MEMORANDUM 


To: Mike Pettis (Owens Corning) 

From: Judy CoHora (Trinity Consultants) 

Date: May 22, 2013 

RE: . Control Technology and Associated Economic Assessment 

Trinity has completed the attached Control Technology ~nd Associated Economic Assessment for the Owens 

Corning DM2 furnace located in Delmar, New York This assessment was performed for the DM2 furnace as it 

would require additional emission controls to meet U.S. EPA's chromium standard thatwas proposed on 

April 15, 2013, under 40 CFR Part 63 Subpart NN. 

If you need additional information, please contact me at (678) 441-9977. 
CONTROL TECHNOLOGY AND ASSOCIATED ECONOMIC ASSESSMENT FOR 


OWENS CORNING DM2 FURNACE IN REFERENCE TO PROPOSED AREA 


SOURCE RULE NN AFFECTING FIBERGLASS MANUFACTURING 


Contents 

1.1. BACKGROUND ......................................................................................................................2 


1.2. U.S. EPA ASSESSMENT.........................................................................................................2 


1.2.1. U.S. EPA Cost Esti mate for Caustic Scrubbi ng ...................................................................... .4 


1.2.2. Caustic Scrubber Train ............................. -...........................................................................6 


1.3. REVISED ASSESSMENT .........................................................................................................7 


1.3.1. Data Sources ......................................................................................................................7 


1.3.2. Cases for Cost Effectiveness ................................................................................................8 


1.3.3. Identification of Potential Control Tecimologies (Step 1) ......................................................8 


1.3.3.1. Proven Controls ...........................................................................................................8 


1.3.3.2. Experimental Controls ..................................................................................................9 


1.3.4. Elimination of Tecimically Infeasible Control Options (Step 2) ...............................................9 


1.3.5. Rank of Remaining Control Tecimologies (Step 3)............................................................... 10 


1.3.6. Evaluation of Most Stringent Controls (Step 4) ................................................................... 10 


1.3.6.1. Economic Feasibility Calculation Process ..................................................................... 10 


1.3.6.2: Experimental Dry/Physical Filtration ............................................. ; .............................. 11 


1.3.6.3. Experimental Wet Scrubbing .................................... ~ ................................................. 12 


1.3.6.4. Proven Controls ~ith Proper Maintenance and Operating Practices ............................. 12 


1.3.7. Selection of Control Technology (Step 5) ...........................................................................18 


1 

1.1. BACKGROUND 


To develop an emission limit under the maximum.achievable control technology (MACT) standard for 

major sources of hazardous air pollutants (HAP) that is based on U.S. EPA's (the Agency's) 112(f) risk 

obligations and then justify a particular tec):mology under 112(d) is not an uncommon methodology. 

When the Agency justifies the emission limit based on the 'ample margin of safety' statute in 112(f), it is 

required to account for economic and technical feasibility. 

U.S. EPA based the proposed generally available control technology (GACT) standard for smaller (area) 

sources of HAP on the above methodology. In the process, an unproven and cost prohibitive add-on 

emission control device was also proposed. It app~ars that U.S. EPA has not sufficiently researched the 

exhaust streams of the affected sources and, as a result, justified this inadequate control technology as 

economically feasible. In reality, it is neither technically nor economically justified and documentation 

to this fact is incl uded herein. It is clear that the only "generally available control technologies" are the 

particulate matter (PM) control devices already in operation on the furnaces, and that further 

consideration in setting the proposed chromium limit was warranted by U.S. EPA in the drafting of this 

rule. 

1.2. U.S. EPA ASSESSMENT 

U.S. EPA is indicating the use of a single caustic scrubber on each furnace that does not meet the 

proposed chromium emission limit of 6.0E-05 lb/ton glass pull. However, U.S. EPA disregarded their 

own proced ures on how to assess the true and reasonable cost of installing and operating this control 

device even ifit were technically sound (which it is not). The U.S. EPA has developed a general 

procedure to determine the feasibility of installing new controls, and it is routinely followed, for 

example, when applying for a major source permit. The Agency has followed this procedure in recent 

rulemakings for other area source GACT rules as means to determine what control technologies are 

economically feasible. However, it is apparent that this procedure was not applied equally in 

development of this GACT standard. U.S. EPA's evaluation ofsuitable control technologies are typically 

as follows: 

Step 1. Identify all possible control technologies (including technology transfer); 


Step 2. Eliminate technically infeasible options; 


Step 3. Rank the technically feasible control technologies based upon emission reduction 


potential; 


Step 4. Evaluate ranked controls based on energy, environmental, and/or economic 


considerations; and 


Step 5. Select control technology. 


Step 1was followed as dust collectors were identified as a viable technology that transfers from major 

sources to area sources. In fact, the proposal states that "major and area sources are equipped with 

technologies that effectively control chromium and metal hazardous air pollutant (HAP) emissions, 

including, but not limited to, ESPs and fabric filters."i 

U.S. EPA clearly states that an ESP is effective at removing chromium emissions. However, this 

statement is in direct contrast with the proposed emission limit, which is set too stringent for several 

area sources operating with an ESP to meet. To account for this difference, U.S. EPA claims. to have 

1 Page 22383, Federal Register, Vol. 78, No. 72. ESPs is an acronym for Electrostatic Precipitators. ESPs includes Dry ESPs 

(DEPs), which is a term used interchangeably within the fiberglass manufacturing industry. 

2 
"searched other industries for controls that would remove chromium and found that a sodium 

hydroxide (NaOH) scrubber is used in both high temperature metallurgical industries and the chrom ium 

electroplating industry for removal of hexavalent chromium."z Based on our recent communications 

with multiple vendors of control technologies, aside from the existing, dry filtration controls (e.g., ESPs 

and fabric filters) none of the vendors were able to provide a proven chromium control technology that 

could be readily transferred to these furnaces. Furthermore, no vendor was prepared to guarantee an 

emission rate that would meet the proposed chromium limit. 

