A federal judge Thursday approved a massive Hudson River cleanup project that could ultimately require the General Electric Co. to spend upwards of $700 million to dredge polychlorinated biphenyls, or PCBs, from the river.

In addition to clearing the way for the long-delayed cleanup, Northern District Judge David N. Hurd upheld the authority of the Environmental Protection Agency to define the boundaries of a Superfund site. The ruling gives the government wide berth in bypassing local waste disposal regulations.