Optimisation of sludge pretreatment by low frequency sonication under pressure

JOURNAL OF ENVIRONMENTAL MANAGEMENT

卷:165

Article

Ngoc Tuan Le^1,2  Julcour-Lebigue, Carine¹  Barthe, Laurie¹  Delmas, Henri¹ 

[1] Univ Toulouse, Lab Genie Chim, INP ENSIACET, F-31030 Toulouse, France

[2] Vietnam Natl Univ, Univ Sci, Ho Chi Minh City, Vietnam

关键词: Audible frequency;    Hydrostatic pressure;    Sequential process;    Pulsed ultrasound;    Sludge disintegration;   

DOI  :  10.1016/j.jenvman.2015.09.015

来源: Elsevier

【 摘 要 】

This work aims at optimizing sludge pretreatment by non-isothermal sonication, varying frequency, US power (P-US) and intensity (I-US varied through probe size), as well as hydrostatic pressure and operation mode (continuous vs. sequential - or pulsed - process). Under non isothermal sonication sludge solubilization results from both ultrasound disintegration and thermal hydrolysis which are conversely depending on temperature. As found in isothermal operation: - For a given specific energy input, higher sludge disintegration is still achieved at higher PUS and lower sonication time. - US effects can be highly improved by applying a convenient pressure. - 12 kHz always performs better than 20 kHz. Nevertheless the optimum pressure depends not only on P-US and I-US, but also on temperature evolution during sonication. Under adiabatic mode, a sequential sonication using 5 min US-on at 360 W, 12 kHz, and 3.25 bar and 30 min US-off gives the best sludge disintegration, while maintaining temperature in a convenient range to prevent US damping. (C) 2015 Elsevier Ltd. All rights reserved.

【 授权许可】

Free