Hydrodynamic cavitation is a pre-treatment method that has shown promising results regarding biodegradability and biogas production in anaerobic digestion. In this thesis, its specific impacts on digestate dewatering, with the potential to reduce operational costs and to achieve higher solid content in the dewatered fraction was assessed. Several methods of evaluating dewaterability were investigated, including capillary suction time and the novel parameter C/N•ash. Two semi-continuous anaerobic digestion reactors were operated for 91 days processing mixed wastewater sludge - primary sludge, biosludge and recirculated digested sludge from a municipal wastewater treatment - under mesophilic conditions. Hydrodynamic cavitation was applied to the biosludge alone in reactor 1 and to biosludge together with the recirculated digested sludge in reactor 2. In terms of digestibility, hydrodynamic cavitation showed limited benets with higher benets when pre-treating biosludge and digested sludge together, with a 3% higher specic biogas yield compared to when only pretreating the biosludge. On the contrary, clear eect of the pre-treatment on dewaterability was observed causing an increment of capillary suction time-values up to 60% when pre-treating both biosludge and digested sludge. Applied to commercial scale, such behaviour could potentially result in signicant economic savings due to reduced polymer dosing.