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Frequent Questions on Survey of Surface Impoundments

Note: EPA no longer updates this information, but it may be useful as a reference or resource.



Q: How many facilities received the Survey of Surface Impoundments?

A: EPA mailed the survey to 215 facilities.

Q: Can I get a list of the 215 facilities that received the survey?

A: A list of the facilities that received the surface impoundment study is no longer available.

Q: What items did each facility receive?

A: Each facility received at least one large envelope, with a hard copy of their signature page, an instruction book, Section A, Section B, at least one copy of Section C, and 4 Appendices. If they had requested an electronic version on their screener survey, they got a diskette. Some facilities with several surface impoundments got additional envelopes with extra copies of Section C.

Most facilities (195 of 215) also received a mailing tube containing the topographic map needed for Section B. In addition, about 100 facilities received a wastewater flow diagram, in the mailing tube, along with the topo map. (A small number of facilities received the wastewater flow diagram but no topo map, or no mail tube at all.)

Q: What items need to be provided to EPA in order to complete the survey?

A: Return the completed signature page, Section A, Section B, and all copies of Section C, the annotated topographic map, the wastewater flow diagram, and sketches from Sections B and C. You can provide all responses on the 3.5" personal computer diskette, except for the map, wastewater flow diagram and sketches and the signature page.

Q: Why did EPA pick my facility to get the survey?

A: EPA picked most of the facilities (direct dischargers and zero dischargers) as a random sample. The factors that influenced whether your facility was chosen had to do with: 1) whether your facility is a direct or a zero discharger; 2) whether you answered in the first survey that you placed "decharacterized" waste in a surface impoundment at your facility, and 3) what industry sector you reported in the first survey. The facilities who are indirect dischargers were not selected randomly. Those facilities were chosen based on their geographic location and their industry sector.

Q: On the front page of the instructions booklet it says the average amount of time it will take to fill out this survey is 90.5 hours. Is this how long EPA thinks it will take my facility to complete this survey?

A: The estimate of how much time it will take is an average, based on a facility with 2.5 surface impoundments. EPA does expect that the survey will take more time than 90.5 hours,for facilities with numerous surface impoundments.

Q: Where should I send my completed survey?

A: If your response does not contain confidential business information (CBI), send it to:

For U.S. Mail:

Attn: E. Darden Research Triangle Institute P.O. Box 12194 Research Triangle Park, NC 27709-2194

For private overnight delivery service:

Attn: E. Darden Research Triangle Institute 3040 Cornwallis Road Hobbs Building Research Triangle Park, NC 27709

If your response contains CBI, send it to:

For U.S. Mail:

Regina Magbie Mail Code 5305W U.S. Environmental Protection Agency Office of Solid Waste, OSW (renamed Office of Resource Conservation and Recovery, ORCR, on January 18, 2009) 401 M Street, SW

Washington, DC 20460

For private overnight delivery service:

Regina Magbie Room 7-W16 U.S. Environmental Protection Agency Office of Solid Waste, OSW (renamed Office of Resource Conservation and Recovery, ORCR, on January 18, 2009) 2800 Crystal Drive Arlington, VA 22202

Q: What is EPA going to do with all of this information?

A: EPA is required by law and consent decree to assess risks to humans and the environment from certain wastes (the Land Disposal Program Flexibility Act of 1996, and Environmental Defense Fund vs. Browner et al., Civ. No. 89-0598). To fulfill these requirements, EPA chose to develop a nationally representative sample of facilities managing their wastes in surface impoundments. For this nationally representative sample, EPA is collecting publicly available data, samples of wastewaters and sludges in impoundments at these facilities, and these survey data to develop descriptive statistics (national profiles) of waste management practices. For example, the national profile of surface impoundments designed or operated with a given feature will help EPA in estimating the probability that a particular harmful outcome could occur. EPA also plans to use these survey data as inputs to mathematical models to assess the probability of risks to humans and the environment. If EPA estimates that risks exist at levels of concern, and that existing regulatory requirements do not address those risks, then EPA may develop federal regulations to address those risks.

