In less than six years, Honolulu must install a permanent replacement for the major Waikiki sewer pipe that ruptured last year and sent 48 million gallons of raw sewage into the Ala Wai Canal.

The U.S. Environmental Protection Agency could levy fines as high as $3,000 per day if the work is not completed by the end of 2012, under terms of an agreement the EPA and city plan to file in U.S. District Court.

The deal, which the City Council approved yesterday, includes numerous other sewer projects that officials estimate will cost $300 million in total.

"We need to do this work," said Mayor Mufi Hannemann. "With this agreement, we will be addressing that portion of our wastewater collection system that had not been addressed in the federal consent decree in 1995."

That agreement with the EPA, which remains in effect until 2019, requires a range of projects worth nearly $1 billion.

The city also may be required to upgrade two major sewage treatment plants, at Honouliuli and on Sand Island, which could cost another $1 billion.

Hannemann is pushing for a "global" settlement with the EPA that would resolve all the city's sewage disputes.

"I remain optimistic that we can continue our good-faith negotiations with the EPA on a settlement that is in the best long-term interests of the people of O'ahu," Hannemann said.

In addition to permanently replacing the Waikiki pipe — called the Beachwalk Force Main — the deal advanced yesterday will require the city to complete a temporary replacement pipe by the end of June. That project is well under way and should meet the deadline, officials said.

Two other force mains, or major pressurized pipes, will also be replaced under the agreement, and the condition of four others will be assessed.

The deal also will require the city to prepare contingency plans by the end of 2008 to contain future spills from the force mains.

Reach Johnny Brannon at jbrannon@honoluluadvertiser.com.