Naples, Fla.

The Corkscrew Swamp is a magnificent natural attraction. With its cathedral-like old growth cypress forest and abundant wildlife, it offers some of the best nature viewing and photographic experiences in the world. When it was established in 1954, it was a remote wilderness, attracting fewer than 10,000 visitors annually in its early years. By 1994 attendance surpassed 100,000 visitors a year. The increase in visitors overwhelmed the sanctuary facilities and the inability to handle waste water from the rest room facilities was an immediate, intolerable, and costly problem. Conventional options included two small “package” plants working in tandem, both running full speed during the tourist season, and one during the off season.

Dr. Todd proposed an Eco-Machine for Corkscrew Swamp Sanctuary that would occupy an area of only 70x70 feet, purify waste without additives, and recycle 90 percent of the purified water back into the restrooms for reuse in the toilets. This innovative system also cost substantially less than the conventional technology. National Audubon Society worked with Dr.Todd to design a treatment system unique to Corkscrew Swamp. Built within pristine wildlife habitat, the conventional systems raised alarm regarding its efficiency and reliability. Maintenance, chemical additives, the ultimate quality of the effluent, and the large amount of space needed were also major concerns. Corkscrew Swamp successfully turned their wastewater problem into a tourist attraction and asset. The Eco-Machine not only naturally purifies wastewater, but it also serves as a public education facility and butterfly aviary.

Waste is first pumped to two below-ground 10,000-gallon fiberglass tanks for initial anaerobic digestion, then to a series of 2,500-gallon tanks, each of which is aerated and supplied with bacteria, green plants from algae to trees, snails, shrimp, insects, and fish. Here ammonia and organic nitrogen are converted to nitrates. Water then flows into a 6th tank. Any remaining sediment is pumped back to the anaerobic tanks. The constructed wetlands consist of two 30’x30’ plastic-lined, artificial marshes filled with crushed limestone. The marshes are planted with typical wetland species from the swamp that remove the last vestiges of nitrogen through the root systems and convert them to harmless nitrogen gas. When the effluent exits these marshes, it is clean. But to satisfy state regulators, it is disinfected with chlorine, pumped to a holding tank, and then pumped to a chamber to de-chlorinate the water with sodium sulfite. The water is then recycled into the restrooms for flushing.