6. Regular building supervision.
7. Commissioning
- functional inspection of the biogas plant and its components - starting the plant
8. Filling the plant.
9. Training the user.
3. The agricultural setting
3.1 Natural parameters for biogas plants of simple design
Climate zones
A minimum temperature of 15 °C is required for anaerobic fermentation of organic material (cf.
chapter 5.1). Since simple biogas plants are unheated, they can only be used in climatic zones in
which the minimum temperature is not fallen short of for any substantial length of time. In general,
this is true of the area located between the two tropics, i.e. in the geographic region referred to as
the "Tropics".
In the climatic sense, however, the Tropics are inhomogeneous, containing various climatic zones
with their own typical forms of vegetation and agricultural practices. Proceeding on that basis, it may
be said that a particular zone does or does not qualify as a "biogas zone'' (cf. table 3.1).
With the exception of subtropical arid regions (deserts and semideserts), all tropical climates are
characterized by:
- increasingly small diurnal and seasonal temperature variation in the direction of the equator,
- decreasing annual rainfall and number of humid months with increasing distance from the
equator.
This basic zonal breakdown, though, is altered in several ways by other climatic factors such as
wind, elevation and ocean currents. Consequently, the climatic zones serve only as a basis for
rough orientation with regard to the climatic evaluation of potential sites for biogas plants. The
locally prevailing climatic conditions are decisive and must be ascertained on the spot.
Fig. 3.1: Global
15ºC isotherms
for January and
July, indicating
the biogas-
conductive
temperature
zone (Source:
OEKOTOP)
15