Figure 4

NS2—Evolution over time of simulated values of glucose \(S_{su}\) (a), butyric acid \(S_{bu}\) (b), acetic acid \(S_{ac}\) (c) concentrations, cumulative hydrogen production \(V_{H_2}\) (d), and concentration of metal in solution \(M_{liq}\) (e) for different initial concentrations of sugar \(S^0_{su}\). R5: \(S^0_{su}=5\,\hbox {gCOD L}^{-1}\); R6: \(S^0_{su}=10\,\hbox {gCOD L}^{-1}\); R7: \(S^0_{su}=15\,\hbox {gCOD L}^{-1}\); R8: \(S^0_{su}=20\,\hbox {gCOD L}^{-1}\); R9: \(S^0_{su}=25\,\hbox {gCOD L}^{-1}\); R10: \(S^0_{su}=30\,\hbox {gCOD L}^{-1}\); R11: \(S^0_{su}=35\,\hbox {gCOD L}^{-1}\); R12: \(S^0_{su}=40\,\hbox {gCOD L}^{-1}\); R13: \(S^0_{su}=45\,\hbox {gCOD L}^{-1}\); R14: \(S^0_{su}=50\,\hbox {gCOD L}^{-1}\). Initial concentration of sugar fermenters and metal concentration: \(X^0_{su} =5\,\hbox {gCOD L}^{-1}\) and \(M={6.5}\,\hbox {g L}^{-1}\). Red rhombus represents the removal efficiency after 24 h.