Pages last updated:

28 June 2017

Running Small-scale

There are a range of designs of biogas plant that are being used in different places. However, the designs that have been used in large numbers are based on two basic design concepts: the floating drum biogas plant, as developed by KVIC in India, and the underground dome plant, as developed in China, but used widely in India and the rest of Asia, as well as parts of Africa.

In places such as India and China, a biogas digester is a cylinder built from masonry in a hole in the ground. The KVIC design uses a metal gas holder that floats in the slurry (or in water in an masonry annulus around the top of the cylinder). The underground dome plant uses a fixed dome made from masonry over the digester. Gas storage is obtained by pushing some of the slurry out into a reservoir pit, and this flows back into the digester as gas is used.

There are two ways of defining the size of a biogas plant, the first is the expected daily gas production, the second is the internal volume. The daily gas production depends on the feed material, so is not an absolute measure. The internal volume can be calculated from the dimensions of the plant.

The shape and dimensions are given for three different designs:

  1. The floating drum KVIC design with a drawing;
  2. The fixed dome Deenbandhu design made of brick, with a drawing; and
  3. The fixed dome GGC 2047 design, with a dome made from concrete, also with a drawing.

The processes involved in generating biogas from biomass are described in both the books and summarised under Technology.  

Technical aspects and design