Even within the communications that U.S. EPA had in establishing a N aOH scrubber as technically and 

economically feasible,3 one vendor clearly stated that "a wet or dry ESP is the recommended technology 

for glass furnace operations ...We also looked at the technologies we do have available and ... we do not 

have a productthatwould address your earlier points below." Upon U.S. EPA's pressing of the matter, 

this point was reiterated by the vendor who stated that "..a pre-quenched gas stream to reduce the 

temperature, along with a wet packed bed scru b ber utilizing a recirculated solution of caustic is NOT 

capable of addressing removing su b -micron chromium ..." 

When we reviewed the referenced U.S. EPA communication with the vendor [Hansen Engineering] who 

proposed a NaOH scrubber as a viable solution, 4 it was clear the design was hopeful at best. The vendor 

caveated this proposed design with "We believe that a 90 to 95% Cr removal is [possible] maybe higher, 

but we can not give [a guarantee]. It would be from our standpoint, experimental." Upon su bseq uent 

communications, the vendor reiterated that "But again I [would] like to emphasize that a certain amount 

of experimenting for scrubbing out elements can not be avoided." Clearly, this vendor's information was 

misconstrued by U.S. EPA, has been significantly updated from their original proposal, and is still 

considered experimental. 

There is also an unsubstantiated conclusion that since one furnace employs a PM control followed by a 

wet scrubber for sulfur dioxide (SOz) emissions control, itis "directly analogous to usinga NaOH wet 

scrubber downstream of the PM controls to achieve additional chromium removaL" The error is the 

assumption that a wet scrubber for SOz control can achieve any sort of chromium reduction 

downstream of a PM control device. Furthermore, while itis possible to add a NaOH scrubber to the 

exhaust of an ESP, U.S. EPA provided no explanation of how technically such a configuration can achieve 

compliance with the proposed chromium emission limit. 

IfU.S. EPA were to have followed their own guidance on selecting controls, the next step would have 

been to eliminate any of the technically infeasible options. Based on the conflicting data that U.S. EPA did 

receive from vendors, it should have been clear that the only decision was to remove NaOH scrubbing 

from the list of technically feasible control technologies. ~aOH scrubbers that might be used in the 

metallurgical and chromium electroplating industries are treating a much higher concentration of 

chromium with a significantly different particle size distribution. Application of this control technology 

to the already well-controlled streams of these furnaces as itwas initially proposed to and evaluated by 

the U.S. EPA is technically infeasible. 

2 Page 22383, Federal Register, Vol. 78, No. 72. 


3 htto:l!www.regulations.gov/#ldocketDetailjD=EPA-HO-OAR-2010-1042.Supporting&RelatedMaterial.11/25/2011. 


ID:EPA-HQ-OAR-2010-1042-0079 


4 Docket ID: EPA-HQ-OAR-2010-1042-0079 


3 

1.2.1. U.S. EPA Cost Estimate for Caustic Scrubbing 

The cost of a N aOH (caustic) scrubberwas assessed by U.S. EPA in the preamble to the proposed rule. A 

cost-effectiveness of$7,600 per pound of chromium removed was estimated by U.S. EPA based on the 

use of a caustic scrubber at three furnaces requiring emissions reductions to meet the proposed 

chromium limit. This estimate is apparently based on an initial capital cost of $250,000 that results in 

an annualized operating cost of $100,000 peryear per scrubber. The annual cost was multiplied by 

three sources. Additionally, an $80,0°0 per year per stack test for eight sources, for a total of $3 B 0,0 °0 

peryearfor all sources was included. This cost was divided by a value of 50 pounds per year of 

chromium reduced from the three sources to provide a cost-effectiveness value of$7,600 per pound. 

The annualized operating cost of $100,000 for a system designed to achieve compliance with the 

proposed limit is thought to be an extreme underestimate, even if the technology where transferrable to 

these systems. The initial capital outlay and ongoing operating costs - based on our recent research as 

outlined later in this document - are underestimated. Also, common practice is to split the costs evenly 

among all sources that will need control. In this case, the total expected emission reduction of 50 lb/yr 

of chromium is for three furnaces, but each one is emitting chromium at very different rates. Given this 

variation and such a small amount of overall reduction, to assume the controls are cost feasible for each 

and everyone of these sources is unreasonable. 

Furthermore, there is no basis to the $100,000 per year estimate of combined annualized cost. We have 

been unable to recreate this value using the U.S. EPA Office of Air Quality Planning and Standards 

(OAQPS) guidance manual on estimating control technology costs. S We could not locate the basis of this 

value in the docket following a review of data provided by industry via Section 114 requests or by 

vendor quotes. When such data are not readily available, then annualized costs should be derived from 

capital and operating costs, each one expressed as a function of known equipment and other costs. Total 

purchased equipment cost should repres~nt the delivered cost of the control equipment, auxiliary 

equipment, and instrumentation. Auxiliary equipment consists of all the structural, mechanical, and 

electrical components required for the efficient operation of the device. Auxiliary equipment costs are 

estimated as a straight percentage of the equipment cost. Direct installation costs consist of the direct 

expenditures for materials and labor for site preparation, foundations, structural steel, erection, piping, 

electrical, painting and facilities. Indirect installation costs include engineering and supervision of 

contractors, construction and field expenses, construction fees, and contingencies. Other indirect costs 

include equipment startup, performance testing, working capital, and interest during construction. None 

of these factors appear to have been considered in the cost estimate provided in the proposed rule. 

Table 1 shows the OAQPS multipliers to use in estimating the total capital investment (Tel) for a 

scrubber installation. Even taking the vendor's estimate of $210,000 for a "total package cost",6 keeping 

in mind that a vendor's estimate is typically for purchased equipment only unless otherwise specified, 

theTel should be 2.25 times the total equipment cost of $210,000; this results in a Tel of over $470,000. 

Instead, itappears that a vendor quote of $21 O,OOOfor the equipment alone plus an undocumented 

additional cost of $40,000 was used to derive U.S. EPA's total capital cost of$250,000. As such, it is clear 

theTel was underestimated for the NaOH scrubber. 

