Emissions of Inorganic and Organic Arsenic Compounds via the Leachate Pathway from Pretreated Municipal Waste Materials: A Landfill Reactor Study

Abstract

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.

In situ ATR–FTIR and surface complexation modeling studies on the adsorption of dimethylarsinic acid and p-arsanilic acid on iron-(oxyhydr)oxides

“…The disposal of arsenic-containing waste (mostly electronics) in landfills also contaminates groundwater with arsenic and releases arsine gases to the atmosphere at concentrations above background levels (ca. 0.1-2 ppt) [8][9][10].…”

Investigation of biomethylation of arsenic and tellurium during composting

“…Both prerequisites are found in biological waste treatment, where microbiological activity is intentionally optimized for rapid conversion of organic waste materials. Indeed, intensive biomethylation was found in waste deposits [2][3][4][5] as well as anaerobic waste treatment [6,7].…”

Water reclamation and nitrogen extraction from municipal solid waste landfill leachate

“…More importantly, the presence of heavy metals, pharmaceutically active compounds (PhACs) and other complex organic chemicals in landfill leachate are of significant concern [4][5][6]. In particular, the contamination of various natural water bodies by landfill leachate poses further stress on the municipal water supply.…”