Q: Is my facility's Surface Impoundments Survey still going to be of use if many of my answers are 'don't know'?

A: Yes, because whatever answers you do provide will help EPA to understand your facility better. When you don't provide information, EPA will generally try to obtain information from public data sources (such as wastewater discharge permits), for your specific facility. However, when there are no public data sources for the information items we need for your facility, EPA may then turn to regional or national databases and estimate values for the data items you have left incomplete or not answered.

Q: Who must sign the certification page on the survey?

A: A senior official having authority over plant operations must sign and date the certification page of the survey. A consultant or other third party may not sign the certification.

Q: Are small businesses required to complete the survey or is there some type of exemption for small businesses?

A: There is no exemption from the requirement to complete the survey. However, in order to be flexible, EPA will consider granting extensions of the 90-day survey completion deadline received from small businesses (e.g., facilities with fewer than 15 employees at the site), who believe that the 90-day deadline would constitute a hardship. Those small business should contact Shannon Sturgeon at (703) 605-0509 for information on requesting an extension.

Q: Am I required to use International (Metric) System measurement units (e.g., meters, liters, and grams) or U.S. Customary System units?

A: You may use any system of units in reporting the requested values. However, you must specify units of measurement for reported values, and if you choose to report values in an unusual system or one that requires complex conversions, EPA may contact you later to clarify your response.

Q: Was there a specific reason why EPA did not ask the survey respondents to indicate which responses are based on estimates (other than for waste characteristics)?

A: No specific reason. If you wish to annotate other responses with an "E" EPA will interpret those annotated responses as being estimates.

Q: How can a facility get an electronic copy of the survey?

A: The facility may contact EPA at (703) 308-8447.

Q: Can I send my electronic version to EPA by e-mail?

A: No, it must be sent on diskette.

Q: Is EPA going to download the electronic survey responses directly into a database?

A: No. For a one-time reporting requirement such as this survey, and the number of facilities who will be submitting it, it is more cost-effective for EPA to simply key-enter the data in the same manner as if you had submitted your paper copy.

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Q: I'm going to need more than 90 days to complete this survey.

A: EPA needs the data from your survey in order to meet its statutory and consent decree deadlines for completing the study (both in March 2001). You may, however, request a time extension by calling Shannon Sturgeon of EPA at (703) 605-0509. EPA will only grant extensions where the requestor provides adequate grounds for needing additional time. For example, an extension will likely be granted where the requestor has only a small number of employees or where the requestor has made every effort to complete the survey by the deadline but finds that a few data items will take longer to complete. In the latter case, if EPA grants your extension for a few data items, you will still be expected to submit the balance of the required information by the 90-day deadline. If you request a time extension, but EPA finds that your grounds are inadequate, failure to submit your survey by the deadline will subject you to possible enforcement action by the Agency.

Q: When will you know which facilities you're going to choose to take wastewater and sludge samples?

A: EPA expects to make the final selection of facilities for the wastewater and sludge sampling in February 2000 (once these surveys are returned).

Q: When will you be doing the wastewater and sludge sampling?

A: April through June, 2000.

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Q: We have a tank that's partially in the ground. We've always called it a tank, because it's made out of concrete. Are we supposed to consider it to be a surface impoundment?

A: If you excavated the surrounding soil, filled it up with the waste it usually holds, and it can support itself structurally, EPA would consider it to be a tank and not a surface impoundment. However, if you excavated the surrounding soil and filled it up with waste, and it cannot support itself structurally, EPA would consider it to be a surface impoundment.

Q: Please clarify whether, for purposes of the survey, a tank-like structure that does not have a lined bottom (such as a primary clarifier with an earthen bottom) is considered a surface impoundment.

