A consortium of developers has broken ground for a privately funded sewage treatment plant near Rockville that will allow them to overcome a seven-year old sewer moratorium and build $500 million in housing and commercial development in wide-ranging areas of Montgomery County.

The $9 million plant, if completed as planned in October, 1978, will provide houses and apartments for about 26,000 additional residents in the county from Olney in northern Montgomery County to Chevy Chase at the District line.

Backers of the plan are calling it a victory for private enterprise that will permit one of the first major expansions of construction in years in areas of the country affected by the moratorium. This comes at a time when local, state and federal officials are squabbling over the future of major sewage treatment expansion for the Washington area.

George Hazzard of the Suburban Maryland Homebuilders Association said other developers are "waiting to see how this one comes out." An attorney for the consortium said other developers will rush to try the same thing if this effort is successful.

While the plan has cleared the County Council and Montgomery County Planning Board, and has received its EPA permit issued through the state, there are a number of other lesser permits that it must receive.

But the consortium's attorney, Charles G. Dalrymple, said that aside from normal builder "headaches," no major stumbling blocks remain - a view confirmed in interviews with relevant county and state officials.

But area governments are ultimately going to balk at a proliferation of such smaller sewage plants whether privately or publicly funded, according to Montgomery County officials. County Executive James P. Gleason, who has backed this private plan, said that while "it allows you to hop along a little bit" it does not provide a real solution to areawide needs.

The new Rockville plant is located near Southlawn Lane and Guide Drive.

Gleason and state officials had backed a giant sewage plant at Dickerson in Montgomery County, but the federal Environmental Protection Agency decided late last year not to finance the Dickerson plant because it was too expensive and would have discharged treated effluent above Potomac River water intakes for the District of Columbia.

EPA would have had to pay 75 per cent of the cost of the $271 million Dickerson plant, which would have treated 60 million gallons of sewage per day - an amount that county officials said they needed for expansion. EPA said the county needed only somewhat more than half that much.

Montgomery County and Maryland have sued EPA over the issue. Housing costs, meanwhile, continue to soar as construction moves at a snail's pace under the pressure of the moratorium in one of the nation's most affluent counties.

The moratorium was imposed by state health officials on May 20, 1970, when the decreasing quality of effluent from overburdened sewage plants posed a health problem. Existing housing construction projects continued for some years, but by 1975, construction in Montgomery and much of Prince George's County had virtually halted and population growth slowed significantly.

But several years ago, officials and frustrated developers came up with the idea of privately funded sewage plants.

There have been several small private projects, but the plant under way near Rockville now is by far the largest of these. Unless Dickerson or some other major plant gets built soon it would represent about one-third of all additional sewage capacity in the county in the next several years.

The other two-thirds would come from additional capacity allocated to the county from the Washington area's major treatment plant at Blue Plains and from another small plant about to open at Seneca in Montgomery County.

The privately funded Rockville plant will treat 3 million gallons of sewage a day and will be entirely financed by the roughly 30 developers involved - a cost that will be passed on in the prices of their developments.

The developers predict that about 2,500 new houses, 1,683 new town houses, 4,887 apartments and an additional 2.6 million square feet of commercial space will become available as a result of the new plant.

After it is built the plant will be turned over to the Washington Suburban Sanitary Commission to operate, with costs borne by the WSSC through its regular user charges.

The developers, led by nine original partners, have been working on the project for more than three years. "We've had a zillion hearings on this bloody thing," said the group's attorney, Dalrymple. He said no major obstacles remain that could halt the project.

The plan cleared the Montgomery County Council in April, 1975, and was subsequently issued an EPA discharge permit through the Maryland Water Resources Administration.

One apparent reason for the plant going through has been a lack of citizen and environmentalist objection. The Council had also approved a similar plan for the White Oak region, but citizen opposition has stopped it, according to Dalrymple.

Charlotte Gannett, vice president of the Montgomery Environmental Coalition, said the plant is "an absolute,utter disgrace" because its effluent, which will discharge into Rock Creek, ought to be cleaner.

David Sobers, director of Montgomery County's Office of Environmntal Planning, said the plant's and in some instances would be clearer than the stream into which it flows.

But he said effluent wouldn't have as high a quality as effluent from the proposed Dickson plant. Gallon-for-gallon, Sobers said, it would cost more than Dickerson, where efficiencies and economies of scale would come into play.

An environmental official at the WSSC said he thinks the plant is "in pretty good shape" from the stand-point of effluent quality, but that a "close look" is still being taken at plans for the plant.

Mike Ruddo, the WSSC official who serves as project manager for the plant, said he is meeting with the developers daily and that they will "utilize a fast-track method where they design (the plant) as they construct it."

He said the EPA effluent permit issued through the state was "pretty tough."

Dalrymple said that ground was broken for the plant about two weeks ago. Actual construction will not begin for several weeks, with the WSSC approving every step of the way.

An "environmental effects report" on the plant prepared by the engineering firm of Greenhorne & O'Mara for the developers gives a generally favorable view, but notes that the planned development frequently does not confirm with official projections of growth.

Thus, the report says, county and state officials may have to revise their capital budgeting plans to avoid "inequitable appropriations or misapplied prorities."

For example, the report notes, the plant will bring more than 5,000 additional people into the Olney area by 1981, but roads there are already jammed and the major arterials there are not scheduled for improvement during the next five years.

Dalrymple listed the original members of the consortium as Bernard and Leonard Kapiloff, Norbeck Joint Venture, Olney Shoppers World, MCD Enterprises, Inc., Carl M. Freeman Associates, Inc., Clarence W. Gosnell, Inc., Old Georgetown Associates, North Bethesda Associates, and Chevy Chase Land Co.