If You Leave It to Mother Nature, Says Biologist John Todd, Sewage Doesn't Have to Go to Waste
updated 11/27/1989 AT 01:00 AM EST
•originally published 11/27/1989 AT 01:00 AM EST
Sound farfetched? Perhaps not—if Todd's current experiment, which began full operation this July in Providence, R.I., begins to prove his thesis. There, amid a 63-million-gallon-a-day sewage treatment plant surrounded by sludge lagoons, Todd has put up a 3,600-square-foot greenhouse crammed with clear fiberglass holding tanks. By harnessing processes that occur in nature, such as photosynthesis, Todd intends to show that sewage can be disposed of in his tanks more cheaply and effectively than through traditional treatment plants.
Todd calls his process solar aquatic water purification. In essence, it works like this: First, raw sewage is pumped into a bank of vats containing scores of algae species and other microorganisms that along with bacteria break down the sewage. Then the liquid is pumped into other tanks where "carefully engineered marshes" of plants (water hyacinths, irises and other flowers, tomato plants and eucalyptus trees) and animals (snails, trout, striped bass) "do what they do naturally," says Todd. Following a final cleansing in polishing vats, the once-filthy liquid gushes forth crystal clear after about five days, as much as 20,000 gallons of it daily.
Amazingly, the process requires no chemicals. Instead it is a vivid demonstration of nature's ability to restore itself by using contaminants as food sources for plants and fish. The snails feast on sludge, the fish eat the plankton, while the plants absorb phosphorus, cadmium and lead. With nets and traps, Todd gathers most of the organisms needed from local streams. Then he creates an ecosystem like a chef cooking up a "bouillabaisse—you need to know the right ingredients and when to add them." The vats act as low-level solar panels, he says. "It's basic photosynthetic activity. We're asking sunshine and plants to do what's usually done with expensive machinery."
Todd says his method should cost about one half to two thirds as much as conventional waste treatment methods, in part because his way creates no sludge. The Providence project, which Todd runs with the help of one full-time assistant, will come in at just $270,000, most of it donated by nonprofit foundations. And his process produces beneficial byproducts unimagined at other sewage dumps. The trees and flowers that "grow like weeds" in his vats can be used or sold by the city.
The project, monitored by scientists from nine universities and research organizations, is admittedly limited, and sanitation engineers are far from persuaded that it will be practical on a giant scale. Similar pilot projects conducted by Todd in Warren, Vt., and Harwich, Mass., however, have brought encouragement from the Environmental Protection Agency, which honored him in June with a merit award. "His is the kind of innovative and creative thinking that we need," says David Struhs of the EPA's regional office in Boston.
Born in Canada, the son of a 3M company executive, Todd has always been something of a free spirit. Though a chronic truant from school, he was inspired at age 13 by a book about a scientist who restored a pollution-ravaged site in Ohio. "From that point on I could look at places that have been destroyed and still see Edens," he says. "I still do."
The lack of a high school diploma did not prevent Todd from talking his way into Montreal's McGill University and earning two agricultural degrees. He went on to the University of Michigan for a doctorate in animal behavior and fisheries, then taught at San Diego State. There, together with his wife, Nancy Jack Todd, 50, a writer, and biologist William McLarney, Todd founded the New Alchemy Institute that, like medieval alchemists seeking to convert base metals to gold, hopes to turn everyday waste into something of value. In 1970 the Todds and their three children relocated to Cape Cod when John went to work for the Woods Hole Oceanographic Institution.
Over the years, Todd's environmental projects have ranged from aquaculture ponds to windmills. The author of several books on ecology, Todd worked with anthropologist Margaret Mead in Indonesia, studying how ancient cultures grew their food. At Mead's urging, Todd helped to found Ocean Arks, a company that has worked on designing solar-and-wind-powered boats suitable for commercial fishing in the gasoline-scarce countries of the Third World.
Todd has never expected to reap great financial rewards from his battles to save the polluted planet. He draws a modest salary as president of Ocean Arks (which has three employees) and spends about 40 percent of his time working as an environmental consultant. Still, he says, "I see myself as part of a tribe of people who are committed to restoring the earth. I'm convinced we can still turn things around."
—Dan Chu, S. Avery Brown in Providence