Drying Technology
Keywords: heatpumpsludgedryer、heatrecoverybeltdryer
A review on sludge deep dewatering technology
With the increasing discharge of sewage sludge in China, sludge treatment and disposal has drawn more and more attention. Dewatering is the bottleneck that restricts sludge disposal. A review on sludge deep dewatering technology was thus studied in this work. Firstly, the classification and characteristics of sludge were reviewed and introduced. Secondly, different sludge deep dewatering techniques were reviewed and the mechanism of these techniques were analyzed.
The dewatering performance, advantages and disadvantages of these techniques were also analyzed. The results showed that the hydrothermal pretreatment in the physical method improves the sludge dewatering performance to the maximum. Ultrasonic treatment with lower intensity and short time can improve the sludge dewatering performance obviously. The chemical method has great advantages in sludge filtration performance and dewatering rate. After the acid/alkali treatment, the zeta potential of the sludge increased,.With the increasing discharge of sewage sludge in China, sludge treatment and disposal has drawn more and more attention. Dewatering is the bottleneck that restricts sludge disposal. A review on sludge deep dewatering technology was thus studied in this work. Firstly, the classification and characteristics of sludge were reviewed and introduced. Secondly, different sludge deep dewatering techniques were reviewed and the mechanism of these techniques were analyzed. The dewatering performance, advantages and disadvantages of these techniques were also analyzed. The results showed that the hydrothermal pretreatment in the physical method improves the sludge dewatering performance to the maximum. Ultrasonic treatment with lower intensity and short time can improve the sludge dewatering performance obviously. The chemical method has great advantages in sludge filtration performance and dewatering rate. After the acid/alkali treatment, the zeta potential of the sludge increased, the sludge，filtration performance, and dewatering rate were improved. Compared to acid/alkali treatment, the dewatering performance of sludge treated by advanced oxidation method is better. The sludge microbial cells are dissolved and organic matter is released during advanced oxidation treatment. The sludge dewater ability is thus improved. Biological treatment can also improve sludge dewatering performance. It is environmentally friendly but time-consuming. Finally, common follow-up sludge dewatering processes and systems were introduced, i. e., mechanical pressure-filter technology, thermal drying technology, hydrothermal technology. Based on different sludge subsequent utilization methods, the optimized sludge pretreatment method was recommended and proposed
