### MEMORANDUM

TO: Steam Electric Rulemaking Record

FROM: Dan-Tam Nguyen, ERG

DATE: September 30, 2015

SUBJECT: Development Memorandum for the Steam Electric Analytical Database for
the Final Rule

1.0 I NTRODUCTION

ERG is providing technical support to the U.S. Environmental Protection Agency’s Office of Water, Engineering and Analysis Division (EPA) for development of effluent limitations guidelines and standards (ELGs) for the Steam Electric Power Generating Industry. ERG developed the Steam Electric Analytical Database for the Fina l Rule (DCN SE05359) (hereafter, “the analytical database”), which is a compilation of the analytical data for wastestreams evaluated as part of the final rule. This database includes data gathered during the rulemaking, including data from EPA fiel d sampling activities, responses to the Questionnaire for the Steam Electric Power Generating Effluent Guidelines (Steam Electric Survey) (DCN SE05903), industry-submitted data, and other data collected from technical sources. This memorandum describes ERG’s general data qual ity review criteria, the data ERG deemed acceptable for inclusion in the database, and the data ERG used for engineering analyses. In addition, this memorandum describes any necessa ry data processing procedures and/or data editing criteria to ready the da ta for subsequent analyses.

2.0 G ENERAL D ATA Q UALITY R EVIEW P ROCEDURES

The main sources of data for the rulemaki ng are EPA/ERG site visit and sampling event program data, data collected from the Steam El ectric survey, and secondary (or existing) data. Secondary data come from sources that already exist and can be used in support of analyses outside the original intent of the data. Thes e sources include plant monitoring data, other monitoring data (such as EPA’s CWA Section 3 08 Letters), articles and technical papers, industry/vendor telephone que ry data, and internet information. To ensure that the analytical data collected for the Steam Electric Rulemaking are of the quality necessary to support EPA in revising the existing ELGs for this industry cate gory, ERG subjected si te visit and sampling event data, data collected from the Steam Electric Survey, and secondary data to the data quality
review criteria outlined for each of these data source types in the Quality Assurance Project Plan for the Steam Electric Effluent Guidelines Rulemaking (“QAPP”) [ERG, 2013a]. For secondary data, ERG applied acceptance criteria to the analy tical data based on use. For instance, analytical data from secondary sources may be used to iden tify pollutants of concern (POCs) for evaluated wastestreams, characterize in-process wastestreams and effluent discharges, evaluate wastewater treatment system performance, and es timate baseline pollutant discharges.In reviewing data sources for each of the wa stestreams, ERG refine d the general criteria
described in the Quality Assurance Project Plan for the Steam Electric Effluent Guidelines Rulemaking (QAPP) to meet the needs of the engineer ing analyses for each wastestream. Section 4 of this memorandum outlines the specific data sources for each wastestream and presents a discussion of data quality review procedures that were specific to individual wastestreams.

3.0 D ATABASE S TRUCTURE

The analytical database was developed using Microsoft® Access 2007 software. It houses a total of six data tables, one representing the database dictionary description of tables (“Database Dictionary_Tables”), one representing the database dic tionary description of fields (“Database Dictionary_FieldNames”), and the remaining four representing sample-specific analytical data for four wastestreams: flue gas desulfurization (FGD) wastewater, combustion residual leachate, gasification wa stewater, and ash transport wa ter (including fly, bottom, and combined ash transport water). Table 1 provide s a summary of the tables included in the analytical database, including table names and thei r descriptions. This tabl e is also included in the analytical database as “Database Dictionary_Tables.”

Table 1. Summary of Final Analytical Database Tables

Table Name Description
DataDictionary_Tables Dictionary describing database tables. DataDictionary_Field Names Dictionary describing database field names.

FGD Data table containing data for FGD wastewater, including pond effluent, purge, and
treatment effluent that ERG evaluate d for FGD POC and pollutant loadings analyses.

