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Public Listening Session; Stakeholder Input on Peak Flows Management

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Environmental Protection Agency (EPA).




The Environmental Protection Agency (EPA) is interested in the views of the public on possible approaches to updating the National Pollutant Discharge Elimination System (NPDES) regulations related to the management of peak wet weather flows at Publicly Owned Treatment Works (POTWs) treatment plants serving separate sanitary sewer collection systems. Consequently, EPA is inviting interested members of the public to three planned listening sessions on: October 16, 2018 at EPA Headquarters in Washington, DC, October 24, 2018 at EPA Region 7 in Lenexa, Kansas, and October 30, 2018 to be held online. EPA welcomes oral or written information at the listening sessions as well as any other information the public may wish to provide EPA through the docket (Docket ID No. EPA-HQ-OW-2018-0420).


The in-person listening sessions will be held at EPA Headquarters in Washington, DC on October 16, 2018 from 9:00 a.m. to 2:00 p.m. EDT; and in EPA Region 7 in Lenexa, Kansas on October 24, 2018 from 9:00 a.m. to 2:00 p.m. CDT. In addition to the in-person listening sessions, EPA will hold an online listening session on October 30, 2018 from 11:00 a.m. to 4:00 p.m. EDT.

For those who intend to submit written statements to the docket, EPA is asking that this information be provided before October 31, 2018.


The in-person listening sessions will be held at the following locations:

  • For the EPA Headquarters in Washington, DC listening session: US EPA Headquarters, William Jefferson Clinton East Building, Room 1153, 1201 Constitution Avenue NW, Washington, DC 20004;
  • For the EPA Region 7 listening session: 11201 Renner Blvd., Lenexa, KS 66219.

The online listening session will be accessible though​npdes/​peak-flows-sewage-treatment-plants.

To register for any of the listening sessions go to:​npdes/​peak-flows-sewage-treatment-plants.

To submit written information to EPA: Submit any written statements or input, identified by Docket ID No. EPA-HQ-OW-2018-0420, to the Federal eRulemaking Portal: Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or withdrawn. EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. EPA will generally not consider comments or comment contents located outside of the primary submission (i.e., on the web, cloud, or other file sharing system). For additional submission methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit​dockets/​commentingepa-dockets.

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Jamie Piziali, Water Permits Division, Office of Water, Environmental Protection Agency, 1200 Pennsylvania Avenue NW, Washington, DC 20460; telephone number: 202-564-1709; or email: Also see the following website for additional information regarding the rulemaking:​npdes/​municipal-wastewater.

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I. General Information

A. Public Listening Session

i. Public Listening Sessions: EPA will hold two public listening sessions to gather feedback from interested members of the public on the issues and concerns that the Agency should be aware of during this rulemaking. The public listening sessions will begin with EPA providing a brief background on peak flows management issues and EPA's goals for this rulemaking. This will then be followed by an opportunity for the public to provide input on these issues. EPA is asking that oral statements be limited to three minutes or less and is welcoming written statements at the sessions. Each listening session will begin at 9:00 a.m. local time and continue until all those wishing to speak have had a chance to provide comments, or until 2:00 p.m., whichever comes first. A transcript of oral remarks made during the listening sessions will be at​npdes/​municipal-wastewater and included in the rulemaking docket.

ii. Online Listening Session: In addition to the in-person listening sessions, EPA will also hold a “virtual” listening session via a webcast on October 30, 2018, from 11:00 a.m. to 4:00 p.m. EDT. The same format will be followed as that for the in-person listening session. After a presentation from EPA, members of the public may call in and give brief (three-minute or less) statements. Audience members will be able to listen to the webcast and all public statements through their computer speakers. A transcript of oral remarks made during the listening sessions will be at​npdes/​peak-flows-sewage-treatment-plants and included in the rulemaking docket.