A: The starting point for this interpretation would be the Land Disposal Program Flexibility Act, Section 2, which twice mentions "land-based units" in its description of the kinds of waste management units on which this particular legislation was focusing. A unit with an earthen bottom would clearly be a "land-based unit." From that starting point, moving to the definition in the screening survey, "...natural topographic depression, artificial excavation, or dike arrangement for storing, treating, or disposing of wastewater...." virtually all such tank-like structures would be placed into or on either a natural topographic depression, or (more likely) into an artificially excavated area. So, even if this unit is able to support itself structurally, our interpretation would be that it is a surface impoundment under the definition in the screening survey.

Q: Can respondents use the list of "out of scope" surface impoundments included in the draft survey questionnaire to determine about which surface impoundments EPA desires information?

A: If you mean the February 9, 1998 draft screening survey, no. That list of "out of scope" impoundments derived from a study that EPA and the states performed in the late 1970s. It includes several types of devices which would not meet the screening survey definition of surface impoundment at all, because they do not manage wastewater (e.g., swimming pools and rice paddies), plus other units that would meet the screening survey definition of a surface impoundment (e.g., an artificial excavation lined with concrete, but which cannot support itself structurally without the surrounding soil). We decided that using this list of "out of scope" impoundments in the screening survey would be too confusing, both because of the awkward question structure that would have been required, and the language excluding concrete-lined units, which sometimes meet the definition of surface impoundment in the final version of the screening survey that we used.

Q: Columns 2 and 3 on Table B-2 appear to include surface impoundments which are handling hazardous wastes (with pH <2 and >12.5) which we believe are not "in-scope" impoundments. Please clarify whether EPA intends to collect information on those impoundments. Shouldn't the survey read >3 and <11?

A: No, the survey should not read >3 and <11. It is worded correctly to meet our intentions. The first set of conditions to meet for having an "in-scope" surface impoundment is that you or someone else completed a screening questionnaire and indicated that there was at least one surface impoundment at the facility which received wastewaters on or after June 1, 1990, from one or more of nine kinds of activities (questions 9 and 10 on the main version of the screening questionnaire), and that at least one surface impoundment held only nonhazardous waste since June 1, 1990 (question 13 on the main version of the screening questionnaire). The second set of conditions to meet is in Question B2 of the long survey, where you list all nonhazardous waste surface impoundments in Table B2. You then apply additional criteria to determine whether your nonhazardous waste surface impoundments are in-scope. A "Yes" answer to any of the three means the impoundment is in-scope: 1) pH below 3 (30 day average basis) 2) pH above 11 (30 day average basis) or 3) Presence of one or more Appendix 2 chemical constituents. Although it is true that a surface impoundment that holds waste with a pH of 2 or less, or that holds waste with a pH of 12.5 or more, contains hazardous waste, you ordinarily would not be reporting that surface impoundment in Table B2 because that surface impoundment holds hazardous waste and should be identified in your RCRA permit or permit application.

Q: We have a surface impoundment that held hazardous waste after June 1, 1990 (we got our delisting petition approved in 1996 and since then it has been considered nonhazardous waste). Is this surface impoundment in-scope?

A: Yes. Evaluate the regulatory status of the waste in the surface impoundment on the date you received the questionnaire, and make the scoping determination based on its status on that date. If, on that date, the waste is classified as hazardous under the federal Resource Conservation and Recovery Act regulations, the surface impoundment would be out of scope for the study. However, if the waste is nonhazardous, the surface impoundment would be in-scope.

Q: We have a surface impoundment that held non-hazardous waste after June 1, 1990, but then the XYZ listing went into effect in 1997 and now the waste is hazardous waste. Is this surface impoundment in-scope?

A: No. Because it held hazardous waste on the date you received your survey, it is not in-scope for this study.

Q: We have a surface impoundment that held hazardous waste back in the 1980s, but we got our delisting petition approved and the delisting went into effect in March 1990. Is this surface impoundment in-scope?

A: Yes. Because it held non-hazardous waste on the day you received this questionnaire, it is in-scope.

Q: How should I determine whether or not my surface impoundments are in-scope?

