Oklahoma Gas & Electric Muskogee Generating Station Best ...

Oklahoma Gas & Electric
Muskogee Generating Station – BART Determination
May 28, 2008
typically contain pyrites and other dense inorganic impurities including silica and trace
metals. The solids are typically dewatered in a mechanical dewatering device and disposed
of in a landfill.
The wastewater stream generally consists of an acidic liquid slurry made up of water,
uncombusted coal fines, and impurities in the coal, including calcium, trace metals,
chloride, sulfate, and dissolved and suspended solids. 17 The wastewater slurry must be
treated to remove solids, coal fines, and trace metals prior to discharge. Coal slurry
treatment systems may include surface impoundments, mechanical dewatering systems,
chemical processing systems, and/or thermal dryers.
While washing may be effective in removing rock inclusions from coal, including sulfurbearing
pyrites, a significant amount of coal may also be lost in the washing process. An
inherent consequence of coal washing, in addition to generating wastewater and solid waste
streams, would be the need for the mine to process significantly more coal to make up for
coal lost in the washing process.
Muskogee Units 4 & 5 are designed to utilize subbituminous coals. Based on a review of
available information, no information was identified regarding the washability or
effectiveness of washing subbituminous coals. Subbituminous coals have a relatively high
ash content and an excessive amount of fines, and significant dewatering equipment would
be required to process and separate the fines from the wastewater stream. It is likely that
the excess fines production, and the difficulties associated with handling and dewatering
the fines, have restricted the commercial viability of subbituminous coal washing.
Furthermore, the coal washing process would generate significant solid and liquid waste
streams that would require proper management and disposal. Based on a review of
available information, there are currently no commercial subbituminous coal washing
facilities, and washed subbituminous coals are not available through commercial channels.
Therefore, coal washing is not considered an available retrofit control option for Muskogee
Units 4 & 5.
4.2.1.3 Coal Processing
Pre-combustion coal processing techniques have been proposed as one strategy to reduce
the sulfur content of coal and help reduce uncontrolled SO2 emissions. Coal processing
17 See, USEPA Report to Congress, Wastes from the Combustion of Fossil Fuels, Office of Solid Waste and
Emergency Response, EPA 530-S-99-010, March 1999 (general composition of selected large-volume and
low-volume wastes).
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