Chemical speciation of heavy metals in power plant ash pond leachate

Theis, Thomas L.; Richter, Richard O.

doi:10.1021/es60150a008

Cited by 54 publications

(22 citation statements)

References 9 publications

(12 reference statements)

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“…More information on the potential environmental influence of fly ash disposal on groundwater is available from laboratory studies, as discussed above, but these may not be fully representative of natural conditions. One method of fly ash disposal is to pump it into lagoons and most field-based studies have been conducted on such disposal sites (Dreesen et al 1977;Theis et al 1978;Theis & Richter 1979). With such a wet ash disposal method the ratio of water to solids is high and the emphasis of the published work has been on the early reactions.…”

Section: Field-based Leaching Studiesmentioning

confidence: 99%

“…With such a wet ash disposal method the ratio of water to solids is high and the emphasis of the published work has been on the early reactions. The work by Theis & Richter (1979) detailed the movement of a seepage plume in the groundwater from an ash disposal pond, and Cr(OH)3, Cuz(OH)2CO 3 and Pb(OH)2 were identified as possible solubility-controlling solids for Cr, Cu, and Pb. A study by Hardy (1981) showed elevated concentrations of Ca, K, Fe, and S (as SO 2 ) and As, B, Mn, Mo, Ni, Sr, and Zn in groundwater samples collected from an area bordering a fly ash settling pond compared with uncontaminated groundwater.…”

Section: Field-based Leaching Studiesmentioning

confidence: 99%

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Geochemistry of leachates from coal ash

Spears

Lee

2004

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The combustion of coal around the world for power generation produces huge volumes of fly ash. In Europe alone this amounted to about 40 Mt in 2000 of which less than 50% was utilized. The waste ends in lagoons, ash mounds, and landfill sites. Coal ashes have high concentrations of many trace elements, some of which are of environmental concern. Although the origin of elements in coals is not considered in this chapter, other aspects of the geochemistry are, and in particular the location of elements within the coal as this influences the behaviour of elements during combustion. During combustion many elements are volatile and are concentrated on the surfaces of the ash particles. Analyses of input coal and combustion residues from Eggborough power station (UK) demonstrate retention of the majority of elements in the solid combustion products, and analyses of size-fractionated fly ash have enabled the percentage surface association to be calculated, which for elements such as As and Mo is considerable. A consideration of the general leaching behaviour leads to the conclusion that it is the surface-associated elements that are most susceptible to leaching in the aqueous environment. The pH is an important control on trace element mobility in water, and in leachates from fly ash ranges from 3.3 to 12.3. Highsulphur coals generate acidic leachates, but not exclusively as the laboratory and field data demonstrate in case studies on UK coals. Batch and column leaching tests on fly ashes are reviewed and data presented for fresh fly ash and weathered fly ashes from two UK mounds dating back 17 and 40 years. The weathered ashes do have lower leachate concentrations than the fresh ash, but in spite of their ages they would not be considered to be inert. The batch leaching tests are of value in simulating high liquid-to-solid ratios encountered in ash lagoons, whereas the column leaching tests relate more closely to ash mounds. Finally, the results of field studies are reviewed and data presented for samples from boreholes in the two ash mounds. Analyses of the ash and extracted porewaters demonstrate depth-related changes due to reaction of the ash with the infiltrating water and whether or not equilibrium was established. Calculations demonstrate that the porewaters achieve saturation with respect to gypsum at depth in the boreholes. Infiltration over the years has led to detectable changes in the concentrations of some of the major elements in the bulk ash, such as Ca, and this enables realistic infiltration rates to be calculated. However, there are not comparable changes in the concentrations of the trace elements in the ash because the rate at which elements are being removed in solution is not sufficiently great.

