MEMORANDUM

TO: Steam Electric Rulemaking Record

FROM: Elizabeth Gentile, ERG

DATE: September 30, 2015

SUBJECT: Ash Handling Documentation from Communications with Clyde Bergemann 

Power Group

EPA published proposed revisions to the effluent limitations guidelines and standards (ELGs) for 

the Steam Electric Power Generating category (40 CFR Part 423) on June 7, 2013 (78 FR 

34431). Based on public comments received from the proposed rule, EPA and ERG contacted 

Clyde Bergemann Power Group (CPBG) several times between January 9, 2014 and September 

30, 2014 to collect additional information on fly and bottom ash handling conversions. This file 

is a compilation of the call notes between EPA, ERG, and CBPG. The call notes included in the 

following sections of this memorandum are listed below by date:

 January 9, 2014: Call between EPA, CBPG, and ERG to discuss fly ash and bottom ash 

handling conversions.

 April 15, 2014: Meeting between CBPG and ERG to discuss the response to questions 

delivered April 7, 2014 and provided design data for one ASHCONTM installation.

 June 2, 2014: Call between CBPG and ERG to discuss bottom ash handling technology 

options.

 August 28, 2014: Call between CBPG and ERG to discuss bottom ash remote mechanical 

drag systems and delivery of three bottom ash cost estimates.

 September 19, 2014: Call between CBPG and ERG to discuss methodology for 

estimating ASHCONTM volume.

Additionally, Appendix A of this memorandum includes all of the email communication between 

EPA, ERG, and CBPG. The email communications included in the Appendix to this 

memorandum are listed below by date.

 January 9, 2014 and February 10, 2014: Email documentation of the CBPG dense slurry 

installations from Gary Mooney, CBPG to Elizabeth Gentile (Sabol), ERG.

 April 7, 2014: Response to follow up questions on fly ash and bottom ash costs delivered 

by ERG on March 25,2014 from Gary Mooney, CBPG to Elizabeth Gentile (Sabol), 

ERG.

 June 10, 2014: Response to follow up questions on fly ash and bottom ash costs delivered 

by ERG on June 9, 2014 from Gary Mooney, CBPG to Elizabeth Gentile, ERG.
Memorandum

September 30, 2015

Page 2

 June 19, 2014: Email documentation of sales tax information from Gary Mooney, CBPG 

to Elizabeth Gentile, ERG.

 September 30, 2014: Email documentation of high pressure pumps (cost and service life) 

from Gary Mooney, CBPG to Elizabeth Gentile, ERG.

1.0 NOTES FROM CALL WITH CLYDE BERGEMANN POWER GROUP ON JANUARY 9, 2014

On Thursday, January 9, 2014, EPA and ERG participated in a call with CBPG to discuss fly ash 

and bottom ash handling conversions. Participants on the call included representatives from 

EPA, ERG, and CBPG, as listed in Table 1.

Table 1. List of Participants

Name Organization

Gary Mooney CBPG

Ron Grabowski CBPG

Ron Jordan EPA

Phillip Flanders EPA

Jezebele Alicea EPA

Deb Bartram ERG (contractor to EPA)

TJ Finseth ERG (contractor to EPA)

Ryan Novak ERG (contractor to EPA)

Elizabeth Gentile ERG (contractor to EPA)

Ms. Alicea began by providing a brief introduction stating that EPA would like to collect 

additional information on fly ash and bottom ash handling conversions in response to public 

comment received on the proposed rule. The remaining topics discussed included: the dense 

slurry fly ash handling technology, backup wet sluicing systems for fly ash, submerged scraper 

conveyors, remote submerged scraper conveyor systems (ASHCONTM), and dry mechanical 

conveyors (DRYCONTM).

