Biological Desulphurisation

Desulphurisation of Biogas

Biological H2S removal works without the use of chemicals. The biogas is mixed with a small amount of air and drawn over a packing media flowing counter current with circulating water in a vertical column. The packing media enlarges the contact surface area between the H2S in the gas flow, the nutrients in the water and the oxygen, are also acting as a carrier for the bacteria. When the limited quantity of oxygen is added, specific aerobic bacteria such as Acidothiobacillus oxidise H2S into elemental sulphur and/or sulphuric acid (dependant on the exact environmental conditions and oxygen concentration). Oxygen is added to the gas as compressed air with an automatic control system adjusting the air flow in correlation with the biogas flow and oxygen concentration. Water and nutrients are automatically refreshed and sprayed on top of the media as required and heat can be added into the water circulation loop via a heat exchanger to create the optimum temperature for the biological process.

Advantages of this process are:

No chemicals needed
Low capital and running costs
High efficiency
> 95% reductions in of H2S for incoming biogas with up to 1 vol. % (10.000 ppm H2S).
Almost no utilities necessary
No waste flow requiring treatment or transportation
Safe process; All equipment & instrumentation Ex-proof
Compressed air supply linked to the biogas flow and oxygen demand
We have reference sites in the UK, Israel, Greece, Germany, Netherlands, Spain.