The GGC 2047 biogas plant was first developed by DCS and improved and used by GGC for the extension work under UNDP. A standardised design was used, to allow for quality control. The plant is built by digging a hole, placing a floor and then building a cylindrical wall, with one or more slurry feed pipes and a slurry outlet put in place. The hole is refilled with soil and the top is shaped with a template, that acts as a mould for the concrete dome. Once the concrete has set, the soil is dug out and the inlet and reservoir tanks built with bricks. The dome is then backfilled with earth to place it under compression. A standard GGC 2047 plant has a calculated total internal volume of 6 m 3 , although not all of the internal volume is used for slurry.  The design is very strong and a survey of installed plants showed that 95% survived an earthquake in Nepal, although many of the gas lines broke. The equations for a volume of a section of a sphere can be used to calculate the volume of the dome while the cylindrical section is given by the relevant equation.