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Project No.: 0317.00.029.032 DISTRIBUTION

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Project Name: Steam Electric Rulemaking

TELEPHONE CALL RECORD

 Conference Call

Date: 1/2/2013 Time: 11:00 am EST

Company Name: Siemens Industry, Inc.

Contact Name: Timothy Peschman, Adam Szczeniak, 

and Jennifer Ellis

Phone No.: 651-638-1325

Names: TJ Finseth and Shelly Schultz 

GENERAL SUBJECT : Discussion of Merrimack Station System Operation and Costs

TOPICS DISCUSSED AND ACTION TAKEN

The purpose of this telephone call was for Eastern Research Group (ERG) to obtain information about the 

wastewater treatment technologies Siemens Industry, Inc. (Siemens) has developed for the treatment of FGD 

wastewater for the removal mercury and arsenic. ERG was specifically interested in the sorption media 

treatment technologies utilized at Public Service Company of New Hampshire's Merrimack Station. These 

systems include the SCU Adsorbent and the GFH® Media. The following provides a summary of the details 

Siemens provided ERG with during the call.

SCU is a single use granular carbonaceous absorbent media that can be used for metals removal in many 

different applications. SCU selectively adsorbs dissolved metal cations including cadmium (Cd), trivalent

chromium (Cr+3), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), and zinc (Zn). Mercury is the targeted

metal at the Merrimack Station. The media is stored in vessels that can be run in series or parallel. At the 

Merrimack Station, there are three vessels installed in series, where two are run together and one is in reserve

(i.e., spare vessel). The system is set up in a way so that any two of the three vessels can be used in any 

combination. Because the media is single use, there is no regeneration associated with the system. Siemens 

designed the size of the vessels at the Merrimack Station such that the media would need to be replaced four 

times per year. Replacement of the media is determined based on target metal concentrations in the effluent 

wastewater. When the target metal concentrations begin to increase (i.e., lower removals through the system), 

then the media needs to be replaced. According to Siemens, at the Merrimack Station, the media in the first 

vessel needed to be replaced after approximately 3.5 months of operation. After the initial replacement, the 

second vessel has been operating for eight months and has not yet needed to be replaced. Depending on the flow 

rate and removals desired, the system can be set up such that multiple small vessels (e.g., 48 inch diameter) are 

used in the system and when the media needs to be replaced, Siemens would come and swap out the vessel with 

a new vessel. Otherwise, large vessels could be installed and when the media needs to be replaced, Siemens 

would come and vacuum out the used media and refill the vessel with fresh media. 

At the Merrimack Station, the permitted maximum effluent mercury concentration was set at 14 parts per 

trillion (ppt). Siemens designed the system based on an influent mercury concentration entering the media at 

100 ppt. The system has been achieving low single digit ppt levels.

The GFH® Media is a granulated ferric hydroxide media that is used primarily for the removal of arsenic, but it

also provides removal of other heavy metals. According to Siemens, it is best suited for arsenic removals from 

wastewater with low silica concentrations. Similar to the SCU media, once the GFH® Media is exhausted, as 

determined by sampling results, the media is removed and replaced. Siemens suggested the GFH® Media has

the potential for some selenium removal, if it is in the selenite form; however, Siemens does not market the 
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GFH® Media for selenium removal. Instead, Siemens is developing a new technology consisting of a reactive 

media with a chemistry feed that is specific for selenium removal. 

During the conversation, Siemens indicated the success of systems with the SCU and GFH® Media are 

contingent on solids removal prior to running through the media. At the Merrimack Station, there is a chemical 

precipitation system and a three stage cartridge filtration system containing 3-micron, 1-micron, and 0.2-micron 

pore filters prior to the sorption media vessels. The cartridge filters are needed to remove very fine suspended 

solids in the wastewater so they do not clog the absorbent media.

Siemens stated that the initial capital costs for a system with SCU and GFH® Media vary significantly 

depending on the system’s features and requirements. Siemens estimates that the capital costs could range from 

$200,000 to $2,000,000, depending the flow rate, influent concentrations, and system configuration. Specific 

costs associated with the Merrimack Station are proprietary; however Siemens provided some general cost 

estimates based their operations. From April to December 2012 the system has processed approximately 10 

million gallons at a rate of approximately 40 gallon per minute. Based on the replacement frequency observed at 

Merrimack, the media costs for the SCU is approximately $2 per 1000 gallons and the GFH® Media is $1 per 

1000 gallons. There are additional costs associated with these systems, such as operating and maintenance labor 

and analytical monitoring/sampling that are not included in these estimates. Siemens stated that the sampling

intervals would be dependent on permit requirements. Typically a new system would be sampled daily during 

the initial start up period and until all issues are worked out, but after that period, Siemens stated that samples 

would likely be collected once per week to confirm treatment.