Dense Slurry System

Mr. Mooney provided background information on dense slurry systems. He stated these types of 

systems are a viable handling option within the industry, particularly at those plants that may add 

limestone to the boiler, and noted that there are several systems installed and operating in Europe 

and one in the United States (JEA Northside). Mr. Mooney explained that these systems can be 

used for fly ash or bottom ash, but may be better to convey fly ash (due to the consistency of fly 

ash). Mr. Mooney further noted that the JEA Northside installation is different from the rest of 

the industry because the plant operates CFB boilers, in which both the fly ash and bed ash are a 

similar consistency. 

Mr. Mooney discussed that in the conversion of a traditional fly ash wet sluicing system to a 

dense slurry system, the plant would need to install different pumps (diaphragm pumps or GEHO 

pumps) to transport the slurry to the final destination. The existing fly ash equipment can be 

reused to transport the fly ash to the mixing point where it becomes slurry. Plants would likely 

have to dewater existing ponds to use that space as the disposal for the dense ash slurry. 

Commented [E1]: Note to CBPG: Is a crusher required for fly 

ash? Or would a crusher only be required for the installation of a 

dense slurry system to transport bottom ash?
Memorandum

September 30, 2015

Page 3

Back Up Wet Sluicing Systems for Fly Ash Handling

Mr. Mooney stated that there have been many wet-to-dry fly ash handling conversions in the 

industry since 1977. Wet fly ash handling systems are actually dry until fly ash is mixed with 

water at a vacuum producer before it flows to a storage impoundment. Because the system 

components directly underneath the boiler to the vacuum producer are dry, plants do not need to 

remove the wet sluicing system, they need to install a diverter valve and/or a dry vacuum source. 

Mr. Mooney explained that there is redundancy within dry fly ash handling conversions, and that 

plants do not need to keep wet handling systems in addition to the dry handling systems for a 

successful conversion. Specifically, the CBPG costs provided to EPA by CBPG to estimate fly 

ash handling conversions included sufficient redundancy (e.g., two vacuum pumps per fly ash 

vacuum line, one standard and one backup). Mr. Mooney explained that plants actually gain 

redundancy by converting to dry fly ash handling systems because redundancy is automatically 

built into the system. With a wet sluicing system, many plants don’t have any redundancy and 

when the system is plugged the system is down.

Some plants use both wet and dry fly ash handling systems after a conversion so that the “best” 

ash is in the silo for plants that market dry fly ash. In this scenario, plants may sluice economizer 

or air heater ash and only transfer marketable fly ash dry to the silo. In order to manage this type 

of scenario without a wet sluicing system, CBPG stated that two separate silos could be used to 

keep ash of differing qualities stored separately. 

Mr. Mooney explained that demolition of the existing fly ash wet sluicing system is not typically 

included in conversion costs and that there is no pressing reason to get rid of the system after the 

dry fly ash handling retrofit. 

Submerged Scraper Conveyor

Mr. Mooney explained that most under the boiler submerged scraper conveyors convey 

dewatered bottom ash out from the boiler wall to a bunker right outside the boiler wall. He noted 

that it is uncommon to go much further than right outside the bunker wall; however, a longer 

conveyance distance can be accommodated by adding a belt conveyor to convey the dewatered 

bottom ash any amount of distance to a common dewatering bunker. Mr. Mooney estimated that 

a belt conveyor is approximately half the price of the submerged scraper conveyor (based on the 

conveyance distance required).

The cost estimates provided to EPA by CBPG for a submerged scraper conveyor installation 

included the demolition of the existing equipment underneath the boiler. The other wet sluicing 

equipment (e.g., piping to the pond) does not need to be demolished for system operation and 

was not included in the costs CBPG provided to EPA. 

