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Notice of EPA Workshop on Sanitary Sewer Overflows and Peak Wet Weather Discharges

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Environmental Protection Agency (EPA).




The Office of Wastewater Management of the U.S. Environmental Protection Agency is holding a workshop to solicit the views of stakeholders concerning a number of issues. These include views on how the National Pollutant Discharge Elimination System (NPDES) regulations should apply to municipal sanitary sewer collection systems, sanitary sewer overflows (SSOs), and peak wet weather discharges at publicly owned treatment works (POTW) treatment plants. EPA will also seek views on the 2005 draft Peak Flows Policy. The workshop will include a facilitated discussion with representatives of organizations that represent POTWs, state NPDES permitting authorities, and non-for-profit environmental groups. EPA invites other interested members of the public to observe the workshop and to offer verbal comments at designated times during the workshop or to submit written comments to the Agency.


The workshop will be held on July 14, from 8 a.m. to 5:15 p.m. and on July 15, from 8 a.m. to 12:30 p.m. If you plan to participate in the workshop as an observer, EPA requests that you pre-register by July 6, 2011 at​npdes/​sso.


The workshop will be held at the Ronald Reagan Building and International Trade Center, Horizon Ballroom, located in Washington, DC at 1300 Pennsylvania Avenue, NW.

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For further information about this notice, contact Greg Schaner, EPA Headquarters, Office of Water, Office of Wastewater Management at tel.: 202-564-0721 or e-mail:

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I. Background

Properly designed, operated, and maintained sanitary sewer systems are meant to collect and transport all of the sewage that flows into them to a publicly owned treatment works (POTW). However, occasional discharges of raw sewage from municipal sanitary sewers occur in almost every system. These types of discharges are called sanitary sewer overflows (SSOs). SSOs have a variety of causes, including but not limited to blockages, line breaks, sewer defects that allow storm water and groundwater to overload the system, lapses in sewer system operation and maintenance, power failures, inadequate sewer design and vandalism. EPA estimates that there are at least 23,000-75,000 SSOs per year (not including sewage backups into buildings). The untreated sewage from these overflows can contaminate our waters, causing serious water quality problems. It can also back-up into basements, causing property damage and threatening public health.

Additionally, aging sewer line infrastructure in many communities allows rain and snow melt to enter sanitary sewer systems and cause excess flow at the treatment plant. During significant wet weather events it is possible for influent flows to exceed the treatment capacity of existing secondary treatment units. Known as “peak flows,” these wet weather flows are sometimes diverted around secondary treatment units and then either recombined with flows from the secondary treatment units or discharged directly into waterways from the treatment plant in order to prevent any damage to the treatment facility. Operators of wastewater treatment plants must manage these high flows to ensure continued operation of the treatment process.

For additional background on SSOs and peak wet weather discharges, refer to the “background” section of EPA's notice announcing the 2010 Listening Sessions at 75 FR 30395 (June 1, 2010) and to information included on EPA's Web site at​npdes/​home.cfm?​program_​id=​4.

II. 2010 Listening Sessions

In 2010, EPA held several listening sessions to obtain information from the Start Printed Page 35216public regarding the potential modification to the NPDES regulations to address SSOs and other types of peak wet weather discharges. See 75 FR 30395 (June 1, 2010). Participants in the sessions offered both verbal and written comments. The Agency received 235 written comments to the docket. You can view these comments at, under Docket ID # EPA-HQ-OW-2010-0464.

III. Purpose of SSO/Peak Wet Weather Flow Workshop

As a follow-up to the 2010 Listening Sessions, EPA will hold a 11/2 day workshop on July 14-15, 2011 in Washington, DC. The purpose of this workshop is to provide interested parties and other members of the public an opportunity to elaborate on their recommendations to the Agency with respect to actions that could be taken to strengthen the permitting program's approach to regulating SSOs and peak wet weather discharges. EPA has invited several stakeholder groups representing non-governmental interests, POTWs and collection systems, and state permitting authorities to recommend members of their community to participate in the workshop as experts. In addition to eliciting the views of the representative groups, EPA will also invite comments during the meeting from any member of the public who wishes to observe and participate at the workshop.

The specific issues that EPA is seeking feedback on have significant overlap with those highlighted for the 2010 listening sessions. See 75 FR 30399-30401 (June 1, 2010). For example, EPA will be interested in the views of the representatives and observers on whether and to what extent specific NPDES permit requirements should be developed to address the following:

  • How SSOs are reported to EPA or state permitting authorities and documented in POTW records, and how and when the public is notified of overflows;
  • What components of POTW programs for capacity, management, operations, and maintenance (CMOM) should be made part of standard NPDES permit conditions;
  • Whether to require NPDES permits for “municipal satellite collection systems”, and what types of requirements should such permits include; and
  • Are there any circumstances under which an SSO may be authorized under an NPDES permit.

EPA will also seek input on the disposition of the 2005 draft Peak Flows Policy (see​npdes/​wetweather.cfm) that pertains to wet weather diversions at POTW treatment plants.

It is not EPA's objective during the workshop to establish consensus among the parties or to obtain a collective set of recommendations. Rather, it is EPA's intention to obtain individual input from interested parties so that the Agency can better understand the differences and commonalities among the individual recommendations. In this regard, EPA has determined that this workshop is not subject to the requirements of the Federal Advisory Committee Act. 5 U.S.C. Appendix 2.

IV. Participation in the Workshop

Members of the public are welcome to participate as observers in the workshop. The agenda will be structured to invite specific verbal comments from observers on key issues. If you plan to participate as an observer at the workshop, in order that EPA may properly anticipate the correct number of people, EPA requests that you pre-register by July 6, 2011 at​npdes/​sso.

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

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Dated: June 7, 2011.

James A. Hanlon,

Director, Office of Wastewater Management.

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[FR Doc. 2011-15003 Filed 6-15-11; 8:45 am]