OFMSW and Thickened Primary Sludge (TPS) led to low VFAs yields of 0.25–0.30 and 0.50 gVFA-COD/gCOD, respectively. The co-fermentation of OFMSW and sewage sludge achieved higher VFAs yields (0.38 gVFA-COD/ gCOD). Co-fermentation yields was further improved (0.85 gVFA-COD/gCOD) by the adoption of thermophilic temperature (55 ◦C). Regarding VFAs profile, it was observed that substrates with lower VFAs yields presented a higher concentration of acetic acid, while the improvement of the acidogenic fermentation’s yield had as consequence the increasing of propionic and butyric acids’ concentrations. Finally, innovative electro-driven approaches, electro-fermentation and electrodialysis, employing polarized electrodes have been investigated
to favor the production of desired VFAs or to enhance acids separation from the fermentation broth.