John Edel is turning a former meatpacking plant on the edge of Chicago's old Union Stockyards into an indoor farm.

CHICAGO — John Edel is turning a former meatpacking plant on the edge of Chicago's old Union Stockyards into an indoor farm.

In the basement, microorganisms are eating tilapia waste, converting it into fertilizer for the lettuce, kale and wheatgrass growing in a shallow pool of water nearby.

This process is called aquaponic farming. It minimizes water use while allowing year-round harvests, and it's just the beginning of Edel's vision for a futuristic, urban farm he has called "The Plant."

"The idea is that nothing leaves the facility but food — period," said Edel, 41. Half of The Plant will be rented to startup food companies, including a commercial brewery.

The heart of America's urban agriculture movement is Milwaukee, where Will Allen, a sharecropper's son and former professional basketball player, has turned a dilapidated plant nursery into a cutting-edge urban farm, raising plants and vegetables, plus the thousands of tilapia needed to fertilize them.

Allen's disciples are converting far less logical sites into aquaponic farms. In Chicago's Bridgeport neighborhood, for example, his daughter, Erika Allen, is building the Iron Street Farm in a former truck depot.

Edel will be among the first to expand this concept across multiple floors of a single building: A shuttered 93,500-square-foot former pork-packing plant.

We're running out land to feed the world's exploding population. New York City's approximately 8 million inhabitants, for instance, eat an amount of food that requires a land mass the size of Virginia to grow, according to Dickson Despommier, a Columbia University professor and prominent vertical farms advocate.

Farms of the future must occupy less space, rely on fewer pesticides and produce food that travels blocks, not miles to our tables, given the skyrocketing cost of fuel. Such requirements have spawned concepts of farms being housed in glass skyscrapers from Chicago to Dubai.

"We're not proponents of these fantasy skyscrapers," said Erika Allen, who is beginning to construct greenhouses and install fish tanks at Iron Street Farm. "The whole goal is to create a farm that's sustainable and makes money. And you can't make money if your infrastructure costs are too high."

What's profitable and achievable, Allen said, are tiered aquaponic systems, or minivertical farms in which fish and plants coexist off each other. Their ecosystems are linked via tubes.

Edel's building is a place children would dare each other to sneak into; the escapade ending when a pipe suddenly clanked and everyone bolted. Keeping scrappers away, however, is a different matter. Edel recently installed a security alarm that blares as loud as a tornado siren to keep them from trying to break in to steal metal.

Inside, broken concrete floors crackle beneath visitors' feet. Dozens of windows have been filled with bricks. It is dark and cold.

But within a few years, Edel says a complex food-production system will be in place, the key to which is a $1 million, yet-to-be-bought anaerobic digester. Everything will be fed into it, from rotting tomatoes and meat, to brown and yellow grease.

On a recent visit, it smelled like yeast outside.

"It gives us cover if we want to make foul smells of our own from time to time," Edel said.

The digester will convert the waste into gas, which will power a generator, which will power the facility. The local utility will not have to supply electricity.

"That's what takes us to the next level" of sustainability, Edel said. Most of "the power for the anaerobic digester will come from neighboring businesses' waste. ... We're looking at 18 tons a day of biomass to power this place."

Edel anticipates receiving 2.1 million gallons a year of "beefy, sludge bioproduct" from a local food-flavoring maker. But the brewery, bakeries and the mom-and-pop tenants who will rent commercial kitchen space from Edel also will send their waste to the digester.

"Oddly enough, one of the great realizations we're having is we aren't going to be heating much at all," Edel said. "We're going to be cooling almost all the year in this building because all of the activities are heat-producing, especially these growing systems."

The building, formerly occupied by Peer Foods, was shuttered four years ago when the meat packer shipped 400 skilled jobs to Columbus, Ind., save a security guard. Edel, a lifelong Chicagoan and general contractor, bought the building last year for $525,000, the estimated value of the metal inside it. He reasoned that its floor drains, vapor-tight light fixtures, stainless steel evaporators and a chemistry lab would be ideal for food businesses.

Edel estimates that apart from the digester, the build-out will cost only $750,000. That's because Edel barters for things he needs and also counts on help.

On average, six volunteers a day are involved in demolition or remodeling. On a recent Saturday, Nick Santillan hammered away at cinder blocks in what was once a worker locker room. By day, he said he's a music producer.

Edel also is a recycler. Meat-hanging rails, for example, will serve as bike racks. Former smokehouses will be remodeled into bathrooms.

Edel, who grew up in Chicago, looks the part of environmentalist/mad genius. He was wearing jeans and a khaki button-down shirt, both covered in dirt, on a recent visit. His reddish beard had grown down the sides of his neck.

"One of the things I always wanted to do was grow plants inside industrial buildings since I was kid," he said. "Walking around in the Garfield Park Conservatory 35 years ago with my grandmother, and seeing this amazing derelict, rusting, collapsing place with water dripping everywhere and beautiful plants in it was kind of a transformative thing for me."

After graduating from the University of Illinois at Chicago, he worked in set design and computer graphics. He has spent the past decade building a resume in the green-building field but quit his day job four years ago.

In 2002, using savings and a $75,000 home-equity line of credit on his Logan Square two-flat, he bought another old building, a motorcycle junkyard at the time, and turned it into the Chicago Sustainable Manufacturing Center.

Relying on bartering and recycling, Edel said it cost him just $25 per square foot to renovate it. There is now a waiting list for green businesses wanting to lease space there. The rental income from the manufacturing center is paying for the mortgage on The Plant.

All that stands in Edel's way are city rules.

The law permits him to conduct aquaponic farming only for educational purposes, so his operation is run through a partnership with the Illinois Institute of Technology.

Commercial fish farming is forbidden in Chicago because fish are classified as livestock. Edel, who is aligned with Advocates for Urban Agriculture, is pushing for changes in zoning that would allow fish farming. "A change to the code is imperative," he said.