微波预处理对制革污泥絮凝脱水性能的影响

分别采用微波、絮凝剂和微波联合絮凝剂对制革污泥进行脱水预处理,考察不同处理条件下制革污泥沉降速率(SV30)、毛细吸水时间(CST)和污泥比阻(SRF)的变化,并通过粘度、水分分布和微观结构的变化探讨相关的脱水机理。结果表明,在微波输出功率为648 W、辐射时间为60 s的预处理条件下,阳离子聚丙烯酰胺(CPAM)投加剂量为8 mg/L时,污泥脱水性能达到最佳。与单独添加絮凝剂的污泥脱水相比,该条件下的SV30、CST和SRF分别降低了25.0%、48.9%和34.7%。污泥絮凝脱水前进行微波预处理能够进一步提高污泥的脱水性能,微波辐射联合CPAM进行污泥脱水时,CPAM则起主要脱水作用。微波辐射通过破坏污泥絮体结构,改变污泥中的水分分布,降低污泥的粘度,从而提高污泥的脱水性能。

Influence of microwave pretreatment on tannery sludge flocculating and dewatering performances

The settling velocity(SV₃₀),capillary suction time(CST)and specific resistance to filtration(SRF)were investigated on the tannery sludge pretreatment by microwave, flocculant and microwave with flocculant co-conditioning respectively. The viscosity, water distribution and microscopic structure were also analyzed to evaluate the pretreatment efficiency and dehydration mechanism. The results showed that the optimal pretreatment conditions were microwave output power of 648 W, radiation pretreatment time of 60 s and cationic polyacrylamide(CPAM)dosage was 8 mg/L. Comparing with the separate flocculant pretreatment, it was observed that the SV₃₀, CST, SRF decreased 25%, 48.9% and 34.7%, respectively under the optimal conditions. It was also indicated that the dewatering performance was improved highly with the pretreatment of microwave and flocculant co-conditioning, while CPAM had played an important role in sludge dewatering. Microwave radiation destroyed the floc structure of the sludge, which changed the water distribution and reduced the viscosity of the sludge, thus improved the dewatering performance of the tannery sludge.