title: The application of electrocoagulation for the conversion of MSWI fly ash into nonhazardous materials.
abstract: This research investigated the electrocoagulation of municipal solid waste incineration (MSWI) fly ash at a liquid-to-solid ratio (L/S) of 20:1. The leachate that was obtained from this treatment was recovered for reutilization. Two different anodic electrodes were investigated, and two unit runs were conducted. In Unit I, the optimum anode was chosen, and in Unit II, the optimum anode and the recovered leachate were used to replace deionized water for repeating the same electrocoagulation experiments. The results indicate that the aluminum (Al) anode performed better than the iridium oxide (IrO2) anode. The electrocoagulation technique includes washing with water, changing the composition of the fly ash, and stabilizing the heavy metals in the ash. Washing with water can remove the soluble salts from fly ash, and the fly ash can be converted into Friedel's salt (3CaO·Al2O3·CaCl2·10H2O) under an uniform electric field and the sacrificial release of Al(+3) ions, which stabilizes the toxic heavy metals and brings the composition of the fly ash to within the regulatory limits of the toxicity characteristic leaching procedure (TCLP). Use of the Al anode to manage the MSWI fly ash and the leachate obtained from the electrocoagulation treatment is therefore feasible.
authors.affiliation: Department of Environmental Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan.
authors.forename: Wing-Ping
authors.initials: WP
authors.lastname: Liao
authors.affiliation: Department of Environmental Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan; Bio-way Environmental Science and Technology (BEST) Corp., Ltd., Taichung 404, Taiwan. Electronic address: renbo.yang@msa.hinet.net.
authors.forename: Renbo
authors.initials: R
authors.lastname: Yang
authors.affiliation: Department of Environmental Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan.
authors.forename: Wei-Ting
authors.initials: WT
authors.lastname: Kuo
authors.affiliation: Department of Environmental Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan.
authors.forename: Jui-Yuan
authors.initials: JY
authors.lastname: Huang
mesh_terms: D000535:Aluminum / Q000737:chemistry; D055664:Electrochemical Techniques; D004566:Electrodes; D019216:Metals, Heavy / Q000737:chemistry; D052638:Particulate Matter; D012037:Refuse Disposal / Q000379:methods*; D062611:Solid Waste; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D019216:Metals, Heavy; D052638:Particulate Matter; D062611:Solid Waste; D014874:Water Pollutants, Chemical; D000535:Aluminum
keywords: Electrocoagulation; Friedel's salt; Heavy metals; MSWI fly ash; Toxicity characteristic leaching procedure