Sludge dewatering by ultrasound & composite flocculants and mechanism analysis
Pingfang Han · Huagong jinzhan · 2007
The enhancement of sludge dewatering by ultrasound and composite flocculants and its mechanism were studied.The results showed that for the sludge treated with composite flocculants PAM-PAFC(1∶1) firstly,then treaded with ultrasound at 20kHz,400W/m2 for 2.5 min,the sludge volume could be reduced by 86%,sludge water content was decreased to 79% and sludge water content(dry basis) was 7% lower than that without ultrasound treatment.It was observed by SEM that lower power ultrasound could accelerate the collision of sludge particles,hence the flocculation of the sludge was enhanced.When PAFC was added,the floccules was continuous and with holes;after adding PAM,the specific area of the sludge was much larger and the floccules had a rough mesh structure.Ultrasound could intensify conglomeration of the sludge,and the holes in sludge became larger.Sludge dewatering with ultrasound treatment was better than using PAFC-PAM alone.