5 U.S. EPA, OAQPS Control Cost Manual, 6th edition, EPA 452/B-02-001,Ju\y2002. 

http://www.epa.gov/ttn/catc/dirl/ollchs.pdf 

6 Docket ID: EPA-HQ-OAR-2010-1042-0079 

4 

Table 1. OAQPS Capital Cost Multipliers for Scrubbers7 

Capital Cost OAQPSNotation 

Purchased Equipment Costs 

Total Equipment Cost 


Instrumentation (e.g., PLC) 


Taxes/Tariffs 


Freight 


Total Purchased Equipment Costs 

Direct Installation Costs 

Foundations and Supports 

Handling and Erection/Interconnection 

Electrical 

Piping/Ductwork 

Insulation 

Painting 

Total Direct Installation Costs 

Indirect Installation Costs 

Engineering 


Construction and Field Expense 


Contractor Fees 


Start-up 


Performance Test 


Contingencies 


Total Indirect Installation Costs 

Total Capital Investment $ 

A 

O.10xA 


O.03xA 


O.05xA 


B= 1.18 xA 

O.06xB 


O.40xB 


O.OlxB 


O.05xB 


O.03x B 


O.OlxB 


C=0.56 x B 


O.10xB 

O.10xB 

O.10xB 

·O.OlxB 

O.OlxB 

O.03xB 

D= 0.35 x B 

TCI=B +C+D 

Annual costs should be comprised of direct and indirect operating costs. Direct annual costs include 

labor, maintenance, replacement parts, raw materials, utilities, and waste disposal. Indirect operating 

costs include plant overhead, taxes, insurance, general administration, and capital charges. Replacement 

part costs should be included, and raw material costs should be estimated based upon the unit cost and 

annual consumption. With the exception of overhead, indirect operating costs should be calculated as a 

percentage of the total capital cost. The indirect capital costs should also be based on a capital recovery 

7 U.S. EPA OAQPS, EPA Air Pollution Control Cost Manual (6th Edition), January2002,Section 6, Chapter 2,page2-48 

(Table 2.8: Direct and Indirect Installation Costs for Venturi Scrubbers). While retrofit costs are excluded, "a retrofit 

multiplier of 1.3 to 1.5 can be applied to the total capital investmentto estimate these costs atthe study level" per the 

OAQPS Manual. 

5 

factor (CRF). However, the $100,000 peryear operating cost has no clear derivation from U.S. EPA's 

total capital cost of $250,000 and no references to these direct and indirect operating factors. Table 2 

shows the OAQPS multipliers to use in estimating annual operating costs. 

Table 2. OAQPS Operating Cost Multipliers for Scrubbers8 

Operating Cost OAQPSNotation 

Direct Annual Costs 

Operating Labor (2 hr, per8·hrshift) E 

Supervisory Labor F =0.15 x E 

Maintenance Labor (1 hr, per 8·hrshift) G 

Maintenance Materials H = 1.00 x G 

Water Quench & Other Consumption I 

Filter Media Replacement 

Solid Waste Disposal K 

Electricity L 

Total Direct Annual Costs DAC=E+ F+ G+ H+ 1+]+K+ L 

Indirect Annual Costs 

Overhead M =0.60 x (E + F + G+ H) 

Administrative Charges N =0.02 x TCI 

Property Tax 0= 0.01 x TCI 

Insurance P =0.01 x TCI 

Capital Recovery Q 

Total Indirect Annual Costs ID,AC = M + N + 0 + P +Q 

Total Annual Cost $ TAC =(DAC + IDAC) 

1.2.2. Caustic Scrubber Train 

Since Hansen Engineering provided the initial design for a NaOH scrubber, theywere consulted again 

and provided with more details on the process, additional data on the exhaust parameters, and the 

proposed limit. Based on discussions with this company, and that most material collected from the 

existing PM control devices on the furnaces is a yellow color, the chromium is likely in the form of 

sub micron sodium chromate, which unfortunately is not a suitable candidate for the initially scoped 

scrubber that Hansen Engineering had suggested to U.S. EPA in earlier communications. The initial 

Hansen proposal appears to be a major part ofthe EPA's justification that NaOH scrubber technology 

was transferable for this application. This change in proposals is significant in that Hansen was the only 

vendor to initially suggest NaOH scrubber technology might be suitable for the application. However, 

B u.s. EPA OAQPS, EPA Air Pollution Control Cost Manual (6th Edition), January2002,Section 6, Chapter 2, page 2·51 

(Table 2.9: Annual Cost Factors for Scrubbers). 

6 
Hansen and others proposed an alternate emission controls that might achieve the required reduction to 

the meet the proposed limit. Since these designs have not been used in practice, trials are needed to 

verify their feasibility. 

In the revised Hansen proposal the basic chemistry would be to reactthe sodium chromate from the 

exhaust with barium nitrate via a series of scrub bers to form a precipitate (barium chromate) and a salt 

(sodium nitrate). The design would include a venturi scrubber and a packed tower scrubber. The 

reaction requires a pH of about 12, which is a caustic environment. If the removal of sodium dichromate 

is also needed, which is not known at this time, then one to two in-series packed tower scrubbers would 

be added to the design. The additional scrubbers are required as removal of sodium dichromate 

requires more time and exposure, and it may take additional experimenting: For example, the lab test 

that Hansen Engineering completed showed that three additional treatments were required to eliminate 

sodium dichromate as compared to sodium chromate. Again, the company offers no warranty on 

performance as the system is experimental. 

When using the OAQPS multipliers shown in Table 2 and a more accurate purchased equipment cost9 of 

$592,200 (the minimum Hansen proposal), we derive an annualized cost of approximately $495,000 for 

an experimental caustic scrubber system for the specific DM2 furnace as tested; details are provided at 

the end of this document. When this value is substituted for the $100,000 used in U.S. EPA's initial 

analysis, the cost effectiveness is greater than $29,700 per pound. As the system is experimental, it 

would need to ungergo a trial period to determine what level of design would be required tomeet the 

proposed chromium limit. If the second level of control is required per the Hansen proposal the cost 

effectiveness is greater than $33,1 00 per pound. 