B. Additional Information and Public Meeting Registration

Prior to each listening session, EPA will post any relevant materials to the following website:​npdes/​peak-flows-sewage-treatment-plants. Information posted to the website will include any handouts that may be provided at the meeting as well as a web link that participants may use to register for the public meeting in advance. Advanced registration is not required, but is requested so that EPA can ensure there is sufficient space and time allotted for those who wish to participate. The listening session will continue until all speakers in attendance have had a chance to provide comments, or the listed end time, whichever comes first. If you choose not to pre-register to speak, it is recommended that you arrive at the start of the listening session to register in person in order to ensure the opportunity to participate.

II. Background

EPA is providing the following background information to assist the public in preparing for the listening sessions. Under the Clean Water Act (CWA), municipal sewage treatment plants or Publicly Owned Treatment Works (POTWs) treatment plants are required to comply with prescribed restrictions on their discharges to a water of the United States. Specifically, each POTW must obtain an NPDES permit that will require, at a minimum, that the treatment plant's discharge meet effluent limitations for secondary treatment. See CWA § 1311(b)(1)(B) and § 1342(a), 40 CFR 133 and 40 CFR 122.44(a)(1). The permit will also require meeting any more stringent effluent limitations that are necessary to meet applicable water quality standards. See CWA § 1311(b)(1)(C), § 1342(a), and 40 CFR 122.44(d). The permit will also require the POTW operator to comply with other terms and conditions based on the NPDES regulations at 40 CFR 122. These include, for example, requirements regarding monitoring and reporting of discharges and proper operation and maintenance of POTW facilities and systems of treatment.

Many sewage treatment processes may be used to comply with these effluent requirements. Most municipalities use a series of unit processes to treat wastewater prior to discharge including the following:

  • Preliminary treatment or screening to remove large solids,
  • primary clarification (or preliminary sedimentation) to remove floating and settleable solids,
  • biological treatment (also referred to as secondary treatment) to remove biodegradable organic pollutants and suspended solids, and
  • disinfection to deactivate pathogens.

Some facilities also provide more advanced treatment, which is designed to reduce constituents, such as nitrogen and phosphorus, that are not removed in any significant quantity by traditional biological treatment processes.

Sanitary sewer collection systems are designed to remove wastewater from homes and other buildings and convey it to a wastewater treatment plant. The collection system is a critical element in the successful performance of the POTW's wastewater treatment operation. Collection systems are designed in one of two ways. Combined sewer systems are designed to collect both stormwater and sanitary wastewater for delivery to the treatment plant. By contrast, separate sanitary sewers are designed to carry only sanitary wastewater (separate sanitary sewers typically are built with some allowance, however, for higher flows that occur during storm events in order to handle minor and non-excessive amounts of stormwater or groundwater that enter the system through infiltration and inflow or “I/I”). EPA notes that, at this time, it contemplates the scope of the rulemaking would be limited to peak flows at POTWs with separate sanitary sewer systems.

Significant increases in flows at a treatment facility can create operational challenges and potentially adversely affect the treatment efficiencies. Biological treatment components at treatment plants are particularly vulnerable to high-volume peak flows. Where peak influent flows during periods of wet weather exceed the treatment capacity of existing biological or advanced treatment units, POTWs must consider ways in which to prevent damage to their treatment plant, while maintaining effective operation of the system to meet applicable NPDES permit limitations. Under these conditions, POTW operators use several different strategies which may include a combination of alternative treatment approaches, storage, and sewer maintenance and rehabilitation work to minimize the amount of stormwater that enters the collection system through I/I.