A: Surface impoundments receiving non-hazardous wastewater that have a 30 day average pH less than 3 or greater than 11, or that contain any chemical constituents from Appendix 2 are considered in-scope impoundments. These criteria are outlined in the survey in Table B2: Determination of In-Scope Surface Impoundments. To compute average pH readings, you will need to convert the pH reading into the hydrogen ion concentration, average the hydrogen ion concentration, and then convert the average hydrogen ion concentration back into a pH reading.

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Q: Are you going to sample wastewaters at my facility?

A: EPA will review the survey responses before making a final selection of facilities for wastewater and sludge sampling (which we're calling "field sampling"). Generally, EPA will weigh the completeness of the data in Questions C22-C24 in assessing whether to sample at a given facility - the more data in the Question C22-C24 responses, the lower the likelihood that EPA will select that particular facility for verification sampling.

Q: What's the purpose of EPA doing wastewater sampling?

A: At selected facilities, EPA is planning to perform sampling of wastewater, sludge within in-scope impoundments, and possibly air immediately above in-scope impoundments, in order to verify the data submitted by the facility. At one or more facilities, EPA may also collect samples for the purpose of performing initial accuracy checks of the source term code of the mathematical fate and transport model that will be used in the risk assessment.

Q: If my facility gets chosen for field sampling, what exactly would EPA sample?

A: At facilities with only one in-scope impoundment, EPA would sample: influent wastewater, from all influent points; effluent wastewater; wastewater within the impoundment; sludge (if any) within the impoundment; and possibly limited air sampling. At facilities with more than one in-scope impoundment, EPA would assess the specific sampling points and might sample only from the first influent point, last effluent, and several within-the-impoundment points in a treatment "train." EPA would not run complete checks for all chemicals listed in Appendix 2; instead, EPA would develop a specific list of analytes tailored for the particular facility being sampled.

Q: What are my facility's chances of being field sampled?

A: EPA expects to field sample at several facilities, and anticipates selecting one facility for each major industry that received the survey. For the industries whose wastes are more homogeneous, how representative your facility's processes are for your entire industry would weigh in the selection, as well as how much data you supplied in your answers to Questions C22-C24. For the industries whose wastes are heterogeneous, it will be more difficult to select one facility as "representing" the industry group as a whole, and thus the quantity of data supplied for Questions C22-C24 would be the primary factor in EPA's selection process.

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Q: Who may be listed as "facility personnel that can be contacted to verify the results of the survey" (survey question A4)?

A: List someone with knowledge of the entire survey's contents (or as many people as are knowledgeable about different parts). You may list a contractor or a consultant.

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Q: What should I do if the wastewater diagram EPA sent is incorrect?

A: If the wastewater diagram is not correct, either annotate the diagram to correct it, or provide a new diagram that is accurate.

Q: Are there any threshold levels for determining the chemical constituents in an impoundment in order to complete table B-2?

A: There is no threshold limit. For completeness, EPA is interested in knowing about any quantities of the Appendix 2 chemicals that you reasonably expect to be present in the impoundment, based on your knowledge of the chemicals in use or produced at your facility. Complete Table B2 for Appendix 2 chemicals that you reasonably expect to be present, even if the chemical is present simply because of naturally occurring background levels in native soils or source water. You may annotate the survey to indicate the source of an Appendix 2 chemical if you know its source and the source is unrelated to your facility's activities.

Q: Question B3 requires facilities to identify all known groundwater supply wells within 2 kilometers of an in-scope surface impoundment. If a facility is located along a river, should the facility identify wells on the opposite side of the river?

A: The facility should identify all known wells within 2 kilometers of the surface impoundment, regardless of any water bodies between the facility and the well. The facility may provide additional notes about the location of the wells.

Q: On Question B3, why do you want us to mark where residences are?

