Analysis - The Institute for Southern Studies

4B.3 Land Disposal Restriction Cost (for dewatering treatment of CCR)
This element consists of two components:
Dry CCR disposal (landfills): Moisture conditioning and compaction to 95% maximum dry density value according to ASTM D 698 or
ASTM D 1557 test methods prior to disposal in landfills.
Wet CCR disposal (impoundments): Dewatering to remove solids prior to disposal in impoundments within 5-years of rule’s effective date.
The potential cost for this treatment standard is estimated below.
However, only the potential cost for the wet CCR disposal dewatering treatment standard is estimated in this section of the RIA because the
potential cost for meeting the dry CCR moisture conditioning and compaction requirements are already estimated in item 4 of the “engineering
controls” in this chapter above:
Examples of CCR Dewatering Methods
Based on the following recent (1997-2009) example descriptions of dry CCR disposal practices at existing or planned coal-fired electric utility
plants, dry CCR disposal may involve different methods for any given plant:
1. Tanks & chain drag: As described in March 2009 by the Basin Electric Power Cooperative. 84 Bottom ash will be dewatered in tanks
and the water will be re-circulated to transport additional bottom ash. Bottom ash will be removed using a chain drag. The ash will
then be hauled by truck to a lined landfill offsite. The fly ash will be conveyed in a dry state. Both ashes will be disposed in a landfill
close to the plant site.
2. Pressure squeeze conveyor: Another tank-based example apparently similar to the Basin Cooperative method is reported for dry
disposal conversion by the coal mining industry, involving the Phoenix Process Equipment company supplier of alternative slurry
processing equipment. This second example involves a thickening tank, porous conveyor belt and pressure to squeeze water out of the
coal washings, producing a semi-solid, 75% dewatered cake which is scraped off the conveyor belt and stacked like a pile of sand. The
cost for this process is reported at $0.50 per ton of coal waste processed. 85
3. Horizontal belt filters: According to a May 2009 technical paper 86 , dewatering gypsum using horizontal belt filters is common in the
electric utility industry, and a new modified horizontal belt filter method involving two feedboxes allows fly ash and FGD (gypsum) to
be dewatered simultaneously.
4. Storage silos & rail system: As described June 2009 87 for a $10 million conversion project located at Detroit Edison’s Monroe
Michigan Power Plant -- a four boiler unit, 3,200-megawatt power station originally constructed in 1974. Installation of equipment to
collect the coal ash in a dry state, plus dry ash storage facilities (storage silos), and truck/rail loading equipment for distribution of the
dry ash to concrete producers in the Midwest United States and Eastern Canada.
84 Source: March 2009 Basin Electric Power Cooperative examples at http://www.basinelectric.com/News_Center/Feature_Articles/Coal_ash_handling.html
85 Source: Dave Cooper, “Better, Safer Ways to Handle Coal Slurry Do Exist”, page 14 of the Nov 2001 “E”-Notes Newsletter of the Ohio Valley Environmental Coalition
at http://www.ohvec.org/newsletters/enotes_97-01_pdf/enotes_2001_11.pdf
86 Source: May 2009 horizontal belt filter technical paper by Alex Hohne at http://www.flyash.info/2009/036-hohne2009.pdf
87 Source: June 2009 Detroit Edison Monroe Power Plant example at http://www.headwaters.com/data/upimages/press/6.30.09MonroeAshRelease.pdf
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