Abstract: 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.

摘要： 研究了超声波结合复合絮凝剂促进剩余生物污泥脱水及其作用机理。实验结果表明，复合絮凝剂PAM-PAFC的投加比（质量比）为1∶1、投加量为污泥干基7‰时，其絮凝效果优于单一絮凝剂，再经20 kHz、400 W/m2超声处理2.5 min后，污泥体积缩小86%左右，含水率可降至79%，比无超声作用时污泥干基含水率减少7%左右。通过电镜观察发现，小功率超声可促进污泥中小团块的碰撞，增加污泥的絮凝性；投加PAFC后，污泥絮体呈现较为平坦的均匀絮状形态，存在孔洞；再投加PAM后，絮体具有起伏不平的链网状结构，形成比表面较大的复杂形体的絮体，脱水效果优于单独投加PAFC；再经超声处理后，污泥絮体比未加超声时团聚性增强，孔洞增大，脱水性能更佳，脱水效果优于单独投加PAFC-PAM。