Hunton & Williams LLP • Counsel to UWAG • 1900 K Street, N.W. • Washington, D.C. 20006 Steering/Audit Committee

Angela M. Grooms,

Chairman C. Richard Bozek Rayburn L. Butts Alan E. Gaulke M. R. (Mick) Greeson David M. Lee James F. Stine John G. Valeri, Esq. Kerry M. Whelan Judson White

February 1, 2010 FILE NO.: 29142. 070324

VIA ELECTRONIC MAIL

Mr. Ronald P. Jordan U. S. Environmental Protection Agency Engineering & Analysis Division 1200 Pennsylvania Avenue, N.W. Mail Code 4303T Washington, DC 20460

RE: Comments on EPA’s Draft Glossary for the Steam Electric Effluent Guidelines Rulemaking ICR, Docket No. EPA-HQ-OW-2009-0819

Dear Ron:

On behalf of the Utility Water Act Group (U WAG), thank you providing us with the draft glossary for the steam electric effluent guidelines questionnaire (Questionnaire or ICR, noticed in 74 Fed. Reg. 55,837 (Oct. 29, 2009)). UWAG requests that the Agency fully consider these comments before submitting a revised ICR to the Office of Management and Budget. We also request that EPA provide a writ ten response to these comments, as it will for all comments submitted by the original December 28 comment deadline.

UWAG would welcome further dialogue with EP A on these comments, as there are several major areas where more clarity is needed. Please note that the attachments to this letter contain many recommendations for substantive change s to the glossary and the Questionnaire.

I. Definitions of “Wastewater Treatment Sy stem” and “Wastewater Treatment Unit” in Part D and Glossary

UWAG said in its December 28, 2009 comments on the Questionnaire that the instructions to Part D are confusing. Unfortunately, the new glossary does not resolve the confusion.

EPA’s concept appears to be to divide th e world into two categories of wastewater treatment systems, “pond/impoundment systems” a nd others (which might be called – and EPA sometimes does – “non-pond” systems but are more often referred to as “wastewater treatment” systems).Mr. Ronald P. Jordan Page 2 February 1, 2010

EPA’s definition of “wastewater treatment sy stem” is “a combination of one or more ‘wastewater treatment units,’ other than ponds/impoundments, desi gned to achieve wastewater treatment.” ICR, p. D-1. EPA defines “wastewate r treatment units” to include “primary settling ponds/impoundments, chemical precipitation, pH ad justment, clarificatio n, biological reactor, thickeners, filters, and constructed wetlands.” Id. The inclusion of only primary settling ponds/impoundments in this definition suggests th at no other types of ponds (e.g., secondary settling ponds, recirculating holding ponds, polis hing ponds) are included within “wastewater treatment units” or “wastewater tr eatment systems.” This interpretation is reinforced by the note on p. D-1 of the ICR. 1

EPA’s definition of “pond/impoundment systems” is “a treatment system consisting of one or more ponds/impoundments.” Id. As we read these definitions, a pond/impoundment system is comprised solely of ponds or impoundments, and a “wastewater treatment system” is comprised of other types of treatment units and only primary settling ponds. Therefore, any treatment system that has, for instance, a clarif ier and any type of pond other than a primary settling pond, is not a “pond/impoundment system” and also is not a “wastewater treatment system.”

EPA should retain the definition of “pond/impou ndment system” but change the definition of “wastewater treatment system” to include a ny type of pond that occu rs within a treatment system with other types of un its. UWAG recommends that “wastewater treatment system” be defined as “a combination of one or more ‘wastewater treatment units,’ including ponds/impoundments, designed to achieve wastewat er treatment, except that ‘wastewater treatment system’ does not include systems in which ponds/impoundments are the only units.” The definition of “wastewater trea tment units” should be revised as follows: “a unit operation used to remove pollutants from process wastewater. Wastewater treatment units include, but are not limited to, ponds, chemical preci pitation, pH adjustment, clarif ication, biological reactor, thickeners, filters, and constructed wetlands.”

We urge EPA to revise these definitions and the instructions to Pa rt D and provide UWAG with an opportunity to review the revised texts. Otherwise, ma ny respondents are likely to be confused and unable to provide the information that EPA is seeking.

1 The note states: “If a settling pond/impoundment is part of a broader ‘wastewater treatment system’ containing non-pond units (e .g., a primary settling pond/impoundment unit in a bi ological wastewater tr eatment system), it is not considered part of a pond/impoundment system.”Mr. Ronald P. Jordan Page 3 February 1, 2010

II. The Definition of “Leachate” Should be Revised

EPA’s proposed definition of leachate is t oo broad. The definition in part provides “[l]iquid, including any suspended or dissolved cons tituents in the liquid . . . that pass through the containment structure (e.g., bottom, dikes, be rms) of a surface impoundment.” The definition specifically includes “the terms seepage, leak, and leakage, which are generally used in reference to leachate from an impoundment.” Under th is definition, EPA’s plans for leachate sampling under Part G of the questionnaire are very expansive. Apparently, it would require each seep from a surface impoundment (no matter how de minimis ) to be sampled if the seep occurred during the sampling period set by the Questionnaire.

