Montgomery County's longstanding landfill battles resumed with gusto last week as Potomac residents attacked county plans to study the possibility of putting a dump in the well-to-do suburb.

More than 300 area residents, bearing printed "Stop the Dump" stickers, maps and brochures, jammed into the county government's Rockville auditorium to jeer plans for the project.

"Why dump garbage in Potomac?" asked Robert Hanley, an area resident. "We're already getting a sewage treatment plant. We don't want garbage, too."

"Save our taxes, save our homes," pleaded Helen Hillstrom, representing the Izaak Walton League and Potomac Highland Citizens Association at the public hearing.

The county Department of Environmental Construction has asked the County Council for $1.7 million to study the feasibility of using the Rockville Crushed Stone Quarry on Travilah Road, a mile south of Rte. 28, as a long-term solution to the county's unending trash woes.

Although the entire project could cost more than $75 million, Jerry Leskiewicz, department director, told the council that the 325-foot-deep quarry could serve the county as a trash repository for more than 50 years.

If preparing the privately owned quarry for a landfill proves possible, the operation could not be ready for use until at least 1985, Leskiewicz said. Rock used in construction is now mined in the quarry.

County environmental plannes envision a system that would compact trash into massive, square bales. The bales would be stacked in portions of the quarry excavated by the mining firm. The space would be leased from the mining company, which would continue to mine the quarry.

Baling the trash, environmental planners maintain, is neater and produces less odor than conventional landfill methods.

Potomac residents, however, fear the trash could pollute local water supplies and lower property values.

Several Potomac citizens at the hearing were angry because Leskiewicz, in an earlier landfill study, had pointed out geological deficiencies that could hinder use of the quarry.

"Nothing has happened to change that," said Philip Thomas, an attorney for about 150 Potomac families.

Leskiewicz explained that the earlier study pointed out that because of the technical complexities involved in turing the quarry into a landfill, it could not be ready for use when space in the present Rockville landfill is exhausted. He said he had not intended to rule out the quarry entirely as a possible future landfill.

Leskiewicz told the council that if funds are granted, a detailed study would explore environmental problems that might result from use of the quarry.

At the same time, another study would look at a different method for solid waste disposal: recycling refuse into a marketable fuel product. The council has already appropriated about $1 million for research of the recycling alternative.

Although the council will not vote until later this month on whether to fund the quarry study, Council President Neal Potter indicated his support for the project at an informal work session following the public hearing.

Calling landfills "an abomination," Potter said, "Recycling is our first priority, but we can't put all of our eggs in one basket."

Potter said he also wanted to look into a system now used in Europe in which trash is combined with sludge to form fertilizer. Potter observed this system when he and other area officials, including Leskiewicz, toured several European cities recently in search of innovative solutions to the metropolitan area's solid waste disposal problems.

Leskiewicz said after the work session that he thought the council would probably appropriate at least part of the money he requested.

Potomac residents apparently also had that impression.

Dr. Steven Pollak, vice president of one of the civic associations opposing the quarry plan, said "there is no question that this is going to go to litigation at some point," if the county pursues plans to study use of the quarry as a landfill.