### MEMORANDUM

TO: Steam Electric Point Source Category ELG Rulemaking Record

FROM: Patrick Goodwin, ERG

DATE: September 30, 2015

SUBJECT: Review of Confidential Business Information for the Environmental Assessment (DCN SE04514)

ERG supported the U.S. Environmental Protec tion Agency (EPA) in the development of final effluent limitations guidelines and sta ndards (ELGs) for the Steam Electric Power Generating Point Source Category (40 CFR Part 423). ERG completed environmental assessment (EA) analyses to evaluate envir onmental and human health impacts under current ( i.e. , baseline) discharge practices and potential improvements associated with the regulatory options (Options A, B, C, D, and E). 1 The results of these analyses are presented in the Environmental Assessment for the Effluent Limi tations Guidelines and Standards for the Steam Electric Power Generating Point Source Category (EA Report), Document No. EPA-821-R-15- 006 (DCN SE04527). The EA included the following analyses:

 Literature review, including documentati on of environmental impacts from steam electric power plant wastewater discharges and summary of damage cases;

 Quantitative assessment of water quality impacts and potential impacts to wildlife and human receptors; and

 Qualitative assessment of water quality impact s and potential impacts to wildlife and human receptors, including comparison of ba seline pollutant loadings to other point source discharges) and discharges to sensit ive environments (impaired waters, waters under a fish consumption advisory, dr inking water sources, Chesapeake Bay watershed, and Great Lakes watershed).

As part of the public docket, EPA includes re ferences and documentation to explain the ELG review process and results of the analyses presented in public documents and the preamble.
This memorandum describes how ERG identified c onfidential business info rmation (CBI) in the EA analyses and how ERG redacted CBI data fr om the EA documentation for inclusion in the public docket.

1 During development of the final rule, EPA decided not to base the final rule on Option F for ex isting sources due primarily to the high cost of that Option, particularly in light of the costs associated with other rulemakings expected to impact the steam electric power generating industry (see S ection VIII.C.1 of the preamble). As a resu lt, EPA chose not to conduct particular analyses for Option F to the same extent that it di d for some of the other options considered.Memorandum September 30, 2015 Page 2

For the literature review , all information is from non-confidential sources ( i.e. , no survey response data). Therefore, none of the literature review sources pres ented in the record needed to
be redacted due to CBI concerns. This included the Literature Search Database (DCN SE01962), the Database of Damage Cases and Other Do cumented Site Impacts from Pollutants in
Combustion Residuals and Steam Electric Power Plant Wastewater (DCN SE04518), and cited literature references in the EA Report. Some of the literature sources, however, are protected by copyright and have therefore been excl uded from the electronic docket system (http://www.regulations.gov/). Copyr ighted materials are available for review at the EPA Docket
Center. See the User Guide to the Docket fo r the Rulemaking for the Steam Electric Power Generating Effluent Limitations Guidelin es (DCN SE03974) for further details.

For the quantitative and qualitative assessmen ts, the only sources of CBI data collected by EPA are as follows:

 Drinking Water NHD Indexed Dataset (DCN SE03569) – The national dataset contains the location of public wells and drinking water intakes (as identified by EPA’s Office of Ground Water and Drinking Wa ter). The dataset is considered EPA sensitive information and is excluded from the public record.

 Questionnaire for the Steam Electric Power Generating Effluent Guidelines (Steam Electric Survey) – The survey results that ERG used as inputs to the EA analyses ( e.g. , the national-scale immediate receiving wa ter (IRW) model, loadings analyses, and case study models) that may have been marked as CBI include the location of plant outfalls, receiving water name s, and cooling water flow rates.

 Pollutant Loadings – Plant-specific, wa stestream-specific, and receiving waterspecific pollutant loadings used as inputs to the IRW model and case study models were calculated using data from the questionnaire, specifically pollutant
concentrations and wastewater flow rate s. A portion of the steam electric power plants claimed these data as CBI. Fo r a complete listing of the supporting documentation used to calculate the po llutant loadings, see the memorandum “Pollutant Loadings Supporting Documentation” (DCN SE04515).

ERG used plant-specific data as inputs to the IRW model. ERG determined that two of the plants evaluated under the EA claimed their outfall locations as CBI and one plant claimed the receiving water name as CBI. However, ERG wa s able to identify publicly available sources that provided the outfall locati ons and receiving water names. ERG cites the publicly available sources where the outfall and receiving water information for these plants is presented in the public record (ERG, 2015a). For th e IRW model, ERG used cooling water flow rates for a subset of steam electric power plants. To protect CBI, ERG excluded the cooling water flow rates from the public record (ERG, 2015a; ERG, 2015b).

The IRW model used site-specific pollutant lo adings. The pollutant loadings are excluded from the public record and remain confidential. To protect CBI, output data calculated in the IRW model using the po llutant loadings ( e.g. , pollutant concentrations in the water column and fish) are also excluded from the public record.Memorandum September 30, 2015 Page 3

For the case study models, ERG selected steam electric power plants that did not make CBI claims on their pollutant loadings. See the ERG memorandum, “Technical Approach for Case Study Water Quality Modeling of Aquatic Sy stems in Support of the Final Steam Electric Power Generating Industry Environmental Assess ment” (DCN SE05570) for further discussion.

The qualitative loadings analyses included onl y aggregate pollutant loadings. Because no plant-level loadings data will be provided in the public record, the aggregate results presented in the EA Report are not CBI-deducible data.

1.0 R EFERENCES

ERG. 2015a. Water Quality Model: Plant and Re ceiving Water Characteristics. Chantilly, VA.

DCN SE04513.

ERG. 2015b. Supporting Documentation for Summ arization of Environmental Assessment Analyses. Chantilly, VA. DCN SE04449.

U.S. EPA. 2010. U.S. Envir onmental Protection Agency. Questionnaire for the Steam Electric Power Generating Effluent Guidelines . OMB Approval Number: 2040-0281. Washington, DC. (2 June). DCN SE00402-SE00402A09.