UWAG recommends that the definition of “leachate” be limited to drainage from landfills, as indicated in Attachment A. If EPA persists w ith plans to sample “leachate” from surface impoundments, it will be an incredibly bu rdensome task to characterize a very minor flow. EPA says it plans to require 175 facilities to respond to Part G, and anticipates only about 50 plants “actually operate leach ate collection systems and theref ore would collect and analyze wastewater samples.” Supporting Statement, p. 2- 2 (footnote b to Table 2-1). This is a gross underestimation due to the broad definition of leachate . It is more likely that all - or almost all - of the 175 facilities required to fill out Part G wi ll have to collect samples, and some of them will have to collect samples at multiple sites.

Many surface impoundments include toe drains, relie f wells, or similar drainage systems as part of overall structural integrity. These drains are used to enhance structural stability and to provide a controlled outlet for water to reduce th e potential for internal erosion through or under the dam. There are many different types of dr ainage systems (including finger drains, chimney drains, blanket drains, trench drains, seepage berms, and relief wells). Many surface impoundments use a mix of different types of dr ainage systems. Some surface impoundments have more than 40 toe drains or drainage pipe s, all of which may, taken collectively, produce a very small flow rate of a few drops per minute to 10 gallons per minute. It is unjustifiable to require facilities to sample the many toe drains or drainage pipes from surface impoundments when the flows involved are minor and th e expense of sampling is significant.

For landfills with leachate collection systems, it may be possible to design an appropriate sampling procedure that is not overly burdensome. But the inclusion of any “leachate” sampling from surface impoundments would be overly burdensome.Mr. Ronald P. Jordan Page 4 February 1, 2010

III. Definition of “Plant” is Too Br oad and Imposes Additional Burdens

EPA proposes to define “Plant” as: “Inclu des all contiguous and non-adjoining property and equipment that is under opera tional control of the facility, including non- adjoining landfills, surface impoundments, and outfall structures.” Th is very broad definition will cause several problems for respondents. First, many facilities contain equipment and st ructures that are not owned by the plant operator, but ar e owned by other entities. For ex ample, as UWAG explained in its original comments, at some sites the plant operat or is in charge of units that are owned in their entirety by unrelated corporati ons or groups of entities. The plant operator may oversee all operations related to the unit, but the operator usually does not have ac cess to the financial information for the unit. This is particularly th e case when a unit on the f acility grounds is owned by an unregulated entity. In that instance, ther e are often legal barriers to sharing information between the regulated power plant operator and th e unregulated owner of the unit. The proposed definition of “Plant” as including all “property an d equipment under the operational control of the facility” would apparently make the plant opera tor responsible for repo rting on the unit it is operating, but does not own, but because of financ ial restriction, the pl ant operator cannot be responsible for collecting some of the types of information EPA is requesting. Therefore, the plant operator is in an untenable positi on – it cannot legally obtain the information that EPA is requiring.

Also, including all non-adjoining property under th e control of the facil ity as part of the “Plant” creates unique burdens in some cases. Some plants control off-site landfills that may be many miles away from the facility. In some cas es, these off-site landf ills are owned by other entities, but remain under the contro l of the facility. In such situ ations, the facility receiving the Questionnaire incurs the burdens of gathering information about an off- site facility that is distant from the facility and may be dependent on the off- site operator to supply the necessary information for the questionnaire.

For these reasons, UWAG recommends that th e definition of “Plant” be revised in two ways. First, it should exclude a ny on-site or off-site equipment, structures, or parcels owned by entities other than the questionnaire recipi ent. Second, non-adjoin ing landfills, surface impoundments, and outfall structures should not be included within the definition unless they are owned by the facility and dire ctly used by the facility.

IV. EPA Should Use Quantitation Levels fo r Data Reporting and the Glossary Should Include a Definition of “Quantitation Level”

The Questionnaire requires repo rting of existing FGD metals data as less than the detection limit (question B3-3). UWAG reco mmends that EPA collect only data above the appropriate quantitation level (QL) (also known as method reporting limit (MRL), minimumMr. Ronald P. Jordan Page 5 February 1, 2010

level, method quantification level (MQL), or lim it of quantitation). Data below the QL are highly variable and are not reliable for complia nce monitoring and therefore should not be included in EPA’s re gulatory effort.

