A field and laboratory study of solute release from sluiced fly ash. Final report

Technical Report · Thu Dec 01 04:00:00 EST 1994

OSTI ID:10127733

Zachara, J M; Rai, D; Moore, D A; Resch, C T ^[1]

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1. Battelle Pacific Northwest Lab., Richland, WA (United States)

EPRI has sponsored a comprehensive field and laboratory study on a sluicing fly ash system at a coal-fired electric generating station. The results provide insights on factors such as ash chemical composition and particle size that need to be considered to predict short- and long-term trends in leachate composition associated with these systems. The composition of sluice water contacting the different fly ashes depended on the chemical composition of the fly ash, which varied widely according to collection systems (ESP versus MS); the pH as a result of condensed sulfuric acid (H{sub 2}SO{sub 4}); the solids concentration of the fly ash in the sluice water; and the fraction of each element that was leachable from the ash. These factors require quantification in order to predict sluice water quality during fly ash disposal. Generally, both the ESP and MS fly ashes contained an immediately soluble fraction of both major and minor elements that was depleted significantly, but not completely, in their sluicing to the pond. The leachable fraction, ranging from 2. 5--10% for minor solutes to 75% for SO{sub 4}, was most responsible for sluice water quality changes. Few long-term changes were observed in the chemical characteristics of the disposed ash over time periods exceeding 20 years. Significant temporal variations in water quality were observed at the sluice outfall as hopper contents of varying chemical composition were discharged to the pond. Lower pH values, more soluble salts, and greater concentrations of minor elements were associated with the ESP ashes. Furthermore, the ESP ash was of smaller particle size and higher surface area than the MS ash and contained higher total concentrations of elements volatilized during the combustion process.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (United States); Battelle Pacific Northwest Lab., Richland, WA (United States)
• Sponsoring Organization: Electric Power Research Inst., Palo Alto, CA (United States)
• OSTI ID: 10127733
• Report Number(s): EPRI-TR--104585; ON: UN95008850
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010900
54 ENVIRONMENTAL SCIENCES
540220
CHEMICALS MONITORING AND TRANSPORT
COAL-FIRED GAS TURBINES
COMBUSTION PRODUCTS
ENVIRONMENTAL ASPECTS
ENVIRONMENTAL IMPACTS
FLY ASH
FOSSIL-FUEL POWER PLANTS
GROUND WATER
LEACHING
SULFURIC ACID
WASTE DISPOSAL