A nine-year, $600-million riverbed remediation in northeastern Wisconsin—the world’s largest river cleanup of its kind—is proving that dredging doesn’t have to be drudgery. Operating in a mode more akin to just-in-time manufacturing and with laser-like precision, contractors there are using a very efficient system of mapping, dredging and filtering river sediment as they clean up 13.3 miles of the lower Fox River near Green Bay, home to the largest concentration of pulp and paper mills in the world.
Over the course of the nearly decade-long project, the massive cleanup will dredge and process 3.8 million cu yd of sediment contaminated with polychlorinated biphenyls (PCBs) to levels reaching 3,000 parts per million. PCBs cause severe health problems for wildlife and are considered a probable human carcinogen. The U.S. Environmental Protection Agency and Wisconsin Dept. of Natural Resources (DNR) mandated the cleanup after identifying eight companies that had flushed 700,000 lb of PCBs into the river from the 1950s to the 1970s, mostly while making and recycling carbonless duplicating paper.