Ash Data table containing data for bottom ash transport water, fly ash transport water, and combined ash transport water that ERG evaluated for ash pollutant loadings analyses. a

Leachate Data table containing data for combustion residual leachate from landfills and surface impoundments that ERG evaluated fo r leachate POC and pollutant loadings analyses.

Gasification Data table containing data for gasificatio n wastewater that ERG evaluated for the gasification POC analysis. b
a – Data evaluated for the ash POC analysis are contai ned in two separate spreadsheets titled “Source Water Ash Treatment Analysis” (DCN SE04744) and “Pollutants of Concern Ash Treatment Analysis” (DCN SE04746). b – ERG did not evaluate gasification wastewater data for use in pollutant loadings analyses because EPA did not calculate pollutant loadings for this wastestream.

3.1 General Data Format

With the exception of the data dictionary, each of the data tables included in this database is provided in a general data format consisting of the fields described in Table 2. The field names in this general data format are also include d in the analytical database table “Database Dictionary_FieldNames.” For each data table, ER G included additional flags to further classify the analytical data for use in subsequent anal yses for each wastestream. Not all data tables contain the same types of flags. Ta ble 3 lists additional fields that are included in each of the data
tables.Table 2. General Data Format fo r Analytical Database Tables

Field Name Field Description
Record ID Unique number assigned to each record in the database. Plant ID Steam Electric Survey plant identification number. CBI Flag Indicator flag for noting the record is CBI.

Plant Name Name of the stea m electric generating plant.

Episode Episode number assigned to each EPA sampling and CWA 308 sampling
data event. Sample Number for each individual sample. Date Collected Date that the sample was collected from a particular wastestream. Lab Name Name of the analytical la boratory that analyzed the sample. Analyte Pollutant name.

CAS_NO Chemical Abstracts Service (CAS) number specific to each chemical substance (analyte).

Method Analytical method used to quantify the amount of the specified analyte in the sample. Procedure Form the analyte is in (e.g ., Total, Dissolved, Filtrate, Solids).

Units Concentration units for the amount, j-value concentrations, MDL, and RL
fields.

Non-Detect Indicator Flag for whether the sample was detected above the sample-specific quantitation limit (QL) or not. “D” repr esents detected values, or samples with concentrations above the QL. “ ND” represents non-detected values, or samples with concentrations below the QL. Amount Concentration of the pollutant in the wastestream.

J-Value Concentrations Maximum potential concentration of the analyte that is detected above the MDL but below the QL.

Method detection limit (MDL) Minimum analyte concentration that can be demonstrated to be different
from zero or a blank concentration at the 99% level of confidence.

Reporting limit (RL) Sometimes referred to as quantitation limit (QL). Lowest concentration of an analyte that produces a quantitative result within specified limits of precision and bias.

Dilution Dilution factor, which is the ratio of the final volume of the sample to the aliquot volume.

Qualifiers Qualifier assigned by the analytical laboratory to flag measured analyte
concentrations that are below the MD L or RL (e.g., “U” indicates the observation is below the MDL). Reason Notes about the sample and qualifier.

Sample Point Either a sample point number or description of where the sample was
collected.

Sample Description Description about where the sample was collected in the wastewater treatment system and what type of wastewater. Type of Wastewater Description of the type of wastewater collected.

Wastewater Classification Standa rdized classification for the ty pe of wastewater collected. QA Sample Flag for duplicate sa mples and field blank samples.

Type of Sampling Source of the sample (i.e., EPA Sa mpling, CWA 308 Sampling, Plant-Self Monitoring, EPRI).

Sample Type Description of whether sample represents a single grab sample or composite of multiple samples.Table 3. Analytical Data base Additional Fields

Field Name Data Tables Including Field Field Description

Included in Loadings FGD, Leachate, Ash Indicator flag noting that the data were used in pollutant loadings analyses

Included in POC Analysis FGD, Leachate, Gasification Indicator flag noting that the data were used in POC analyses Unit ID Leachate Unique identifier for landfill and surface impoundment units.