1.3. REVISED ASSESSMENT 

We are providing a revised assessment of potentially feasible chromium emission controls. This 

approach follows U.S. EPA's traditional methodology used in setting GACT standards of first selecting 

technically feasible controls and then determining the cost effectiveness of such controls. This 

assessment focuses on one of three furnaces that would require additional controls to meet the 

proposed chromium emission limit: Owens Corning's furnace DM210cated in Delmar, New York 

1.3.1. DataSol.lrces 

The following data sources were used: 

> Section 114 stack test report (2012) for the Owens Corning Delmar furnace, which contains the 

tested chromium emissions from furnace DM2 with DEP 

> Actual cost ofDEP installation on the Delmar furnace 

> Communications (emails and call logs) with Monroe Environmental for site-specific application of a 

chrome emission control technology on the Delmar furnace 

> Communications (emails and call logs) with Met-Pro for site-specific application of a chrome 

emission control technology on the Delmar furnace 

> Communications (emails and call logs) with Hansen Engineering for site-specific application of a 

chrome emission control technology on the Delmar furnace 

9 Upon detailed communications with Hansen Engineering in April and May 2013, it was determined that more 

equipment will be required and thatsuch a design is still experimental in nature. Hansen Engineering provided an 

estimate for equipment costs in the range of $592,200-$787,700 fortreatmentofa 15,000 acfm flowrate. 

7 

> Prior communications (emails and call logs) between u.s. EPA and multiple vendors of 

environmental control equipment for general information on chrome emission control technologies 

> u.s. EPA published information such as the OAQPS cost manual for assumptions on capital costs 

excluded from vendor estimates and operating costs 

> Consumer price index for adjusting OAQPS cost calculations 

1.3.2. Cases for Cost Effectiveness 

Once the cost effectiveness was determined for Delmar, separate calculations were performed to 

determine the cost effectiveness (order of magnitude) for the remaining furnaces. While the same 

annualized cost is used, the range in cost effectiveness reflects the variation in emissions from each of 

the three furnaces that would require additional controls to meetthe proposed limit. Specifically, 

Owens Corning developed cost effectiveness estimates for the following cases: 

> Case A - Delmar furnace 

> Case B Example case for an Owens Corning furnace that might require the most control 

> Case C -Example case for an Owens Corning furnace that might require the least control 

> CasEl D - Revised case for an average reduction of 16.67Ib/yr for each of the three furnaces that 

req uire control (50 lb /yr divided by 3 sources) 

1.3.3. Identification of Potential Control Technologies (Step 1) 

Potentially applicable emission control technologies were identified for the reduction of chromium 

emissions byresearchingthe U.S. EPA control technology database, technical literature, control 

equipmentvendor information, and by using process knowledge and engineering experience. The 

Reasonably Available Control Technology (RACT)/Best Available Control Technology (BACT)/Lowest 

Achievable Emission Rate (LAER) Clearinghouse (RBLC), a database made available to the public 

through the u.S. EPA's Technology Transfer Network (TTN), lists technologies and corresponding 

emission limits that have been approved by regulatory agencies in permit actions. A search of the RBLC 

database in April 2013 was performed to identifythe emission control technologies and emission limits 

that were imposed by permitting authorities within the pasttenyears for all sources of chromium 

emissions. The following category was searched: 

> Chromium/ Chromium Compounds,-3 &-6 (CAS No. 7440-47-3) 

The RBLC search results contained mostly combustion devices. However, one candidate control option 

was identified from a manufacturing process which employs the same type of chromium emission 

controls as those presently in place for the furnaces: dry filtration (i.e., traditional dust collection 

devices). 

In addition to the RBLC, the existing controls for fiberglass manufacturing furnaces were assessed. 

These controls are similarto that identified in the RBLC database (Le., traditional dust collection 

devices). 

1.3.3.1. Proven Controls 

Dust collectors, baghouses, ESPs, and similar devices are a form of dry/physical filtration and are used in 

this field extensively. Each such technology has a means by which to collect or trap the chromium, which 

8 

is in particulate form. Emissions from the existing furnaces in this source category are already being 

reduced using these proven controls. 

1.3.3.2. Experimental Controls 

All of the designs that we have analyzed, and which are listed below, are completely experimental in 

nature, and have never been applied to any source in the United States. As such, any selected technology 

would require a trial period and such costs are not included in the evaluation. 

> 	 3-Stage filter consisting of a quench tower, coalescing pad and fiber bed filters. This custom design 

has the option of utilizing a water system to clean the filter media; otherwise, the filter media would 

need replacement on a more frequent basis. 

> 	 Series of in line high efficiency particulate air (HEPA) filters with water quench. This custom design 

would require changeouts at an unknown frequency. 

> 	 Venturi scrubber train (custom design) with water quench, sub-cooling (required to create water 

droplets in the gas stream onto which the fine particulates might collide), a series of venturi 

scrubbers (each designed for a minimum pressure drop of 50" water column), and a final mist 

eliminator vessel (to capture the fine liquid mists generated in the venturi). Ancillary equipment 

would include heat exchange, cooling water, cooling tower, liquid filters, and specially designed high 

pressure fans. 

> 	Caustic scrubber train (custom design) using a venturi scrubber with caustic, a collection tank, and a 

finishing scrubber jwash tower. This design would introduce a reactant to precipitate out the 

chromium, which would be collected and sent to a filter press to reduce the water content before 

disposal. 

