ALCOSAN says to stay out of Pittsburgh-area waterways for 48 hours after power outage at plant

The Allegheny County Sanitary Authority is advising people to stay out of local waterways for 48 hours after a power outage at its wastewater treatment plant.

A "full" power outage at the plant happened on Friday between 6 p.m. and 8 p.m., the authority said in a news release. ALCOSAN could not process wastewater during the two-hour outage, leading to the plant's wet well filling to capacity. This led to a discharge into the river, according to ALCOSAN. 

Per standard procedures, ALCOSAN said the public should limit contact with river water when boating, fishing, water skiing, or participating in any other recreational activity in the river for 48 hours.

Three power feeds from Duquesne Light usually come into the plant, according to ALCOSAN operations director Doug Jackson. At first, two feeds went down, then 10 minutes later, the third went down. 

"I've been with the authority for almost 36 years, and I've never experienced a time where we've lost all of our feeds from the utility and caused this event to occur," Jackson said. 

In total, around 20 million gallons of raw sewage were discharged into the river in the two hours they were down, Jackson said. For comparison, the plant treated a duration of 270 million gallons of wastewater on Friday. 

The complex treats the wastewater of 850,000 people across the county. When it went down, the already nearly at-capacity system, due to rain, had to send all new wastewater into the rivers. 

"We took extreme measures to make sure that not only the folks within the region are protected and notified of the impact that might be out there," Jackson said. 

ALCOSAN issued an advisory similar to what it releases during the summer when storms cause rainwater to overwhelm the system, forcing wastewater to be sent into the rivers. 

"It is really to advise folks to try to avoid contact with the waterways, because there is a higher level contributed by our overflows, primarily bacteria in the rivers," Jackson said.

They do have an emergency generator, but Jackson said it has a small capacity and is only used for critical needs, for instance, for parts of the facility that have to be kept "on" or else they could face a catastrophic failure. In other words, there's no backup generator to power the full process. 

"The on-site generation that we would need for as large of [an] electricity supply [as we use] had never been factored into our contingency planning, just because of the reliability and service that we've gotten over many, many years from Duquesne Light," Jackson said. 

They plan to conduct a debrief to examine whether their discharge could have been prevented, which could include making capital expenditures, Jackson said.  

While discharges happen regularly due to the storms, each one is something they would like to avoid. To that end, they are making upgrades to their system, which should lead to fewer discharges

The authority said Duquesne Light was contacted and restored power to the facility on Friday. 

"All partnering water agencies have been notified, as well as state regulatory authorities, including the Pennsylvania Department of Environmental Protection," Friday night's press release said. 

ALCOSAN said it will continue to monitor the situation and provide more updates over the weekend if additional information becomes available.