Page last updated 30/08/2018
Small-scale Rural Biogas Programmes
Appendix Abstracts - 1
Appendix 1 Chemistry of Simple Digestion
A basic analysis of the process by which food materials are converted to biogas provides an
understanding of the energy released by this process. Calculations are provided for the conversion of
two basic food materials: sugar and starch. A simple first order rate model is also presented, which
allows the gas production from a biogas plant to be estimated, based on the plant working volume
and the daily feed volume. (7 references).
http://dx.doi.org/10.3362/9781780448497.013
Appendix 2 Biogas Plant Design Details
Various designs of a biogas plant have been developed by the different biogas extension projects.
Since these plants have been designed to do similar jobs, basic dimensions are similar. Earlier designs
used longer retention time, and therefore larger volumes. The required retention time is affected by
the local ambient temperature.
The mathematical formulae required to calculate various volumes are given. Actual measurements
may be slightly different from those calculated from the formulae, as the shapes produced when
plants are built may not fit exactly to the shapes defined by the formulae. (10 references).
Appendix 3 Building a Masonry Biogas Plant
Biogas units made in large numbers in Asia are made from masonry by manual labour, using
cylindrical or spherical shapes. The basic building techniques are defined and use basic skills that
need to be gained by the masons who are doing the work. Similar approaches need to be used for the
different designs, although there are particular approaches required for each different design. (8
references).
Note: clicking on a dx.doi link gives a list of references in that chapter, as well the opportunity to download the text as
a PDF file, for a fee.