Data Source Category Ash Broad descriptor of the data source (e.g., 1982 TDD, Detailed Study Ash Pond Sampling, EPRI Reports, Form 2c, Industry Submitted Data, and UWAG Public Comment)

Data Classification Ash Indicator if the data point wa s accepted for use in specific ash analyses (e.g., loads, sensitivity analysis (SA), or excluded from all analyses)

Project Notes Ash This field contains general notes about the sample that is not captured in the other fields but was considered during evaluation (i.e., why a result was excluded)

3.2 Data Processing Procedures

EPA collected data in a variety of different formats, including, but not limited to, Excel spreadsheets, Access databases, and hard copy re ports. To facilitate the use of the data in subsequent engineering analyses, ERG processed the data sets into a general data format for the analytical database, as describe d in the previoius s ection. This section summarizes the data format and quality assurance procedures ERG used to maintain the integrity of the data during this database processing step.

ERG evaluated each data source individually an d determined the appropriate procedures to convert the original format to the general data format used in the analytical database. The general data format has a comprehensive list of fi elds that characterize eac h analytical data point. The data processing involved the addition or renaming of fields to match the general data format prior to importing the data source into the anal ytical database. Where the data source did not
have information for these additional fields in the general data format, the import would leave
these fields blank. ERG conducted a quality check of the data pr ior to and after importing the data into the analytical database to ensure that none of the data were altered or incorrectly updated.

Although not required in the QAPP, ERG conducted a screen ing-level data review of secondary data against industry-provided an alytical laboratory re ports and subsequent correspondence with facilities to address inconsistencies in reporting. Where appropriate, ERG
documented information that was added to the data base separate from the original data set and based on these additional correspondences fo r the appropriate analytical results.

4.0 D ATABASE C ONTENTS

This section describes the speci fic data sources considered fo r inclusion in the analytical database and the data selected for use in subseq uent analyses. It also documents any processing procedures and corrections to the data collected and compiled for the rulemaking development.4.1 FGD Wastewater

The review of data specific to FGD wastewat er involved a number of steps to evaluate and process the data. This review and the developm ent of specific data tables presented in the analytical database are detailed in a separa te memo titled “Flue Gas Desulfurization (FGD) Wastewater Data - Development Memo for the Analytical Database for the Steam Electric Rulemaking” (DCN SE05880).

4.2 Fly Ash and Bottom Ash Transport Water

The review of data specific to fly ash a nd bottom ash transport water involved a number of steps to evaluate and process the data. This review and the development of the ash table presented in the analytical database are detailed in a separate memo titled “Ash Analytical Data Review Memorandum” (DCN SE05567).

4.3 Combustion Residual Leachate

ERG reviewed data sources containing analyt ical data for combusti on residual leachate. As part of the Steam Electric Survey, EPA request ed that a subset of plants provide sampling
data for untreated landfill and/ or impoundment leachate collec ted at the plant. For more information on the Steam Electric Survey, includ ing which plants were required to provide landfill and/or impoundment leachate sa mpling data, see Section 3 of the Technical Development Document for the Effluent Limitations Guidelin es and Standards for the Steam Electric Power Generating Point Source Category (DCN SE05904). EPA received data from active and inactive landfills and impoundments at 39 plants. EPA did not receive or collect additional analytical data
for combustion residual leachate.

4.3.1 Data Included in the Analytical Database

Based on ERG’s review, ERG excluded data from retired or closed landfills and impoundments for use in subsequent analyses becau se combustion residual leachate from retired units is not representative of landfills and impoundments generating combustion residual leachate; therefore, not regulat ed in the final rule. The remaining data received through the Steam Electric Survey meet the data acceptance cr iteria outlined in the QAPP for questionnaire data. For this reason, ERG included in the anal ytical database data for combustion residual leachate (excluding those from retired landfills or surface impoundments) from the “Final Steam Electric Technical Questionnaire Database ” (“survey database”) (DCN SE05903).

4.3.2 Data Processing Activities

After extracting the relevant data from the Steam Electric Survey database, ERG processed the data into the general data form at described in Secti on 3.1. The data processing required renaming field names from the survey data base to make them consistent with the field names in Table 2. The reformatting step did not popul ate fields that did not exist in the original data set nor corrected any sample results.ERG included an additional field, “Unit ID,” to indicate whether the combustion residual
leachate data were collected from a landfill or surface impoundment.