These experimental control technologies fall into one of two types of control systems: dry jphysical 

filtration or wet scrubbing. Dry jphysical filtratLon is in the form of dust collectors, ESPs, HEPA filters, 

candle filters, and other similar materials used to trap the chromium. It should be noted that the size of 

the chromium being collected is sub micron since the exhaust stream is already treated for particulate 

reduction. Also, the material on which the residual chromium and non-chromium particulate is 

deposited must either be cleaned continuously with a water system or replaced frequently. Wet 

scrubbing uses a series of either very high pressure drop venturi scrubbers to trap the,material in the 

water or caustic scrubbers to chemically react and precipitate out chromium. In most cases, there must 

be an initial step to quench the exhaust. That is, the temperature of the exhaust must be lowered for any 

of these controls to be effective. 

1.3.4. Elimination of Technically Infeasible Control Options (Step 2) 

After the identification of control options, the second step in the assessment is to eliminate any 

technically infeasible options. A control option is eliminated from consideration if there are processspecific conditions that would prohibit the implementation of the control or if the highest control 

efficiency of the option would result in an emission level that is higher than any applicable regulatory 

limits. 

The existing furnace PM controls are achieving chromium reductions of greater than 97%. This amount 

of reduction is proven in the field and is likely the highest control efficiency of all proven and 

experimental options. As such, in a typical analysis, the existing PM controls would have already been 

considered the highest ranking. Since the Agency proceeded with an evaluation ofthe less effective, 

experimental controls to determine if additional controls were feasible, we have continued the analysis 

of the following controls using U.S. EPA's own guidance to provide more accurate results: 

9 

> 3-Stage filter 

> HEPA filters 

> 3-Stage filter with water cleaning 

> Venturiscrubbertrain 

> Caustic scrubber train (updated from U.S. EPA proposal) 

Based on discussions with vendors, it will be difficult, if not impossible, to design and operate a system 

for the Delmar furnace that would meet the proposed limit. While some level of reduction can be 

predicted, the fact that the furnace exhaust stream is already being treated with a particulate control 

device (i.e., a DEP) means thatthe majority of chromium emissions from the furnace (in some cases, 

over 99.97%) are already controlled. Confirming this assertion is the fact that a DEP is the type of 

. control device that U.S. EPA has accepted as MACT and GACTfor other furnaces. Additional control of a 

stream with such low concentrations of chromium is above and beyond whatshould be required for any 

source of HAP - major or area. 

Aside from the fact that existing PM controls should be considered as GACT for these furnaces, there is 

another factor that U.S. EPA did not consider in their control analysis. The particulate is in submicron 

form, which is difficult to remove with wet scrubbing. Thus, U.S. EPA's proposed method of a scrubber is 

technically infeasible. Even if the cost of the scrubber was feasible, and even if caustic were added to a 

wet scrubber, this system alone would not be sufficient to meet U.S. EPA's proposed chromium emission 

limit. As such, a stand-alone caustic scrubber should be removed from further consideration. 

Because none of these technologies have been demonstrated in practiee, it is optimistically assumed that 

each option would achieve U.S. EPA's proposed emission limit for chromium emissions, and thus each is 

given equal weighting in this regard. However, the vendors do not guarantee a specific level of control 

efficiency that meets the proposed limit for any of these systems at this time. Following a period of trial 

and error, some vendors may be able to provide a better defined system and estimate a removal 

efficiency for chromium compounds. 

1.3.5. Rank of Remaining Control Technologies (Step 3) 

The third of the five steps in the top-down assessment procedure is to rank technically feasible control 

technologies by control effectiveness. The existing PM controls have the highest control reductions. All 

experimental options are presumed to have the same reduction efficiency though none have been shown 

to meet such a requirement in practice. 

1.3.6. Evaluation of Most Stringent Controls (Step 4) 

The fourth of the five steps in the top-down assessment procedure is to evaluate the most effective 

control and documentthe results. This step has been performed for an control technologies on the basis 

of economic, energy, and environmental considerations, and is described herein. 

1.3.6.1. Economic Feasibility Calculation Process 

Economic analyses are performed to compare total costs (capital and annual) per ton of pollutant 

removed for various potential control technologies that have been deemed technically feasible. In these 

analyses, however, the cost per pound of removal was assessed. 10 Capital costs include the initial cost of 

10 A cost per pound basis was used for consistency with US EPA's cost analYSiS, as provided in the preamble to the 


proposed rule. 


10 
the components intrinsic to the complete control system. Annual operating costs include the financial 

requirements to operate the control system on an annual basis including overhead, maintenance, 

outages, raw materials, and utilities. 

The capital cost estimation techniq ue used is based on a factored method of determining direct and 

indirect installation costs. That is, installation costs are expressed as a function of known equipment 

costs. This method is consistent with U.S. EPA's control cost manual. 

Total purchased equipment cost represents the delivered cost of the control equipment, auxiliary 

equipment, and instrumentation. Auxiliary equipment consists of all the structural, mechanical, and 

electrical components required'for the efficient operation of the device. Auxiliary equipment costs are 

estimated as a straight percentage of the equipment cost. Direct installation costs consist of the direct 

expenditures for materials and labor for site preparation, foundations, structural steel, erection, piping, 

electrical, painting and facilities. Indirect installation costs include engineering and supervision of 

contractors, construction and field expenses, construction fees, and contingencies. Other indirect costs 

- include equipment startup, performance testing, working capital, and interest during construction. 

Annual costs are comprised of direct and indirect operating costs. Direct annual costs include labor, 

maintenance, replacement parts, raw materials, utilities, and waste disposal. Indirect operating costs 

include plant overhead, taxes, insurance, general administration, and capital charges. Replacement part 

costs were included where applicable, while raw material costs were estimated based upon the unit cost 

and annual consumption. With the exception of overhead, indirect operating costs were calculated as a 

percentage of the total capital costs. The indirect capital costs were based on the CRF, defined as: 

i(l+ on 


CRF = (1 + on - 1 


where i is the annual interest rate and nis the equipment life in years. The equipment life is based on 

the normal life of the control equipment and was set to 15 years. The same interest rate was applied to 

all control equipment cost calculations. For this analysis, a conservative interest rate of 4% was used, 

which is lower than the 7% that is provided in the OAQPS Control Cost Manual.ll 

Note that all calCulations presented herein are based on March 2013 dollars. Detailed calculations for 

the economic analyses are provided in Tables 3,4, and 5. 

