. To achieve this, we must first calculate the production rate per hour. This can be done by dividing the daily production rate by 24 hours. We then multiply the hourly production rate by the duration of the unused period.


VZEROBiogas Volume generated during the longest period of zero consumptionm3
QGASBiogas Production Rate m3/d
tZEROMaximum zero consumption timeh/d

The larger volume determines the size of the gasholder. In our case, 7.2m3.

Some guidelines suggest a safety margin of 10- 20%, resulting in 7.9 – 8.6m3.