Date: July 20, 2012 

Subject: Cost to Reduce HAPs with Potential for Ecological Effects 

EPA Contract No. EP-D-11-084; Work Assignment No. 0-03 

From: Katie Hanks 

To: John Bradfield 

Bill Schrock 

U.S. Environmental Protection Agency 

Research Triangle Park, NC 27711 

The purpose of this memorandum is to present the cost analysis for reducing hazardous 

air pollutants (HAP) with the potential for environmental effects from the pulp and paper 

national emission standards for hazardous air pollutants (NESHAP) source category (40 CFR 

part 63, subpart S). This analysis focuses on acid gases and key persistent and bioaccumulative 

HAP because of their potential for adverse effects to ecological receptors (e.g., wildlife, aquatic 

life, natural resources). 

For the ecological cost assessment, the emissions inventory data used for risk modeling 

were reviewed to determine the predominant sources of the HAP of interest for ecological risk 

(referred to as ”eco HAP”). Table 1 presents the nationwide and maximum facility emissions 

estimates of eco HAP from the subpart S emissions inventory. 

Table 1. Emissions of Eco HAPs from the Pulp and Paper Subpart S Source Category 

 Pollutant Category emissions (tpy) 

Number of facilities in 

category reporting 

emissions 

 Emissions for highest-emitting 

facility 

tpy lbs 

HCl 259 55 31.95 63,900 

Cl2 24 53 2.5 5,000 

POM 0.008 29 0.0008 2 

Cadmium 0.01 28 0.006 12 

Mercury 0.002 27 0.0007 1 

Bleaching of virgin kraft pulp is responsible for nearly all of the hydrochloric acid (HCl) 

and chlorine (Cl2) emissions. Caustic scrubbers are already required to reduce HCl and Cl2 by 99 

percent or greater. The nationwide emissions are the residual emissions remaining after 

implementation of 99 percent or better control. No other technology exists to reduce chlorinated 

HAP emissions from bleaching further. Although some totally chlorine free (TCF) bleaching 
2 

processes exist, these technologies are not applicable for virgin kraft fibers in which the lignin 

must be removed to obtain target final product brightness. 

About one third of the HAP metal emissions of cadmium (Cd) and mercury (Hg) are 

from incineration control devices used to reduce HAP emissions from Subpart S processes. The 

remaining two thirds of metal HAP emissions are primarily associated with fuel burning for 

paper machine dryers. Emissions of POM are also associated with fuel burning for paper 

machine dryers. Several of these incineration-based systems are already equipped with wet 

scrubbers (e.g., for total reduced sulfur control in the case of thermal incinerators) and for these 

units there is no means to further reduce emissions. Fuel switching was considered, but would 

not reduce emissions because most mills are already using natural gas. Natural gas has lower 

emissions factors on a pound per million British thermal unit (lb/MMBtu) basis for POM and the 

HAP metals of concern, as shown in Attachment 1. 

 Table 2 presents estimated venturi scrubber control costs to further reduce POM and 

HAP metals emissions from fuel-burning equipment. The footnotes under Table 2 provide details 

and information sources used in the cost estimates. Ballpark costs were estimated for a single 

mill and then compared to the nationwide emission reduction that could be obtained if all of the 

eco HAP could be eliminated. This approach clearly underestimates costs and overestimates the 

emission reduction that could be achieved, and even without further refinement, results in cost 

effectiveness values that are extremely high (and would only increase if refined). Apart from cost 

impacts, installation of scrubbers would result in secondary air emission impacts from electrical 

energy use and wastewater impacts (i.e., a new wastewater stream to be treated and discharged 

into the environment). 

Based on the information presented in this brief memorandum, there do not appear to be 

any feasible control measures for further reducing HAP emissions with the potential for

environmental effects from the subpart S source category. 

