The recycling industry, which quietly went about its business for decades, suddenly has been thrust into the spotlight as everyone scrambles to become ''recycle friendly."

One industry report estimates more than $2 billion will be spent across the nation for recycling equipment over the next five years to keep up with the enormous interest.Two years ago, the National Solid Wastes Management Association featured only two recycling waste trucks at its annual convention.

At the most recent convention, there were 27 models.

Supermarkets are collecting plastic grocery sacks for recycling. Procter & Gamble Co., a leading maker of consumer products, has started introducing plastic and paper containers that take advantage of recycled materials.

Wal-Mart Stores Inc., a leading retailer, has begun tagging shelves to inform shoppers about recycled materials and other environmentally conscious products.

"I have been in this business a long time, and I have never seen anything like what's going on today," said John Veidt, a 20-year veteran of the recycling business who runs the reclamation division of Clayton, Mo.-based Jefferson Smurfit Corp.

For a century, the recycling industry has pretty much operated on its own, chugging along on a supply-meets-demand basis with about 2,000 member companies of the National Association of Recycling Industries.

But the 1980s brought big changes, most notably the involvement of government, which created unprecedented expansion opportunities.

"Generally, I think industry is recognizing that recycling is just good business," said Richard Keller, a spokesman for the National Recycling Coalition and chairman of the group's subcommittee on market development.

The government - at every level - has become a major player in supplying raw materials that need to be recycled, mandating the use of recycled products and buying the products.

In the fall of 1986, 13 states had legislation favoring the use of recycled products. Today, that number has grown to 34 states with laws affecting 17 out of every 20 Americans, the coalition said.

One measure of the market's growth is the Official Recycled Products Guide. The first edition, published by Robert Boulanger in April 1989, listed 177 products that were made with recycled materials, most of them paper products. In nine months, the number of listings has climbed to 1,500.

Now, the New York-based guide includes building construction, landscaping, rubber and plastic products.

Mr. Keller remembers the days in the early '80s when he could do his seminars on developing markets for recycled items "in a phone booth and have room left over.

"Today, everybody is interested," he said.

That interest has been good and bad. The paper side of the business is oversupplied; the glass side is undersupplied.

"The dilemma we have ourselves in is that we have the collection process geared up and hot, but it's going to be three years before . . . We are ready to start using the material," said Mr. Veidt of Jefferson Smurfit, the nation's largest collector of waste paper.

The supply glut has dropped prices for a ton of used newspapers to all- time lows and tons of the stuff are sitting in warehouses. In some parts of the country, people have to pay to drop off their newspapers, said Mr. Veidt.

The glass industry faces the opposite problem. Glass makers would like to increase the percentage of waste glass used in the manufacture of new containers, but supplies are tight.

Experts differ on how profitable the recycling business will be. While government interest has been intense, growth may depend on private investment. "Companies know that recycling is the wave of the future and they are all trying to get in a position to do it," said Vishnu Swarup, a stock analyst for Prudential Bache Securities in New York. "Right now, they're sharing the profits and losses with the community, but some day they'll tell the community we can't keep doing this."