Mr. Mooney stated that many new generating units are installing submerged scraper conveyors 

compared to wet sluicing systems. However, he reiterated that some plants cannot convert 

existing wet sluicing bottom ash handling systems to submerged scraper conveyors due to space 

constraints in the boiler house.
Memorandum

September 30, 2015

Page 4

Remote Submerged Scraper Conveyor (ASHCONTM)

Mr. Mooney provided a brief overview of the ASHCONTM. He stated that plants typically look 

into this type of bottom ash handling system because the plant cannot fit a submerged scraper 

conveyor or a DRYCONTM underneath the boiler. He explained that it is standard procedure to 

drain the ASHCONTM once every five to six years for standard maintenance. Other maintenance 

on the system includes re-threading the 2 strands of drag chain used for dewatering the bottom 

ash. Mr. Mooney confirmed that estimating compliance costs for one ASHCONTM per generating 

unit at the plant would be accounting for sufficient redundancy. He explained that plants 

typically keep the option in to sluice to the surface impoundment. 

During the conversation, Mr. Mooney explained that the ASHCONTM does not take the place of 

settling and/or surge tanks, it simply dewaters bottom ash. Therefore, plants that partially close 

their system may have a high fines carryover. He stated that a heat exchanger or bath (e.g., tank 

or pond) may be necessary to allow the bottom ash transport water time to cool prior to being 

recirculated back to the boiler house for additional bottom ash sluicing. There have been several 

bids by CBPG for the ASHCONTM system that include both a clarifier with chemical addition to 

remove ash and control pH and a recirculation or storage tank. However, it is CBPG’s 

experience that many plants are holding on bottom ash system conversions until the CCR rule 

and ELG are finalized. 

Dry Mechanical Conveyor (DRYCONTM)

Mr. Mooney provided a brief overview of the DRYCONTM bottom ash handling system and 

noted that there are two plants operating this type of system in the United States: Seminole 

Generating Station (Palatka, FL) and Crystal River (Crystal River, FL). Some plants may not be 

able to install the DRYCONTM due to space constraints underneath the boiler. The outage time 

associated with the DRYCONTM is approximately 4-6 weeks. He believes the DRYCONTM is 

likely the most cost effective conversion for bottom ash because there are savings associated 

with the following: 

 Maintenance (approximately $650,000/year in labor, spare parts, and operating

personnel);

 Power Savings (approximately $125,000/year);

 Water usage (greater than $200,000/year);

 Water Heat Reduction (greater than $300,000/year in head loss reduction); and

 Boiler Efficiency (not estimated).

CBPG is working on quantifying the savings associated with boiler efficiency (reduced loss on 

ignition and fuel consumption).

2.0 NOTES FROM MEETING WITH CLYDE BERGEMANN POWER GROUP ON APRIL 15, 2014

On Tuesday, April 15, 2014, Gary Mooney, CBPG and Elizabeth Gentile, ERG met at the CBPG 

Material Handling Product office in Malvern, PA to discuss fly ash and bottom ash handling 

Commented [E2]: Note to CBPG: Are there any current 

ASHCONTM installations that operate some form of treatment to 

remove fines? What type of treatment systems are installed? Are 

there any that operate without treatment?

Commented [E3]: Note to CBPG: Are there any current 

installations that require a heat exchanger or bath? Are there any that 

operate without a heat exchanger or bath?
Memorandum

September 30, 2015

Page 5

conversions, particularly the responses provided to follow up questions on ash handling 

conversions provided to EPA and ERG on April 7, 2014. 

Mr. Mooney began by providing a brief overview of how plants typically initiate an ash handling 

conversion. He described that plants typically hire an engineering firm, who works with the plant 

to draft engineering procurement and construction specifications and develop a request for 

proposal to capture several design and supply tasks. In this scenario, CBPG would submit a 

proposal for design and supply tasks related to ash handling.

Mr. Mooney described that a turnkey fly ash system is a system where everything (including 

installation) is included in the design and cost. We discussed that CBPG fly ash bids are typically 

not turnkey fly ash systems, and therefore the costs provided by CBPG represent purchased 

equipment and the other elements outlined in CBPG’s response to questions provide on April 7, 

2014.

