- WEB EXCLUSIVE
- PE COFFEEHAUS
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. The EPA estimates that there are at least 23,000 to 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 snowmelt 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 website at this URL link.
The Office of Wastewater Management of the EPA 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, SSOs and peak wet weather discharges at POTW treatment plants. The 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 not-for-profit environmental groups. The agency 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, the EPA requests that you pre-register by July 6, 2011 at www.epa.gov/npdes/sso.