## MEMORANDUM

TO: Steam Electric Rulemaking Record



### FROM: Mark Briggs and Danielle Lewis, ERG



### DATE: September 30, 2015



### SUBJECT: Analysis of Polishing Filter Costs for FGD Effluent

Per EPA’s request, ERG prepared an estimate of the capital and annual costs that would be incurred by a steam electric power plant if final polishing filte rs were added to the flue gas desulfurization (FGD) wastewater treatment train as is done at Keystone G enerating Station, one of the model plants for determining mercury and arsenic limitations and sta ndards for FGD wastewater based on chemical precipitation. To estimate capital costs for the p olishing filters, ERG contacted FiltraSystems Inc. located in Farmington Hills, Michigan and requested “book” prices for three sizes of cartridge filter systems. The attached product information brochure provided by F iltraSystems shows the cartridge filter systems. Using the “book” prices for a single cartridge filt er system provided by FiltraSystems (DCN SE06320 – SE06322 and SE06330), ERG estimated installed capit al costs for a steam electric facility. These installed capital costs are provided in the table b elow.

Table 1. Estimated Installed Capital Cost for a Pol ishing Filter System at Steam Electric Plants

Cartridge

Filtration Unit Design

Flow (gpm) FiltraSystems

Cost per Unit Number of

Systems Required at Facility a Total

Equipment

Cost b Installation

Cost c Indirect

Costs d Total

Installed Capital

Cost

70 $1,270 2 $2,540 $2,540 $ 2,180 $7,26 0

180 $3,750 2 $ 7,500 $ 7,500 $ 6,450 $ 21, 50 0

300 $4,540 2 $ 9,080 $ 9,080 $ 7,800 $ 2 6

, 000
1,200 $18,4 00 2 $36, 900 $36, 900 $31,7 00 $10 6

, 000
a - Assume a redundant unit on standby for use duri ng cartridge filter change-out. b - Total equipment cost include an initial 2 boxes of 20 cartridge filters (replacement filters are $ 150/box).

c - Installation cost assumed to be 100% of total e quipment cost. d - Indirect costs are 43% of the total equipment c ost plus installation cost, consistent with EPA’s c ost methodology for FGD wastewater treatment systems.



### The cartridge filter systems provided by FiltraSyst ems, Inc. are fully assembled and the 180, 300, and 1,200 gpm systems are manufactured with 316 stainle ss steel that is appropriate for high chloride wast e streams. The 70 gpm system quoted by FiltraSystems is manufactured with 304 carbon steel and therefore ERG increased the quoted cost by 39 percent to acco unt for 316 stainless steel. 1 

### Cartridge filters are sized to remove particles larger than 10 microns. 2

1 Percentage increase based on the difference in cos t for a FiltraSystems Inc.180 gpm unit constructed with 304 stainless steel versus a FiltraSystems Inc. 180 gpm unit constructed with 316 stainless steel.

2 The filtration unit can filter smaller particles b y using filter cartridges of different micron ratin gs. For example, according to the vendor, a 1-micron filter could be used instead without any increase in cost.Memorandum

September 30, 2015 Page 2



### To estimate annual operating and maintenance (O&M) cost s for the cartridge filter system, ERG assumed that the existing effluent pump already included in the F GD wastewater treatment system cost is sufficient to pump water through the cartridge filters. ERG also a ssumed that one unit would require complete cartridge filter replacement on a weekly basis, and that general operating labor and other maintenance materials would be approximately 6 percent of the install ed capital cost. The table below shows the estimated annual operating and maintenance cost for t he three sizes of cartridge filtration units from FiltraSystems, Inc.

Table 2. Estimated Annual Operating and Maintenance Costs for a Polishing Filter System at

Steam Electric Plants

Cartridge

Filtration Unit Design Flow (gpm) Filter

Cartridges per System a Estimated

Filter Cartridges per Year Annual Filter

Cartridge Replacement Cost b Annual

Operating Labor and Equipment

Cost c Es timated

Total Annual

O&M Cost ($/yr)

70 7 364 $2,730 $440 $3,17 0

180 12 624 $4,680 $1,290 $5,97 0

300 20 1,040 $7,800 $1,560 $9,36 0
1,200 80 4,160 $31,200 $6,330 $37,500

a - Number of cartridge filters per filter system from FiltraSystems, Inc. b - Cost is based on $7.50 per cartridge from FiltraSyste ms, Inc. The system evaluated for this cost estimate is based on using 10-micron filters; however, according to the vendor the cost for 1-micron filter cartridges would be the same. c - Annual operating labor and equipment based on 6% of installe d capital cost per Perry’s Chemical Engineers Handbook,

Sixth Edition.



### ERG compared the added capital cost for a polishing filter t o the overall estimated capital cost for a FGD treatment system, and found the costs are minimal. ERG first indexed the total capital costs and total O&M costs from Table 1 and Table 2 to 2010 dollars, using the RSMeans construction cost indexing values for 2015 and 2010 (DCN SE06331). Next, using the indexed capit al and O&M costs, ERG developed a relationship between the design flow rate and the t otal installed capital cost and total annual O&M costs for the polishing filter.

Total Polishing Filter Capital Cost = 77.431× FGD Wastewa ter gpm + 1739.9 EQ (1)

Total Polishing Filter O&M Costs = 27.632 × FGD Wastewat er gpm + 363.08 EQ (2)

ERG then used Equation 1 and Equation 2 to estimate the capi tal and O&M costs to install a polishing filter for each plant discharging FGD wastewater.

The estimated installed capital cost for a chemical pr ecipitation system treating approximately 180 gpm of FGD wastewater is approximately $17 million dollars. The installed capital cost for an additional polishing filter treating the same flow is approximately $19,000 i n 2010 dollars, or 0.09 percent of the total capital cost. 3 

### Results are similar for annual O&M costs. The esti mated annual cost for a chemical precipitation system treating approximately 180 gpm of FGD was tewater is approximately $1,000,000/yr and the annual cost for the polishing filter is $5,300 per year, or 0.5 percent of the total annual O&M

cost. 4

3 The cost for a polishing filter are an even smaller per centage of the total cost for a treatment system that includes both chemical precipitation plus biological treatment, less than 0.06 percent.

4 The annual cost for the polishing filters is less than 0.4 percent of the total annual cost for the chemical precipitation plus biological treatment system.Memorandum

September 30, 2015 Page 3



### For plants with a flow rate greater than 1,200 gpm, ERG as sumed that multiple filters would be installed and the wastewater flow would be equally split between t hem. For example, a plant with a flow rate of 2,200 gpm would require two filters with a design flow of 1, 200 gpm each. 5 

### This plant is costed for a total of 4 filters (two operating and two spare) to be consis tent with the methodology described above.

Finally, ERG estimated the industry-level cost for all plants discharging FGD wastewater to install and operate polishing filters, ERG estimates a total capital cost of $1,750,000 and an annual O&M cost of $608,000. On an industry-level, polishing filter costs represent less than 0.25 percent of total capital costs and 0.9% of annual O&M costs for chemical precipitation. When compared to industry-level costs for chemical precipitation plus biological treatment, polishing f ilter costs represent 0.1% of total capital costs

and 0.6% of annual O&M costs.

5 Of the 69 plants discharging FGD wastewater, the largest di scharge flow is 2,170 gpm. ERG estimates a capital cost of $170,000 and annual O&M cost of $60,300 for the polishing filt ers needed to handle this flow rate.