Comments on the Long Term 2 Enhanced Surface Water Treatment Rule Toolbox Guidance Manual (Review Draft, February 2009)

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1 Government Affairs Office 1300 Eye Street NW Suite 701W Washington, DC T F The Authoritative Resource on Safe Water SM Headquarters Office 6666 W. Quincy Avenue Denver CO T F May 18, 2009 Michael Finn U.S. EPA Office of Ground Water and Drinking Water Ariel Rios Building 1200 Pennsylvania Avenue, N. W. Mail Code: 4606M Washington, DC RE: Comments on the Long Term 2 Enhanced Surface Water Treatment Rule Toolbox Guidance Manual (Review Draft, February 2009) Dear Mr. Finn, The American Water Works Association (AWWA) appreciates the opportunity to submit comments on the U.S. Environmental Protection Agency s (EPA s) Long Term 2 Enhanced Surface Water Treatment Rule Toolbox Guidance Manual (Review Draft, February 2009). AWWA hopes that you will find our review of this draft guidance helpful. This guidance is particularly important to the implementation of the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR). The microbial toolbox (see 40 CFR ) was a central concept underlying the Stage 2 DBPR Agreement in Principle (AIP), on which the LT2ESWTR is based. The flexibility in the microbial toolbox that was agreed upon in the AIP was, in theory, to balance some of the variability with the analytical method for Cryptosporidium, as well as some other assumptions underlying the rulemaking. This Review Draft does not meet the spirit or intent of the AIP. That agreement and the subsequent Economic Analysis underlying the LT2ESWTR is premised on each of the tools included in the microbial toolbox being available for compliance. Each one of these tools is important for utilities so that multiple choices are available for compliance. In finalizing the LT2ESWTR, the agency set certain design and implementation criteria in regulatory language (see 40 CFR (b)). It appears to us that through this guidance document, EPA is further constraining the tools available to drinking water systems attempting to comply with LT2ESWTR. Unfortunately, the language and tone of the draft guidance manual:

2 Michael Finn April 17, 2009 Page 2 1. Describes the need for actions not reflected in 40 CFR (b) , and 2. Imparts skepticism that particular tools allowed under LT2ESWTR might actually be employed for compliance purposes. In effect, the guidance leans too strongly toward state primacy agencies only being satisfied with system compliance through adding additional disinfection to a water treatment plant. In summary, AWWA believes that in order to finalize the document, the document should be revised to: 1. Re-draft existing text on demonstration of performance and riverbank filtration per the detailed comments attached; and 2. Insert additional information pertinent to efficient application of ozone treatment per detailed comments which AWWA will forward in the near future. 3. Review and delete all uses of the words must and should that are not directly drawn from the regulatory text of LT2ESWTR. Attached to this letter are detailed comments indicating specific concerns with the draft guidance document. This attachment is the first of two sets of comments that AWWA will forward to EPA with detailed recommendations to assist in further refining the draft guidance. A second set of detailed comments specific to ozone treatment will also be forwarded to EPA. AWWA is deeply concerned that this guidance manual has not received any meaningful attention since the rule was published over three years ago. Now, states and water systems have actively engaged in rule implementation and this guidance continues to have significant inadequacies, including issues that AWWA brought to the agency s attention at rule proposal. AWWA will appreciate the agency s consideration of our concerns and recommendations. If there are any questions, please direct them to me or Steve Via at (202) Best regards, Thomas W. Curtis Deputy Executive Director AWWA Government Affairs cc: Ron Bergman, EPA/OW/OGWDW Pam Barr, EPA/OW/OGWDW

3 American Water Works Association Comments on the Long Term 2 Enhanced Surface Water Treatment Rule Toolbox Guidance Manual (Review Draft, February 2009) Overview The following contains comments relevant to each of the respective chapters of the Long Term 2 Enhanced Surface Water Treatment Rule Toolbox Guidance Manual : Introduction, Watershed Control Program Bank Filtration Combined and Individual Filter Performance Second Stage Filtration Ozone Demonstration of Performance Ultraviolet Light Introduction [Chapter 1] The guidance manual does not, but should, communicate the concept of incremental removal credit under Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) and previous rules. Inclusion of text and an accompanying exhibit in the introduction would be most effective. Current compliance is based on CT and many water system, states, and consultants have developed spreadsheets for CT compliance. This guidance should describe a framework for comprehensively describing a facility s overall removal credit from various activities from the toolbox. Such a common reference, were it available to water systems, would be a common point-of-departure for water treatment plant (WTP)-by-WTP discussion of removal credits. This type of framework also sets the stage for maintaining compliance when a particular unit operation fails to perform (e.g., filtration performance criteria are not met); with a summary table of removal at the WTP in hand, one could easily determine if a system is still in compliance, by looking at the remaining credits achieved thorough other system activities or unit operations. Watershed Control Program [Chapter 2] Chapter 2, Watershed Control Program, is improved from previous draft. AWWA appreciates the Agency s considerations of our earlier comments of February Water utilities will find this chapter better organized and easier to follow than the previous draft. Several additional comments include: 1. Section , states the disadvantages of watershed control program option in such a way that states are unlikely to be open to water systems using the tool to comply with LT2ESWTR. The tone in combination with the overall requirements imposed, will make it unlikely that very many communities will employ watershed control programs for purposes of LT2ESWTR compliance. Most water systems who have developed and implemented SWP efforts like those needed for the State-approved WCP credit have found that these efforts