4.3.3 Data Acceptance Criteria

ERG also generated two indicator flags to i ndicate whether the data were “Included in POC Analysis” and “Included in Loadings.” Error! Reference source not found. 4 presents the leachate data acceptance criteria for th e POC analysis and loads analysis.

Table 4. Leachate Data Acceptance Criteria

Acceptance Criteria POC Analysis Loadings Sample locations must be unambiguous and clearly described such that it can be categorized by type (e.g., landf ill leachate or impoundment leachate) and level of treatment (e.g., untr eated, partially treated).  

Sample must be representative of act ual combustion residual leachate (not
leachate from retired landfills or surface impoundments).  

Analytical data must represent individual sample results or plant-level average sample concentrations rather than average results representing multiple plants.  

Sample must be representative of fu ll-scale, typical plant operations.  
Sample analysis must be completed using accepted analytical methods. a  
Data must not be duplicative of other accepted data.   Sample data must provide sufficient information to identify units.   Non-detect results were not accepted if no limit (e.g., DL, QL) was provided.   Sample results must represent total (i.e ., dissolved results were not accepted except for TDS).  

4.4 Gasification Wastewater

ERG reviewed data sources containing analyt ical data for gasification wastewater. As part of the CWA 308 monitoring program, ERG supported EPA in collecting data from two plants operating integr ated gasification combined cycle (IG CC) systems. Both plants, Tampa Electric Company’s Polk Station (Polk) and Wa bash Valley Power Association’s Wabash River Station (Wabash River), treat their gasification wastewater with an evaporation system. Both plants sampled the influent streams transferred to the evaporation system and the neutralized weak acid and steam stripper effluent streams, which are defined as gasification wastewater sreams. Each plant collected 10 samples. EPA did not receive or collect addi tional analytical data for gasification wastewater.

4.4.1 Data Included in the Analytical Database

ERG reviewed data collected under EPA’ s CWA 308 monitoring program and reported the results of the analytical data review in a separate memorandum titled “Final Power Plant Monitoring Data Collected Under Clean Wa ter Act Section 308 Authority ("CWA 308 Monitoring Data")” (DCN SE01326). The data m eet the acceptance criteria for industrycollected data as outlined in th e QAPP and confirmed in ERG’s re view of the CWA 308 data.4.4.2 Data Processing Activities

ERG processed the data into the general da ta format described in Section 3.1. The data processing required renaming field na mes from the survey database to make consistent with the field names in Table 2. The reformatting step di d not populate fields that did not exist in the original data set nor co rrected sample results.

4.4.3 Data Acceptance Criteria

ERG also generated one indicator flag to i ndicate whether the data were “Included in POC Analysis.” Pollutant loadings analyses were not conducted for ga sification wastewater.
Error! Reference source not found. 4 presents the data acceptance criteria for the POC analysis.

Table 4. Gasification Data Acceptance Criteria

Acceptance Criteria POC Analysis Sample locations must be unambiguous and clearly described such that it can be categorized by type (e.g., IGCC evaporator influent, steam stripper effluent, neutralized weak acid waste stream). 

Analytical data must represent individual sample results or plant-level average sample concentrations rather than average results representing multiple plants. 

Sample must be representative of fu ll-scale, typical plant operations. 
Sample analysis must be completed using accepted analytical methods. a 
Data must not be duplicative of other accepted data.  Sample data must provide sufficient information to identify units.  Sample data were not accepted if it represente d effluent from the evaporation technology.  Non-detect results were not accepted if no limit (e.g., DL, QL) was provided.  Sample results must represent total (i.e., di ssolved results were not accepted except for
TDS). 

5.0 R EFERENCES

ERG. 2013a. Quality Assurance Project Plan fo r the Steam Electric Effluent Guidelines Rulemaking. (5 April). DCN SE02951.