High levels of sulfide in biogas may require removal to protect equipment if the gas is to be used in internal combustion engines, turbines, or fuel cells. The concentration of hydrogen sulfide in the gas is a function of the digester feed substrate and inorganic sulfate content.
Fixed Dome Biogas. The fixed dome biogas system is also known as Chinese model biogas plant which was developed and built in China the 1930s. The unit consists of an underground brick masonry compartment (fermentation chamber) with a dome on the top for gas storage. Fig 1. Fixed dome biogas plant. Numbers in thefigure correspond to: 1.
Cement-plastered/rendered masonry is a suitable - and inexpensive - approach for building an underground biogas digester, whereby a dome-like shape is recommended. For domes larger than 20 m digester volume, steel reinforcement is advisable.
Pretreatment of feedstock Methods used to assess pretreatment 6 The most informative test is full-scale anaerobic digestion, but even at full scale it is difficult to assess whether or not a pretreatment method increases biogas yield as there can be significant variation between dif-ferent biogas plants.