UA-8412995-1 The Southport Globe: How to remove contaminated sediment from Mill River

Friday, March 2, 2012

How to remove contaminated sediment from Mill River

The 6.2-acre vacant lot of the former Exide Group Inc.'s battery factory at 2190 Post Road will be the staging facility for the removal of about 21,500 cubic yards of lead-contaminated sediment from Mill River.The process is complex, involving heavy machinery and innovative engineering work, and is expected to begin this summer, according to Robert Bell, assistant director of the remediation division of the state Department of Energy and Environmental Protection.
First, engineers bore for sediment cores, using aluminum rowboats and onboard GPS units, sometimes dredging as far as three feet below the river bottom.
The vacant plot will be the primary access point to the river, the center for de-watering, handling and stockpiling equipment, and offices for contractors and officers, according to the October 2011 "Remedial Plan for Lead Impacted River Sediments."
Although there may be minor adjustments to the proposal, which is an agreement between Exide Group Inc. and the state DEEP, remediation plans will mostly be retained, said project manager Ralph Klass.
Once sediment "slurry" is pumped from Mill River, it will be moved to the upland staging area, where it can be "de-watered" so contaminated sediment cake can be transported cost-effectively to out-of-state permitted landfills, according to the proposal.
The plan has drawn contaminated river areas into five subplots, with an average of 4,300 cubic yards to be removed from each, using "hydraulic cutterhead dredging."
Most dredging will occur in "Area 3," the stretch of river just south of Post Road toward Southport Harbor. READ MORE: http://www.acorn-online.com/joomla15/fairfieldsun/news/localnews/116078-how-to-remove-sediment-from-mill-river.html

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