This animation illustrates how a standard Polychem chain and flight scraper system is assembled and installed.
Details effectiveness of first phase, as well as challenges encountered
After completing the first phase of dredging PCB-contaminated sediment in the upper Hudson River, the U.S. Environmental Protection Agency (EPA) released a detailed technical assessment of the work to a panel of independent scientific experts for review.
The EPA report and a similar one prepared by the General Electric Company (GE) are being submitted to the panel in accordance with the agreement under which GE performed the first phase of the dredging, to ensure that the Hudson River dredging project is evaluated using the best scientific and technical information. The EPA report details the effectiveness of the first phase of dredging, as well as the challenges encountered during the first dredging season. It also lays out the agency’s modifications to the engineering performance standards for dredging re-suspension, residuals and productivity proposed for the second phase of the project, set to begin in 2011.
“The Hudson River is a magnificent resource that has been negatively impacted by PCB pollution for decades,” said Judith Enck, EPA regional administrator. “The completion of the first phase of dredging, while not without problems, has gone very well and is moving us closer to achieving the goal of a cleaner Hudson River. The problems in Phase 1 will be addressed during the careful scientific review, which is now underway.”
During the independent peer review, EPA is also seeking public comments on the reports, which replace draft versions released last month. These comments will be provided to the panel members for consideration during their evaluation.
The panel has been asked to consider certain questions relating to the engineering performance standards and the monitoring program for Phase 2 of the project. EPA’s report includes the New York State Department of Environmental Conservation’s observations and recommendations as an appendix. The peer review panel will publicly discuss its views on the EPA and GE reports in May 2010. The panel members will then submit their individual views on the questions presented to them by EPA; these views will be compiled into a report, which is expected to be complete by the end of June.
Once the peer review report is completed, EPA will consider the panel’s recommendations and determine whether changes to the performance standards should be made.