Emissions of inorganic and organic arsenic compounds via the leachate pathway from pretreated municipal waste materials: a landfill reactor study.
The emission of arsenic (As) with leachate from mechanically biologically pretreated municipal solid waste (MBP-MSW) was quantified over one year using landfill simulation reactors. Arsenic mobilization and transformation processes were studied by simulating different environmental conditions (anoxic conditions with underlying soil or oxic/anoxic conditions). Amounts of mono-, di-, and trimethylated As in MBP-MSW prior to simulation were < 48 microg As kg(-1) and were magnified to 300-390 microg As kg(-1) under anoxic conditions, whereas methylated As was undetectable in the oxic setup. The highest leachate concentrations (up to 84 microg L(-1)) occurred during the first four weeks of manipulation. The annual Astotal release with leachates averaged 19.6, 7.6, and 4.5 microg kg(-1) under an anoxic environment with underlying soil, oxic conditions, and anoxic conditions, respectively, with 15-50% occurring as organic As. The annually released As represented 0.2-0.8% of the Astotal pool, suggesting that As mobilization from waste is a slow process. The anoxia diminished As release rates, whereas anoxic conditions with underlying soil material elevated the As mobilization, probably due to reductive dissolution of soil-derived Fe and Mn (hydr)oxides. The mass balance of methylated As in MBP-MSW and leachates before and after the treatments highlights As methylation under anoxic conditions and demethylation under oxic landfill conditions.
Huang
J H
JH
Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology Zurich CHN, CH-8092 Zurich, Switzerland. jenhow.huang@env.ethz.ch
Ilgen
G
G
Vogel
D
D
Michalzik
B
B
Hantsch
S
S
Tennhardt
L
L
Bilitewski
B
B
D000332:Aerobiosis; D000693:Anaerobiosis; D001151:Arsenic / Q000032:analysis; D001152:Arsenicals / Q000032:analysis*; D001673:Biodegradation, Environmental; D002852:Chromatography, Ion Exchange; D002947:Cities; D012987:Soil / Q000032:analysis; D014866:Waste Products / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D001152:Arsenicals; D012987:Soil; D014866:Waste Products; D014874:Water Pollutants, Chemical; D001151:Arsenic