Fig 2. Hydrogen sulfide concentration and methane production as a function of residual oxygen concentrations in micro-aerated FS digesters.
A, Influence of aeration on H2S concentrations in biogas. Values are means of 2 to 12 daily measurements from duplicate aerated field scale digesters operated for 18 weeks. During this period, H2S concentrations from duplicate non-aerated digesters ranged from 3000 to 4000 ppmv with a mean value of 3570 ppmv. Vertical bars show standard error values (three error bars are clipped at the axis limit). B, Effect of aeration on CH4 production. Values are calculated from weekly means from duplicate aerated field digesters operated with and without aeration. Vertical bars show standard error values.