An Effective Energetic Application of Orange Waste in Multi-Component Co-Digestion with Municipal Sewage Sludge

A strategy allowing for the application of orange waste (OW) in anaerobic co-digestion with municipal sewage sludge (MSS) has been proposed. For this purpose, the introduction of an additional component represented by ice-cream processing waste (IPW) has been chosen. The experiment was conducted in batch mode at a temperature of 37 °C. Four series were conducted: S1—the mono-digestion of MSS; S2—two-component co-digestion of MSS and 1.5 g of OW; S3—two-component co-digestion of MSS and 1.0 g of IPW; and S4—three-component co-digestion of MSS, 1.0 g of IPW, and 1.5 g of OW. The obtained results indicate that the highest methane production was achieved in the presence of IPW in two- and three-component mixtures (S3 and S4). It was also accompanied by improved kinetics, enhanced organic removal, and stable process performance. The related methane yields were 407.6 and 401.6 mL/g VS in S3 and S4, respectively. In turn, in S1 and S2, this parameter was established at the level of 351.3 and 344.3 mL/g VS. Additionally, as compared to MSS mono-digestion (S1), the energy profit was enhanced by 54 and 62% in S3 and S4, respectively. The obtained results indicate the possibility of effective management of OW with energy recovery in the anaerobic digestion process (AD).