Microaeration

The microaeration is a highly efficient and simple technology to reduce the sulfur content in anaerobic digesters. Due to the dosage of the oxygen into the recycle-flow of the digester, no precipitation of elemental sulfur in the gas pipes occurs. Moreover, reduction of methane concentration in the biogas is negligible


At a Glance

Microaeration

»    Efficient Desulfurization
»    Reduction of methane content negligible
»    Dosage in recycle-flow of digester

 


Description

Microaeration has recently proved to be a highly efficient biological method of sulfide removal regarding anaerobic digestion of wastewater and sludge. The process is based on controlled dosing of a limited amount of air or pure oxygen into the digester to ensure the oxidation of sulfide to elemental sulfur. Precipitated elemental sulfur is then removed from the digester together with digested sludge. Presence of oxygen does not negatively influence the activity of anaerobic bacteria because it is consumed quickly and almost completely. The amount of sulfide in the reactor depends on the input composition and applied leading rates. As a result, in most digesters a variable air/oxygen dosing rate is necessary. Besides, residual oxygen in the biogas must meet the requirements of the downstream biogas utilization technology in such cases. An optimal process control is the key to the successful microaeration during a stable digestion process (constant biogas production and H2S concentration).