The idea started with Chinese rice farmers long ago They had learned that rice grew best when they flooded the fields, then drained them to harvest the crop at the end of the season. That was good farming, but why waste all that water that was doing nothing for all those months? One of them got the idea of throwing a bucketful of baby tilapia into the fields when they planted the rice seedlings, and, sure enough, then when they harvested the rice they also harvested a handsome crop of eating-sized fish,
That was what first started the tilapia boom a couple of decades ago, but an Illinois city farmer named John Edel has carried the idea a lot of steps farther. When tilapia eat they also excrete, and the water is fouled; when the are marketed they have to be degutted and beheaded, producing more waste. Edel puts the waste water and its polluters in a tank that he seeds with bacteria. The bacteria eat the waste and turn it into high-grade fertilizer … which, of course, is what closes the circle by making his next year’s rice crop grow so abundantly.
His objective, as Edel puts it from his indoor factory farm, The Plant, in Chicago’s old Stockyards district, is, “Nothing leaves the plant but food.”
If you happen to be in Chicago on May 7, you can tour the place, during its open house.