A German manufacturing firm and an American subsidiary of a German engineering firm have agreed to build an advanced technology plant in the Prince George's County Foreign Trade Zone near Bowie, according to an announcement made last week by Maryland Gov. Harry Hughes and County Executive Lawrence J. Hogan.

The German firm, which is called Goema, will combine with Eticam, a subsidiary of Emmisions Technisches Institut (ETI), in a joint venture to produce valves and plastic resin fittings for Eticam's industrial effluent facilities.

The groundbreaking for the first phase of the project is expected to take place in the spring of next year. Eticam representatives have said this initial phase of construction will create 125 jobs for skilled and technical workers.

The next phase is projected to begin in the spring of 1983, with the completion of the 200,000-square-foot operation set for the fall of 1984. When the manufacturing equipment is in place, the plant will employ over 250 workers.

The lease of the 10-acre site was negotiated by the state, the county and by Harkins Associates, developers of the Foreign Trade Zone. The Goema-Eticam plant will be located near the entrance to Prince George's County International Commerce Center.

Goema's decision to locate in Maryland represents the company's first entry into the U.S. market. Goema currently has over 1,100 European facilities, as well as satellite operations in Brazil, Finland, Yugoslavia, Italy and Switzerland.

In addition to industrial effluent facilities, Goema-Eticam constructs a variety of industrial waste recovery plants, including facilities for the retrieval of ferrous and precious metals