1.3.6.2. Experimental Dry/Physical Filtration 

Costs for installation and operation of the following dry/physical filtration de signs were developed: 

> 3-Stage filter (Option A) 


> HEPA filters (Option B) 


> 3-Stage filter with water cleaning (Option C) 


Even if the use of any of these devices was technically feasible on a furnace, the cost of using such a 

device exceeds the benefit of the chromium reduction it offers. For the site-specific application at the 

Owens Corning Delmar furnace (Case A), the cost of controlling chromium with additional dry filtration 

is estimated at between $49,100 - $63,900,per pound of chromium removed, depending on the device 

11 u.s. EPA, OAQPS Control Cost Manual, 6th edition, Section 2,Chapter 1, page 1-52. 


http://www.epa.govIttn/catc/dir1/c allchs.pdf 


11 
selected. The cost effectiveness for Case B for a furnace that would require the most control to meet the 

proposed limit was estimated in the range of$lS,500 - $24,100 per pound. The cost effectiveness for 

Case C for a furnace that would require the least control to meet the proposed limit was estimated in the 

range of $235,000 -$306,000 per pound. Finally, the cost effectiveness for Case D, which is based on an 

average reduction of 16.67 pounds per year for each of the three furnaces that require control (as noted 

in U.S. EPA's proposal), was estimated in the range of $24,100-$31,400perpound. 

These high costs are largely due to the initial capital cost of not only the control device but also the 

related infrastructure and installation cost. The ongoing cost of cleaning the filters and the cost to 

dispose of a new hazardous waste stream are significant. There would also be associated energy and 

environmental im pacts resultant from use of the electricityto operate the system, as well asthe transfer 

of this compound into either a wastewater stream or a solid waste stream. The detailed cost calculations 

are provided as Attachment 1 of this document. 

1..3.6.3. Experimental Wet Scrubbing 

Costs for installation and operation of the following wet scrubbing designs were developed: 


> Venturi scrubber train (Option D) 


> Caustic scrubber train - revised U.S. EPA estimate (Option E) 


Again, even if the use of any of these devices was technically feasible on a furnace, the cost of using such 


a device exceeds the benefit of the chromium reductionit offers. For the site-specific application at the 


Owens Corning Delmar furnace (Case A), the cost of controlling chromium with wet scrub bing is 


estimated at between $60,500 - $S4,900 per pound of chromium removed, depending on the device 


selected. The cost effectiveness for Case B, for a furnace thatwould require the most control to meetthe 


proposed limit, was estimated in the range of $ 22,SOO - $32,000 per pound. The cost effectiveness for 


Case C, for a furnace that would require the least control to meet the proposed limit, was estimated in 


the range of $289,000 - $405,000 per pound. Finally, the cost effectiveness for Case D, which is based on 


an average reduction of 16.67 pounds per year for each of theth ree furnaces that require control (as 


noted in U.S. EPA's proposal), was estimated in the range of $29,700-$41,700 per pound. 


These high costs are largely due to the initial capital cost of not only the control device but also the 


related infrastructure and installation cost. In addition to similar requirements as dry filtration, a new 


hazardous waste stream is generated that must be treated and disposed of (Le., wastewater). Unlike 


particulate collected from the DEP at Delmar, the wet material collected from this system will be treated 


with chemicals and will be unsuitable for reuse in the furnace. There would also be significantly higher 


energy and environmental impacts resultant from the use of these systems. The detailed cost 


calculations are provided as Attachment 1 of this document. 


1.3.6.4. Proven Controls with Proper Maintenance and Operating Practices 

The only remaining technology to consider is proper maintenance and operating practices of the 

furnaces and therr associated PM control devices, a logical option since a properly maintained and 

operated furnace with PM control can effectively reduce chromium emissions. This control option 

should be considered acceptable for the furnaces. A baseline scenario for the Owens Corning Delmar 

DEP is presented in the attached cost calculations, which has a cost effectiveness of$1,350 per pound of 

chromium removed. The material collected from the DEP is returned tothe process and therefore does 

not generate a hazardous waste stream. 

12 

ATTACHMENT A 

Table 4. Cost Analysis for Technically Feasible Controls 

, 

-

Capital Cost1 

Current 

Controf~ 

DEP 

Potential Add-On Chrome Removal 

OptionA3 OptionB4 Option C5 Option D6 Option 

Causti 

Scrubb 

3-Stage Train 

Filter with Venturi (REVISI 

3-Stage "EPA Water Scrubber EPA 

Filter Filters Cleaning Train Estimal 

PUrGhased Equipment Costs 

Total Equipment Cost 

Instrumentation (e.g., PLC) 

Taxes/Tariffs 

Freight 

Total Purchased Equipment Costs 

300,000 225,000 tOOO,OOO 592,200 592,~ 

30,000 22,500 100,000 59,220 59,~ 

9,000 6,750 30,000 17,766 17,~ 

15,000 11,250 50,000 29,610 29,t 

354,000 265,500 1,180,000 698,796 698,1 

Direct Installation Costs 8 

Foundations and Supports 21,240 15,930 41,928 41,~ 

Handling and Erection/Interconnection 141,600 106,200 279,518 279,~ 

Electrical 3,540 2,655 6,988 6,~ 

Piping/Ductwork 17,700 13,275 34,940 34,~ 

Insulation 10,620 7,965 20,964 20,~ 

Painting 3,540 2,655 6,988 6,~ 

Total Direct Installation Costs 198,240 148,680 391,326 391,5 

Indirect Installation Costs 8 

Engineering 35,400 26,550 69,880 69,~ 

Construction and Field Expense 35,400 26,550 69,880 69J 

Contractor Fees 35,400 26,550 69,880 69,~ 

Start-up 3,540 2,655 6,988 6/ 

Performance Test 3,540 2,655 11,800 6,988 6,~ 

Contingencies 10,620 7,965 35,400 20,964 20,~ 

Total Indirect Installation Costs 123,900 92,925 47,200 244,579 244,:' 

