Hybrid conditioning before anaerobic digestion for the improvement of sewage sludge dewatering

So far, the most common method of conditioning to increase the efficiency of sludge dewatering is by adding chemicals (polyelectrolytes). This method effectively increases dewatering, thus causing the possibility of getting into the environment of hazardous chemicals. The use of physical conditioning methods (thermal, ultrasonic field) or a combination one (so-called hybrid conditioning) is an alternative to chemical methods for sludge preparing. A preliminary modification of excess sludge before the fermentation process affects the stabilization process, thereby changing the parameters characterizing the efficiency of sewage sludge dewatering. The article presents a study determining the impact of pre-conditioning of excess sludge before anaerobic stabilization on the final efficiency of their dewatering. Sludge conditioning methods of thermal and ultrasonic pre-treatment and combination of these two methods (hybrid conditioning) were used. The ability of sludge dewatering was determined on the basis of the capillary suction time, the effectiveness of their compaction and microscopic observation of the structure.