1. Confirm the year and approximate acreage of the land sold to Lafarge? 

The area sold to LaFarge was 88.3 acres per attached dwg # H-0515-D-01-000000. 

2. Please provide the chloride content of the coal?

Chlorine of the As-received coal has been in the 0.17% range.

3. If you converted, would you modify the existing boilers or install new units for the 

change to natural gas? If installing new units, would you install combined cycle units?

This is in the feasibilty study stage. Unknown at this time.

4. Seminole required to do any groundwater monitoring around the percolation ponds?

Yes, there are four monitoring wells downgradient from the percolation ponds that are monitored 

quarterly.

5. Please provide an estimate of the reduced thermal energy losses realized after installing 

the DRYCONTM system.

20 million btu/hr per the 2009 Burns & McDonnell project study report attached.

6. Please provide the moisture content of dry bottom ash.]

7. Please provide data on the specific cost savings experienced from converting from the 

wet sluicing system.]

The following data is from the attached 2009 Burns & McDonnell dry bottm ash project study 

summary of O&M cost savings: 1.) Electrical power cost savings = $459,000/year/Unit, 2.) 

Maintenance costs $300,000/year/Unit, 3.) Spare parts use = $216,000/year/Unit, 4.) Make-up 

water $68,000/year/Unit, and 5.) recovered thermal energy cost = $400,000/year/Unit.
 

8. The design maximum chlorides level is 20,000 ppm. Seminole sends blowdown to the 

wastewater treatment system constantly at a rate of 850 GPM. Please confirm that the 

plan blows down continuously at a rate of 850 GPM?

The system has been permitted to blowdown at 800 gpm but is not currently capable of that flow 

rate. Maximum rates are approximately 550 gpm but typically average around 500 gpm.

9. Please provide the total flow from the supernatant tank to the treatment system, recycled 

back to the scrubber, and to the pond system.

Water to be treated in the FGD blowdown system is drawn off in batches for treatment, ~24,000 

gals. per batch, averaging ~32 batches per day. Supernate from the Thickener overflow tanks is 

pumped back to the FGD system continuosly for use in those systems. Any overflow back to the 

ponds is dependent on the FGD system demand. Rain fall also impacts that as that is fresh water 

introduced in the system via any containment that the FGD system would capture thus becoming 

part of the scrubber bleed/supernate loop.

10. Seminole sends samples of the influent to the batch reactors to a laboratory to measure 

selenium concentrations using atomic absorption. Selenium concentrations at the influent 

to the batch reactor can range from between 180 ppb to 400 ppb. The treatment system 

reduces the selenium levels in the wastewater to 20 ppb and less. Historically, Seminole 

has observed 98 percent selenium removal. [QUESTION FOR SEMINOLE: Please 

confirm the 98 percent selenium removal.

The data for 2013 indicates an average of 96.2% removal with a range from 94.5 % to 98.0%.

11. Please provide the flow rate from the batch reactors to the clarifier.

The discharge rate from each Reactor is approx. 1200 gpm when pumping to the Clarifier.

12. How often do you dewater the FGD sludge with the filter presses? Why do you use the 

fly ash to stabilize the FDG solids instead of selling the fly ash and dewatering the FGD 

solids in the filter presses?
The filter presses are operated 2 to 4 days per week depending on the sludge bed level in the 

FGD Blowdown Treatment Clarifier. Presently that is the only means to landfill the FGD 

treatment system sludge, due to it’s properties even after using the filter presses still requires 

stabilization with Fly Ash. The moisture content from the presses is in the 70% range.

13. Please provide some information on iron cycling? What type of negative effects could 

iron cycling have on the gypsum?

We have not performed those studies as yet but we are concerned about color of the gypsum 

produced.

14. Do you have any sampling results for dissolved mercury in the system? Was the 50 

percent reduction in mercury concentrations based on bench scale testing, pilot scale 

testing, theoretical calculations, or another basis?

A vendor took the only data we have ever developed and we cannot locate the information. We 

will contact the vendor and see if we can come up with this information as soon as possible.