Anne Arundel County officials explained plans yesterday to build a $5 million umbrella over the tons of trash buried at the county's Sudley Landfill and shut off the flow of pollutants into the ground water below.
The umbrella -- which will be made of 24-foot-wide, 60 millimeter-thick polythylene sheets -- is necessary to stop rain from washing through the garbage and carrying pollutants into the ground water, said John Zohlen, deputy director of the county Department of Public Works.
Mr. Zohlen and other officials described for neighbors of the landfill, which already is closed to commercial haulers and is to shut down completely by Oct. 1, how the umbrella, or cap, is to be constructed.
The county operates two landfills. The largest, Millersville, is expected to continue operating until about 2008.
Mr. Zohlen said Sudley was being closed because its existing dump areas are full and new federal environmental regulations make operating two landfills unnecessarily expensive.
Already the county expects to spend $160 million or more on plastic liners, caps and monitoring wells at the two landfills over the next 17 years, officials said.
"When you close a landfill, you can't just walk away and lock the gate," said Jody Vollmar, a customer relations specialist with public works.
Sudley Landfill, which has a dirt floor, was considered state-of-the-art when it was opened in 1982, said Richard Waesche, a project manager at public works. But, in 1989, the county discovered contaminants -- mostly solvents from household and industrial cleaners -- in a monitoring well near Tracys Creek.
The contaminants have not flowed beyond the 166-acre landfill on Nutwell-Sudley Road, said Lisa Ritter, a county public information officer.
And the construction of an umbrella over the trash should dry up the flow of contaminants into the ground, Mr. Zohlen said. The plastic material used in the cap is resistant to chemicals, punctures and abrasions.
Residents who attended the meeting at Christ Church in Owensville said they were promised the landfill would be converted into athletic fields after it was shut down.
But Mr. Zohlen said that would no longer be possible because federal environmental rules require the disposal areas be mounded to allow rain to roll off. He also said sports activity could damage the cap even though it would be buried under two feet of top soil.
The county may consider converting the site into a nature preserve or more passive park, he said.
The county will maintain trash containers and a recycling center at the site for the use of residents, Mr. Zohlen said.