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Section: Field-based Leaching Studiesmentioning

confidence: 99%

Section: Field-based Leaching Studiesmentioning

confidence: 99%

Geochemistry of leachates from coal ash

Spears

Lee

2004

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“…Theis and coworkers have investigated the potential for contaminants to leach fiom ash fills into soils and groundwater (Theis et aL, 1978;Theis and Richter, 1979).…”

Section: Potential Problems Of Inorganics In Coalmentioning

confidence: 99%

Development and evaluation of Mn oxide-coated composite adsorbent for the removal and recovery of heavy metals from coal processing wastewater. Final report, December 1995

Fan¹,

Anderson²

1995

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“…Precipitation (Hem, 1970, p. 201-202;Kopp and Kroner, 1967, p. 18) and sorption by iron and manganese hydroxides (Hem, 1972;Jenne, 1968) are common removal mechanisms of these metals in soil. Similarly, Theis and Richter (1979) concluded that dissolved cadmium and nickel are adsorbed by iron and manganese oxides, whereas copper is precipitated as hydroxides and carbonates.…”

Section: Trace Elementsmentioning

confidence: 99%

Effects of coal fly-ash disposal on water quality in and around the Indiana Dunes National Lakeshore, Indiana

Hardy¹

1981

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Prepared in cooperation with the National Park Service Abstract (Limit: 200 words)Dissolved constituents in seepage from fly-ash settling ponds bordering part of the Indiana Dunes National Lakeshore (the Lakeshore) have increased trace elements, and gross alpha and gross beta radioactivity in ground water and surface water downgradient from the settling ponds.Data suggest that concentrations of some dissolved trace elements may be greater beneath interdunal pona 2 than in the pond. The soil system downgradient from the settling ponds seems to have affected the concentrations of dissolved ions in the settling-pond seepage. Calcium concentrations were greater in ground water downgradient from the settling ponds than in the ponds. Where organic material was present downgradient from the settling ponds, concentrations of arsenic, flouride, molybdenum, potassium, sulfate, and strontium were greater in the ground water than in the ponds. In contrast, the concentrations of cadmium, copper, nickel, aluminum, cobalt, lead, and zinc were less. Document Analysis a. DescriptorsAlkaline earth metals, Atmospheric fall-out, Electric powerplants, Fly ash, Great Lakes Region, Groundwater, Indiana, National Lakeshores, Ponds, Radioactivity, Seepage, Settling basins, Trace elements, Water chemistry, Water quality b. Identifiers/Open-Ended TermsGross alpha activity, Gross beta activity, Fly-ash leaching, Fly-ash settling ponds, Indiana Dunes National Lakeshore, Interdunal ponds, Coal-combustion products, Settling-pond seepage Dissolved constituents in seepage from fly-ash settling ponds bordering part of the Indiana Dunes National Lakeshore (the Lakeshore) have increased the concentrations of major ions (calcium, fluoride, potassium, and sulfate), trace elements (aluminum, arsenic, boron, iron, manganese, molybdenum, nickel, strontium, and zinc), and gross alpha and beta radioactivity in ground water and surface water downgradient from the settling ponds. Data collected from September 1976 through May 1978 suggest that concentrations of some dissolved trace elements may be greater beneath interdunal pond 2 than in the pond. The soil system downgradient from the settling ponds seems to have affected the concentrations of dissolved ions in the settling-pond seepage. Calcium concentrations were greater in ground water downgradient from the settling ponds than in the ponds. Where organic material was present downgradient from the settling ponds, concentrations of arsenic, fluoride, molybdenum, potassium, sulfate, and strontium were greater in the ground water than in the ponds. In contrast, the concentrations of cadmium, copper, nickel, aluminum, cobalt, lead, and zinc were less.Leachate from an ash fill bordering the Lakeshore increased concentrations of boron, molybdenum, and potassium in surface water.Although concentrations of chemical constituents were variable, data indicate that ground-water in a confined aquifer beneath the study area was not significantly affected by settling-pond seepage.

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Chemical speciation of heavy metals in power plant ash pond leachate

Cited by 54 publications

References 9 publications

Geochemistry of leachates from coal ash

Geochemistry of leachates from coal ash

Development and evaluation of Mn oxide-coated composite adsorbent for the removal and recovery of heavy metals from coal processing wastewater. Final report, December 1995

Effects of coal fly-ash disposal on water quality in and around the Indiana Dunes National Lakeshore, Indiana

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