4 are able to substantially improve source water quality (Ashendorff et al. 1997, Vaux 2000). However, seldom will watershed activities result in immediate realization of benefits. Many land use policies, wildlife management, and public education programs require significant implementation timeframes. This challenge is further complicated by the target organism in this rulemaking, Cryptosporidium. Cryptosporidium occurs in low concentrations and is difficult to detect using existing analytical methods, consequently, it can be hard to discern reductions in Cryptosporidium concentrations resulting from watershed control programs even if substantial changes are realized in the watershed Furthermore, it may not be possible to discern the improvements in source water quality using these monitoring approaches due to natural environmental variability, the characteristics of the source water improvements, and the limitations of the current analytical methods for Cryptosporidium or other fecal indicators. 2. In Section , Annual Status Report, the following state implies that Cryptosporidium monitoring should be an element of watershed control programs under LT2ESWTR. "The original watershed control program plan should include specific measures by which the PWS can evaluate the effectiveness of the program. It may be helpful to provide examples of how program effectiveness could be evaluated in the absence of monitoring. 3. In Section , Maintenance of the WCP Credit, the third paragraph references annual watershed sanitary surveys. This should be changed to reflect that sanitary surveys are required only every three to five years. 4. Section under Watershed Hydrology, the term vulnerability analysis is used. The term should be changed here, and elsewhere in the guidance, to susceptibility analysis or some other term so that it is not confused with terrorism-related vulnerability analysis. 5. While Section does explicitly state that Cryptosporidium monitoring is not required language in the section and other portions of Chapter 2 imply that Cryptosporidium monitoring should be an element of watershed control programs under LT2ESWTR. Influence of Precipitation PWSs may find it prudent to determine the extent to which Cryptosporidium occurrence in their watershed coincides with extreme rainfall. 68 percent of waterborne disease outbreaks between 1948 and 1994 were shown to be associated with heavy precipitation (Curriero et al. 2001). Cryptosporidium occurrence may also be related to seasonal variations in infection among livestock, but any correlation is site-specific and depends on the source. Loading Once you have gathered information about Cryptosporidium sources and the likelihood of the oocysts reaching your source water (based on watershed characteristics and fate and transport), you should determine the amount and proportion of oocysts that each source is expected to contribute to the overall - 2 -

5 Cryptosporidium load. Loading can be calculated fairly easily for constant point sources such as wastewater treatment plants but is more difficult for farms and urban runoff; monitoring and water quality modeling may be necessary (see section below on monitoring) What Role Should Monitoring Play in the Evaluation of Potential and Existing Sources of Cryptosporidium? Monitoring of Cryptosporidium is not required to develop the WCP plan or to implement it once approved by the State. The high cost and limitations of current analytical methodology pose significant challenges to monitoring for Cryptosporidium. In addition, it is noted that it may take years to realize measurable improvements in water quality after initiating source water protection efforts. Furthermore, discerning improvements in source water quality using monitoring can be difficult due to natural environmental variability, the nature of the source water improvements, and the limitations of the current analytical methods for Cryptosporidium as well as other fecal indicators. However, PWSs that choose to employ this option, either separately or in combination with other approaches, may gain some benefit using this approach. For example, while the State and/or PWS may already have some knowledge of potential Cryptosporidium sources through land use information or discharge permit data, monitoring can help determine the extent to which these sources are impacting a source and can help target portions of the watershed for extra protection or BMP implementation. Although not required for WCP plan development, implementation, or maintenance, monitoring throughout the watershed for Cryptosporidium (or indicators of fecal contamination) can be a useful tool in evaluating the success of watershed control program controls WCP plan development, implementation, or maintenance, monitoring throughout the watershed for Cryptosporidium (or indicators of fecal contamination) can be a useful tool in evaluating the success of watershed control program controls 6. Similarly, language in Section 2.3 strongly endorses hydrologic modeling of water bodies and pollutant loads. Such an expectation effectively limits application of watershed control programs to the most sophisticated (and typically largest) drinking water systems. 7. Section should be updated to reflect revisions in implementing concentrated animal feeding operation (CAFO) regulations that have occurred since section was drafted (see In section , consider adding stormwater bmps as possible ways to address some point sources (i.e., CSOs) through reduced burden on sewer infrastructure. 8. The numbering of subsections in Section 2 should be re-worked. Numbering goes from to 2.4, then back to Section , Delineation of Area of Influence, references Section which does not exist. 9. Website references should be checked to make sure they are still active (e.g., Section 2.4). 10. Update references that did not have a date. For example, Gullick et al., was published in 2007 (Gullick, Richard W., Richard A. Brown, and David A. Cornwell (2007). Source - 3 -

6 Water Protection for Concentrated Animal Feeding Operations: A Guide for Drinking Water Utilities. AWWA Research Foundation, Denver, CO.). 11. The best management practices (BMP) section was an area were improvement is possible. This section is an opportunity to provide references to resources on BMPs and case studies of successes achieved. Appendix E and sections , , and overlap considerably. EPA should streamline these sections and add more references to Appendix E. 12. Appendix E [Watershed Control Best Management Practices (BMPs) and Case Studies] o First paragraph refers to section which does not exist. o Section E.1.3, first paragraph states that EPA s Drinking Water State Revolving Fund allows a percentage of the fund to be set aside for land acquisition associated with watershed protection. This should be qualified that some states (e.g., Pennsylvania) may not allow for funds to be used in this manner. o In Section E.2.3, consider adding stormwater BMPs as possible ways to address CSOs via reduced burden on sewer infrastructure. o In Section E.3.3., consider adding a statement about the potential for Urban/Suburban BMPs to reduce burden on sewage infrastructure and thus address some point sources (i.e., CSOs) in addition to addressing non-point sources. 13. Appendix F [Assessment Criteria for Use By States When Reviewing Watershed Control Program Plan] o Appendix contains a checklist for States to use, but that list/appendix is not mentioned in Chapter 2 (it was mentioned only in the Introduction to Section 1.2). That checklist was Table 2.1 ("Assessment Criteria for Use By States When Reviewing Watershed Control Program Plans") in the original version of the manual, and that has now been moved to Appendix F. EPA should introduce the list/appendix somewhere in Chapter 2. o EPA should clarify the purpose Appendix F. Appendix F includes a checklist of all potential tools to be used in creating a watershed control program and labels it "assessment criteria". Some of the actions listed in Appendix F are explicitly required by the rule, some are recommended guidelines in order to facilitate development of a WCP, and some are options which the states take depending on the specific situation of a PWS. Labeling these elements assessment criteria may conflict with the rule and confuse users about actions that are required versus actions that are simply recommended. o The checklist that contributes limitations to the utility of the checklist is that the questions are not sequenced in a logical order. The checklist does not proceed through a sequence of questions that lead to a resolution or conclusion. Completing the checklist does result in decision as to whether the system will be awarded the credit or not. Therefore, rather than just a collection of questions, the checklist needs a starting point, a clearly defined objective or endpoint, and a pathway between them so that utilities applying for the credit as well as the primacy agencies (states) reviewing the - 4 -

