What kind of residues are generated from production process?Do you know total and volatile solids content of these substrates? Often leather industry residue produce a lot of H2S in biogas, so an appropriate desulphurization systems (biological+chemical+active carbon) have to be installed in this kind of biogas plant.

Thanks for your valuable suggestions

It is also important consider the heavy metals content of your residue, specially regarding the hexavalent chromium due its strong oxidizing nature, even though several papers have shown the ability of some thermophilic methanogens to reduce chromium concentration in groundwater and subsurface sites.