Controlled Sanitary Sewer Overflow at Piscataway Wastewater Treatment Plant for Maintenance

Valve Needed Repair - Overflow Volume Update

| News Release



Laurel – March 18, 2016: An emergency bypass pumping system was activated at the Piscataway Wastewater Treatment Plant (WWTP) in Accokeek Tuesday March 1, 2016 as a result of a controlled Sanitary Sewer Overflow (SSO).

The bypass was required so crews could repair a valve at the plant’s raw wastewater pumping station (WWPS). Untreated domestic wastewater was pumped and retained in an onsite pond that was formerly part of the treatment process at the plant.

The valve was serviced and closed and the bypass pumping was stopped. An estimated net volume of 625,200 gallons of untreated domestic wastewater seeped into the ground in the unlined dry pond at the plant.

After the majority of the initial discharge of stored wastewater was pumped out of Pond 2B (on-site pond) and returned to the raw wastewater pumping station (WWPS) at the Plant for treatment. Pond 2B was flushed with Piscataway final effluent (fully treated) on four dates:

  • Friday, March 4 (2.16 million gallons)
  • Saturday, March 5 (3.71 million gallons)
  • Tuesday, March 8 (3.17 million gallons)
  • Friday, March 11 (5.91 million gallons)

All flushing water was pumped back to the Plant’s raw WWPS for full re-treatment prior to discharge at the normal Piscataway WWTP discharge point. A revised conservative estimate of seepage into the ground of unlined Pond 2B is 625,200 gallons.

This emergency operation was preapproved by the Maryland Department of the Environment (MDE). Prince George’s County Health Department was also notified.

WSSC is committed to protecting the health of the public and the environment. With more than 5,400 miles of sewer mains throughout its service area, WSSC appreciates notification from citizens if a sewer back up is suspected.  Citizens can call 301-206-4002 or toll free 1-800-828-6439 at any time to report water or sewer emergencies in Prince George's or Montgomery counties.

WSSC Water is the proud provider of safe, seamless and satisfying water services, making the essential possible every day for our neighbors in Montgomery and Prince George’s counties. We work to deliver our best because it’s what our customers expect and deserve.

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