A: To run our mathematical models of how chemicals move from your in-scope surface impoundments and affect nearby humans, we need to know the direction and distance the humans are in relation to the surface impoundments. Without your answers to Question B3, EPA would use U.S. Census Bureau data to infer where people live. However, those data would not be as precise, and the 1990 census data are now somewhat outdated.

Q: Survey question B3 requires the facility to identify with an "R" all known residences and schools that are not already depicted on the map and are located within 2 kilometers of the perimeter of any in-scope impoundments. Does each individual residence in a subdivision need to be labeled with an "R"?

A: No. For a subdivision that is shown on the topo map, you can draw a circle around the entire subdivision and label it with an "R" For a subdivision not shown on the topo map, use dots to represent individual residences, then circle the subdivision and label it with an "R."

Q: Survey question B3 requires the facility to identify with an "R" all known residences and schools that are not already depicted on the map and are located within 2 kilometers of the perimeter of any in-scope impoundments. What if I have apartment buildings or multifamily dwellings within 2 kilometers?

A: If multifamily dwellings are shown on the topo map, simply label them with an "R". For multifamily dwellings not shown on the topo map, use rectangles to represent the dwellings (for example, one rectangle to represent one apartment building). For multifamily dwellings that are grouped together, you can draw a circle around them and label the circle with an "R".

Q: Survey 6question B3 requires the facility to identify all known groundwater supply wells that are located within 2 kilometers of the perimeter of any in-scope impoundments. Is additional research required to determine whether there are any such groundwater supply wells?

A: No additional research is required. You are only required to provide information that is already available to you. However, you may elect to conduct specific analyses to obtain information that you do not currently have, in order to respond to the survey. EPA will also investigate other data sources (such as U.S. Geological Survey data) to infer the amount of groundwater use in the vicinity.

Q: Survey table B2 requests information on pH averages for each surface impoundment. Should answers to these questions be based on any specific time periods?

A: No, answers should be based on the entire time period that the surface impoundment was used for managing nonhazardous wastewater. For example, the facility should answer "yes" for question 2 if at any point the surface impoundment held wastewater with a 30-day average pH less than 3.

Q: Why are three NOAA stations listed in survey question B7 as being closest to the facility?

A: EPA has listed the NOAA stations that are nearest to the facility and that will be used as a means of estimating meteorological conditions at the facility. If you feel these stations will not provide a reliable estimate, provide an explanation in B7 and offer an alternative meteorological station.

Q: Survey questions B8-B12 require information on subsurface characteristics at the facility. If the facility has had a hydrogeologic evaluation completed previously, must they complete these questions?

A: If a hydrogeologic evaluation was performed at your facility, you may simply attach that evaluation to survey section B. If the report does not contain all of the information requested in Section B, EPA staff or EPA's contractors may contact you to obtain the missing information.

Q: In answering survey questions B8-B12, is the facility required to complete separate tablesfor each in-scope surface impoundment?

A: No, the facility may group any surface impoundments that have the same subsurface characteristics. The facility must indicate at the top of each table which surfaceimpoundments are being addressed in that table, using the appropriate surface impoundment names or numbers from question B2.

Q: Clarify what test method should be used to determine percent organics. Should it be the LOI Test?

A: The LOI test would give results too high. We would prefer a total carbon reading. However, if LOI results are the only results you have, go ahead and provide them, but please annotate them with "LOI" in the margin.

Q: Clarify what is meant by saturated zones "laterally continuous across your facility." Is the issue that the zone should be interconnected to other ground water bodies?

A: Not necessarily that it should be interconnected to other groundwater bodies - just that it extend at least to your property boundary (such that someone off your property might be able to install a supply well that withdraws from it), or that it might discharge to a surface water located off your property.

Q: Clarify what is meant by "water suitable for drinking." Is EPA interested in water with sufficient quantity such that it could provide a usable drinking water source, high enough quality so that it could be used for drinking water, or sufficient quality so that it could be used for drinking if treated first?

A: The quantity has no bearing on what we meant - simply that it be of high enough quality as is (without treatment) to be suitable for drinking.

