title: Experimental study of fry-drying and melting system for industrial wastewater sludge.
abstract: In South Korea, ocean dumping of organic sludges has been prohibited by the London Convention and by Korean regulations. Therefore, the Government of South Korea has sought an alternative process for the disposal of organic sludges. Recently, the combined fry-drying and melting system has been recognized as an efficient way to utilize the energy content of organic industrial sludge. Three kinds of fry-dried industrial sludges (obtained from industrial sites DG, DJ and GM), which had average heating value of 20,470kJ/kg and less than 5% water content, were tested. Unlike sewage sludge, industrial sludge contains high concentrations of heavy metals and thus cannot be directly utilized as refuse-derived fuel. The dried sludges were melted in a furnace and then rapidly cooled to form vitrified slags; the vitrification of SiO2 securely encapsulates hazardous heavy metals within the crystalline structure of the slag. To evaluate the hazard of vitrified slag, the heavy metal elution concentration was analyzed. Following vitrification, Hg, Cd, Cr(+6), HCN and Pb concentrations were not detectable, whereas Cu concentration decreased from 26.78mg/L to 0.42mg/L in DJ sludge, from 27.10mg/L to 0.13mg/L in DG and from 49.47mg/L to 0.047mg/L in GM sludge.
authors.affiliation: Department of Civil & Environmental Engineering, Hanbat National University, Deajeon, Republic of Korea.
authors.forename: Jong-Seong
authors.initials: JS
authors.lastname: Chae
authors.affiliation: Department of Civil & Environmental Engineering, Hanbat National University, Deajeon, Republic of Korea.
authors.forename: Su-Ah
authors.initials: SA
authors.lastname: Choi
authors.affiliation: Department of Civil & Environmental Engineering, Hanbat National University, Deajeon, Republic of Korea.
authors.forename: Young-Hyo
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Environmental Engineering, Kongju National University, Chungnam, Republic of Korea.
authors.forename: Sae-Cheon
authors.initials: SC
authors.lastname: Oh
authors.affiliation: School of Mechanical Engineering, Sungkyunkwan University, Suwon, Republic of Korea.
authors.forename: Chang-Kook
authors.initials: CK
authors.lastname: Ryu
authors.affiliation: Department of Civil & Environmental Engineering, Hanbat National University, Deajeon, Republic of Korea. Electronic address: tiohm1@hanbat.ac.kr.
authors.forename: Tae-In
authors.initials: TI
authors.lastname: Ohm
keywords: Elution; Heavy metal; Industrial wastewater sludge; Smelting furnace; Vitrification