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April 21, 2012

Chemical engineer briefs ACSA on chloramines

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DailyProgressBy Sean Tubbs
Charlottesville Tomorrow
Saturday, April 21, 2012

A chemical engineer with the firm Hazen and Sawyer briefed the Albemarle County Service Authority Thursday on the forthcoming use of chloramines to disinfect treated drinking water. 
 
“Chloramines have been in use since 1917 and we have a very long history of using [them],” said Ben Stanford, director of applied research at Hazen and Sawyer. 
 
The Rivanna Water & Sewer Authority uses free chlorine to remove bacteria and viruses from raw water as its primary disinfectant. The U.S. Environmental Protection Agency requires water treatment plants to use a secondary disinfectant to ensure no bacteria or viruses re-enter the treated water as it passes through the distribution network. 
 

 

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Currently the RWSA also uses free chlorine as its secondary disinfectant, but that chemical will not allow the agency to meet higher standards that will be in effect in October 2014. 

“More utilities across the country have said [they] can no longer do free chlorine as a secondary disinfectant because of the need to meet these increasingly stringent regulations,” said Thomas L. Frederick, Jr., the RWSA’s executive director. 
 
The RWSA hired the firm Hazen and Sawyer to evaluate potential secondary disinfectants. They met with ACSA and city utilities staff and presented several options. 
 
“To convert our secondary  disinfectant to chloramines to meet the EPA’s stage 2 rule would result in $5 million in capital costs… and an additional $102,000 in operating costs a year,” Frederick said. “The next cheapest alternative to meet the stage 2 rules is add granular activated carbon filtration to the water treatment plant. That capital cost is $18.3 million.” 
 
Frederick said ACSA and city staff recommended going with chloramines, a move that was approved by the RWSA board as part of its capital budget. 
 
However, some people have expressed concerns that chloramines will present health and environmental risks. An online petition organized by city resident Galen Staengl claims that byproducts can be carcinogenic and can cause lead to leach from water pipes. 
 
Stanford acknowledged that these by-products can be carcinogenic if they are present in very high levels, but he said the amount used in water treatment is well below the threshold. 
 
“Both free chlorine and chloramines form the exact same disinfection by-products,” Stanford said. “What’s different is the ratio and the amount that’s formed.”  
 
With respect to lead and problems with chloramines in Washington D.C., Stanford said that water system experienced higher lead levels due to human error and that chloramines were not directly responsible. 
 
“When they switched, they did not control for the change in water chemistry,” Stanford said. “Their pH changed and they did not add a corrosive inhibitor.”  
 
Stanford added that the D.C. system continues to use chloramines today, and that Hazen and Sawyer will take steps to make sure that does not occur in the RWSA’s urban system. 
 
The petition also states that chloramines will lead to fish kills in public water. Stanford disagrees. 
 
“Both free chlorine and chloramines will kill fish,” Stanford said. “If you have a massive main break of chlorinated water and chloraminated water, both of them have the same potential to kill fish…. I’ve never once heard of a case of fish being killed from responsible or irresponsible lawn-watering or from swimming pools being drained into yards.” 
 
Another change will be that people who own fish as pets will have to add sulfate to their water to counteract the chloramines. 
 
Steps will also need to be taken to protect some special populations on the water system.  For instance, Stanford said chloramines will pose a risk to people who need to go through dialysis. 
 
“We don’t want chloramines directly interacting with the blood stream as they would in a dialysis center,” Stanford said. “It’s a very easy thing to treat the water to the level needed to remove the chloramines out to make it safe and effective.”
 
Gary O’Connell, executive director of the ACSA, said the agency is already reaching out to hospitals and dialysis centers to make them aware of the change. 
 
Frederick said the RWSA must comply with the tougher guidelines by October 2014. Implementation is set to begin in March 2014.
 
“The EPA… makes decisions and promulgate regulations and then they give water utilities across the country a very tight time-frame to comply,” Frederick said. “We do not have time to stop and talk about this if we’re going to comply with the deadline.” 
 

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