Among the peak flow management approaches that have been used or considered are those involving the diversion of a portion of the peak flows around biological or advanced treatment units. The diverted flow is then recombined with flows from the biological treatment units. Other alternatives include the installation of various treatment processes at the POTW that supplement the plant's ability to process and treat peak flows. Refer to EPA's Draft Summary of Blending Practices and the Discharge of Pollutants for Different Blending Scenarios (EPA, June 2014) at​sites/​production/​files/​2015-10/​documents/​sso_​lit_​review_​draft.pdf. These approaches have been the subject of previous EPA policymaking efforts that have not been adopted. See 68 FR 63042 (November 7, 2003), and 70 FR 76013 (December 22, 2005). EPA has also looked at the potential public health implications of these different approaches. See Summary of June 19-20, 2014, Experts Forum on Public Health Impacts of Blending (EPA, May 2015) at https://Start Printed Page​sites/​production/​files/​2015-10/​documents/​experts_​forum_​summary.pdf.

POTWs with separate sanitary sewer systems can also lessen the impact of peak flows by implementing a variety of strategies to minimize the introduction of stormwater into the collection system. While virtually every separate sanitary sewer system has some groundwater infiltration and stormwater-derived I/I, it may be considered excessive when it is the cause of overflows or causes disruptions in the treatment system. POTWs with excessive I/I have a number of different methods for identifying the largest sources of I/I in their sewer system. These include system mapping, flow monitoring, conducting smoke or dye tests, sensor technology, and using optical devices to view sections of the system. Developing plans for correcting and rehabilitating the highest priority sources of I/I into the collection system may involve such strategies as repairing manholes, replacing and repairing private building lateral pipes, ensuring building downspouts are not connected to the sewer system, sealing sewer joints, inserting sewer liners, or even replacing sections of the sewer line. Other strategies may focus on maximizing existing collection system capacity through real-time controls to optimize flows within the system, or building additional storage within the collection system or treatment plant.

EPA acknowledges the significant expertise that exists among states, tribes, POTWs and municipal officials, engineering firms, public health agencies, and the public related to these issues. These listening sessions are designed to take advantage of this information from a variety of perspectives to help provide a complete picture of the considerations that should go into any rulemaking to address permitting requirements for the management of peak flows at POTWs with separate sanitary sewer systems.

III. Areas of Feedback Requested for Public Listening Sessions

Interested members of the public who plan to provide oral or written testimony at the listening sessions, or to submit written material to EPA separately as detailed in the instructions provided in the ADDRESSES section of this notice, are welcome to provide their input on any issue related to the topic of peak flow management at POTW treatment plants with separate sanitary sewer systems. But EPA particularly welcomes feedback from the public on the following specific questions.

  • What strategies have you found to be successful in reducing peak flow volumes at the POTW treatment plant?
  • What permitting or other regulatory approaches are you aware of that in your opinion provide a good basis for any rulemaking in this area?
  • What treatment technologies have POTWs with separate sanitary sewer systems used successfully to manage peak excess flows during wet weather? How effective are these technologies at meeting effluent limitations? What are examples of technologies addressing other pollutants not typically subject to discharge requirements in NPDES permits (e.g., pathogens)? Related to these questions, do you have supporting treatment efficacy data that you would be willing to share with EPA for this rulemaking?
  • What are your specific suggestions regarding conditions that could be included in NPDES permits to allow diversions of some peak flows around biological treatment units to protect the treatment plant? Considerations could include:

—What information might the NPDES permitting authority need in order to determine whether such diversions are necessary to protect the treatment plant?

—Should the number of times such diversions are permitted to occur be limited or reported?

—Are there any requirements that should be considered for ensuring that the treatment plant is operated and maintained in an effective manner to minimize the number of peak flow diversions that occur?

—What requirements would be appropriate for ensuring that maintenance of the collection system to minimize the introduction of stormwater into the sanitary system through inflow and infiltration is occurring?

—What monitoring and reporting requirements would be important to demonstrate that applicable effluent limits are still being met?

—How may the permit ensure that public and ecological health is protected?

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Authority: Clean Water Act, 33 U.S.C. 1251 et seq.

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Dated: August 24, 2018.

Martha Shimkin,

Acting Director, Office of Wastewater Management.

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[FR Doc. 2018-19016 Filed 8-30-18; 8:45 am]