title: The effects of waste-activated sludge pretreatment using hydrodynamic cavitation for methane production.
abstract: Disintegration of waste-activated sludge (WAS) is regarded as a prerequisite of the anaerobic digestion (AD) process to reduce sludge volume and increase methane yield. Hydrodynamic cavitation (HC), which shares a similar underlying principle with ultrasonication but is energy-efficient, was employed as a physical means to break up WAS. Compared with ultrasonic (180-3600 kJ/kg TS) and thermal methods (72,000 kJ/kg TS), HC (60-1200 kJ/kg TS) found to consume significantly low power. A synergetic effect was observed when HC was combined with alkaline treatment in which NaOH, KOH, and Ca(OH)2 were used as alkaline catalysts at pH ranging from 8 to 13. As expected, the production yield of CH4 gas increased proportionally as WAS disintegration proceeded. HC, when combined with alkaline pretreatment, was found to be a cost-effective substitute to conventional methods for WAS pretreatment.
authors.affiliation: Department of Civil and Environmental Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Ilgyu
authors.initials: I
authors.lastname: Lee
authors.forename: Jong-In
authors.initials: JI
authors.lastname: Han
mesh_terms: D002126:Calcium Hydroxide / Q000737:chemistry; D002384:Catalysis; D057446:Hydrodynamics; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides / Q000737:chemistry; D008697:Methane / Q000096:biosynthesis* / Q000737:chemistry; D017680:Potassium Compounds / Q000737:chemistry; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D012972:Sodium Hydroxide / Q000737:chemistry; D013010:Sonication / Q000295:instrumentation; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology
chemical_list: D002126:Calcium Hydroxide; D006878:Hydroxides; D008697:Methane; D017680:Potassium Compounds; D012722:Sewage; D012972:Sodium Hydroxide; D062065:Wastewater; C029943:potassium hydroxide