Safety of chloramines questioned: Disinfectant to be added into local water supply starting in 2014
The Rivanna Water & Sewer Authority is making plans for a new approach to treating drinking water in the city of Charlottesville and in Albemarle County’s urban ring.
Chloramines disinfection equipment in Los Angeles, CA
Photo used by permission of LEE & RO, Inc.
Download chloramine documentation
March 9, 2012 memo summarizing basis for chloramines project
July 2011 Executive Summary from consultant Hazen and Sawyer
EPA background information on chloramines
Starting in 2014, the RWSA intends to replace chlorine with chloramines as the second step in the water treatment process. The water authority says it is being compelled by tougher federal regulations, and that chloramines are the best bang for the treatment buck.
Upgrading system facilities and adding new equipment could cost more than $9 million, but RWSA officials say other alternatives that would satisfy Environmental Protection Agency requirements would cost even more.
However, some local residents and members of Charlottesville’s City Council are questioning the risks versus the benefits, particularly when RWSA’s own data show the water supply is currently acceptable by federal standards.
“We can’t confidently meet these new requirements with the process that we have now,” Thomas L. Frederick, Jr., the RWSA’s executive director, said in an interview. “We have to make a change.”
As first reported by Charlottesville Tomorrow last month, the RWSA has approved a new capital budget that allocates $9.3 million toward the project. While the urban areas get chloramines, the water treatment plants in Crozet and Scottsville are recommended to receive a carbon filtration system with continued use of chlorine.
“They create a lot of byproducts that aren’t as well studied as the traditional chlorine byproducts,” Staengl said in an interview. “It is unclear to me why the RWSA wants to put chloramines in the water. I don’t see the need for the measure.”
The discussion by the council triggered the RWSA to prepare a four-page memo explaining the project. It notes that the RWSA currently uses chlorine as both a primary and secondary disinfectant.
“Secondary disinfection is a trace residual disinfectant that remains in the water to prevent re-infection as it moves through the RWSA transmission pipelines and the city or [Albemarle] distribution pipelines,” the memo explains.
In order to meet more stringent EPA regulations, the RWSA plans to switch from free chlorine to chloramines in 2014. To do so, the RWSA will need to enlarge its current water holding tanks so they can ensure the water has fully reacted with the chloramines before being distributed.
Chloramines are created through the combination of ammonia and chlorine, creating a more stable compound. Increased stability means chloramines will remain present in the water, disinfecting it as it travels through the pipes.
Traditional chlorine reacts with organic matter in the water to form two disinfectant byproducts, trihalomethane and haloacitic acid. The EPA states they are carcinogenic if ingested in high doses. Chloramines produce a significantly lower amount of these carcinogens.
The EPA’s regulations call for haloacitic acid levels to be less than 60 parts per billion and trihalomethane levels to be less than 80 ppb. The RWSA’s haloacitic acid levels currently vary between 19 and 42 ppb and its trihalomethane levels are between 22 and 58 ppb; both values are well within the legal limit.
So why switch to chloramines? RWSA consultant Hazen and Sawyer concluded continued compliance with federal regulations “could not be assured without capital construction upgrades.”
“The addition of chloramines to the present process was, by a significant margin, the most cost-effective of the techniques that will comply with the new regulations,” Frederick said. “The study also confirmed that, as important as watershed protection is, further water treatment techniques are required.”
“There is no mandate that a system use chloramines,” said Victoria Binetti, associate director of the Water Protection Division for EPA Region 3. “The requirement is that the standards for disinfectant byproducts be achieved.”
Binetti stated that the EPA also supports other methods of water disinfection and filtration. Some citizens have said that they would like the RWSA to pursue other types of filtration or enhanced watershed protection measures to reduce the amount of treatment required.
“The [World Health Organization] recommends not using chloramines but using better filtration systems upfront. I would like to see the RWSA pursue that method,” added Staengl.
Frederick’s memo makes clear other alternatives were considered, including complex filtration methods and the use of UV light. Those ranged in costs from $11.2 million to almost $36 million in capital costs alone. Hazen and Sawyer determined that a chloramine facility would be the most cost-effective approach.
The EPA acknowledges that risk assessments have shown uncertainties regarding the health effects of chloramines. Chloramines are toxic when exposed directly to the blood stream and can corrode pipes under certain conditions. If treated water were to leak into waterways it could harm aquatic life forms that breathe through their skin or gills.
“One of the big things involved with chloramines is that it doesn’t dissipate like normal chlorine does. The potential for it to go into streams is a lot higher,” said Lonnie Murray, a new member of the Thomas Jefferson Soil and Water Conservation District. Speaking for himself, Murray said, this is disconcerting because “[chloramines] decrease the ability of fish to breathe.”
Because of the changing water chemistry, the RWSA will not be the only group monitoring the use of chloramines. It presents a potential problem for medical and biotech facilities where special filters may need to be installed to remove the chemical before the water can be used.
“Our partners — the city of Charlottesville and the Albemarle County Service Authority — are in the process of learning [what additional] monitoring they will need to do in the future within the pipes that they own that distribute the water to homes and businesses,” Frederick said.
The RWSA says it is confident the chloramines will not negatively impact the public if they are correctly monitored.
“At the levels we’re talking about there is no concern about [health] problems,” Frederick said. “There is going to be a higher level of effort [to monitor], but it will be equally safe for the public to drink.”
Frederick’s March 9 memo to the RWSA board concludes that stopping the project has its own risks, including fines of up to $25,000 per day for non-compliance.
“Unless elected officials are willing to fully support and ‘champion’ much higher water rates … stopping this project would be very risky,” Frederick wrote. “Our drinking water regulations come from the federal government through EPA, and the federal law does not allow compliance or non-compliance with those regulations to be at the discretion of local officials.”