Total Capitallnvestmcnt $ 1,962,500 676,140 507,105 1,227,200 1,334,700 1,334,1 

Operating Cost1 

Direct Annual Costs 

Operating Labor (2 hr, per 8-hr shift)9 

Supervisory Labor9 

Maintenance Labor (1 hr, per 8-hr shift)9 

Maintenance Materials 9 

Water Quench & Other Consumption1O 

DEP 

56,673 

8,501 

28,336 

28,336 

0 

3-Stage 

Filter 

56,673 

8,501 

28,336 

28,336 

1,088 

Potential Add-On Chrome Removal 

Causti 

Scrubb 

3-Stage Train 

Filter with Venturi (REVISI 

"EPA Water Scrubber EPA 

Filters Cleaning Train Estimal 

56,673 56,673 56,673 56,t 

8,501 8,501 8,501 8,~ 

28,33,6 28,336 28,336 28,~ 

28,336 28,336 28,336 28,~ 

,1,088 1,133 2,246 2,~ 
Notes to Table 4; 

1, Capital and Operating Costs based on a combination ofVendor estimates and U.S. EPA OAQPS, EPA Air Pollution Control Cost Manual (6th Edition) , Jan 

OAQPS percentages for scrubbers are specified in the OAQPS Manual, Section 6, Chapter 2, page 2-48 (Table 2.8; Direct and Indirect Instollation CostsJ 

(Table 2.9: Annual Cost Factors for Scrubbers). The scrubber OAQPS multipliers were selected, as they are the same or less than those provided for sir 

Filters, Gas Adsorbers and Electrostatic Precipitators) and thus provide a more conservative estimate of the total cost. See, for example, Section 6, Ch, 

Factors for Fabric Filter. While retrofit costs are excluded, "a retrofit multiplier of 1.3 to 1.5 can be applied to the total capital investment to estimate I 

the OAQPS Manual. 

2 Actual cost ofDEP installation on wood fiberglass manufacturing Oxy-fuel furnace. Comprised of$1,600,000 forDEP equipment and installation + $n 

batch handling (25% * $1,150,000) for DEP dust portion of handling. Costs are in 1999 $. 

3 Budgetary cost estimate of $300,000 was provided (November 2012) for a Monroe Three Stage Filter composed of Quench Tower, Coalescing Pad anc 

16,000 ACFM at 420°F, 223' ASL, 10% moisture. Excludes equipment for the cleaning system. Exclusions in quote, which have been estimated using f" 

include the following: Installation, Offloading services, External piping, Taxes/Tariffs, Insulation, Ductwork, PLC/ HMI, Freight, Interconnecting ductw 

in quote, which have not been estimated and if required will increase the estimated costs are as follows; Special packaging, Chemicals, Chemical stora 

VFD's or Dampers, Freeze Protection, Fume hoods, Pumps, and Explosion Proof motors. 

4 The cost for a'HEPA filter system was assumed to be similar to the Three-Stage Filter, but with less parts. As such, an estimate of75% ofThree-Stage : 

analysis. 

5 Order of Magnitude estimate (-0%/+50%) for Three Stage Filter with Cleaning System per email communication within Owens Corning dated 12/14/ 

costs for the water supply, drains, containment/handling for the collection of a hazardous substance, engineering, foundations, installation, start up c( 

existing exhaust to the filter and bypass system for servicing the filter. The scope also includes a membrane filter system to clean the water for reuse 

hazardous sludge. Under this design, the expectation is that the 3rd stage filter candles, which are similar to HEPA filters, should last longer ifthey arE 

ability to clean these filters has never been demonstrated. Assuming that all direct installation costs are included. 

6 Proposed system by Met-Pro (March 2013) would include the following steps (italics as provided by Met-Pro): 

The gas would be quenched to the wet bulb temperature. 


The gas would need to be sub-cooled below its wet bulb temperature. Sub-cooling the gas will create water droplets in the gas stream for the fine partia 


• The gas then would go through a couple ofventuri scrubbers that are each designed for pressure drop of50" w.c. or more. 

The gas stream will then go through a final mist eliminator vessel to capture the fine liqUid mists generated in the venturi. 

- The system will require significant ancillary equipment as well such as heat exchange, cooling water; cooling tower, liquid filters, and specially designed I 

Since the cost for this Venturi Scrubber Train is not known, it was set equal to the Caustic Scrubbing Train. However, purchased equipment cost may I 

additional required process components. 

7 A cost estimate for a single caustic scrubber was provided by Hansen Engineering to US EPA on 07/10/2011 as Total Package Cost of$210,000.ln the 

flowrate was specified and an exhaust fan was not specified for this system, which is now known to be needed. Upon more detailed discussions betwe 

Engineering in April and May 2013, it was determined that more equipment will be required, and that such a design is experimental in nature and not 

the US. Hansen Engineering provided an equipment cost on 05/17/2013 in the range of $592,200-$787,700 for treatment of a 15,000 acfm flowrate. 

a venturi scrubber, a collection tank, and a final scrubber. If needed, one to two in-series scrubbers would be added to the design, which represents th 

means to treat and dispose of the chrome-laden wastewater (i.e., precipitation and filter presses) was not included in the cost, and as such has been e! 

provided in the proposed rule [i.e., a $250,000 capital cost, $100,000 total annualized costs, plus $10,000 per year for stack tests ($380,000/yr /3 sOl 

on page 22384, Federal Register, Vol. 78, No. 72] were revised. The following changes were made: since a Total Capital Investment of $250,000 equat! 

ofless than $115,000 when the OAQPS Cost Manual factors are applied, this amount was revised to reflect the lowest purchased equipment cost of$5 

Engineering. Also, as the basis of the $100,000/yr operating costs was not provided, these costs were revised using the methods defined in EPA's OA( 

8 Where no value is shown, the cost is included in the Total Equipment Cost. 

9 Values based on minimum requirements specified in OAQPS Manual, Section 6, Chapter 2, page 2-51, and Section 6, Chapter 2, page 2-55. Maintenanc( 

materials, not filter media. 

