Performance evaluation of intermediate cover soil barrier for removal of heavy metals in landfill leachate.
This pilot-scale study evaluated the use of intermediate cover soil barriers for removing heavy metals in leachate generated from test cells for co-disposed fly ash from municipal solid waste incinerators, ash melting plants, and shredder residue. Cover soil barriers were mixtures of Andisol (volcanic ash soil), waste iron powder, (grinder dust waste from iron foundries), and slag fragments. The cover soil barriers were installed in the test cells' bottom layer. Sorption/desorption is an important process in cover soil bottom barrier for removal of heavy metals in landfill leachate. Salt concentrations such as those of Na, K, and Ca in leachate were extremely high (often greater than 30 gL(-1)) because of high salt content in fly ash from ash melting plants. Concentrations of all heavy metals (nickel, manganese, copper, zinc, lead, and cadmium) in test cell leachates with a cover soil barrier were lower than those of the test cell without a cover soil barrier and were mostly below the discharge limit, probably because of dilution caused by the amount of leachate and heavy metal removal by the cover soil barrier. The cover soil barriers' heavy metal removal efficiency was calculated. About 50% of copper, nickel, and manganese were removed. About 20% of the zinc and boron were removed, but lead and cadmium were removed only slightly. Based on results of calculation of the Langelier saturation index and analyses of core samples, the reactivity of the cover soil barrier apparently decreases because of calcium carbonate precipitation on the cover soil barriers' surfaces.
Faculty of Life Applied Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Akiha-ku, Niigata 956-8603, Japan. kazuyuki@nupals.ac.jp
Kazuyuki
K
Suzuki
Aya
A
Anegawa
Kazuto
K
Endo
Masato
M
Yamada
Yusaku
Y
Ono
Yoshiro
Y
Ono
D000327:Adsorption; D002119:Calcium Carbonate / Q000378:metabolism; D002244:Carbon / Q000032:analysis / Q000737:chemistry; D060729:Coal Ash; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007700:Kinetics; D019216:Metals, Heavy / Q000032:analysis*; D052638:Particulate Matter / Q000032:analysis / Q000737:chemistry; D012037:Refuse Disposal / Q000379:methods; D012987:Soil / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D060729:Coal Ash; D019216:Metals, Heavy; D052638:Particulate Matter; D012987:Soil; D014874:Water Pollutants, Chemical; D002244:Carbon; D002119:Calcium Carbonate