Wastewater Wetlands Could Be Answer For Developing Nations

June 13, 1996

GAINESVILLE — Developing nations, where drinking the water or even swimming in the ocean can be dangerous, may find a low-cost solution to their environmental woes by using wetlands for wastewater treatment, says a University of Florida scientist who is building such a system in Mexico’s Yucatan Peninsula.

“What I see, and I have traveled extensively through Latin America and some portions of Asia as well, is that most developing countries do not have wastewater treatment at all. The majority of them are dumping raw sewage into rivers and oceans and estuaries. Some don’t even have sewage collection systems,” said Mark Brown, associate scientist in the Department of Environmental Engineering Sciences and associate director of UF’s Center for Wetlands.

According to the World Health Organization, fewer than 10 percent of the sewage systems in Latin America and the Caribbean have treatment plants, and only 5 to 10 percent of the wastewater collected receives any kind of treatment.

Most developing countries simply can’t afford traditional wastewater treatment plants. Brown believes using wetlands, an idea pioneered by scientists at the center in the early 1970s, will be an economical and environmental solution.

The technology, in use in several places in the United States, is relatively simple. It uses the free services of nature, Brown said, to do the technological work that is normally part of the engineering in waste treatment plants.

The sewage is treated to remove solids before being released into the wetland, where it will spend the next 10 days to two weeks. The sun’s ultraviolet rays kill off bacteria and viruses. Microorganisms in the wetlands then consume the bacteria, thus acting as a living consumer of bacteria that could harm humans. Plants filter the water, taking out much of the organic material and sediments.

“These wetlands can be designed and constructed where there aren’t any,” Brown said. “You’ve got water, you’ve got nutrients, you can build a wetland. In some places where there are wetlands, you can use existing natural wetlands for this treatment process.”

And the benefits don’t necessarily end there. If it’s a forested wetland, trees will grow faster. Wastewater wetlands also can be designed to grow other vegetation, such as trees to be used as firewood by local residents.

Brown has witnessed the lack of wastewater treatment in several developing countries first hand. While some hotels in popular tourist destinations could afford to install wastewater treatment plants, often there were no spare parts or anyone who really knew how to run the facility. Waste moves through these systems untreated, often being pumped back into a nearby lagoon or into the ocean just offshore.

“The bottom line is in many tourist destinations, it’s not safe to swim in the ocean,” Brown said. “The water is in pretty bad shape.”

Wastewater wetlands, however, are self-maintaining, Brown explained. Once they’re built, you don’t have to do anything to them. “They do it themselves,” Brown said. “It’s a solution to the problem and we don’t have to export costly technology that’s too complex for people to use.”

Brown and Mark Nelson, a UF doctoral student in Environmental Engineering Sciences, will begin work on a wastewater wetland in the Yucatan this summer. The wetland will serve a research and educational facility for the Planetary Coral Reef Foundation. There is no wastewater treatment in the area, Brown said, and foundation officials are concerned that adjacent reefs can be seriously affected by over-nutrification of the water. On a recent trip to the area, Brown met several local hotel owners and realized the future possibilities for wastewater wetlands.

“We had people lining up wanting us to work with them on wastewater wetlands systems,” Brown said. “They realize that what’s important to their survival and to attracting more tourists is their environment, and that their untreated sewage is a threat to that environment.”