By Gary Budzak firstname.lastname@example.org
April 8, 2014
City of Delaware home owners may have noticed a “Drinking Water Notice” with their April water bills. The city said it doesn’t expect to have to issue any more of these notices in the future.
“One of the results of the improvements at the water plant is that this will no longer be an issue we’ll have to deal with anymore,” said Community Affairs Coordinator Lee Yoakum. He said the $30 million improvements to the water treatment plant is being done in stages through 2015.
The new plant will use ultrafiltration and nanofiltration membranes to treat the water.
The notice said “that trihalomethane levels in the public water system exceeded drinking water standards.” Trihalomethanes (TTHM) are formed when organic materials (such as fall foliage) react with the chlorine and chloramine used to disinfect water. The average level of TTHM over the last four quarters was 0.095 mg/l, and the standard is 0.080 mg/l.
“Often a sample or reading like this will show up in areas where there’s not a lot of water usage,” Yoakum said. “This sample was in the southeast part of the city where we have recently installed a significant amount of water infrastructure in anticipation of new development in that area. Because there has not been the level of development, there’s not been the level of water usage.”
Although the problem with TTHM levels is only in the southeast portion of the city, the notice appears on all Delaware residents’ water bills.
A similar notice was issued in December.
“Because of it being a rolling average, until it rolls through the final quarter, we’re required (by the Ohio Environmental Protection Agency) to notify water customers,” Yoakum said of the elevated TTHM levels.
The bill said, “The levels detected do not pose an immediate health risk and it is not necessary to use alternative (bottled) water sources.”
According to the city, a person drinking water containing TTHM in excess of the standards “would have to consume two liters of city water every day for 70 years for there to be the possibility of liver, kidney or central nervous system problems and increased cancer risk.”
The City’s Public Utilities Department have done several things to reduce the TTHM levels, Yoakum said.
“We’re pumping additional groundwater from our three groundwater wells and decreasing the surface water intake. What this does is it reduces the amount of potential organic materials that are in a raw water source. We also added a powder-activated carbon material, and what this does is it helps settle out any of the remaining organic materials that might be in a raw water source.”
As a result of this, the most recent sample results show TTHM levels of 0.043, nearly half the maximum contaminant level of 0.080.
“The steps that we’ve taken have corrected the problem, and we’re confident we won’t have the higher readings again that we had in the past,” Yoakum said.