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Drawing of Concrete Dome Design

The plant made in Nepal uses a design that was finalised by the Gobar Gas Company, called GGC 2047. This uses a cylindrical pit covered by a dome made from concrete. The dome is usually a segment of a sphere, although for certain sizes, it is made slightly oblate (with an elliptical cross-section), so allow the gas storage volume to be larger.

The underground pit is made as a brick lined hole. The usual way to make the dome is to re-fill the hole with soil and cast the concrete over a carefully shaped earth mould.

Typical values for a 4 m3 plant are:




1.020 m


0.860 m


0.650 m


1.130 m

These figures can be used to calculate the volume of the digester pit and the gas storage dome.