Montgomery County plans to sell a 225-acre site near Dickerson formerly used to compost sludge now that the county has moved its composting operation to another location near Calverton.

County officials said the abandoned Dickerson site is not a health hazard because no sludge remains on it. But the site is bound by myriad legal agreements between the county, state and neighbors that limit its use.

"There are restrictive land-use covenants that prevent the property from being used as a landfill or waste-disposal site and for other things," said Gloria W. Kretz, county director of leasing. "It was once a farm and is zoned for residential or agricultural use."

Kretz said the property, in a rural area of the county, has not been appraised and that the county has not settled on an asking price.

Meanwhile, the Washington Suburban Sanitary Commission, a state agency that operates in Montgomery and Prince George's counties, has its own former sludge site up for sale -- 716 acres along New Hampshire Avenue between Silver Spring and Burtonsville.

The agency advertised the land in national newspapers and magazines in August in an attempt at an auction but received no bids for it, said WSSC counsel Henderson J. Brown. He said the agency has not set a price on the land but hopes to recoup the $3.5 million paid for it in 1976.

The WSSC property, which is zoned for residential use, has generated little enthusiasm from developers, but not because it is a former sludge site, said Brown. He said developers are reluctant to buy the land because it does not have sewer lines and because it is so large.

"We are ready now to break the 716 acres down to more manageable sizes," he said. "The sludge has nothing to do with why it isn't selling as quickly as we had hoped."

The WSSC and the Dickerson properties are the first former sludge sites up for sale in Montgomery County in recent memory. But, county and state officials said, a number of former sludge dumps in the county will be put on the market over the next few years because the county has centralized and simplified its sludge-disposal procedures. They say the sites are environmentally safe, but are located in sparsely populated areas with restrictive zoning clauses and few utility hookups.

Since 1974, Montgomery, Prince George's and Fairfax counties and the District have been required to dispose of a percentage of sludge from the Blue Plains treatment plant in Washington, which all use to treat their garbage.

At first, Montgomery County, with the help of state agencies, bought land throughout the county and buried its share of sludge in troughs several feet deep. One of these sites is the WSSC property on New Hampshire Avenue that is now for sale.

In the late 1970s, the county decided to compost the sludge rather than bury it, for economic and ecologic reasons.

"It costs a lot in terms of land and labor to bury sludge, and once it's buried, it's gone," said David G. Sobers, county director of enviromental planning. "Sludge is actually quite rich in nutrients."

Composting sludge consists of mixing the raw sludge with wood chips and setting it out to dry on asphalt slabs. The dried residue is then sold to farmers as fertilizer.

After an exhaustive search, Montgomery County chose to set up its new composting operation near the Montgomery County Office Park off Route 29 near Randolph Road, about a mile from the Prince George's border. But the choice was met with a howl of protest from neighbors in Prince George's, who sued to block the move, said Sobers.

While the dispute wound its way through the courts, Montgomery opted to set up a temporary composting facility on the Dickerson site. Sobers said this decision also created controversy with the state and neighbors, but an agreement was reached that allowed the county to compost 300 tons of sludge a day on the former farm for two years.

Last year, the U.S. Supreme Court ruled in favor of Montgomery and the compost operation was moved from Dickerson to the original site off Route 29.

This month, County Executive Charles W. Gilchrist formally proposed selling all but 50 acres of the Dickerson site. Sobers said the remaining 50 acres is being used to compost leaves that the county collects from residents.

State health departments have ruled that the Dickerson site can be sold immediately because no sludge remains on the site. The WSSC property, on the other hand, had to undergo five years of tests to monitor its safety because sludge was buried there.

"The state requires a five-year monitoring period, which we have done," said Brown. "They environmentalists have been looking for potential runoffs and water contamination. There has been no evidence of that as far as I know, and we are ready to sell."