Bay cleanup slow, steady

Nitrogen: Howard expects an expanded sewage treatment plant to reduce pollution of the bay.

November 09, 2003|By Larry Carson | Larry Carson,SUN STAFF

Howard County's sewage treatment plant is on the Chesapeake Bay Foundation's "needs improvement" list for nitrogen pollution, but county officials say completion next year of a major plant expansion should help change its status.

"We're working very diligently toward upgrading our nitrogen removal ability. There was a goal, which we are meeting," said county Department of Public Works Director James M. Irvin, referring to a promise not to put more nitrogen into Maryland's waterways despite enlarging the plant.

Theresa M. Pierno, a vice president of the foundation, a nonprofit group pressing for more progress in bay cleaning efforts, agreed that Howard "is moving in the right direction." But she reaffirmed that "the goal obviously is to get down to 3 milligrams [of nitrogen] per liter" - a level that would help reduce the total amount of nitrogen entering the bay from sewage plants.

Irvin characterized that goal as "a real leap of faith," even as the county attempts to reach it. Howard's plant, which is in Savage, was releasing 6.7 milligrams of nitrogen per liter of water last year, according to a foundation study, and should be down to 5.5 milligrams by next year, county officials said.

The foundation released a report last month that said only 10 of the 300 sewage treatment plants that release treated water into the Chesapeake Bay are using the right equipment to remove nitrogen, which spurs algae growth. Algae block sunlight and kill underwater plants that produce oxygen.

Only 14 of Maryland's 65 treatment plants were rated "good" or "excellent" in the report. The huge plants at Back River and on the Patapsco River that serve the Baltimore metropolitan area were rated "unacceptable" in the report.

Wastewater treatment plants account for about 20 percent of the nitrogen polluting the bay but are the easiest source to identify and improve. The foundation wants mandatory nitrogen-discharge limits on plant operating permits.

Maryland's plants have cut nitrogen discharges in half since 1985, but the foundation's leaders have said that is not good enough, especially as the area's population increases.

Howard's plant takes in two-thirds of the county's public sewer system waste, with the other third going to the Patapsco Wastewater Treatment plant in Baltimore's Wagner's Point. That plant was rated "unacceptable" in the report for discharging 16.9 milligrams of nitrogen per liter, though improvements there are under way. The Back River plant in eastern Baltimore County discharged 8.5 milligrams of nitrogen per liter.

The $48 million worth of construction at Howard's plant is more than 90 percent complete. Dan Ward, process control engineer for the county's Little Patuxent Water Reclamation Plant in Savage, said nitrogen released into the Patuxent River should be down to about 5.5 milligrams per liter when the three-year project is finished.

That amount is still above the foundation's goal of 3 milligrams per liter, but Howard officials say it should enable them to meet their primary goal - handling more waste without increasing the total amount of nitrogen going into the river and, ultimately, the Chesapeake Bay.

This winter, the county will try several pilot projects to find ways of achieving the 3-milligram goal, said Ward and Robert M. Beringer, chief of the county's utilities bureau. Howard is also exploring other ways to use treated wastewater without releasing it into the Patuxent River - such as irrigating parks and golf courses, and reducing construction dust. Dried, treated solid wastes are trucked to commercial landfills in Virginia.

"Overall, they're on track," said Richard McIntire, spokesman for the Maryland Department of the Environment.

Monthly figures on plant operations show the Savage plant had nitrogen discharges lower than goals in January and February, when average daily flows were just above 17 million gallons a day. But the plant exceeded target limits during the spring and early summer, mainly because of the increased rainfall that pushed daily water flows above average.

In June, for example, with daily flows at 23.9 million gallons a day, nitrogen discharges were 6.1 milligrams per liter, above the goal of 5.84 milligrams, McIntire said.

"They're doing pretty good. They're just missing it slightly," he said.

The Howard plant expansion that began in 2001 is designed to raise the facility's capacity from an average of 18 million to 26 million gallons a day by 2010, to be ready for the thousands of new homes, offices and businesses planned in southern Howard. In a peak emergency, Ward said, the plant can handle up to 52 million gallons.

During the past wet summer, the average daily flow was 19 million gallons a day, Ward said, compared with 16 million during the drought in the summer of last year.

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