In the response to questions provided by CBPG on April 7, 2014, he stated that the controls 

included in the system were “assumed to be only system logic for integration into existing plant 

DCS systems, not new PLC systems.” Mr. Mooney elaborated stating that modern power plants 

typically have a distributed control system (DCS). The controls included in the costs for the fly 

ash handling conversions include the system logic so the DCS programmer at the plant can run 

the new dry handling system in concert with the other systems at the plant. ERG confirmed with 

Mr. Mooney that costs for programmable logic controllers (PLC) were not included in the cost 

estimates and are not needed because the plant only needs the system logic for the DCS.

Ms. Gentile requested information on cost estimates for insulation, heat tracing, or other 

winterization equipment for dry fly ash handling conversions. Mr. Mooney stated that some heat 

wrap may be necessary for some plants in northern climates. Mr. Mooney stated that large 

engineering firms may have rules of thumb for pricing heat tracing or other winterization 

equipment.

Ms. Gentile explained that EPA and ERG are looking into public comments on redundancy for 

dry fly ash handling systems. As shown in the responses provided by CBPG on April 7, 2015, 

the costs for a second filter-receiver were requested and received. Mr. Mooney explained that it 

is common to include an extra standby pump or blower in a design to account for redundancy, 

and that adding capital costs for a second filter-receiver accounts for additional redundancy. Ms. 

Gentile explained that EPA and ERG are also looking into additional capital costs for vacuum 

pumps and pressure blowers for redundancy costs for plants that operate dry fly ash handling 

systems with wet sluicing systems as back up (and require additional redundancy to handle all 

fly ash dry).1

Mr. Mooney stated that the remote submerged scraper conveyor (ASHCONTM) may have an 

issue with particulate control causing too much wear over the equipment. He also stated that the 

 

1 The cost estimates provided by CBPG can be found in Attachment 6 to this DCN (DCN SE05933A6: Additional 

Post Proposal Follow Up Questions for Clyde Bergemann Power Group With Responses, Including Updated Fly 

Ash Conversion Costs (SE04165_Cost Methodology Questions for CBPG_06092014 - RESPONSES 

06102014.pdf)).
Memorandum

September 30, 2015

Page 6

temperature of the sluice water may have an impact on the bottom ash falling from the boiler. 

For example, when bottom ash falls from the boiler into cool water, the water cracks and cools 

the ash. In warmer water, bottom ash is less likely to crack and will have more irregularity. Mr. 

Mooney recommends having a water clarifier and/or cooling tank for the ASHCONTM and 

estimated that it would cost approximately $1 million. He stated that the potential issue with a 

high concentration of fines could affect the type of piping required to return the water back to the 

system (e.g., fiber glass vs. carbon steel), valves, and nozzles on jet pumps.

Mr. Mooney and Ms. Gentile discussed the use of surface impoundments in conjunction with the 

ASHCONTM system. Mr. Mooney explained that some plants installing this type of system could 

use the existing pipes, pumps, and chemical addition associated with an existing surface 

impoundment to achieve zero discharge. 

Mr. Mooney provided a copy of design data for one ASHCONTM installation (DCN SE05927). 

This file is confidential business information. 

3.0 NOTES FROM CALL WITH CLYDE BERGEMANN POWER GROUP ON JUNE 2, 2014

On Monday, June 2, 2014, Elizabeth Gentile, ERG called Gary Mooney, CBPG to discuss 

bottom ash handling technologies for slagging cyclone boilers and additional details about the 

ASCHONTM.

Ms. Gentile asked Mr. Mooney about the bottom ash handling technologies available for 

handling slag from cyclone boilers. Mr. Mooney explained that the DRYCONTM is not a feasible 

technology because of the way the slag drops from the bottom of the boiler (in the slag neck). 

However, he noted that submerged scraper conveyors can be used, and that one plant in the 

United States (Kansas City Power & Light’s La Cynge Generating Station) is successfully 

operating this type of system on a cyclone boiler.