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Q: What is the "reference time period" referred to in Section C of the survey?

A: "Reference time period" is the time period from June 1, 1990, to the present, or, if this surface impoundment has permanently ceased receiving wastes, the period from June 1, 1990, to the date the impoundment permanently ceased receiving wastes.

Q: For question C5, a facility has a series of surface impoundments. If the facility states the manufacturing processes that contribute wastewater to the first impoundment in the series, how should the facility answer C5 for the downstream impoundments? Should the facility repeat the information given for the first impoundment in the series, or simply indicate the previous impoundment as the source?

A: For the downstream impoundments, the facility can either refer to or repeat the answers given for the first impoundment in the series, or indicate the previous impoundment as the source.

Q: For question C7b, should I quantify the portion of influent flow that is exempt or excluded?

A: No. Simply check the box that best represents the portion of influent that is exempt or excluded.

Q: We believe that clays which have been removed from a surface impoundment site and engineered (remolded, compacted, etc) are liners. Does EPA agree?

A: Yes.

Q: Page C-11 in the draft questionnaire included an instruction that stated if the surface impoundment has no liner, skip to Question C15. That instruction is not on the final questionnaire. How should the respondent answer Questions C11 - C14 if there is no liner in the impoundment?

A: Removing the instruction that was in the draft questionnaire was an error - the version you received should have had an instruction on page C11 telling you to skip to Question C15 if the impoundment has no liner. If the impoundment has no liner, simply skip to Question C15, or leave Questions C11, C12, and C13 blank, and answer NO for C14a, then skip to Question C15. We will interpret unanswered C11, C12 and C13 along with a "NO" answer for C14a as "NO LINER."

Q: In question C11, may the scale cross-sectional liner drawings be hand drawn roughly to scale?

A: Yes. The liner drawings need not be drawn to an exact scale, since the table in question C12 asks for the thickness of each liner layer.

Q: Table C15 requests informaton on cell yield coefficients. Because sludge digestion occurs over time in aerated stabilization basins (ASBs), the net cell yield coefficient (i.e., growth minus digestion) for ASBs is significantly different than the classic activated sludge value. How should this be addressed?

A: Although you are not required to do so, if you write "ASB" in the margin next to your response, we will understand your situation better. If you are responding on the electronic version instead of hard copy, you could mention this fact in a cover letter that you return with your diskette.

Q: The questionnaire requires information about surface impoundments with wastewaters which are defined as waters with <5% solids. However, the questionnaire later asks for information regarding sludges which, by their nature, are >5% solids. Please clarify where the <5% solids must be measured and where >5% solids must be measured.


Q: In questions C16 and C24, the survey refers to sludge influent and effluent. However, these are terms not regularly used by the forest products industry. Please clarify what is meant by sludge influent and sludge effluent. Does sludge influent mean sludge that enters the impoundment in concentrations of less than 5% solids only? Does sludge effluent include, for example, material removed by dredging?

A: For Question B2, if any of the wastestreams entering the unit has <5% solids at the point it enters the unit, then the unit is managing "wastewater" according to the definition of wastewater in the screening questionnaire and in the long survey. Several questions in section C (such as in C2 and C4) refer to both wastewater and sludge, since in many surface impoundments the sludge becomes a separate layer on the bottom, or might be removed and recirculated back into the surface impoundment. For these questions we used both terms to cover various situations. Question C15 requests data for wastewater and sludges separately, and since it is requesting data on conditions within the impoundment, measure the % solids in the impoundment itself, report data for waste with <5% solids in the wastewater column of Table C15, and if there is a separate phase of the waste within the impoundment with 5% solids or more, and for which you have separate data on water quality characteristics, report those data in the sludge column of Table C15. For Question C16, Table C16, Rows 1 and 2, measure the % solids within the impoundment itself, and report the relevant data in the appropriate column; Rows 3, 4 and 5, measure the % solids in the influent streams; and Rows 6, 7 and 8, measure the % solids in the effluent streams (sludge removal equates to effluent in this context, so report the sludge removal rates in Rows 6, 7 and 8, Column 2). In Question (Table) C22b and C22c, measure the % solids within the impoundment itself, and report the relevant data in the appropriate table (C22b for waste with <5% solids, C22c for waste with 5% solids or more). In Question (Table) C23a and C23b, measure the % solids in the impoundment itself, and report the relevant data in the appropriate table (C23a for waste with <5% solids, and C23b for waste with 5% solids or more). In Question (Table) C24a, C24b, C24c and C24d, measure the % solids at each requested point (again, sludge removal equates to effluent in this context), and report in the appropriate table (C24a and C24c for waste with <5% solids, C24b and C24d for waste with 5% solids or more). Table C24d is mislabeled SLUDGE INFLUENT and should read SLUDGE EFFLUENT.