7 application will know whether the credit can be awarded or not. Equally as important is an understanding of the process and requirements associated with maintenance and continuation of the credit; in other words what the utility must do in order for the state to continue to award the credit. o The Vulnerability Analysis Section needs clarification. i. Much of the information for larger watersheds may not be available at a high degree of resolution. As long information is taken into account in an aggregated sense then analysis remains viable and should be acceptable. At present the table can be misinterpreted require detail to a point that is unrealistic for any watershed management program to produce. (Row 2 in table) ii. The scope of the analysis must be feasible. Evaluation of activities within the watershed that could result in Cryptosporidium contamination of the water supply should be constrained to those that are likely to be present and relevant and significant. (Row 5) iii. Identifying the location and timing of sludge / biosolids application and disposal will depend on the state s ability to track biosolids application and Natural Resource Conservation Service (NRCS) programs. This information may not be available to water suppliers and it is beyond the ability of most water systems to be the primary collector of data. (Row 9) iv. Locating stormwater discharges will be complicated by implementation schedule of CWA regulations. At present, MS4 Phase II communities are just now putting their outfalls into GIS maps, consequently, in larger watershed / multi-jurisdiction watersheds this analysis will not be challenging to accomplish at a significant level of detail. (Row 10) v. Information on the location, age and condition of septic systems is not available in many areas and not required. Aggregate estimates can be prepared from census information estimating loadings and comparing sources. An aggregate analysis may find that detailed source information is not necessary for minor load contributors in a given watershed. (Row 11) vi. Land use is more significant than zoning and should be recognized as a useful analysis. (Row12) vii. Specific farming information at the parcel and farm level is protected private information that NRCS and USDA will not make available to water suppliers. Consequently, information is not available to support analysis of types of farming, feedlot locations, manure application, etc. Again, the question becomes what level of detailed information is needed for the task. (Row 13, 14) viii. Clancy et al. demonstrated that there is no concrete and universal relationship between bacteria and Cryptosporidium. Consequently, - 5 -

8 evaluating bacterial levels of tributaries or areas of the reservoir is unnecessary. (Row 19) o Potential Control Measures to Control Cryptosporidium Contamination i. While assessment of economic feasibility is inherent to any decision process. The questions before the state, e.g., the assessment criteria are not an opportunity for the state to second guess the water system s political or economic choices. ii. Similarly, the questions posed by EPA suggest that the agency does not understand how local stakeholder partnerships work. People are not contracted, there is voluntary cooperation, not documents. It is more important to capture (1) what actions are being done and (2) who will undertake particular actions. States do not need to make decisions based people s motives. Bank Filtration [Chapter 4] AWWA reviewers of the bank filtration chapter included nationally and internationally recognized experts in environmental microbiology, hydrogeology, riverbank filtration, and drinking water quality / treatment. The universal consensus of the review team was that this chapter requires extensive revision prior to its adoption as formal EPA guidance. The manual should emphasize that aquifer material with favorable properties in a setting with favorable water quality provides a reliable and effective means of treatment. Expert universally agree that bank filtration is a treatment technique with multiple water quality benefits and a technique that should be encouraged. This guidance needs to be rewritten toward that end. EPA s rule requirements, skeptical tone, and statements in the draft guidance combine to create a very negative environment for a drinking water utility to pursue bank filtration, despite the obvious benefits to water quality. This posture is at direct odds with international expert opinion. For example, in Germany, Carston Schmitt estimates that 16% of Germany s drinking water was relied on bank filtration and direct withdrawal has dropped to a minor fraction of Germany s supply: approximately 16 % of the drinking water in Germany is produced from bank filtrate or infiltrate. Because of pollution, direct treatment of river water has dropped to 1 %. 1 Currently, EPA s policy posture is such that water systems seeking to take advantage of bank filtration are best served by pursuing a ground water well source through their state primacy agency and being managed under the Ground Water Rule (GWR) or if testing results require it, under the Surface Water Treatment Rule (SWTR) Ground Water Under Direct Influence (GWUDI) provisions. This situation is a clear illustration of EPA policy impeding innovation and incorporation of technological improvements into drinking water treatment that both regulators and CWSs agree are beneficial. The general view of AWWA s reviewers was that this chapter provides ineffective and misleading guidance with respect to the microbiological aspects of assessing bank filtration. It is contradictory 1 Schmidt CK, Lange FT, Sacher F, Baus C, Brauch H-J, Assessing the fate of organic micropollutants during riverbank filtration utilizing field studies and laboratory test systems, Geophysical Research Abstracts (2003) Vol. 5,

