Hydrodynamic cavitation (HDC) reduces sludge particle size and viscosity, accelerating hydrolysis and gas availability while improving dewatering. Bench-scale mesophilic CSTR trials assessed HDC+BOC on mixed primary/secondary biosolids (Claymills, Severn Trent Water). Three lanes were fed: DG1 control 70:30; DG2 HDC+BOC 70:30; DG3 HDC+BOC 50:50.

Results show material performance gains. Methane yield uplift vs control & biogas quality improvement. Post-AD dewatering improved with less polymer required and lower supernatant turbidity as well as higher free drainage volume. VS destruction increased substantially. HDC visibly improved rheology/pumpability. 

Implications for utilities: higher biomethane yield and production rate (boosting site energy and effective capacity), reduced polymer and disposal volumes, lower return liquor load, and Scope 1/3 carbon savings. HDC+BOC on a 70:30 blend emerges as a robust, high-value optimisation pathway for existing AD assets.