Michael W. Tryon has been named vice president of sales and marketing for GPI, a division of Harmony Enterprises Inc., Harmony, Minn.... The National Association for Plastic Container Recovery, Charlotte, N.C., has named Michael F. Schedler director of technical affairs.... Terry J. Lo-gan has been named president of Pan-American N-Viro Inc., Toledo, Ohio.... Nancy W. Newkirk has joined Perkins Coie, Seattle, as environmental lawyer and partner in its Washington, D.C. office.... William C. Fulkerson has been named partner by Warner Norcross & Judd LLP, Grand Rapids, Mich.... Bob Scheid-erich has joined Otto Industries Inc., Charlotte, N.C., as vice president of operations. The company also has named Bill Sutton Midwest regional sales manager in the St. Louis office; David Taylor materials manager; and Bob Durdin technical service representative in the Southhaven, Miss., office.... Robert C. Marini has been e-lected president of the American Academy of Environmental Engi-neers in Cambridge, Mass.... SCS Engineers, Long Beach, Calif., has named John H. Coll hazardous substance division leader in the Cincin-nati office.... Thomas N. Sargent has been named principal and senior vice president in the Atlanta office of GeoSyntec Consultants, Boca Raton, Fla.... Lindemann Recycling Equip-ment Inc., Charlotte, N.C., has named Lon R. Robinson manager of engineering in the research and development department.... Jeff Ritchie has been named president and chief operating officer of Mash-burn Waste & Recycling Services Inc., San Marcos, Calif.... GO of Wisconsin Co., Racine, Wis., has named Richard Becker general manager... John Scholefield has been appointed director of European sales by Harris Waste Management Group Inc., Peachtree City, Ga.... Golder Associates Inc., Atlanta, has named James F. Durrett III manager of project development.... Eckenfelder Inc., Nashville, Tenn., has named Gary Di-Pippo vice president.... Thomas M. Kelly has rejoined Mack Trucks Inc., Allentown, Pa., as director of materials management. The company also has named William J. Dougherty vice president of its vocational product line.... WMX Technologies Inc., Oak Brook, Ill., has named Michael J. Cole CEO of Chemical Waste Manage-ment Inc. He replaces Pat Payne, now a senior vice president of WMX.