9 in many places and serves more to confuse than clarify. EPA has not clearly and consistently reviewed and discussed the literature; rather the agency has selectively taken bits and pieces and ignored other valid data. This document does not clearly discuss the advantages and drawbacks of the various surrogates and in many instances clearly misleading information is presented. The chapter needs to be rewritten for clarity and consistency and include clear information on the use of the various surrogates that have been successfully used in these evaluations. This chapter should be 1. Re-written by a practicing expert in the field of bank filtration using appropriate references to the literature and sound engineering practices, example publications include: a. NGWA 2nd Edition of Manual of Water Well Construction Practices, b. AWWA Water Well Standards, and c. Roscoe Moss Handbook of Water Well Development; 2. Shortened to simply the information required to comply with the LT2ESWTR requirements. At present this is unnecessarily the longest chapter in the guidance manual; 3. Accurately reflect LT2ESWTR requirements; 4. Recognize that surrogates for Cryptosporidium removal are imperfect but that a range of options are available and can be used in combination; and 5. Focus on established engineering principles and delete those that are not, e.g. delete the excessive focus on scour. Specific comments on the limitations of the current text and recommendations with respect to these individual sections include: 1. Currently, Chapter 4 implies that Cryptosporidium removal may drop from 3.5 log to 0.5 or 1 log during flood episodes (see p 26). Experts familiar with the bank filtration literature were not able to find any data to substantiate this concern. In comparison, coliform occurrence has been observed during flood events, but have not been tied to stream levels. Typically coliform counts in surface streams increase substantially with flood events, while densities in RBF facilities are very low. 2. Section 4.1, Introduction, immediately implies that bank filtration has limited application: In optimal locations and under optimal conditions, bank filtration is suitable for accomplishing sufficient Cryptosporidium removal to partially meet the requirements of the Long Term 2 Enhanced Surface Water Treatment Rule. Similarly, the Chapter does not give a full accounting of the treatment mechanism provided by bank filtration. An example in this section is the failure to recognize microbial processes: Geologic units consisting primarily of fine-grained (e.g., clay-sized) materials will have higher removal but will be incapable of yielding economically significant water flow rates. In aquifers containing both sand-sized and finer grains, the presence of fine grains increases the possibility that pathogens will encounter a grain surface. This is because flow is slower and flow paths are longer than they would be in aquifers without such fine grains

10 3. Section 4.2, LT2ESWTR Compliance Requirements, The requirements for a bank filtration demonstration of performance (DOP) study include sampling both from the production well(s) and monitoring wells that are screened and located along the shortest flow path between the surface water source(s). But, SDWA regulations do not include a definition of monitoring wells. A monitoring locations at suitable sampling point(s) (like the under-the-river lateral, which is more in the flow path than would be a monitoring well for horizontal wells would provide better data than a specially constructed monitoring well and preserve the integrity of the aquifer. The guidance should be open to allow for such interpretations. 4. Section 4.2.1, Credits. As written the guidance is incorrect. 40 CFR 417(c)(4) requires systems with vertical wells to identify the distance between the to the well screen and surface water using the floodway boundary or 100 year flood elevation boundary as delineated on Federal Emergency Management Agency (FEMA) Flood Insurance Rate maps. As currently written, this important distinction is lost, and this inclusion is critical to the viability of bank filtration. 5. Section 4.2.1, Credits. As written the guidance is incorrect. CFR reads as follows: Systems must extract a core from the aquifer and demonstrate that in at least 90 percent of the core length, grains less than 1.0 mm in diameter constitute at least 10 percent of the core material. Guidance on page 4-4 reads as follows: System must characterize the aquifer The recovered core length must be at least 90 percent of the total depth to the projected bottom of the well screen and each sampled interval must be a composite of no more than 2 feet in length. An aquifer is eligible for removal credit if at least 90% of the composited intervals contain sufficient fine-grained material as defined previously. This is a clear example of EPA instituting a regulatory requirement through guidance as previously discussed in our cover letter. While the regulatory requirement is an oversimplification of aquifer characterization for purposes of bank filtration, the current guidance further exacerbates the situation by imposing a requirement for distribution of media over the entire depth of the well that does not exist within the regulatory requirement. 6. Section 4.3, Toolbox Selection Considerations, The draft manual reads Bank filtration is best suited to systems that are located adjacent to rivers with reasonably good surface water quality and that plan to use bank filtration as one component of their treatment process. What is reasonably good surface water quality? What peer-reviewed data does EPA have to guide such a determination? In Europe, bank filtration is used on some of the most - 8 -

