Chemical to be added to Pittsburgh drinking water to reduce lead contamination
Pittsburgh Water and Sewer Authority has received state approval to add a chemical to the drinking water supply to reduce lead contamination from lead pipes and fittings.
PWSA Executive Director Robert Weimar said the authority plans to start adding the chemical, orthophosphate, by August. The authority selected orthophosphate over other options after conducting a study to test the effectiveness of various additives. Orthophosphate forms a protective coating inside lead pipes, preventing lead from leeching into the water.
Weimar said he expects to see reductions in lead levels by year's end.
“Normally it's a three-month minimum, six-month process,” he said. “We're anticipating by the end of the year we'll see some marked reductions in some areas. Probably by June of next year we'll be in position to say that we've succeeded in abating the problem throughout the city.”
PWSA submitted the study to the state Department of Environmental Protection on March 30 and regulators approved the additive this month. PWSA intended to begin adding orthophosphate in March. Weimar said it took longer than expected to get DEP approval.
The authority will stop using soda ash and lime to reduce lead containment once it begins adding orthophosphate.
He said PWSA needs to install equipment to feed the chemical into the system, estimating the total cost at $2.5 million. DEP must approve that work.
PWSA submitted an application May 10 detailing its plans to construct four stations for adding the chemical: one at the Aspinwall Pump Station, one at the Bruecken Pump Station and two near the Highland 1 reservoir.
“We don't have a firm (equipment) delivery date yet,” Weimar said. “That's really going to determine when it starts up.”
The authority has started preparing for the new additive by flushing the entire system. Customers could experience water discoloration over the next few months.
PWSA has been exceeding a federal threshold for lead since summer 2016. Its most recent 90th percentile result, reported to the U.S. Environmental Protection Agency in January, was 21 parts per billion . The threshold is 15 parts per billion.
Results from the latest round of lead testing, now underway, are due in July. Weimar said PWSA would continually monitor and test water after adding the orthophosphate. He said lead testing in December should reflect the chemical's impact.
Marc Edwards, a Virginia Tech water quality expert who helped expose the water contaimination crisis in Flint, Mich., said orthophosphate is usually effective and could result in a single-digit lead level for PWSA.
“Very good things tend to happen when orthophosphate is added to systems with lead pipe,” Edwards told the Trib in September. “Single digits are probable within 18 months, as long as they do not skimp on dose. In England, to really control release from lead pipe, they dose about one part per million as phosphorus, which is about three to four times the typical dose in the U.S.”
Theresa Clift is a Tribune-Review staff writer. Reach her at 412-380-5669, firstname.lastname@example.org or via Twitter @tclift.