 
Table 2. Ballpark Estimates of Costs to Further Reduce Pulp and Paper Subpart S HAP Emissions of Potential Interest for Ecological Risk

HAP

Adjustednationwidebaseline

emissions, tpy Predominant emission sources Available controls

Control costs for a single mill

(underestimated), $1

Nationwide emissionreduction (overestimatedassuming emissionseliminated)2

Cost effectiveness(underestimated),$/ton4 

Cd 0.01

‐HAP emissions control devices (e.g.,

thermal oxidizers); and‐Fuel burning for paper machine

dryers

‐Scrubbers3 ‐ already used by some mills

‐Fuel switching is not likely to reduce emissionsbecause most mills are already using natural gas. $ 40,000 0.013 3,160,775 $

Hg 0.002 $ 40,000 0.0019 20,956,02 $ 9

HCl 259 Bleaching

Caustic scrubbers are already used to reduce

chlorine and HCl by 99%. Nationwide emissions

are the residual emissions remaining after

implementation of 99% control. No other

technology exists to reduce emissions further. NA

Chlorine 24 NAPOM 0.008

Fuel burning for paper machine

dryers

‐Scrubbers3

‐Fuel switching among the liquid fuels burned is

not likely to reduce emissions because most millsare already using natural gas which has lower

POM emissions that oil. $ 40,000 0.0082 4,851,643 $

1. The costs presented in the table above are underestimated because they are lower than the costsa single mill would face; they are not nationwide costs for all affected mills. Examples of per‐mill 

Median gas flow from direct‐fired paper machine dryer vents is 63,750 acfm. EPA fact sheet for venturi scrubbers (http://www.epa.gov/ttn/catc/dir1/fventuri.pdf) provides annualized cost range of $

Assuming dryer gas flow is 50% water vapor, then median flow is approximately 50% x 63,750 = 31875 scfm. Using the minimum cost of $5.7/scfm x 31,875 scfm = $181,688/yrper mill.

Median flow from HAP incinerator is 15,000 acfm (or 7,500 scfm assuming exhaust is 50% water). Using the minimum cost of $5.7/scfm x 7,500 scfm = $42,750/yrper mill.

2. Assuming emissions are eliminated is an overestimate because: (a) controls are less than 100% efficient, and (b) no further reduction could be achieved at mills already operating controls

3. A particulate scrubber was considered to reduce POM since POM compounds are present in the atmosphere in particulate form. (http://www.epa.gov/ttn/atw/hlthef/polycycl.html

Scrubbers were considered for mercury because scrubbers were considered for the other metal HAP and a fraction of the mercury is in particulate form.

4. Cost effectiveness ($/ton) is considerably underestimated because the costs are underestimated and the nationwide emission reduction is overestimated
ATTACHMENT 1 ‐ COMPARISON OF EMISSION FACTORS FOR POM AND HAP METALS

Analysis:  Emission factors were compared to show that natural gas is the lowest‐emitting fuel for POM

  and the eco HAP metals.  Natural gas is the prevalent fuel for thermal oxidizer controls and paper

  machine dryer burners.

AP‐42 Emission Factor Comparisons for Natural Gas and Oil POM

Nat. gas POM detected:

2.40E‐05

3.00E‐06

2.80E‐06

1.70E‐05

5.00E‐06

5.18E‐05 total lb/MMscf

5.08E‐08 total lb/MMBtu

Fuel Oil POM lb/1000 gal lb/MMBtu

No. 6 0.0013 8.67E‐06

Dist. 0.0033 2.36E‐05

Conclusion:  On a lb/MMBtu basis, natural gas POM emissions are lower than for oil.

AP‐42 Emission Factor Comparisons for Metals (Cd, Hg, and Pb)

Nat. gas Fuel oil

HAP lb/MMscf lb/MMBtu lb/1000 gal lb/MMBtu

Cd 1.10E‐03 1.08E‐06 3.98E‐04 2.74E‐06

Hg 2.60E‐04 2.55E‐07 1.13E‐04 7.79E‐07

Conclusion:  On a lb/MMBtu basis, natural gas Cd and Hg emissions are lower than for oil.

Att1_EF_compare