As much as 5 million gallons of untreated sewage spilled into Bush Creek in the Abingdon area after a major sewage main broke late last week, according to Harford County public works officials.
Public works crews and a local heavy construction contractor worked through the weekend to repair a break in a 30-inch concrete pipe that was discovered around noon Friday by a pumping station mechanic that had visited the Bush Creek station, according to Joel Caudill, deputy director of public works in the Water and Sewer Division.
The operator said he noticed the wastewater flowing across the ground when he was leaving the station in the 700 block of Pamela Drive and hadn't noticed anything when he arrived, Caudill wrote in an e-mail Monday. In addition, the county didn't receive any reports of sewage odor from the area.
"We are still gathering flow data to determine the amount – a rough estimate is approximately 5 million gallons," Caudill wrote.
The pumping station handles million gallons of sewage collected along the Route 24 corridor. Bush Creek is a tributary of Bush River which flows into the Chesapeake Bay.
The break was caused by tree roots that grew into the pipe about 500 feet away from the station. The roots grew through a joint over time, according to a county government news release.
The county used its tankers and contracted with septic haulers to pump and haul as much as it could to a another portion of the county collection system, Caudill wrote.
"We were also able to retain a portion of the wastewater in the collection system but our storage was exhausted by 10 p.m. on Friday night and the wastewater flowed out of some manholes near the station," he continued.
The repair was made as soon as possible after it was discovered, he said, noting that time was needed to mobilize
Personnel and equipment had to be mobilized on-site, the pipe had to be excavated (it was 10 feet under ground) and the structural condition of the pipe had to be assessed to determine a repair strategy.
Temporary repairs were made but they also required a relatively long period of time because a lot of concrete was needed and the concrete required cure time before the county could repressurize the line.
"If we didn't allow enough time for the concrete to develop strength it may not have held up to the pressure of the pumps we could have lost the whole thing again and set us back even longer," Caudill wrote.
The temporary repair included having Comer Construction cut out section of a pre-stressed concrete cylinder pipe and install a section of ductile iron pipe. That pipe couldn't be joined together without a specially made transition coupling, so the county adapted with materials that were available.
The temporary repair was tested Saturday evening and pumping was resumed by about 5:30 p.m., Caudill wrote.
The county hopes to have the fabricated transition pieces available by Wednesday and will make the permanent repair by this Friday, he said.
The Maryland Department of Environment and the Harford County Health Department were notified.
"The most serious concern for the Bush River is the bacterial contamination that results from sanitary sewer overflows," Caudill wrote. "People should avoid contact with the water. Signs have been posted advising the public to avoid contact with the water in the vicinity of the overflow. We are working with the health department and will maintain the signs until they advise that they can be removed."