11 polluted waterways explicitly because they are so polluted and the beneficial effects of bank filtration on water quality are desired Section 4.3, Toolbox Selection Considerations, The draft manual reads: Wang et al (2000, 2002) documented high removal of Cryptosporidium surrogate organisms at production well sites in The Netherlands and in Louisville, Kentucky. There was very little occurrence of Cryptosporidium in river water at the Kentucky site and no Cryptosporidium was found in the well water at either site. The amount of Cryptosporidium removal at either site is unknown." Why is this information included in the manual? It appears that the agency is implying that bank filtration does not have appropriate supporting data and, in particular, that the agency is dismissing data from a specific group of researchers. 8. Revise Section 4.3.1, Advantages and Disadvantages, to include additional advantages of bank filtration include: o Fewer chemicals added compared with conventional treatment. o Relative to conventional or membrane treatment processes, no waste stream is produced that requires addressing environmental issues related to management and disposal of these wastes. o Typically, lower energy consumption and reduced greenhouse gas generation. 9. Revise discussion throughout Chapter and expand Section , Additional Treatment Steps, to reflect that that the aquifer, not just the hyporheic zone, contributes to removal (see page 4-10). A more complete description of treatment mechanism in bank filtration is important given concerns expressed regarding scour. For example, Section discourages the use of bank filtration by over-emphasizing scour: Much of the removal of the contaminants and microbes discussed above occurs during the first few centimeters of the flow path, due to the significant filtering and sorptive capabilities of sediments in the riverbed. These sediments are often organic-rich, highly biologically active, and fine-grained. The effectiveness of bank filtration, however, may be temporarily threatened during high flows if this active layer is washed away or scoured. EPA suggests the potential for stream channel scour be evaluated during riverbank filtration site selection (section 4.4). Section 4.5 provides further discussion of scour and its implications for riverbank filtration system operation. 10. Section , Significance of deoxygenation is not provided, but by inclusion is implied to be quite high, especially given the agency s verbiage. Does EPA possess data that deoxygenation is a frequent concern relative to the recognized benefits of bank filtration? Is the likelihood that deoxygenation will occur reflected in the agency s criteria for reasonably good water quality? 2 Carsten K. Schmidt, Frank Thomas Lange, Heinz-Jürgen Brauch, Wolfgang Kühn. Experiences with riverbank filtration and infiltration in Germany. DVGW-Water Technology Center (TZW) Karlsruher Straße 84, D Karlsruhe, Germany

12 In addition to clogging and scour, there are several disadvantages to bank filtration which utilities may wish to consider and balance against the advantages and cost savings described in section One disadvantage is that an additional aeration step may be required during water treatment due to the possible depletion of oxygen as biological activity consumes oxygen during riverbank filtration pretreatment (Kuehn, et al., 2000). This oxygen depletion may lead to extremely anaerobic conditions over a portion of the flow path, which may sometimes result in the release of iron and manganese from the bank sediment into the flowing water. This process occurs due to a redox reaction which reduces iron and manganese to their water-soluble forms. This condition may necessitate the removal of these metals during subsequent treatment steps (Kuehn, et al., 2000; Tufenkji et al., 2002). 11. Section 4.4.1, Coring, This section only includes descriptions of two drilling methods. At a minimum, it should be expanded to include discussions of rotasonic drilling (because of the relatively undisturbed cores which can be obtained) and cable tool drilling (possibly in combination with split-spoon sampling), another method which can be used for coring. Both of these methods will handle borehole stability issues that are mentioned in the text. 12. Section , The manual is not clear whether the rule is prescriptive in requiring all vertical wells (including existing) to be out of the 100 year floodplain or outside the floodway to achieve credits, or to what extent the manual is providing guidance on locating new vertical wells. In particular, it is not clear if both setback and demonstration requirements exist for those facilities that conduct a demonstration of performance (DOP)? Also, it is not clear from the guidance what constitutes sufficient separation as required by 40 CFR and A vertical well that is screened in different aquifers, using appropriate construction methodology (e.g., grout seal, conductor casing, etc.) such that the distance to the top of the filter pack from the riverbed is greater than 25 feet should meet the rule requirements. It should be deemed as compliant, even if the horizontal distance from the river boundary to the well casing is less than 25 feet. 13. Exhibit 4.6 is a very poor graphic, and it should be modified or deleted. 14. Section 4.7, Demonstration of Performance, It is important that the document provide flexibility in the development of a DOP given the inherent variability of sites where bank filtration is applied each DOP needs to be tailored to site conditions. The current guidance text minimally discusses site conditions that are critical in assessing the effectiveness of bank filtration including soil grain metal oxide chemistry and the concentration and type of DOC. These issues should be discussed. The requirement of having monitoring wells along the shortest flow path may mean that wells will have to be installed in the river which is impractical from a logistical and regulatory perspective. Short-circuiting caused by such wells also needs to be considered. In several places, the document emphasizes the negative impact of scour, however, recent work (Gupta, et. al. ES&T, 2009) shows that this may not be as significant as assumed

13 15. Section 4.7.3, Ground Water Travel and Residence Time, must be described with practical expectations. By setting expectations that cannot be met within a typical CWS s fiscal constraints and rule compliance deadlines, this guidance prevents the use of bank filtration as an LT2ESWTR compliance tool. For example, determining the dilution with groundwater is a non-trivial challenge for many systems, and will be a dynamic condition seasonally and yearly. The text seems to suggest that ambient groundwater is less susceptible to contamination by pathogens or other constituents of concern. This is not always the case - terrace gravel mining, agricultural operations (feed lots, dairies, etc.), septic systems, and other industrial activities need to be considered. This is especially true if the geology surrounding the alluvial aquifer is comprised of fractured bedrock. 16. Section 4.7.4, Surface and Ground Water Data Collection, the last paragraph of this section states that the DOP should provide data that ensures that indicator organisms are not coming from sites other than the source river water. This seems to require that indicator organisms exclusively originate in source river water, however, some indicator organisms exist in environments other than surface water such as soil or groundwater. The meaning and intent of the following statement is unclear: The presence of alternative sources will invalidate any monitoring data obtained from the collection devices. Do alternative sources refer to local sources mentioned in the prior sentence? If so, this leads to several questions. Does this statement refer to existing facilities? Does the presence of alternative sources alone invalidate any monitoring data? What are alternative sources and what criteria are used to identify alternative sources? 17. Section 4.7.5, Monitoring Tools, Microspheres should also be included as they can also be a representative surrogate in column and in-situ studies. See Metge, Harvey et. al. (Geomicrobiology Journal, 2007). The fate and transport of the Cryptosporidium surrogates listed is not clear and is not certain that they behave in a similar manner to oocysts. It is not just a matter of size and morphology; physiochemical parameters (such as surface charge buoyant density, etc.) can be more important. How would aerobic spore concentrations be used to evaluate pathogen removal efficiencies for situations where underflow dominates? For these situations, what is ambient groundwater and how will background spore concentrations in groundwater be determined relative to spores derived from surface water? Does it matter that spores could have originated from surface water miles upstream of bank filtration facilities? In the last paragraph of page 4-45, the text goes too far in speculating that aerobic spores are superior indicators because they are more mobile in the subsurface than total coliform and would yield a different result. In addition, the text infers that carboxylated microspheres would yield a similar result as spores. Column and in-situ studies at this site using microspheres show significant removal capacity of streambed sediments. If aerobic spores were used it might provide a differing assessment (as perhaps any other surrogate would), but would it be a more meaningful assessment? That is highly debatable because it is not certain that aerobic spores behave like oocysts in granular material and, if detected in extracted water, how would you know where they came from? A possibility is that the spores from the river are removed by the poorly sorted high iron sediments (in a low DOC [in terms of concentration and reactivity] environment) while