Most existing data sets are almost certai nly reported by laboratories using instrument detection limits (IDL) determined by replicate anal yses of an ideal dilute acid reagent blank or dilution of a low calibration standa rd. IDL’s serve as a guide of instrument (method) sensitivity. However, the actual method detec tion limits (MDLs) are sample ma trix dependent and may vary as the sample matrix varies. This situation is particularly true for complex, elevated TDS FGD wastewaters where the true matrix-specific MDL is likely several fold higher than the IDL. Very few, if any, laboratories have matrix-s pecific MDLs on FGD wastewaters.

EPA should not request data that are less than the QL. Even though QLs are derived from IDLs, the use of QLs will lessen the chance of reporting inaccurate data. In addition, some laboratories report existing data as less than th e Practical Quantitation Limit (PQL) which has been approved for compliance monitoring in some states. Because FGD wastewater may require dilution to lower the TDS levels prior to analysis by Method 200.8, the sample-specific quantitation limit is the most appropriate level to use when reporting data. The sample-specific quantitation limit is the appropriate QL for a uni que sample multiplied by the total dilution from the original sample at which a unique sample was quantified.

EPA should also request any si gnificant modifications to th e standard EPA method used to obtain the existing metals data in FGD wastewaters. For exampl e, if a respondent is reporting data obtained using a standard inductively coup led plasma-mass spectrometry (ICP-MS) method incorporating an interference control technology such as a dy namic reaction cell (DRC) or collision cell (CRC), then the modification shoul d be provided in the Questionnaire response. For example, EPA Method 200.8 modified for CRC-IC P-MS using helium as the cell gas for all metals except selenium where hydrogen is used as the cell gas.

The Questionnaire requests that the nominal quan titation limit stipulated for the standard EPA method employed should be used to calculat e the sample-specific quantitation limit. For many methods (e.g., EPA 200.7 and EPA 200.8), no nomi nal QL is given in the method. Again, the Questionnaire should request the sample-specific quantitati on limit based on the laboratory’s QL. For example, if the appropriate QL is 5 ppb and the sample was diluted 10 fold prior to being analyzed, then the sample specific quant itation limit would be 50 ppb (i.e., 5 x 10).

This methodology for reporting data should apply to any new data required by EPA, such as the leachate data in Part G.Mr. Ronald P. Jordan Page 6 February 1, 2010

In addition, UWAG recommends the following definition for “quantitation level”:

The lowest concentration at which the entire analytical system gives a recognizable signal and acceptable calibration point (see EPA method 1638 section 18.26). The MRL can be calculated by multiplying laboratory-determined MDL by 3.18 and rounding result to nearest multiple of 1, 2, 5, 10, etc. in accordance with procedures used by EAD and described in EPA Draft National Guidance for the Permitting, Monitoring, and Enforcement of Water Quality-Based Effluent Li mitations Set Below Analytical Detection/Quantitation Levels , March 22, 1994 (see EPA method 1638 page 39).

V. Definitions of Air He ater Cleaning Wash Water, Boiler Fireside Cleaning Wash Water, and Boiler Tube Cleaning Wash Water Should be Revised

EPA proposes to define air he ater cleaning wash water as “Any water or cleaning solution used for or generated from cleaning the air heater.” This definition – and the similar definitions for boiler fireside cleaning wash water and boile r tube cleaning wash water – blur the current distinction in 40 CFR Part 423 between metal clean ing wastes and chemical metal cleaning wastes by not distinguishing between wate r-only rinses and rinses that mix water and chemicals. EPA should be careful to gather information in a mann er that allows it to distinguish between water used by itself for cleaning purposes and water used with other substances to clean. By mandating that air heater cleaning wash wa ter includes both water-only rinses and water and chemical rinses, EPA is likely to gather data in a way which lumps the two types of cleaning together. This is not appropriate, as the water quality of the two types of cleaning wash waters will be different. For example, water-only rinses may be appropriate for reuse or recycling, but EPA will not be able to evaluate possible reuses if it combines water-onl y rinses and chemical rinses into the same category.

VI. Glossary Includes Terms that Are Not Found Within the Questionnaire

The glossary includes some terms that do not appear in the version of the Questionnaire that was released for public comment in October 2009. It is difficult to assess the appropriateness of a defined term for purposes of the Questionnair e when we do not know the context in which the term will be used. The new terms included in the glossary but not appearing in the October version of the Questionnaire incl ude: carbon capture wastewater, cost of service, floor drain wastewater, gypsum pile, SCR catalyst wa shing, and uncontaminated stormwater.Mr. Ronald P. Jordan Page 7 February 1, 2010

Based on these new terms, it appears that EPA is making some significant changes to the Questionnaire. UWAG urges EPA to provide it with an additional opportunity to review the full Questionnaire before it is sent to the Office of Management and Budge t. We believe such a review would be mutually beneficial, and is warranted due to the complex ity of the Questionnaire and its importance to the overall rulemaking.

