Hydrogeology of an alkaline fly ash landfill in Eastern Iowa

摘要: The hydrogeology and chemical quality of the shallow ground-water regime at a coal fly ash landfill was investigated near Montpelier, Iowa. An embankment dam retains two-hectare deposit silt-sized alkaline in an upland ravine. operated between 1964-1973 subsequently capped with thin loess layer seeded to pasture. is underlain by loess, over clay-rich till, sandstone. Ground water now saturates lower one-half ash. Nineteen monitoring wells were installed around within landfill. Sampling 1983-1984 conducted for levels, temperature, pH, alkalinity, specific conductance, calcium (Ca/sup 2+/), magnesium (Mg/sup sodium (Na/sup +/), potassium (K/sup sulfate (SO/sub 4//sup 2-/), chloride (Cl/sup -/), arsenic (As), selenium (See). Calculated ion balances 30 analyses had error less than 4%. Native loess-derived ground bicarbonate type enters landfill, then shifts type. A distinct leachate plume presently extends least 46 meters downgradient from passing under through dam, discharging into small pond. SO/sub 2-/ Se concentrations exceed EPA drinking watermore » standards, trace As detected. Although pH increased after entering alkalinity declined. Results equilibrium solubility calculations suggest that this condition evolved calcite supersaturation precipitating carbonate. Dissolution oxides on glassy spheres sustains highly strength.« less