14 spores detected in extracted water could come from aerobic zones in the aquifer and overlying soil. This paragraph does not seem consistent with the text in the fourth paragraph of page 4-41 stating that no single surrogate organism is best. 18. Exhibit 4.7.1, Some of these cost estimates are from as far back as 2001, and some have no year listed for the estimate. All of the cost estimates should be updated to 2009 estimates and noted as such. 19. Section , When re-drafting chapter 4, it should be re-written in everyday language of engineers and working hydrogeologists. For example terms like: alluvial aquifer, wellsorted, fine-grained sediments, etc. are common and well understood. Terms like fluvial depositional processes and modern streams are terms that have different means based on the context of the application and are not appropriate in this guidance. 20. Section Correct per modification to address Section This section, as written, further expands on regulatory text: Collect relatively undisturbed continuous core samples from the surface to a depth at least equal to the projected bottom of the well screen for the proposed production well. If core recovery is insufficient, another well core must be obtained. Examine each 2 foot long composite sample of recovered core in a laboratory using sieve analysis to determine grain size distribution. If more than 10 percent of the sediments in each 2 foot long composite sample are less than 1.0 mm in diameter (very coarse sand), then the core interval from which it was taken is noted as containing a sufficient quantity of fine-grained material to provide adequate pathogen removal. To receive Cryptosporidium removal credit, at least 90 percent of the analyzed composited core intervals from the sampled aquifer will meet criterion number (4) above. 21. Section Units of measure. Review the manual for consistent use of units consistent with the typical use in the field, e.g., distances are measured in feet or miles, volumes in gallons, concentrations in mg/l, etc. 22. Section Required separation Distance, This section states: At most typical bank filtration locations, high log removal rates (e.g. 3.5 log removal over 13 m) may be expected with the surface water discharges that predominate during most of the year. During short flood periods, however, there may be substantially lower removal (e.g. 0.5 to 1.0 log removal over 13 m) due to scouring of the surface water ground water interface, as discussed below in section After a review of the scientific literature, AWWA was not able to verify that the theory of diminished log removal can be justified based on available science. Data is available on coliform detections during flood surges, and these have not been tied to log removal (no data on the source, but likely very elevated), only presence in the infiltrate. The implication that Cryptosporidium removal in bank filtration decreases from 3.5 down to 1.0 is conjecture

15 23. Section Locating Wells at Greater than Required Distances, Section further illustrates that this Chapter should be re-written by a consultant familiar with the practical, rather than simply the theoretical constraints associated with bank filtration development (e.g., by an individual with practical experience developing bank filtration facilities in the United States.). This section states: For example, if mapping the bedrock-alluvial interface and the water table at a particular site indicates that the aquifer is fairly thin, it is unlikely that infiltrating river water will be diluted by much ambient ground water. This may be useful at riverbank filtration sites, where water table layer and depth to bedrock can be used to determine aquifer thickness - an important parameter in determining how much dilution of bank filtrate with ambient groundwater is occurring. Thinness isn t as much the issue as that many of these systems lie in glacial outwash, and the boundary walls are fairly well defined, so there is very little lateral movement of groundwater towards the well because of a vertical rock valley wall. While thickness affects how much water you can draw into a well, the spatial variance in conductivity and presence of boundary walls, rainfall, and other sources of ground water recharge are more likely to affect ground water flow. For example, in the Florida panhandle, the aquifer is particularly thin at the stream, yet a high amount of recharge occurs from adjacent higher elevation areas of very porous soils. The section goes on to focus on variability in the saturated zone and linking that concern to a single aspect of design, distance between the source and the well: When the aquifer contains fine-grained material, it is possible that well overpumping may break the hydraulic connection between ground water and surface water, yielding a variably saturated zone underneath a perched stream, as shown below in Exhibit 4.5. If possible, the potential for formation of a variably saturated zone can be investigated in order to provide additional information regarding the desirability of locating wells at greater than required distances from the surface water source. Considerations surrounding maintaining an installation and operating regime within appropriately bounded saturated conditions are inherent to sound bank filtration system design. Rather than point to the literature for appropriate references for design, this manual text frames the issue as a regulatory barrier to bank filtration. As the agency is aware, production volume typically decreases with increased setback distance, consequently, using this single tool to manage the phenomena described rapidly makes bank filtration less economically attractive. Note. The referenced graphic (exhibit 4.5) is illegible. Section describes uses of seismic hydrogeologic investigation methods as being suitable for: Estimate depth to bedrock (ideal for riverbank filtration applications). Determine the nature of bedrock (e.g., cavernous) or location of cavities. Note that karst buried by alluvium may contain unexpected ground water flowpaths