VII. FGD Terminology, Revised Figure B-1, and New Figure B-2

UWAG has reviewed EPA’s revised FGD term inology and the new Figure B-1. In the attachment, UWAG has provided so me recommendations for revisions to the FGD terms. We believe the revised terms will be clearer to a ma jority of industry personnel than the terms EPA proposed. We have also revise d Figure B-1, which illustrates a typical FGD scrubber system (Attachment B) and have provided new Figure B-2, which illustrates a single pass scrubber system.

VIII. EPA Has Failed to Define Some Key Terms

In its original comments, UWAG listed many ke y terms that would benefit from definition and would improve the clarity of the Questionnaire for respondents. Some of the terms remain undefined by the new glossary. Those terms include the following:

 byproducts

 storage

 disposal

 permanently

 temporarily

 closed

 retired

 idle

 extended period of time

 normal operation

 Eastern bituminous/western bituminous

 mechanically aided

 residence time

 episode

We reiterate that these terms shoul d be clarified with proper defin itions. To illustrate the problem of leaving these terms undefined, respondent s will have no way of knowing what EPA meansMr. Ronald P. Jordan Page 8 February 1, 2010

when it requires respondents to “provide information for all steam electric generating units which were operated in 2009, including systems which have been idle for an extended period of time .” Questionnaire, p. A-24 (emphasis added). UWAG ur ges EPA to clarify all of these terms and to provide UWAG with an adequate opportunity to review the new definitions.

Additionally, EPA has bolded some terms in the glossary without providing definitions (see, e.g., “byproducts” within the definition of “non-contact cooling water,” “surface waters” within the definition of “NPDES permit,” and “disposal” within the definition of zero discharge). If EPA is preparing definitions for these terms, please provide them to UWAG as soon as possible for our review.

Please see Attachment A for additional comments on individual definitions, and Attachments B and C for diagrams illustra ting two types of FGD scrubber systems.

UWAG would be glad to meet with EPA to explor e these issues in more detail. Please call me if you have any questions about these comments.

Very truly yours,

Donna B. Hill Chair, Effluent Guidelines Committee AttachmentsAttachment A

EPA Definition UWAG Comment
Aerobic biological reactor – A tank in which material is converted from an unwanted form into a desired form by microorganisms in the presence of free oxygen. UWAG recommends rewording the definition as follows: “A tank in which material is converted from one form into another form by microorganisms in the presence of free oxygen.”
Air heater cleaning wash water – Any water or liquid cleaning solution used for or generated from cleaning the air heater. See discussion above.

Anaerobic biological reactor – A tank in which material is converted from an unwanted form into a desired form by microorganisms not in the presence of free oxygen. UWAG recommends rewording the definition as follows: “A tank in which material is converted from one form into another form by microorganisms not in the presence of free oxygen.”
Background concentration

– The concentration of a substance in an environmental media (air, water, or soil) that occurs naturally or is not the result of human activities. UWAG recommends rewording the definition as follows: “The concentration of a substance in an environmental media (air, water, or soil) that is not associated with plant processes or activities.”
This rewording is necessary for consistency in how background concen trations in intake water are treated under Clean Water Act regulations. See, e.g., 40 CFR 122.45(g).

Base load unit – A unit normally operated to produce electricity at an e ssentially constant rate and runs continuously. Reword the definition as follows: “A unit normally operated to produce electricity at an essentially constant rate and which typically runs for extended periods of time .”
Boiler fireside cleaning wash water – Any water or liquid cleaning solution used for or generated from cleaning the boiler fireside. See discussion above.

Boiler tube cleaning wash water – Any water or liquid cleaning solution used for or generated from cleaning the boiler tubes. See discussion above.
Reword the definition as follows: “Any water or liquid cleaning solution used for or generated from cleaning the interior surface of

boiler tubes.”2 EPA Definition UWAG Comment

Bottom ash – The heavier ash particles that are not carried out of the boi ler with the flue gas, and which settle in the furnace or are dislodged from furnace walls. Includes boiler slag collected in wet-bottom furnaces. Economizer ash is included when it is collected with bottom ash. This definition should be consistent with the current definition of “bottom ash” within 40 CFR § 423.11: “The term bottom ash means the ash that drops out of the furnace gas stream in the furnace and in the economizer sections. Economizer ash is included when it is collected with bottom ash.”

Unless this definition is consistent with the common industry-specific definition, EPA is likely to find that recipients provide

erroneous answers. Carbon capture system – An air pollution control system intended to reduce emissions of carbon dioxide. Includes both post-combustion and pre-combustion carbon capture/reduction technologies. Replace the definition with the following: “An air pollution control system that removes carbon dioxide from a manufacturing or power generation process for beneficial reuse (i.e., enhanced oil recovery, food processing, chemical manufacturing) or for permanent storage. Capture systems include post-combustion, pre-combustion, and oxy-fired combustion.”
Chemical precipitation/flocculation

– Process involving the addition of chemicals to alter the physical state of dissolved and suspended solids and facilitate their removal by sedimentation. There should be separate definitions for chemical precipitation and flocculation. The definition of chemical precipitation should be reworded as follows: “Process involving the addition of chem icals to alter the physical state of dissolved and suspended solids and facilitate their removal by sedimentation or filtration .”

