Prince George's County Executive Lawrence J. Hogan has been actively trying to persuade county and D.C. officials to buy land that could give a longtime friend and sometimes business associate a $3 million short-term profit.

The land, an 80-acre tract beside the Potomac River, has been offered for sale by John W. Lyon, a former Hogan business associate, as a sludge compost site for the area sewage facility. Lyon wants $3,484,000 for the property he bought in September 1974 for $495,000.

Hogan's effort to help Lyon sell the property have included conversations with D.C. Mayor Marion Barry and letters to the D.C. government and the Prince George's County Council.

Both Lyon and Hogan were out of town yesterday and could not be reached for comment. Hogan issued a statement through his son, Lawrence Hogan Jr., an aide to his father, defending his position on the sludge site

"The Washington metropolitan area has wrestled for several years with the difficult problem of locating a regional sludge composting facility," Hogan said. He called the site's location, just south of the Blue Plains sewage treatment plant, "ideal."

The site, a combination of land, marshland and shallow water on the Potomac, is across Oxon Creek from Blue Plains. All but two of the 80 acres are in Maryland.

Hogan and Lyon are longtime personal friends. On many occasions, according to sources, Lyon and associates have made corporate aircraft available to Hogan for congressional campaigning and for flights to Ocean City, Md.

As an attorney, Hogan has represented Lyon "off and on since I left Congress," the county executive said last fall.

As he prepared to enter the county race earlier last year, Hogan became first president, then general counsel, and a potential stockholder (as compensation "in lieu of fees") in corporations that Lyons formed to market new technologies in waste treatment and energy recovery.

It could not be learned yesterday whether Hogan now has an interest in any of the firms.. His wife and law partner, Ilona Hogan, said through her secretary that she does "sporadic legal work" for one of the corporations.

Lyon first approached the District with an offer to sell the property in July, 1977. In a letter to Herbert L. Tucker, the District's environmental services director, Lyon offered to fill the marshy ground with 1.5 million yards to excavation and rubble in three years from any sale.

The sticking point - then and now - was Lyon's insistence that the District obtain all required government permits to use the land for dumping sludge. According to Tucker, the project would require permission from the Army Corps of Engineers, the Interior Department and the Maryland Health Department.

"My people advised me we'd have a very difficult time getting permits." Tucker said. In August, 1977, Tucker wrote Lyons that his sale proposal was "fraught with problems."

However, the need for a regional facility to dispose of increasing amounts of sludge from the expanding Blue Plains plant remained. As the various jurisdictions wrestled with this unresolved issue, Lyons renewed his offer to the District this spring.

Lyon wrote to D.C. Mayor Barry on April 2. He also wrote to Hogan and to Montgomery County Executive Charles Gilchrist. Gilchrist was not interested in Lyon's proposal, a Gilchrist aide said yesterday.

On April 16, Hogan's chief administrative aide, Kenneth V. Duncan, urged the D.C. government to give Lyon's proposal serious consideration.

"The county has recently been approached by an individual who is interesting in discussing use of his property for composting [converting the sludge to a form of fertilizer] at Blue Plains," Duncan wrote.

Once trucked to the site, the sludge would be mixed with wood chips and aerated. After three weeks, the sludge would decompose into "compost," a form of fertilizer that can be sold commercially.

Substantial amounts of landfall first would be required to render the entire site usable, since some of the 80-acre tract is in the water and is a virtual swamp. Lyon has also offered to provide 1.5 million cubic yards to excavation fill from construction sites to fill in the swamp.

Lyon is president of Excavation Construction, Inc., a major Metro subway constractor. The firm regularly has excess landfill and the opportunity to dump it at a site near the Potomac could be an added financial incentive for Lyon.

Hogan urged the Prince George's Council last month to consider the site near Blue Plains. The council has supported a composting facility at an existing sewage treatment site near Upper Marlboro, known as the Western Branch.

The council had settled on the Western Branch plan after years of debate with Montgomery County, which had recently proposed a composting plant at Calverton, near the Prince George's County line. Price George's officials, including Hogan, had opposed Calverton because of cose.

"A site in the vacinity of Blue Plains," Hogan wrote to the Council May 31, "would offer the benefit of lower hauling costs. It makes no sense to truck sludge from Blue Plains to Western Branch with all the adverse impact on Prince George's County roads and communities." CAPTION: Picture, LAWRENCE J. HOGAN . . . site "ideal" for sludge disposal