16 Determine the location of faults that may juxtapose bedrock against alluvial material. Determine stratigraphy (useful where sands and clays may be interlayered). Determine porosity. Determine ground water particle velocities (an important parameter for riverbank filtration systems). Neither determination of porosity or ground water particle velocities are routine applications of seismic methods in geotechnical engineering. Section describes uses of electromagnetic (EM) investigation methods as being suitable for understanding subsurface flows in bank filtration systems: Electromagnetic (EM) methods have been used in groundwater investigations to delineate contaminant plumes, and thus can be useful in conceptualizing flow systems in a riverbank filtration context when the quality of infiltrating river water is especially poor. Pulse-transient EM (TEM) surveys (a type of EM method) may be useful in conceptualizing flow for riverbank filtration systems where infiltrating water quality is poor. It may also be useful in monitoring the quality of infiltrating water. When data is available from both borehole and surface instruments, EM and electrical methods can be used to map subsurface geology such as the locations of coarse-grained and fine-grained units. This section is a mis-application of EM. If water quality is so poor that EM cannot be used effectively then the location is unlikely to be used as a public water supply. This section text should be removed, as it may lead uninformed readers to the conclusion that EM methods can be used to monitor subtle changes in water quality, a task to which it is not well suited. 24. Section , Delineating the Edge of the Surface Water Source. As noted previously, this guidance must be consistent with LT2ESWTR regulatory requirements. The requirements are: For vertical wells, the ground water flow path is the measured distance from the edge of the surface water body under high flow conditions (determined by the 100 year floodplain elevation boundary or by the floodway, as defined in Federal Emergency Management Agency flood hazard maps) to the well screen. For horizontal wells, the ground water flow path is the measured distance from the bed of the river under normal flow conditions to the closest horizontal well lateral screen. Most bank filtration facilities are located within the 100 year floodplain on pedestals. Effective well construction and operating protocol can reduce the risk of contamination during floods. As written, the current guidance: o Is inappropriately ambiguous as the regulatory text is clear that the separation distance is measured between the surface water body and the well screen. o Inappropriately directive, by purposefully directing readers toward use of the 100-year floodplain as the delineation of the surface water body, and thereby effectively precluding use of bank filtration in most locales

17 o Mischaracterizes the criticality of considering the floodway to delineate the surface water body. Systems seriously considering vertical wells for bank filtration are very likely to employ the floodway delineation in locating wells. This delineation will have bank filtration well installations outside the floodway but within the 100-year floodplain. This guidance should direct readers to appropriate construction guides for wells build within the 100- year floodplain. 25. Section and , Typographical errors. Broken sentence: The following website can be used to order these maps: flood (i.e. the 100-year flood) without increasing flood levels by more than 1.0 foot. It is determined by specified methods according to FEMA guidelines, as described below. Missing verb: For simplicity, if the well if closer to being a vertical. 26. Section , Measuring Separation Distances for Horizontal Wells. As noted previously, this guidance must be consistent with LT2ESWTR regulatory requirements. The requirement for turbidity monitoring for bank filtration reads: Systems must monitor each wellhead for turbidity at least once every four hours while the bank filtration process is in operation. If monthly average turbidity levels, based on daily maximum values in the well, exceed 1 NTU, the system must report this result to the State and conduct an assessment within 30 days to determine the cause of the high turbidity levels in the well. If the State determines that microbial removal has been compromised, the State may revoke treatment credit until the system implements corrective actions approved by the State to remediate the problem. The guidance document incorrectly states: To ensure that the assigned log removal credit is realized, systems are expected to perform continuous turbidity monitoring for all wells that receive a credit. Continuous turbidity monitoring is discussed in section Section discusses turbidity measurements every 4 hours, or continuous turbidity monitoring, but Section inappropriately creates the regulatory expectation for all systems employing bank filtration for LT2ESWTR to do continuous monitoring at every wellhead for turbidity. 27. Like Section , Section is inappropriately focused on bed scour and, in this instance, over emphasizes stream migration as a threat to bank filtration performance. As noted above regarding section , this chapter should be rewritten by an individual with practical experience developing bank filtration facilities in the United States. Alluvial rivers that are experiencing active, progressive erosion as an adjustment to new flooding regimes or sediment loads, or in relation to natural lateral migration, may pose serious, longer-term challenges to bank filtration systems. For example, significant log removal reductions may be more frequent in an urbanizing basin as a consequence of more frequent flooding

18 and associated scouring. In extreme cases, long term degradation of the bed or banks may reduce the threshold separation distances between the surface water source and bank filtration well. Recall that these separation distances - 25 feet for 0.5 log removal credit and 50 feet for 1.0 log removal credit - are required to receive log removal credits under the LT2ESWTR. As a practical matter, separation distances in LT2ESWTR for bank filtration well installation, the nominal topic for this text, are based on floodway and 100-year floodplain boundaries. Both are typically over-bank limits, which are only marginally impacted by eroding banks. Indeed, morphology changes can make floodways narrower or move the channel away from the well installation. 28. Section 4.7, Demonstration of Performance, has the stated objectives: provide additional guidance on the design and conduct of a demonstration of performance study as well as guidance on the interpretation of the study data and the award of Cryptosporidium removal credits, if warranted. Finally, this chapter describes the necessity for long term performance evaluation monitoring to determine if the log removal credit continues to be appropriate. As noted previously, this chapter should be rewritten by an individual with practical experience developing bank filtration facilities in the United States. Section 4.7 does not provide information that reflects: o A practical understanding of the costs or feasibility of the tools suggested, o An understanding of the regulatory requirements, o A clear prioritization of what is information that is important versus ancillary topics of marginal relevance, or o An understanding of the microbiology of surrogate organisms described. Information included without attention to practical import: Environmental tracer data (isotopes, CFCs, pharmaceutical compounds, etc.) should be collected to verify lag times calculated using temperature, chloride and other parameters. The mentioned environmental tracers are both expensive and of uncertain quality (e.g., CFCs and pharmaceutical compounds). Such tracers have little likelihood of providing conclusive data where travel times are short. Perhaps more importantly, there are much cheaper and effective ways to collect meaningful data, using water quality parameters such as temperature, hardness, and fluoride. Temperature, chloride, and bromide are recognized but the guidance does not say that these more applicable parameters should be collected. Equally importantly, this text sends the message policy that isotopes, CFCs and pharmaceuticals are reasonable tracers for bank filtration facilities with complex flow lines. This takeaway message is wrong, and if needed modeling is a more reasonable method to estimate the shortest flow line than measuring for exotic compounds. Late summer or drought low flow conditions should also be more intensively sampled if the low water levels represent a possible worst case scenario. In the interest of investing samples at the most important time, a single sample in the drought condition would suffice, as the conditions leading up to the event are gradual and