See definition for flocculation below.

Clarification

– A sedimentation process to remove solid particles from a liquid stream by gravitational force. Reword the definition as follows: “A sedimentation process to remove solid particles from a liquid stream usually by gravitational force.”
Coal pile runoff – The runoff from or through any coal storage pile. Revise the definition to be identical to the current Part 423 definition: “The rainfall runoff from or through any coal storage pile.”3 EPA Definition UWAG Comment
Coal washing – Coal washing, also known as coal cleaning, entails separating out foreign material from coal in a liquid medium and may also include processes to remove ash, sulfur and moisture. The liquid medium may be combined with finely ground heavier minerals, such as magnetite, in a dense medium fluid, better to effect separation of unw anted rock and mineral matter from coal particles. Reword the definition as follows: Coal washing, also known as coal cleaning, entails separating out foreign material from coal in a liquid medium and may also include processes to remove ash, sulfur and moisture. The liquid medium may be combined with finely ground heavier minerals, such as magnetite, in a dense medium fluid, to achieve better separation of unwanted rock and mineral matter from coal particles
Cogeneration plant – A plant that produces electricity and another form of useful thermal energy (such as heat or steam), used for industrial, commercial , heating, or cooling
purposes. UWAG recommends revising the definition as follows: “A generating facility, otherwise known as a combined heat and power plant , that produces electricity and another form of useful thermal energy (such as heat or steam), used for industrial, commercial, heating, or cooling purposes.”

Cost of service – A ratemaking concept used for the design and development of rate schedules to ensure that the filed rate schedules recover only the cost of providing the electric service at issue . This concept attempts to correlate the utility ’s costs and revenue with the service provided to each of the various customer classes. This definition is not in the published version of the ICR. UWAG cannot adequately comment on the definition without seeing it used in context.
UWAG believes the following definition is better than the EPA definition, but again the appropriateness of the definition will depend on its usage:
“The total costs incurred by a company in providing utility services, and which usually refers to annual costs unless otherwise specified. This amount, which consists of estimated operating expenses, depreciation, taxes, a return on the rate base (investment), and possibly other costs, is used to design and establish regulated ‘cost-based’ rates.”
Cycling unit – A unit used in a constant and specific cycle. For example, a unit that runs daily, but reduces capacity or shuts off at night would be a cycling unit. Reword definition as follows: A unit for which operation is un dulated through a generally routine cycle. For example, a cycling unit may run daily, but reduce capacity or shut off at night.

Detection limit – The minimum result which See disc ussion above regarding the use of4 EPA Definition UWAG Comment can be reliably discriminated from a blank (for example, with a 99% confidence level). Quantitation Levels.
Replace the definition with the definition of Method Detection Limit (MDL) from 40 CFR Part 136.2(f): “The minimum concentration of an analyte (substance) that can be measured and reported with a 99% confidence that the analyte concentration is greater than zero as determined by the procedure set forth in Appendix B of Part 136.”
Discharge – The conveyance of process wastewater to: (1) surface waters ; or (2) a publicly owned, privately owned, federally owned, combined, or other treatment works. The definition should be identical to the definition of “discharge” set forth in the Clean Water Act regulations. See 40 CFR 122.2.
Dry FGD system – Dry FGD system, also referred to as semi-dry FGD system, captures sulfur dioxide from flue gas by a spray dryer absorption process that produces calcium sulfite with low moisture content. Reword definition as follows: “Dry FGD system, also referred to as semi-dry FGD system, captures sulfur dioxide from flue gas by a spray dryer absorption process that produces calcium sulfite with low moisture
content.
FGD scrubber purge – Process wastewater that exits an FGD scr ubber system (typically from a solids separation process) and that is transferred to a wastewater treatment system or discharged . Note: The scrubber purge stream may be the same as the FGD slurry blowdown stream if the plant does not operate a solids separation system prior to wastewater
treatment. FGD scrubber purge – As depicted in Figure B-1

