Hamilton Kent Blog

A watertight solution for WSSC

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The Washington Suburban Sanitary Commission (WSSC) is the eighth largest water and wastewater utility in the nation, with a network of more than 5,400 miles of sewer pipeline and 5,500 miles of fresh water pipeline serving 1.8 million residents in Prince George’s and Montgomery counties in Maryland since 1918.


Part of this vast network is located in beautiful, environmentally sensitive Maryland woodlands, so when Sanitary Sewer Overflows (SSOs) occur, it is especially serious.


The Maryland counties’ SSO problems were brought to the forefront when WSSC entered into an SSO-specific consent decree with the U.S. Environmental Protection Agency, the Maryland Department of the Environment and the U.S. Department of Justice.


In response to the decree, the WSSC developed a Sewer Basin Repair, Replacement and Rehabilitation Plan (SR3) to identify and repair areas contributing to SSOs.


As part of the plan, WSSC conducted a Flow Monitoring and Collection System Modeling, finding that access points from manholes have been a major contributor of inflow and infiltration (I/I), particularly during rain events.


Complicating the problem was that the SR3 plan includes 24 environmentally sensitive areas (ESAs), some of which contain manholes requiring rehabilitation or replacement. Permits and access to these areas is problematic and due to restricted vehicle access, the replacement manhole systems had to be light enough for crews to carry in by hand.


Clearly, an innovative solution was needed.


In order to meet its existing spec for ESAs, as well as the mandate set out in the SR3, WSSC selected The Lifespan System as its manhole frame and cover system of choice.

WSSC selected Lifespan for a variety of reasons: firstly, the repairs had to be executed with minimal tree clearing and ground disturbance. Lifespan’s rubber frame and lid were light enough for crews to hand-carry into the wooded areas, reducing the need for vehicle access.

Secondly, the solution had to be watertight, not just water-resistant. Lifespan’s locking mechanism not only creates a watertight seal between the lid and the frame, but also helps ensure the lids will remain securely in place long-term, a bonus for manholes located in remote areas.

And finally, the solution was expected to prevent surcharge into the ESAs. The Lifespan System® is securely bolted and sealed to the manhole structure itself. In combination with the watertight frame and lid, it is a sure-fire strategy for eliminating surcharge.

As you can see in the gallery below, the wooded areas where the ESAs are located are quite scenic. We think Lifespan does the landscape justice quite nicely – but what can we say, we’re the proud parents!





Related content: "Does your submarine have a screen door?" Join Hamilton Kent's Henry Flattery as he explains how Lifespan can help solve I/I problems associated with traditional manhole systems.