The Montgomery County Council reacted favorably yesterday to County Executive Sidney Kramer's proposal to expand the county's mandatory recycling program, but several members suggested that the plan didn't go far enough.

Kramer appeared before the council to present a multifaceted plan that would require residents in much of the southern part of the county to separate bottles and cans from their household trash for curbside pickup.

The plan would be the first of its kind in the region.

The proposal also would double to roughly 150,000 the number of homes required to recycle newspapers.

Potomac, Germantown, White Oak and possibly other communities would be added to the existing newspaper recycling area.

Kramer's plan, which would involve building a processing plant for bottles and cans at Shady Grove, is designed to reduce the county's trash flow, thereby diminishing the need to expand landfill space and incinerator capacity.

The county plans to burn virtually all its trash in a $170 million incinerator in rural Dickerson by 1990, and use landfill space for the ash.

Saying his plan would increase the amount of waste recycled from 13 percent to 22 percent of all county trash, Kramer cautioned the council to resist calls for a more ambitious program.

If the county undertakes an overly ambitious recycling plan, he said, it may underestimate its need for incinerator and landfill capability and then be saddled with excess trash.

"Reaching beyond our grasp," he said, could result in failure with the county "undersizing {a planned trash incincerator}, frustrating our citizens and causing excess waste to be landfilled."

Several council members pointed out that when they directed the executive this year to devise a plan with a recycling goal of between 15 and 30 percent, they believed current recycling was 7 percent.

The recent revelation by a county consultant that public and private recycling programs already account for 13 percent suggests "it will be easier to reach 22 percent . . . and shouldn't we aim higher?" asked council member Rose Crenca, whose view was shared by council member Neal Potter.

Council member Bruce Adams also said he understood Kramer's concern but still felt the county could do better than 22 percent.

Plastic, such as milk and soda containers, also should be recycled, Adams said, because there would be less material to put in a landfill and because incinerating plastic could be environmentally damaging.

Citizens in the Dickerson area, who opposed building the incinerator, share Adams' concern about emissions caused by burning plastic.

Karen Kalla, a member of the Sugarloaf Citizens Association, said, "All the information isn't in {on environmental damage} so why take a chance? If people can recycle their glass bottles, why not their plastic bottles?"

John L. Menke, the county's director of environmental protection, said it is entirely safe to burn plastic.

And, he said, it is not cost-effective to recycle it because there are no good markets for it. It makes little sense to collect a material if there is no one willing to accept it, he said.

Menke said that the yearly cost to run the recycling program would be between $4 million and $6 million, roughly equivalent to what it would cost the county to dispose of the same quantity of trash.

Much has to happen, starting with obtaining council approval, before county residents would feel the effects of the plan. A public hearing has been set for Jan. 21.

Menke had on hand a 10-gallon covered plastic can that the county would provide to residents of 75,000 homes in the southern county now served by trash haulers hired by the county.

Residents outside this collection district contract individually with trash haulers, haul their own trash or live in incorporated areas like Rockville or Takoma Park that have their own trash collection.

The first curbside separation of glass and bottles would be in the southern collection district that includes Bethesda, Silver Spring and Wheaton, communities that already have mandatory newspaper recycling.

Menke said the glass and bottle recycling could begin when the processing plant is completed, in about three years.

Menke said that the expansion of mandatory newspaper recycling could begin in about a year, with a system to serve the densely populated areas in the northern, western and eastern reaches of the county. The eventual plan is to have this area also recycle cans and bottles, Menke said.

While the programs would be mandatory, county officials said they would not be rigorously enforced and that compliance would come through education and peer pressure.