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Dehydration of Sludge Using the Polyethylene Glycol Solution Dialysis Method and the Mechanism of Dehydration

Lian S Tang, Deng H Zheng, Zhan L Zhao, Long J Zhang

J Environ Sci Health A Tox Hazard Subst Environ Eng. 2018;53(14):1199-1206.

PMID: 30596328

Abstract:

This study was undertaken to develops a new sludge dewatering technology based on polyethylene glycol solution dialysis. This method significantly reduced the final water content of sludge when compared to conventional dewatering methods. It was found that when the osmotic pressure difference between the polyethylene glycol solution and the sludge reached 8 MPa, the moisture content in the sludge was reduced to 28.6%, facilitating deep dehydration. To further improve the dehydration effect and explore the technical feasibility of dialysis dehydration, a dehydration experiment was designed using the polyethylene glycol solution dialysis method combined with external pressure. By applying external pressure to the dialysis membranes, the particles in the sludge were compacted, which reduced the internal voids of the sludge and propelled continuous water discharge. The results demonstrated that the dehydration effect was significantly improved when compared to single dialysis. A scanning electron microscope (SEM) was used to observe and quantitatively analyze the microstructure of the sludge before and after dehydration and to compare the variations in sludge microstructure throughout the dehydration process. The relationships between the sludge moisture content and the porosity and pore equivalent diameter were obtained. This demonstrated the effectiveness of the dewatering experiment using sludge dialysis combined with external pressure. This study also investigates the dehydration mechanism of this method during the sludge dehydration process. This study provides a novel solution for sludge volume reduction that can be applied to sewage treatment in the future.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP25322683-P Polyethylene glycol solution Polyethylene glycol solution 25322-68-3 Price
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