Average operational parameters for the steady state of each scenario (M: mono-digestion of pig manure (PM); C1, C2, C3: co-digestion of PM with different co-substrates; FW: fish wastes; MW: molasses wastes; BW: biodiesel wastes; VW: vinasses wastes; OLR: organic loading rate; HRT: hydraulic retention time; Q: daily flow; COD: chemical oxygen demand). Biogas and digestate characteristics of scenario C2 were estimated by data reported by Regueiro et al. (2012); the characteristics for scenarios C1 and C3 were unpublished data.