Journal of Ecology and Rural Environment ›› 2018, Vol. 34 ›› Issue (5): 469-473.doi: 10.11934/j.issn.1673-4831.2018.05.012

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Characteristics of High Solid Sludge During Simultaneous Pretreatment With Ultrasonic and Thermo-Chemical

XU Hui-min1, QIN Wei-hua1, LI Zhong-lin1, GU Qi1, DAI Xiao-hu2,3   

  1. 1. Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, Nanjing 210042, China;
    2. National Engineering Research Center for Urban Pollution Control, Tongji University, Shanghai 200092, China;
    3. College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
  • Received:2017-07-21 Online:2018-05-25 Published:2018-05-25


The effects of simultaneous pretreatment with ultrasonic and thermo-chemical on high solid sludge disintegration for improved energy efficiency were investigated. The sludge was pretreated at specific energy of 9551 kJ·kg-1 total solids (TS), temperature of 73℃, and alkaline dosage of 0.085 g·g-1, which were optimal conditions obtaining maximum sludge disintegration in previous study. Experimental results show that the mean particle diameters (dp) of pretreated sludge with solid contents of 3%, 5%, 10%, and 15% were decreased by 40.14%, 58.01%, 93.63%, and 17.46%. Besides, the dp10, dp50, and dp90 of pretreated sludge with solid content of 10% decreased by 88.38%, 93.85%, and 96.74% after pretreatment. In terms of sludge disintegration, the increased soluble chemical oxygen demand (SCOD) concentration of pretreated sludge had a positive correlation with solid content of sludge, while the disintegration degree (DD) showed a reverse trend. The maximum DD of 50.3% was obtained in sludge with solid content of 3%. The organic matter composition of pretreated sludge was also examined. It indicated that soluble protein and carbohydrates concentrations of sludge with 10% solid content were much higher than those of sludge with 3%, 5%, and 15% solid content. Moreover, the biodegradability of pretreated sludge with 10% solid content was as high as 88.94%. Therefore, the simultaneous pretreatment with ultrasonic and thermo-chemical has a good application prospects in high solid sludge disintegration.

Key words: high solid sludge, combined ultrasonic and thermo-chemical, particle diameter, disintegration degree

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