, process wastewater that exits an FGD scrubber system (typically from a solids dewatering process such as hydroclone overflow ) and that is transferred
to a wastewater treatment system or discharged . Note: The scrubber purge stream may be the same as the FGD slurry blowdown stream if the plant does not operate a solids dewatering system prior to
wastewater treatment.
FGD slurry blowdown – Slurry water that exits an FGD scrubber absorber to control the solids/chlorides levels in the FGD scrubber absorber . FGD slurry blowdown is typically transferred to a solids separation process. FGD slurry blowdown – As shown in Figure B-1 , slurry that exits an FGD scrubber absorber to control the concentration of suspended solids in the FGD scrubber absorber . FGD slurry blowdown is typically transferred to a solids dewatering process.5 EPA Definition UWAG Comment
FGD slurry preparation process water – Water used for the preparation of FGD slurry
water (e.g., water that is added to ball mills for limestone slurry preparation). FGD reagent preparation water – As shown in Figure B-1 , water used for the preparation of FGD reagent slurry (e.g., water that is added to ball mills for limestone slurry preparation).
FGD slurry water – All water that enters into, is used within, or recycles through the FGD scrubber absorber . FGD slurry water is replenished by make-up water and the solids level is controlled by FGD slurry blowdown

. FGD reagent slurry – As shown in Figure B-1 , slurry stream providing all of the reagent and a portion of the water to the FGD scrubber absorber.

FGD solids – Any solid material generated by the FGD scrubber system . This may also be called FGD sludge (e.g., calcium sulfite and calcium sulfate). FGD solids – As shown in Figure B-1 , any solid material generated by the FGD scrubber system . This may also be called FGD sludge (e.g., calcium sulfite and calcium sulfate).
FGD solids separation – The process that separates FGD slurry blowdown into two separate streams: the so lids-rich stream (i.e. underflow) that contains FGD solids and the solids-lean stream (i.e. overflow) that contains water and fines. FGD primary solids dewatering – As shown in Figure B-1 , the process that separates FGD slurry blowdown into two separate streams: the so lids-rich stream (i.e. underflow) that contains FGD solids and the solids-lean stream (i.e. overflow) that contains water and fines. Hydrocyclone (or hydroclone), thickener, settling pond, and gypsum stacking are examples of FGD primary solids dewatering

. FGD solids separation recycle – The FGD
wastewater that is returned to the FGD scrubber absorber following the FGD solids separation process. FGD reclaim water – As shown in Figure B-1 , the FGD wastewater from the solids dewatering process that is used as FGD Reagent Preparation Water or FGD scrubber purge

. Flocculation We recommend adding the following definition for floccula tion: “A process where colloids come out of suspension in the form of floc or flakes. The action differs from precipitation in that, prior to flocculation, colloids are merely suspended in a liquid and not actually dissolved in a solution.”6 EPA Definition UWAG Comment
Forced generator outage – The hours for any failure, misoperation, or malfunction that results in the immediate automatic or manual removal of a generating unit from connection to the transmission system, or that prevents such connection from being accomplished when desired. UWAG recommends changing the defined term to “forced generating unit outage.”

Reword the definition as follows: “The removal of a generator from the connection with the transmission grid, either automatically or manually , that has not been scheduled. These outages are usually the result of a mechanical failure of a critical component of the generating system.”
Gypsum wash water – Process wastewater generated during the solids dewatering operation or gypsum or gypsum solids. UWAG recommends changing the term to “cake wash water.”

Reword the definition as follows: “Water used to wash/displace dissolved solids from gypsum cake.”
Hydrocyclone or hydroclone - equipment used to separate solid s from slurry using centripetal force.
Independent power producer – A corporation, person, agency, authority, or other legal entity or instrumentality that owns or operates facilities for the generati on of electricity for use primarily by the public, and that is not a utility

. Replace the definition with the following:
“Also known as nonutility power producers, these facilities are wholesale electricity producers that operate within the franchised service territories of host utilities and are usually authorized to sell at market-based rates. Unlike traditional electric utilities, independent power producers do not possess transmission facilities or sell electricity in the retail market.”

This definition is based on the EIA definition of “independent power producer.”

Intermediate unit – A unit that not used in a constant and specific cycle. The unit is instead used more sporadically on an as needed basis when energy requirements are less than peak load but more than base load. Reword the definition to add the word “is” in the first line after “that.”

Leachate – Liquid, including any suspended or dissolved constituents in the liquid that has percolated through or dr ained from waste or other materials emplaced in a landfill , or that See discussion above.

Reword the definition as follows:
“Liquid, including any suspended or7 EPA Definition UWAG Comment pass through the containment structure (e.g., bottom, dikes, berms) of a surface impoundment. Leachate also includes the terms seepage, leak, and leakage, which are generally used in reference to leachate from an impoundment. dissolved constituents in the liquid, that has percolated through or dr ained from waste or other materials emplaced in a landfill .”

Nameplate capacity –The full-load continuous rating of a generator, prime mover, or other electric power production equipment under specific conditions as designated by the manufacturer. Installed generator nameplate rating is usually indicated on a nameplate physically attached to the generator. Reword the definition as follows: “The fullload continuous nominal rating of a generator, prime mover, or other electric power production equipment under specific conditions as designated by the manufacturer. Installed generator nameplate rating is usually indicated on a nameplate physically attached to the generator.”

