Simple biogas desulfurization by microaeration - Full scale experience

- Long-term full-scale operation of sludge digesters in microaerobic conditions.
- The lack of operating experience with microaeration has been overcome.
- Simple, highly efficient and stable method for H2S removal from the biogas.
- High H2S removal efficiency (99%) at high initial H2S concentration (4000 mg m−3).

Hydrogen sulfide in biogas is common problem during anaerobic treatment of wastewater with high sulfate concentration (breweries, distilleries, etc.) and needs to be removed before biogas utilization. Physico-chemical desulfurization methods are energetically demanding and expensive compare to biochemical methods. Microaeration, i.e. dosing of small amount of air, is suitable and cost effective biochemical method of sulfide oxidation to elemental sulfur. It has been widely used in biogas plants, but its application in anaerobic reactors for wastewater treatment has been rarely studied or tested. The lack of full-scale experience with microaeration in wastewater treatment plants has been overcome by evaluating the results of seven microaerobic digesters in central Europe. The desulfurization efficiency has been more than 90% in most of the cases. Moreover, microaeration improved the degradability of COD and volatile suspended solids.

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