Once the sonicated sludge leaves the sonicator is mixed with the primary sludge, and together, are fed to the anaerobic digester.
In addition to the increase in biogas production, greater sludge dryness up to 30% may be achieved after dewatering, while reducing the consumption of polyelectrolyte.
Digested sludge is even more stable since performance in volatile solids removal can be increased from a typical value of 45% up to 55-60%..
The advantages of this system over investment and operating costs make it highly efficient, with a return period of less than 4 years.