Metropolitan Boston, last in the nation to come to grips with a sewage-pollution problem in its harbor, is a small step closer to a cleaner Massachusetts Bay, according to the regional administrator of the Environmental Protection Agency. In an announcement Tuesday, EPA's Michael R. Deland said the 500 million gallons of waste water that flow through the area's sewer system each day must have additional treatment, even though that treatment will be much more costly to provide. Currently the system provides only primary treatment, which skims, settles, and disinfects the waste stream before releasing the effluent into the harbor.
Mr. Deland said secondary treatment, which is more sophisticated, removes 85 percent of major pollutants and more than 90 percent of the toxic chemicals that end up in the sewer system. Secondary treatment is the ``minimum level of treatment'' mandated by the federal Water Pollution Control Act of 1972, he noted.
Deland's decision came as a rebuttal to the state, which had applied to waive the requirement for secondary treatment. The state had proposed a more advanced level of primary treatment, but wanted to discharge the waste nine miles out into Massachusetts Bay.
Deland said the EPA recently denied a similar proposal for Puget Sound near Seattle. That waiver was turned down because the waste water would be released in an area that was not deep enough, at 600 feet, to be safe for marine life. In the Massachusetts proposal, he noted, the wastes would be discharged in water only 118 feet deep.
During the past decade, the idea of building a new sewage-treatment plant has met with a giant wave of political opposition, even though the present facilities are decrepit and inadequate.
But the political sands appear to be shifting. James S. Hoyte, Massachusetts secretary of environmental affairs, said Tuesday that the state now supports the EPA's decision and will not appeal it.
``The time has come to move on to the job of cleaning up Boston Harbor in the most expeditious manner,'' he said.
Even so, the requirement for secondary treatment will make the job of the state's new Water Resources Authority much more difficult. The authority has yet to decide on a site for the new facility, and a battle is heating up between Winthrop, Mass., and the City of Boston. Winthrop residents, who have lived with the stench of the existing sewer plant for almost 30 years, don't want a new plant in their backyard.
But Boston officials say the other option, the city-owned Long Island, is slated to become a recreation center for metropolitan residents.