ALCOSAN More Than Doubling Wastewater Treatment Plant To Diminish Sewage Overlows

Jan 30, 2018

The Allegheny County Sanitary Authority, ALCOSAN, expects to design the expansion of its treatment plant this spring, with construction beginning in late 2019. 

The build out is part of ALCOSAN’s Wet Weather Plan, which was created to bring the authority into compliance with the federal Clean Water Act by eliminating sanitary sewer overflows and to decrease combined sewer overflows.

A 2008 consent decree from Pennsylvania’s Department of Environmental Protection and the Allegheny County Health Department requires ALCOSAN to meet those goals by September 2026. That deadline is expected to be extended to 2032 or 2036, said the authority’s Executive Director Arletta Scott Williams.

“We got to a point where we and the regulators recognized, ‘You’re not going to be able to accomplish this in the time period that we wanted you to,’” she said during a presentation at ALCOSAN’s annual public meeting on Tuesday. “I like to say you can’t get blood from a turnip. There’s only so much money and resource available.”

Negotiations are ongoing.

ALCOSAN treats wastewater for 83 of the county’s 130 municipalities. Located on Pittsburgh’s North Side, under the McKees Rocks Bridge, the plant can currently handle 250 million gallons per day. By 2027, it will be retrofitted to manage 600 million gallons per day.

Some nine billion gallons per year of diluted sewage—rain or snowmelt mixed with sewage—overflows into rivers and streams, said Scott Williams. While the authority will invest roughly $2 billion in infrastructure upgrades under the Clean Water Plan to handle increased flow, officials say that investment includes prioritizing green infrastructure projects to divert water before it ever gets to the conveyance and treatment system.

With the expansion of the wastewater treatment plant, rates are expected to increase. However, Scott Williams said affordability remains one of the authority’s main concerns.