Mr. Mooney also explained that the ASHCONTM would also work because at the point of the jet 

pumps the system looks exactly like a pulverized coal boiler. He further described that a cyclone 

boiler may even be easier for the ASHCONTM to handle because there are no fines and the 

material is heavier (resulting in easier settling). Mr. Mooney did not suggest that a clarifier 

would be necessary for an ASHCONTM installation on a cyclone boiler.

Ms. Gentile and Mr. Mooney discussed the ASHCONTM and the need for a clarifier and 

recirculation/surge tank for pulverized coal boilers. Mr. Mooney stated that to estimate the size 

of a surge tank required for each plant, we would need to estimate 5-10 minutes worth of storage 

time based on the pump rating and sluice line sizes (which vary plant to plant). Mr. Mooney 

explained that including a clarifier could help with temperature control and achieving TSS 

concentrations down to 30 ppm. 

Ms. Gentile and Mr. Mooney also discussed the number of ASHCONsTM required at a plant for 

redundancy, as multiple units can be serviced by one ASHCONTM. Mr. Mooney stated that the 

reliability of one ASHCONTM is higher than one submerged scraper conveyor underneath the 

boiler. We discussed an example for a plant that had four generating units. In this scenario, two 

units were smaller requiring a smaller conveyor and two units were larger requiring a larger 

conveyor. Mr. Mooney stated that three ASHCONsTM could be installed, all sized for the larger 

Commented [E4]: Note to CBPG: We’d like to confirm that we 

can include this document in our record as confidential business 

information.

Commented [E5]: Note to CBPG: Is this necessary to achieve 

complete recycle? Or is this more for plants with a goal of 

discharging under the current BPT regulation?
Memorandum

September 30, 2015

Page 7

units so that they were interchangeable among the generating units (increasing redundancy). 

Additionally, because plants only sluice and dewater bottom ash once per 8 or 12 hour shift 

(which lasts approximately 2 hours) that multiple units can sluice to one ASHCONTM during one 

shift.

Mr. Mooney stated the maintenance associated with the ASHCONTM includes the replacement of 

a wear plate at the bottom of a section of the trough that the scraping flight bars will wear over 

time. This is the only maintenance that requires the system to be drained. 

4.0 NOTES FROM CALL WITH CLYDE BERGEMANN POWER GROUP ON AUGUST 28, 2014

On Thursday, August 28, 2014, Elizabeth Gentile, ERG called Gary Mooney, CBPG to discuss 

fly ash silos and surge capacity for draining ASCHONsTM.

Ms. Gentile asked Mr. Mooney about the redundancy required for dry fly ash silos. Mr. Mooney 

stated that he has not seen two silos located at a plant purely for redundancy. He explained that 

some plants elect to install two silos if the capacity for one silo is so large that it is more 

economical to install two smaller silos. Some plants may also elect to install a sale silo and a 

non-sale silo (for marketing dry fly ash). Redundant equipment in a fly ash handling system 

would include the blowers and pugmills (two per silo). He stated that level indicators may not be 

appropriate to separate saleable and non-saleable ash in a silo because the ash mixes within the 

silo. 

Ms. Gentile also asked Mr. Mooney about estimating the water volume of an ASHCONTM. He

stated that this information depends on the design of the ASHCONTM at a particular plant, the 

size of the bottom ash hopper (and therefore volume of water required to fill the bottom ash 

hopper), and the piping in the system. Mr. Mooney stated that there is no rule of thumb for sizing 

the ASCHONTM and that it purely depends on the bottom ash sluice flow rate at the plant.

Ms. Gentile and Mr. Mooney discussed options for surge capacity for when the ASHCONTM 

needs to be drained for maintenance (once every five years to replace a wear plate). Mr. Mooney 

stated that an onsite surge tank or concrete basin could be sized for each system to handle the 

volume of water during system maintenance. Another option discussed was renting tanks for 

additional surge capacity. Plants with more than one ASHCONTM also have additional surge 

capacity because additional ASHCONsTM at a plant can serve as surge tanks.

