Performance Analysis and Microbial Community Evolution of In Situ Biological Biogas Upgrading with Increasing H₂/CO₂ Ratio

Figure 2

Mean values of parameters measured during each of the eight experimental periods (in brackets the H₂/CO₂ ratio): (a) box plots of methane rate (circles indicate outliers); (b) biogas composition; (c) TVFA composition and alcohols; (d) box plots of alkalinity concentrations (circles indicate outliers).

(a)

(b)

(c)

(d)