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Arsenic-Laced Sludge Heads for Landfill

July 17, 2012

NEWPORT CITY – A high level of arsenic has changed the way the city disposes of its sludge from the city’s treatment facility.
Arsenic in certain forms is a carcinogen and in other forms it can be a poison. 
Newport previously disposed the sludge in cornfields near the Newport State Airport runways. However, Ernie Kelley, section chief of the residuals management section of the VT Department of Environmental Consevation said that, because of security concerns at airports in general, Newport City started spreading the sludge on land owned by New England Waste Services. Now, because of the change in state regulations regarding allowable arsenic levels, Newport can no longer spread the sludge there.
The department, after consulting with the Vermont Department of Health, lowered state standards for arsenic from 50 parts per million to 15 parts per million. The new standards went into effect March 15. The Vermont Department of Health initially wanted to set the standard set at 10 parts per million.
“Because of the complex nature of sludge, it is difficult for a laboratory to be able to measure arsenic down to 10 parts per million,” Kelley explained during a telephone interview Tuesday. “You get inference from all the other organic material and everything else that’s in there. We didn’t want to set a standard that typically laboratories can’t show whether you're meeting or not.”
Vermont’s standard is significantly lower than the federal standard, which is 41 parts per million.   
The Newport City Council, Monday evening, accepted a proposal from We Care Organics to "dewater" sludge from the wastewater treatment plant for an estimated cost of $70,010.
The work will consist of taking about 700,000 gallons of sludge from a storage tank at the wastewater facility and pumping it to a portable trailer mounted centrifuge complete with grinder, polymer dosing systems and a discharge conveyor. There it will be "dewatered" and turned into a filter cake containing 20 percent to 25 percent solids. Staff from the New England Waste Services Landfill will pick up the container, empty it at an approved landfill, and bring it back to the city.
The Newport area traditionally has had naturally high levels of arsenic in groundwater, something that leaves state officials scratching their heads. Some communities, like Newport City, have treatment facilities that remove high levels of arsenic before it goes into the water system. The problem lies on water systems outside the municipal water system. Newport City takes waste from communities not on the city system.
“The treatment plant is really the only one in that region that can take septage that’s pumped from onsite septage systems rather than being on the municipal water system” said Kelley. “They take fairly significant volumes of septage at that plant for treatment"
Kelley believes the arsenic is coming from homes that are not on an arsenic removal system. Kelley said he would like to identify the source of the arsenic.
“It is the highest we’ve seen in any treatment plant in the State of Vermont,” said Kelley. “That would entail a fairly expensive investigation.  We would need to go out and take numerous, numerous samples from really all locations in the collection system and the septage that’s coming in.”
The city can’t simply stop taking septage from outside Newport, Kelley said.
“That would leave a large chunk of the Northeast Kingdom really with greatly increased costs of having to truck it to another treatment facility,” he said. “The cost of that alone will affect the maintenance of septic systems.”

 

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