AROUND 700 persons from 33 states will converge on the Mall this week to present "ACT," an alternative technology fair that promises to be one of the largest ever attempted on the East Coast.

With sponsorship and financial backing from an array of federal and local government agencies, the fair will occupy a number of temporary buildings and sites on the mall area between the Lincoln Memorial and Washington Monument, south of the reflecting pool, this coming Friday through April 30.

"This is not a visionary fair, nothing grandiose," said project director Michael Duberstein. "We're presenting alternatives that exist in communities throughout the country today."

The fair highlights energy and lifestyle atlernatives primarily for home and community use, such as solar collectors, waste-recycling units, alcohol-based car fuels, fish ponds, organic gardening and community gardens, weatherization to save energy, solar greenhouses and many others.

Several community organizations from around the country are involved in the project, with names such as Solar Sustenance and Freedom Farm. The fair is sponsored by the National Park Service and the District of Columbia Cooperative Extension Service.

Among the federal agencies involved are the Department of Energy, the Environmental Protection Agency, the National Endowment for the Humanities and the Small Business Administration, the Smithsonian Institution and the Community Services Administration.

The fair is divided into three areas: town, rural and wilderness, showing how alternative technologies can be applied in each. In one corner the EPA will collect waste from the fair-paper, bottles and tin cans-to show how these can be recycled in new products, such as cheap solar collectors.

The Agriculture Department will operate a fish pond. The Small Farms Energy Project from Iowa also will demonstrate the construction of low-cost solar collectors and their operation. Many of the fair activities will run on power produced on site to show practical application. Another group will be building geodesic domes, another solar greenhouses.

Throughout the fair, organizations and individuals will lecture and show films on everything from producing methane gas to building a wood stove for less than $100.