Home Running Small-scale

Large Underground Designs

A large underground plant, of 50 m3, was built in Nepal under the DCS project in 1983. The Agricultural College had over 30 cattle in a field with a shed. The gas generated was piped to staff houses nearby.

It worked for a few years until the college moved the cattle. A few more plants were built to this design by BSP/N, for local farmers with larger cattle or chicken farms.

Larger domes (100 m3 and more) have also been built in Rwanda under the KIST project and Ghana by BTAL (Biogas Technology Africa Ltd). The plants use the same displacement principle as the small fixed dome domestic plants and are constructed in the same way.

A system for processing food waste was built in 2014 for CMC Vellore. It used two 75 m3 underground digesters. The process for building is very similar to that used for domestic plant, so technicians trained for smaller plants can build the bigger ones.

These systems are displacement digesters. The gas dome is fixed, so as gas collects, slurry is displaced into a reservoir. A 3D PDF picture is shown below.

Extended dome biogas plant


Clicking on the picture will open a PDF file.

The file can be viewed in 3-D using Adobe Acrobat 8 and above


Large dome built in Vellore

Small domestic dome