Q: Question C16 describes sludges "generated in the course of treatment". Please clarify what that means. For instance, if ash is sluiced into an impoundment where it is dewatered and then removed, is that ash considered "generated in the course of treatment"?

A: If the ash was less than 5% solids when it was sluiced into the impoundment, and 5% solids or more when removed, the ash is a sludge which was "generated in the course of treatment" for the purpose of this survey.

Q: In answering question C20, a facility uses a surface impoundment for both oil/water separation as well as sedimentation. Is the oil/water separation process considered "treatment" and if so, which type of treatment should be marked?

A: Both sedimentation and oil/water separation are "treatment" as defined on page C-20 of the survey. The facility should check both sedimentation and other in Question C20. The facility can describe other as oil/water separation or physical treatment.

Q: For question C21a, how can I determine the type of aeration that occurs in my facility's surface impoundment?

A: The manufacturer of the aeration equipment may define its type in written materials supplied with the equipment.

Q: We have a surface impoundment that we used until April 1995, when we stopped putting waste in it, and drained it. Your questions in section C ask about the latest three complete calendar years. Are we supposed to answer those questions for this surface impoundment, since we didn't use it in the last three complete calendar years?

A: Questions C15, C22, C23 and C24 all ask for data from the latest three complete calendar years the surface impoundment was in use. In your case, the latest three complete calendar years were 1992 through 1994. Please provide information for those years.

Q: We have a surface impoundment that we used until July 1992, when we stopped putting waste in it, and drained it. Your questions in section C ask about the latest three complete calendar years we used the surface impoundment, which would be 1989, 1990, and 1991. But in the first survey you sent, you asked for surface impoundments we used after June 1, 1990. Do we report information from 1989 and the first part of 1990, or do we start at June 1, 1990?

A: Start at June 1, 1990. For Questions C15, C22, C23 and C24 for this impoundment, you would furnish information for the period between June 1, 1990 and December 31, 1991.

Q: If a facility is going to provide only estimations for Tables C22-C24, does the facility need to fill out Table C22, which asks about sampling frequencies and methods?

A: If the facility has only estimations and is not planning to do any sampling, the facility should enter DK for Tables C22a, C22b, and C22e, and either NA or DK (whichever is appropriate) for Tables C22c, C22d, and C22f.

Q: The caption of Table C24d appears to be incorrect. We believe it should read "Sludge Effluent", not "Sludge Influent". Is that correct?

A: Yes. The table heading should be "SLUDGE EFFLUENT" rather than "SLUDGE INFLUENT."

Q: For questions C22-C24, how should I determine which constituents to include?

A: Include all constituents listed in Appendix 2 that you know or reasonably expect are present in the surface impoundment. EPA has supplied a list of constituents reasonably expected to be in the facility's surface impoundments, but you should add or remove constituents from this list by examining Appendix 2 and reviewing the activities at the facility.

Q: For questions C23 and C24, a facility uses a given analytical method to test for organics as a class, and does not detect levels of certain organics that appear on Appendix 2. Should the facility report those constituents in Tables C23 and C24 as below detection, or not include them at all?