19 cumulative (e.g., flow lines steepen, velocities increase, and media becomes un-saturated gradually over time). This is not the case in flood surge events, where hydraulics can change dramatically over a period of hours. The study design should ensure that the number and location of river water samples collected are representative of high and low consumptive use (e.g. pumping for drinking water supply, irrigation, etc.) periods. River water samples should be representative of the entire river volume, rather than consisting only of samples collected at the surface water intake for the treatment plant. If point sources discharge upstream and the stream is not well mixed, then the river samples should be proportionate in number and location to the volume of the highly concentrated plumes emanating from the point sources. This section should be redrafted to reflect the task at hand, demonstrating removal. Language that imparts the impression that the guidance is a regulatory requirement should be removed, and concepts inconsistent with the LT2ESWTR regulatory requirements must be deleted. With these changes in mind, the task is best described as sampling the concentration of the monitored parameter in the surface water supply as near to the area of infiltration as possible and the concentration of the water drawn from the well. A more elaborate monitoring scheme not only unnecessary to support the LT2ESWTR framework, it is unlikely to provide significant additional value-added information. These samples can be dangerous to get in high-flow situations but the point is to let the reader know what the ideal sample would be, and then to get the best sample possible given site and safety considerations. EPA does not have the need or authority to impose worst-case sampling or distributional sampling structures within the guidance document. Section should focus on a practical list of water quality data. It currently reads: Suitable parameters measured could include, but are not limited to, organic carbon, chloride, bromide, TDS, hydrogen, oxygen, uranium and other isotopes, and CFCs. A more practical list would include temperature, hardness and dissolved (oxygen) rather than hydrogen, oxygen, uranium, and other isotopes. It could also point out that chloride, hardness, temperature, and dissolved oxygen (DO) represent the central elements of this data set. The discussion of dissolved oxygen should note the challenges of monitoring when levels are below 3 mg/l and effects of atmospheric exposure in the sampling well and during collection. Section also sets numerous additional regulatory requirements for DOP data collection that are not found in the LT2ESWTR: Data collection activities should be designed to ensure that the collected samples are representative and random. Data analyses should include quantitative assessment of the uncertainty associated with each conclusion. Study design should include sufficient sample numbers so as to determine statistical significance for each conclusion to a pre-determined confidence level. The study design should also include a quality assurance project plan, identifying 1) reference to the analytical method and laboratory, 2) a reasonable

20 number and percent of blank, replicate and spiked samples, 3) detection limits, and 4) sample holding times. The presence of multiple data collection wells can serve to increase confidence in the conclusions. Monitoring well data (preferably from multiple wells) collected along the flow path must show a decrease in indicator concentration with distance from surface water to improve overall confidence that the measured log removal results are meaningful. The DOP should determine the capture zone of each collection device and/or conduct dye trace studies from local sources such as septic tank leach fields to ensure that indicator organisms are not coming from sites other than the source river water. The presence of alternative sources will invalidate any monitoring data obtained from the collection devices. This text covers a number of useful concepts, but none are required by the rule and as included here give the appearance that the agency is attempting to erect roadblocks to the use of bank filtration. Examples of information included of marginal relevance: o It is not clear what section is intended to communicate. Suggest deletion. o Section 4.7.2, cannot be represent the agency s views on sampling as it is at odds with the sampling premise underlying LT2ESWTR s risk-based rule structure. As proposed, Section is neither premised on representative loadings as LT2ESWTR is based, nor does it reflect worker safety as LT2ESWTR monitoring provisions clearly address. Suggest deletion. Examples of information of uncertain technical content: o Section refers to stream tubes in the context of river water quality sampling. What are stream tubes? Suggest deletion. Section 4.7.5, Monitoring Tools continues to establish requirements that are not included in LT2ESWTR regulatory text: The DOP study should consist of monitoring for Cryptosporidium or a suite of Cryptosporidium surrogate organisms at each collection device (or device type cluster) and the source river water. Pathogen monitoring could also include Giardia and perhaps members of the Microsporidia family (Brusseau et al., 2005). In the absence of Cryptosporidum oocyst removal data (calculated using measurable oocyst concentrations in the river and in the collection device) Monitoring for Cryptosporidium is of little value since it is essentially impossible to find it in bank filtrate. Even in surface waters, the levels are relatively low and the vast majority of raw water samples are non-detect. If MPA is done, then using the Pall Envirochek filter and analyzing a portion for Giardia and Cryptosporidium can be added easily to the analysis and while it is expected that no cysts or oocysts will be detected, it can be easily demonstrated. While pathogen monitoring could include Giardia, it is not the same size or shape as Cryptosporidium, and finding it is as unlikely. One has to rely on the surrogates to develop meaningful data