Reduction of hydrogen sulfide (H2S) from poultry based biogas by aeration technique

Biogas, produced in anaerobic digestion (AD)-plants, primarily consists of methane (CH4) and carbon dioxide (CO2) with smaller amount of hydrogen sulfide (H2S) and ammonia (NH3). Trace amount of some other gases are occasionally present in biogas. For electricity generation from biogas needs reduction of H2S, because it forms a complex bond with iron hence damage the generator. Reduction of Hydrogen Sulfide (H2S) from poultry based biogas can be done by dosing air/oxygen to the main digester into the digestion process. For optimization there are two sets of aeration technique have been followed. Firstly two hour interval air injection and secondly air injection based on percentage of hourly gas production. The optimum air percentage to minimize H2S should be at least 3.00%. After aeration H2S level comes to the desired level (<50ppm) within 1.5–2 hours and remains constant up to 7–9 hours and biogas can be used for effective power generation. A complete aeration system has been developed which is simple and cost effective for H2S reduction to the desired level from poultry based biogas plant. This system can be applied for any size of poultry based biogas plant for effective power generation.