Phase separation as a strategy to prevent sulfide-related drawbacks in methanogenesis: performance and energetic aspects.

The establishment of sulfate (SO) reduction during methanogenesis may considerably hinder the efficient energetic exploitation of methane, once removing sulfide from biogas is obligate and can be costly. In addition, sulfide generation can negatively impact the performance of methanogens by triggering substrate competition and sulfide inhibition. This study investigated the impacts of removing SO during fermentation on the performance of a second-stage methanogenic continuous reactor (R2), comparing the results with those obtained in a single-stage system (R1) fed with SO-rich wastewater (SO of up to 400 mg L, COD/SO of 3.

Performance improvement of a thermophilic sulfate-reducing bioreactor under acidogenic conditions: Effects of diversified operating strategies.

The establishment of a sulfidogenic environment under thermophilic (55 °C) acidogenic conditions was assessed in an innovative structured-bed bioreactor to enhance sulfate removal and acetate production prior to methanogenesis. Diversified operating strategies, i.e.