title: An executive review of sludge pretreatment by sonication.
abstract: Ultrasonication (US), which creates hydro-mechanical shear forces in cavitation, is an advanced technology in sludge pretreatment. However, there are many factors affecting the efficacy of cavitation and ultrasonication disintegration of sludge as a consequence. The objective of this work is to present an extensive review of evaluation approaches of sludge US pretreatment efficiency. Besides, optimization methodologies of related parameters, the differences of optimum values and the similarities of affecting trends on cavitation and sludge pretreatment efficiency were specifically pointed out, including ambient conditions, ultrasonic properties, and sludge characteristics. The research is a prerequisite for optimization of sludge US pretreatment efficiency in lab-scale and practical application. There is not-yet a comprehensive method to evaluate the efficiency of sludge US pretreatment, but some main parameters commonly used for this purpose are degree of sludge disintegration, proteins, particle size reduction, etc. Regarding US parameters, power input PUS, intensity IUS, and frequency FS seem to have significant effects. However, the magnitude of the effect of PUS and probe size in terms of IUS has not been clearly detailed. Investigating very low FS seems interesting but has not yet been taken into consideration. In addition, static pressure effect has been marginally studied only and investigation on the effect of pH prior to US process has been restricted. Their effects therefore should be varied separately and simultaneously with other related parameters, i.e. process conditions, ultrasonic properties, and sludge characteristics, to optimize sludge US pretreatment process.
authors.affiliation: University of Science, Vietnam National University, Ho Chi Minh City, Viet Nam; Université de Toulouse, Laboratoire de Génie Chimique, INP-ENSIACET, France. Electronic address: lntuan@hcmus.edu.vn.
authors.forename: Ngoc Tuan
authors.initials: NT
authors.lastname: Le
authors.affiliation: Université de Toulouse, Laboratoire de Génie Chimique, INP-ENSIACET, France.
authors.forename: Carine
authors.initials: C
authors.lastname: Julcour-Lebigue
authors.affiliation: Université de Toulouse, Laboratoire de Génie Chimique, INP-ENSIACET, France.
authors.forename: Henri
authors.initials: H
authors.lastname: Delmas
mesh_terms: D000818:Animals; D012722:Sewage / Q000737:chemistry / Q000382:microbiology; D013010:Sonication / Q000379:methods*; D018505:Waste Management / Q000379:methods*
chemical_list: D012722:Sewage
keywords: Acoustic frequency; Intensity effect; Pressure effect; Sludge disintegration; Ultrasonic pretreatment; Waste activated sludge