A: For the Appendix 2 constituents the facility reasonably expects are present but were not detected, the facility should list those constituents on Tables C23 and C24, and place a check mark in Column 2 of those tables, where appropriate (if the facility does not elect to make an estimate of the quantity present). If the facility does not reasonably expect them to be present, the facility should not report them in Tables C23 and C24.

Q: For Questions C22-C24, I have some data that characterizes the chemical composition of my waste, but it's five years old. Do you still want it?

A: If you have sparse or no data for the latest three complete calendar years the in-scope impoundment was in use, but you do have some data which are older, you are not required to submit it. However, EPA encourages you to submit it if you believe it reflects your impoundment waste's composition.

Q: For questions C22-C24, the facility performed wastewater sampling in a pretreatment area upstream of the surface impoundment. Can the facility use these data to characterize the wastewater in the surface impoundment?

A: If the data from the pretreatment area adequately represents the wastewater in the impoundment, the facility may use it. The facility may also use this data to estimate constituents and levels for the wastewater in the surface impoundment. The facility should annotate the survey indicating the actual measurement point.

Q: For question C23, if a facility has analytical data for influent wastewater flow and effluent wastewater flow, but not analytical data for wastewater in the surface impoundment, should the facility estimate constituent levels for the wastewater in the surface impoundment?

A: EPA prefers that the facility estimate the Appendix 2 constituent quantities in the surface impoundment. If the facility does not make this estimate, EPA would likely use the analytical data for the influent and effluent wastewater as a logical starting point for developing an estimate of the constituent quantity in the impoundment.

Q: For questions C23 and C24, what type of estimation (e.g., mass balance) should a facility use in completing the survey?

A: EPA does not require the use of a particular estimation technique. However, unless the facility notes the technique used, EPA will assume a mass balance technique.

Q: For C24f, a facility does not directly collect leachate from their surface impoundment but has some groundwater monitoring wells nearby. Can the facility use the concentrations of Appendix 2 chemicals in the groundwater monitoring wells to report the requested leachate data in C24f?

A: Yes, if the facility feels the groundwater data best represents the leachate values (i.e., there are no other sources nearby that affect the concentrations in the groundwater, and the groundwater data represents the leachate during the time period requested in the survey). If the facility does use groundwater data rather than leachate data, the facility should annotate the hard copy of the survey to specify that the data source is not actual leachate data, but is groundwater data.

Q: Table C25 asks for information about upsets and overtopping since the impoundment was put into service. Many impoundments are decades old. Does EPA want data for incidents after June 1, 1990 or from the date the impoundment was actually put into service?

A: The instructions read, from the date the impoundment was put into service. However, EPA recognizes that for impoundments that have been in use for many years, or even decades, the knowledgeable parties may have long since left the current owner's employment. Please provide as much information as you can.

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Q: What if I want to claim my survey response as confidential business information?

A: Appendix 1 explains how EPA will handle information that you claim as confidential, and the Instruction book explains where to send your confidential business information and how to prepare the envelope for mailing it back to EPA.

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Q: How did EPA develop Appendix 2: Alphabetic List of Chemical Constituents of Interest for this study?

A: EPA developed the list of chemicals in Appendix 2 by starting with chemical constituents from the Hazardous Waste Identification Rule list and from the universal treatment standards (UTS) list, and removing chemicals which cannot be analyzed in a laboratory and chemicals for which there were no available ecological and/or human health effects data. A consent decree requires EPA to study an additional 105 chemicals, so EPA added those chemicals to the list. Finally, EPA added seven chemicals that are known to cause specific human health effects (five known human carcinogens and two chemicals that affect the human endocrine system)

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Q: Where are the technical terms defined in the survey? Does EPA recommend any particular texts for use as references while filling out the survey?

A: The technical terms used in the survey are defined in Appendix 4 of the survey, beginning on page 4-2. For additional information on technical issues, consult a published reference such as a textbook on wastewater engineering. EPA does not recommend any particular texts.

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