Natural wetlands

– An area created naturally, not man-made, that is saturated by surface or ground water with vegeta tion adapted for life under those soil conditio ns, as swamps, bogs, fens, marshes, and estuaries. Reword the definition as follows: “A natural area (not man-ma de) that is saturated by surface or ground water with vegetation adapted for life under those soil conditions, as swamps, bogs, fens, marshes, and estuaries.”

NO x control system – An air pollution control system that removes NO x from air emissions. Types of NO x control systems include, but are not limited to, the following: selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR), overfire air, and low NO x burners. Reword the definition as follows: “An air pollution control system that prevents NOx formation during fuel combustion or removes NO x from flue gas . Types of NO x control systems include, but are not limited to, the following: selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR), overfire air, and low NO x burners.”
Peaking unit – A unit normally used only during peak-load periods of electricity demand. Reword the definition as follows: “A unit normally used only during peak-load periods of electricity demand, or as an example, needed to replace the loss of another unit .”
pH Adjustment

– Decreasing the acidity or alkalinity of a substance by adding alkaline or acidic materials, respectively. We recommend the definition be amended as follows: “Changing the acidity or alkalinity of a substance by adding alkaline or acidic materials.”8 EPA Definition UWAG Comment

Plant – Includes all contiguous and nonadjoining property and e quipment that is under operational control of the facility, including non-adjoining landfills, surface impoundments, and outfall structures. See discussion above.

Pond/impoundment – A natural topographic depression, man-made excavation, or diked area formed from earthen materials or man-made materials or a combination of them, which is designed to hold an accumulation of liquid process wastes or proces s wastes containing free liquids, and which is not an injection well. Examples of ponds/impoundments include holding, storage, settling, and aeration pits, ponds, and lagoons. We recommend that EPA clarify this definition to specify that it does not include building sumps and outdoor collection/transfer concrete basins.

Power marketers – Business entities engaged in buying and selling electricity. Power marketers do not usually own generating or transmission facilities. Power marketers, as opposed to brokers, take ownership of the electricity and are involved in interstate trade. These entities file w ith the Federal Energy Regulatory Commission (FE RC) for status as a power marketer. Reword the definition as follows: “Business entities engaged in buying and selling electricity. Power marketers do not usually own generating or transmission facilities. Power marketers, as opposed to brokers, take ownership of the electricity and may be involved in interstate trade. These entities file with the Federal Energy Regulatory Commission (FERC) for status as a power marketer.
Primary purpose – Provides the predominant source of revenue for the plant. The principal reason for which the plant operates. Reword the definition as follows: “The process or manufacturing activity that provides the predominant source of revenue for the plant. The principal reason for which the plant operates.”
Quantitation Level (A lso known as Method Reporting Limit, Minimum Level, Minimum Quantification Level (MQL) or Limit of Quantitation) The lowest concentration at which the entire analytical system gives a recognizable signal and acceptable calibration point (see EPA Method 1638 section 18.26). The MRL can be calculated by multiplying laboratory-determined MDL by 3.18 and rounding result to nearest multiple of 1, 2, 5, 10, etc. in accordance with procedures used by EAD and described in EPA Draft National Guidance for the Permitting, Monitoring, and Enforcement of Water9 EPA Definition UWAG Comment Quality-Based Effluent Limitations Set Below Analytical Detection/Quantitation Levels, March 22, 1994 (see EPA Method 1638 page 39).
Sample-specific Detection Limit The appropriate MDL for a unique sample multiplied by the total dilution from the original sample at which a given sample was analyzed. For example, if the appropriate MDL is 5 ppb and the sample was diluted 5% during sample digestion and then had to be diluted another 10 fold prior to being analyzed, then the sample specific detection limit would be 52.5 ppb (i.e., 5 x 1.05 x 10).
Sample-specific nominal Quantitation Limit The appropriate MQL for a unique sample multiplied by the total dilution from the original sample at which a unique sample was quantified. For example, if the appropriate MQL is 20 ppb and the sample was diluted 5% during sample digestion and then had to be dilute d another 10 fold prior to being analyzed (quantified), then the sample specific quantitation limit would be 210 ppb (i.e., (20 x 1.05 x 10).
Scheduled generator outage – The hours during which the generati ng unit is offline due to planned, scheduled repairs, maintenance, or upgrades, such as routine repetitive maintenance and repair that have be en programmed into the power schedule. UWAG recommends changing the defined term to “scheduled generating unit outage.”

Single-pass scrubber - a scrubber designed such that there is no r ecycle of slurry to the absorber. See Figure B-2.
Solids dewatering – The process that removes water from the solids-rich stream generated in the solids separation process. Typically a vacuum belt filter or a vacuum drum filter is used in this process. FGD solids such as gypsum are produced by this process. UWAG recommends changing the defined term to “FGD secondary solids dewatering.”

