April 30, 2012

Via Electronic Mail

Ronald P. Jordan

U. S. EPA Headquarters

Engineering & Analysis Division (4303T)

Ariel Rios Building

1200 Pennsylvania Avenue, N.W.

Washington, DC 20460

RE: Pleasant Prairie Monitoring Data - Monthly Sampling Events

Dear Mr. Jordan:

Thank you for the opportunity to comment on the draft data from the additional samples taken at

Pleasant Prairie Power Plant in September, November, and December 2010, and January

2011. We Energies worked with the Utility Water Act Group (UWAG) to develop the following

comments. Requested split sample results for mercury are also provided.

I. GENERAL COMMENTS

Data Usability

We Energies agrees with EPA’s efforts to identify and flag potentially erroneous (outlier) data

points in the Pleasant Prairie data set. However, outlier values should be discarded from the

data set and not used for any purpose. Also, there is no discussion of how flagged data points

will be used (or excluded) from consideration in calculating the new steam electric effluent

guidelines. For example, data points flagged B, Est, F and T indicate potentially significant

inaccuracy (bias) in the associated data.

Inadequate Treatment System Design and Operations Information

In our comments on the draft Sampling Episode Report (SER) for Pleasant Prairie, we noted the

lack of some basic technical information regarding treatment system design and operations that

is very important to a comprehensive understanding of the analytical results. This information is

also key to understanding the conditions under which a certain level of treatment can be reliably

achieved. All of those comments also apply to the additional monthly sampling data. However,

we reiterate here an essential point:

 EPA’s study plan should have included a comprehensive study of the coal feed stock

during each sampling event. It is clear that coal characteristics have a very significant

We Energies

231 W. Michigan St.

Milwaukee, WI 53203

www.we-energies.com
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impact on flue gas desulfurization (FGD) system chemistry and wastewater treatment.

While EPA gathered some information about coal constituents during the sampling

events, it should have collected full information about levels of sulfur, metals, and

chlorides in the coal, as well as the heating value of the coal being burned during the

relevant period for the sampling event.

Analytical Methods Descriptions

The analytical descriptions in the draft SER and the analytical narratives provided with both the

draft SER and the additional monthly sampling data omit some basic information that should be

included and would be helpful in making data evaluations and comparisons. We reiterate our

request for this basic analytical information, including how trace metals and mercury samples

were digested, how dissolved mercury samples were filtered, and how known interferences in

FGD matrices were controlled, as stated in our January 31, 2012 comments.

Quality Assurance/Quality Control Issues

Detections in laboratory preparation blanks (“B” qualifier) — Where EPA detected analytes

in laboratory blanks the results are flagged with a “B.” Some “B” qualified results are close to or

even below the reporting limit, and thus also flagged with a “J.” For example, the Set 2 effluent

iron result (Table B5-11) and the Set 3 phosphorus effluent result (Table B5-12) are flagged with

both “J” and “B.” The actual result of the blank is not reported. If the blank were taken into

account in the data review process, then the results could be fully evaluated. Without the actual

blank results, our ability to evaluate these data points is limited.

Problems with ICV, CCV, ICB, CCB, ISA, ISB, CRI or MRL Standard (indicated by a “^”) —

This “catch all” mark appears to have been used by EPA to indicate a multitude of possible QC

problems that would only be evident from an examination of the raw laboratory data. For

ICP/MS, problems with the ICV (initial calibration verification) are supposed to be resolved

before analysis proceeds. Also, the CCV analyses (continuing calibration verification,

performed once every ten samples) are supposed to be corrected by recalibration and reanalysis. It is unclear why any of the samples would be qualified for either ICV or CCV outliers.

MS/MSD QC Excursions (“F”) — Any “F” qualified results should be considered estimated

values and excluded from the EPA dataset. The “F” flag appears on the following FGD effluent

data:

Set 1 COD, Cyanide, Phosphorus, Silver

Set 2 COD

II. SPECIFIC COMMENTS/SPLIT SAMPLE RESULTS

Table B4-3 for Pleasant Prairie includes an incorrect title for column 5. The title indicates that

the information in that column is for a bioreactor, but the plant does not have a bioreactor. The

title instead should refer simply to effluent samples (from the physical/chemical treatment

system).
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EPA requested that Pleasant Prairie provide the split sample influent and effluent mercury data

for all the data sets. We did not collect any influent split samples and, therefore, have no

influent mercury results. However, as you requested, we are providing the following split

sample mercury results for sets 1, 2, 3, and 4 FGD effluent:

Pleasant Prairie Split Sample Results - Total Recoverable Hg Data for SP-2

Sampling Date SP-2,

Total Rec. Hg, μg/L

09/30/2010 0.207

11/03/2010 0.122

12/08/2010 0.034

01/26/2011 0.143

We appreciate your consideration of our comments. Please contact me at (414) 221-2158 or by

e-mail (David.Lee@we-energies.com) if you have any questions regarding our comments.

Sincerely,

David M. Lee, P.E.

Manager – Water Quality