In order to review some design information for the types of systems discussed during our call, 

Mr. Mooney mailed copies of design data for one ASHCONTM installation (DCN SE05928), one 

dewatering bin installation (DCN SE05929), and one DRYCON installation (DCN SE05930) for 

review. These files are confidential business information. 

5.0 NOTES FROM CALL WITH CLYDE BERGEMANN POWER GROUP ON SEPTEMBER 19, 2014

On Friday, September 19, 2014, Elizabeth Gentile, ERG called Gary Mooney, CBPG to discuss 

ERG’s proposed methodology to estimate ASCHONTM volume based on the design data for 

ASHCONTM installations provided by CBPG. 

Commented [E6]: Note to CBPG: We’d like to confirm that we 

can include these documents in our record as confidential business 

information. 
Memorandum

September 30, 2015

Page 8

Ms. Gentile asked Mr. Mooney if it would be appropriate to draw a relationship between two 

design parameters presented in the design data: bottom ash produced (in tons per hour) and 

AHSCONTM volume. Mr. Mooney agreed and confirmed that for all design proposals, the 

ASHCONTM is assumed to store bottom ash for up to eight hours. Mr. Mooney also noted that 

adding additional storage time has an impact on the length and height of the ASHCONTM design. 

However, Mr. Mooney did state that the ASHCONTM volume presented in the design data is 

actually the storage volume. Therefore, he recommended multiplying the storage volume by two 

to estimate the full volume of water that could be held in the ASCHONTM to draw the 

relationship between bottom ash produced and ASHCONTM volume.
APPENDIX A – Email Communication between EPA, ERG, and CBPG

The email communications included in this Appendix to this memorandum are listed below by 

date. Any attachments included in the emails are noted below and can be found in the 

attachments to this DCN.

 January 9, 2014 and February 10, 2014: Email documentation of the CBPG dense slurry 

installations from Gary Mooney, CBPG to Elizabeth Gentile (Sabol), ERG, which 

included the following attachments:

o DCN SE05933A1: Power plant life extension and Improved availability using 

environmentally friendly Dense_Phase conveying solutions Power Point (Eraring 

Project CBMH Australia.pdf)

o DCN SE05933A2: Circumix Mixer in Dense Slurry System of GEA EGI Co. Ltd. 

Power Point (Circumix_dense_slurry_technology.pdf)

o DCN SE05933A3: Clyde Bergemann Materials Handling Installations of High 

Concentration Slurry Disposal (HCDS) System (CBD Ref List - HCSD System 

2-10-14.pdf)

 April 7, 2014: Response to follow up questions on fly ash and bottom ash costs delivered 

by ERG on March 25,2014 from Gary Mooney, CBPG to Elizabeth Gentile (Sabol), 

ERG, which included the following attachments:

o DCN SE05933A4: Post Proposal Follow Up Questions for Clyde Bergemann 

Power Group with Response (SE04697_CBPG_Followup_03252014 With CBPG 

Responses.pdf)

o DCN SE05933A5: Fly Ash Conversion Costs (EPA FLY ASH SYSTEM COST 

SUMMARY - APRIL 7 2014.pdf)

 June 10, 2014: Response to follow up questions on fly ash and bottom ash costs delivered 

by ERG on June 9, 2014 from Gary Mooney, CBPG to Elizabeth Gentile, ERG, which 

included the following attachments:

o DCN SE05933A6: Additional Post Proposal Follow Up Questions for Clyde 

Bergemann Power Group With Responses, Including Updated Fly Ash 

Conversion Costs (SE04165_Cost Methodology Questions for CBPG_06092014 -

RESPONSES 06102014.pdf)

o DCN SE05933A7: Wet to Dry Fly Ash Conversions Power Point (Wet Vacuum 

System.pdf)

 June 19, 2014: Email documentation of sales tax information from Gary Mooney, CBPG 

to Elizabeth Gentile, ERG.

 September 30, 2014: Email documentation of high pressure pumps (cost and service life) 

from Gary Mooney, CBPG to Elizabeth Gentile, ERG.