10 The water quench step is needed in all scenarios. The water quench is essentially a set ofwater spray nozzles located in the ductwork prior to each c( 

reduce the temperature ofthe DEP exhaust gas. In addition to water use from the quenching step, a small amount ofwater is needed for the 3-Stage F 

ongoing cleaning of the filter media to extend life). Significant water usage is needed for designs involving water scrubbers. The cost ofwater use for t 

equal to that estimated for the Venturi Scrubber Train. 

11 Frequency of6 months for changeouts with no cleaning or 1 year for changeouts with cleaning. Unlike typical applications, where the filter bags have 

years (OAQPS Manual, page 1-46 of Section 6, Chapter 1), application ofthis technology to a wool fiberglass furnace, even post-PM control device, is e: 

to 2 times per year or more. Since this technology has never been applied to the proposed process, it is unknown how frequent the, changeouts will Q( 

need to bypass this system during changeouts to continue to operate. 

12 Estimated based on the weight of PM collected on the filter media and frequency of filter changeouts. For option with water cleaning system, sludge is 

of, in addition to the spent filter media. Set DEP cost equal to 3-stage filter cost. 

13 The electricity requirement provided for the basic 3-stage scrubber system was used for all filter media devices and for the caustic scrubber train. Set 

cost. 

14 In place of the cost manual methodology, which is (0.1098 *TCI), a lower multiplier was used to calculate these factors. As the DEP was installed in l' 

assessed for 14 years. However, the ongoing budget to maintain and repair the DEP will require a similar, annualized cost after the originallyestimat. 

15 Values taken from Table 1. Cost Analysis Supporting Information Technically Feasible Controls. 

16 Current Surrogate PM removal rate (ton/yr) [(2Ib/hr maximum, additional PM control) *(8760 hr/yr) * 1 ton PM/2000 lb]/ (100% - 97% DEP Rell 

17 Add-On System Surrogate PM removed (ton/yr) (2Ib/hr maximum, additional PM control) *(8760 hr/yr) * 1 ton PM/2000 Ib 

18 Cost per lb ofChromium Removed ($/lb) = (Total Annual Cost, $) / (Pollutant Removed, lb/yr). 

19 Cost per ton ofSurrogate PM Removed ($/ton) =(Total Annual Cost, $) / [(Pollutant Removed, Ib/yr) *(2000 lb/ton)] 
Table 5. Cost Comparisons for Alternate Scenarios 

Parameters 

Chromium Emission Inputs (lb/yr) 

Current, Future, Incremental 

Controlled Proposed Chromium 

Emissions Emissions Removed 3-Stage Filter 

Cost Effectiveness ($/lb removed)1 

3-Stage Filter Venturi 

with Water Scrubber 

HEPA Filters Cleaning Train 

CaseA2 

CaseB3 

CaseC 

CaseD5 

11.48 3.29 8.19 

25 3.29 21.72 

5 3.29 1.72 

- - 16.67 

51,845 

19,555 

247,602 

25,478 

49,163 63,980 84,91: 

18,544 24,132 32,02: 

234,795 305,558 405,52: 

24,160 31,442 41,72' 

Notes to Table 5: 

1 Annual cost divided by incremental chromium removed. Annual Cost ($/yr) taken from Table 2 for Case A. Costs are assumed to be the same Order of 

$ 424,638 3-Stage Filter 

$ 402,673 HEPA Filters 

$ 524,031 3-Stage Filter with Water Cleaning 

$ 695,481 Venturi Scrubber Train 

$ 495,826 Caustic Scrubber Train (REVISED EPA Estimate) 

2 Case A is based on reducing the Owens Corning, Delmar furnace to the proposed US .EPA limit of 6.0E-05Ib/ton glass pull, converted to a mass emissi( 

glass pull rate and 8760 hrs/yr operation. 

3 Case B is a 'best case' for Owens Corning when reducing the highest expected emission rate that would requite controls to meet the proposed US EPA 

glass pull, converted to a mass emission rate using a 6.25 ton/hr glass pull rate and 8760 hrs/yr operation. 

4 Case C is 'worst case' for Owens Corning when reducing the lowest expected emission rate that would require controls to meet the proposed US EPA I 

glass pull, converted to a mass emission rate using a 6.25 ton/hr glass pull rate and 8760 hrs/yr operation. 

5 Case D is based on reducing the emissions presented in the proposed rule, page 22384, Federal Register, Vol. 78, No. 72 [i.e., SO lb/yr /3 sources'" 16 

to a level that would meet the proposed US EPA limit of 6.0E·05Ib/ton glass pull, converted to a mass emission rate using a 6.25 ton/hr glass pull ratE 

17 
1.3.7. Selection of Control Technology (Step 5) 

Based on steps 1 through 4 of this analysis, it has been determined that proper maintenance and good 

operating practices for the existing particulate control devices are the only controls that are truly 

feasible for these furnaces. All other potential control technologies should be eliminated for the reasons 

outlined in this assessment. This is especiallytrue considering that none of the removal costs include the 

unknown cost of developing these technologies for production operations and the potential to have 

removal efficiencies that do not meet the proposed emission rate even with these additions. Without an 

adjustment ofthe proposed emission rates for chrome the DMZ furnace, which is three and a half times 

the proposed limit, will have to install experimental technology costing at least $50,000 per lb of chrome 

removed. All this to remove 8.19 pounds of chrome annually, which has been shown not to pose a risk to 

the community. This is well above the costs referenced by the U.S. EPA asnot viable in the proposed 

rules. For furnaces that only marginally exceed the proposed limits the costs can easily exceed $ZSO,OOO 

per pound of chrome removal. 

18