As reported by the Los Angeles Times, the city of Los Angeles is seeking federal permission for an subterranean experiment that could both resolve a messy environmental situation and alleviate tensions with rural neighbors over sewer sludge dumping, officials say. If the unprecedented plan is approved, the city would inject treated sludge into a nearly depleted oil and gas reservoir underneath Terminal Island in the Los Angeles Harbor. The reservoir is located one mile below the ground and a half mile under the water table.

The paper reports that the proposal could appease residents in Kern and Riverside counties where coal-black muck - the final product of treated urban wastewater - has been dumped on farmlands for years. However, many concerned citizens are worried about potential contamination of freshwater sources. Also, officials expect opposition from harbor-area residents, many of whom think there already has been too much pollution dumping in their neighborhood.

According to the request filed with the U.S. Environmental Protection Agency, the pressure at that depth and the high temperature would theoretically kill disease-causing microbes within 24 hours. Furthermore, entombment under layers of impermeable clay and shale would prevent contamination of ground water, the Times reported.

Nevertheless, George Robin, environmental engineer for EPA Region 9, told the newspaper that the city and its partner, Terralog Technologies USA Inc., an Arcadia, Calif., firm that currently holds patent on the untested technology, have "a lot of proving to do before a permit can be granted."

Terralog president Michael Bruno told the Times that while the process has not been tested on treated human wastes, his company has already used its technology to inject a less controversial waste product - oil sludge - beneath the earth in Alberta, Canada, and in La Habra in Orange County. And he has extreme confidence in the project, saying, "With two to four wells at Terminal Island, we could handle all of Los Angeles' treated sewer waste for at least two decades."

EPA officials are not expected to give a final determination on the $3-million, three-year project until early next year.