Reword the definition as follows: As depicted in Figure B-1 , the process that removes water from the solids-rich stream generated in the primary dewatering process. Typically, a vacuum belt filter or vacuum drum filter is used in this process.10 EPA Definition UWAG Comment
FGD solids such as gypsum are produced by this process. A wet FGD system may not have a secondary solids dewatering system.
Utility – Any entity that generates, transmits, or distributes electricity and recovers the cost of its generation, transmission or distribution assets and operations, either di rectly or indirectly, through cost-based rates set by a separate regulatory authority (e.g., State Public Service Commission), or is ow ned by a governmental unit or the consumers that the entity serves.Examples of these entities include: investorowned entities, public power districts, public utility districts, munici palities, rural electric cooperatives, and State a nd Federal agencies. Electric utilities may have Federal Energy Regulatory Commi ssion approval for interconnection agreements and wholesale trade tariffs covering either cost-of-service and/or market-based rates under the authority of the Federal Power Act. The term should be “ele ctric utility” rather than “utility.”

Vacuum drum filter – A system that consists of a tank containing a rotating drum covered with a cloth filter. A vacuum is used to pull water through the cloth filter to dewater the solids. Also referred to as a rotary drum filter. Revise the definition as follows: “A solids dewatering system that consists of a tank containing a rotating drum covered with a cloth filter. A vacuum is used to pull water through the cloth filter to dewater the solids. Also referred to as a rotary drum filter.”

Vacuum filter belt – A system that uses a vacuum to remove water by pulling it through a revolving filter belt. Revise the definition as follows: “A solids dewatering system that uses a vacuum to remove water from solids by pulling it through a revolving filter belt.”

Variable O&M costs – Operation and maintenance costs that vary directly in proportion to the amount of electricity generated by a plant. As UWAG originally commented, there are several possible ways to calculate variable O&M costs. The definition provides no guidance on the calculation. EPA needs to specify which variable O&M calculation should be used to ensure consistency of information.

Waste coal – Usable material that is a byproduct of previous coal processing operations. Waste coal is usually composed of Reword the definition as follows: “Usable material that is a byprod uct of previous coal processing operations. It is also known as11 EPA Definition UWAG Comment mixed coal, soil, and rock (mine waste). Most waste coal is burned as-is in unconventional fluidized-bed combustors. For some uses, waste coal may be partially cleaned by removing some extraneous noncombustible constituents. Examples of waste coal include fine coal, coal obtained from a refuse bank or slurry dam, anthracite culm, bituminous gob, and lignite
waste. mixed or secondary coal . Waste coal is usually composed of mixed coal, soil, and rock (mine waste). Most waste coal is burned as-is in unconventional fluidized-bed combustors. For some uses, waste coal may be partially cleaned by removing some extraneous noncombustible constituents. Examples of waste coal include fine coal, coal obtained from a refuse bank or slurry dam, anthracite culm, bituminous gob, and lignite waste.

Wastewater treatment unit – A unit operation used to remove pollutants from process wastewater. Wastewat er treatment units include, but are not limited to, primary settling ponds, chemical precipitation

, pH adjustment, clarification, biological reactor, thickeners, filters, and constructed wetlands. Revise the definition as follows: “A unit operation used to remove pollutants from process wastewater. Wastewater treatment units include, but ar e not limited to, ponds, chemical precipitation, pH adjustment, clarification, biological reactor, thickeners, filters, and constructed wetlands.”
Wastewater treatment system – A combination of one or more wastewater treatment units , other than ponds/impoundments, designed to achieve
wastewater treatment

. Revise the definition as follows: “A combination of one or more ‘ wastewater treatment units ,’ including ponds/ impoundments, designed to achieve
wastewater treatment , except that ‘wastewater treatment system’ does not include systems in which ponds/ impoundments are the only units.” In the Questionnaire, information is collected separately (see Part D, section 3) for wastewater treatment systems that include only pond/impoundment units.
Zero discharge – Disposal of process and/or

non- process wastewaters other than by direct discharge to surface water or by indirect discharge to a POTW . Examples include evaporation

, deep-well injection , hauling, and/or offsite recycle/ recovery

. Reword the definition as follows: “Disposal of process and/or non- process wastewaters other than by direct discharge
to surface water or by indirect discharge to

a POTW . Examples include evaporation

, deep-well injection , hauling, and/or onsite /offsite recycle/ recovery

.Attachment BAttachment CFigure B-2Single Pass ScrubberFGDReagentPreparationFGDScrubberAbsorberAbsorberMakeupWaterScrubbedFlueGastoStackFGDReagentPreparationWaterFGDReagentFlueGasInOxidationAir(ifnecessary)FGDSlurryDischargeToFGDWastewaterTreatmentSystemSinglePassScrubberFGDReagentSlurry