April 8, 1997
by Becky Gillette
An environmental scientist from southern Mississippi has been changing the way the world treats its wastewater. Dr. Bill C. Wolverton, of Wolverton Environmental Services, at Picayune, is considered one of the world's foremost authorities on using natural constructed wetlands to purify wastewater, systems that are not only good for the environment, but extremely cost effective.
While working for the National Aeronautics and Space Administration's Stennis Space Center in southern Mississippi, Wolverton's job was to design a system for future Moon or Mars colonies or space stations that could recycle air and wastewater with minimum energy loss. What he learned was that the most energy- efficient method to treat air and wastewater is to use plant systems that naturally filter wastewater and indoor air. The plants use human waste as fertilizer, while exchanging the carbon dioxide exhaled by humans for life- giving oxygen.
Wolverton quickly realized that this technology was needed more on Earth than in space, and participated in a NASA technology-transfer program that offered the innovative, cost-effective marsh systems to municipalities and industries searching for better solutions to treating their wastewater.
Mississippi has been leading the world in the development of marsh systems for wastewater treatment. The state has marsh systems in numerous locations, including Carthage, Union, Picayune, Ocean Springs, Leakesville, DeKalb, and Collins. A number of those systems were designed by Wolverton, who has designed numerous other systems in other states and in foreign countries.
Visitors from throughout the country and from several other countries have traveled to Mississippi to take a look at the marsh systems.
Studies by the South Mississippi Resource Conservation and Development District have shown that initial construction costs average 60 to 90 percent less than mechanical systems, and operation and maintenance costs average 95 percent less. And, unlike the machines, the marsh systems don't wear out and have to be replaced every 15 to 20 years.
Other benefits include greater shockloading flexibility to handle stormwater intrusion, and lower labor costs because the systems can be operated by non- technical personnel. The marsh systems provide habitat that can help conserve rare or endangered plants and animals, and nature- watching opportunities for visitors.
Wolverton believes it is imperative that greater steps be taken towards sustainable wastewater treatment. "In the 21st century, we will have to come to grips with some serious changes in the way we manage our waste," he says. "As the population on Earth has continued to multiply and the economy has tightened, we can no longer afford to mechanically treat our waste. We need to combine agronomic technology with engineering technology to take our waste and clean it in a way that is beneficial. If we use our waste as a fertilizer to grow a valuable feed product, then we will turn a liability into an asset. This benefit, coupled with its cost-effectiveness, can offset the additional land mass needed by marsh systems. It is simply taking technology that is as old as the earth itself and refining it into the technology for the next millennium."
The marshland systems have also been popular with industry because of cost savings. For example, the Logan Aluminum plant in Russellville, Kentucky, estimates that it is saving more than $500,000 per year with the marsh system compared to the mechanical-treatment system used previously.
Wolverton says the marsh technology has now spread across the world, and is particularly welcome in Third-World countries that can't afford mechanical treatment facilities. He believes the challenge now is to gain wider acceptance of the use of plant systems to solve another serious problem: indoor air pollution.
Wolverton explains that specially designed planter systems can be built into buildings to help with what is known as the "sick building syndrome." Studies have shown that when new buildings are tightly sealed for energy efficiency, outgassing from synthetic materials such as carpets and building materials can make the indoor air very unhealthful.
Wolverton has been a pioneer advocate of the use of indoor plant systems to treat both wastewater and indoor air. The first application of the technology was NASA's Biohome at Stennis Space Center, a building designed to test the abilities of common indoor house plants to purify indoor air. Wolverton then designed an indoor plant system at his home office using wastewater from the bathroom to water planter systems filled with attractive houseplants that purify the indoor air.
Wolverton's test projects with the Biohome and his home proved that plants have a valuable role to play in preventing the sick-building syndrome. The technology recently had its first application in a large commercial building when a science building at a junior college in Booneville, Mississippi was built with an indoor atrium that is fertilized and watered by wastewater from the building's bathrooms.
There are no sewage odors from the planter systems, which use light-weight expanded clay pebbles--not soil--to grow the plants. The top few inches of the planter systems are dry, which prevents odors and prevents people from coming in contact with the sewage.
Wolverton is now working on a similar project at the University of Mississippi that will use plant systems to treat polluted air from laboratory fume hoods. And he's helping solve a serious sick-building syndrome problem at a middle school in Marshall, Virginia.
Marshall Middle School students were getting sick frequently because of chemical outgassing from the materials used in their new, energy-efficient school. Wolverton had the school remove carpeting and replace it with vinyl flooring before installing plant systems that will make the school a more healthful place for students and teachers.
"For new schools, this is a simple technology that will allow them to be energy efficient without making the students sick," Wolverton said. "We can build in these simple planters systems that will give them healthy air in the classrooms. We put plants in room which are being maintained by students. So far, what the students are saying is that they all want to go to the room with clean air, the room that doesn't make them sick."
Because of their small size and more rapid respiration, children are more susceptible than adults to health problems from chemical exposure. Chemical exposure can lead to asthma or a condition known as "multiple chemical sensitivity" which results in allergic reactions to hundreds of different types of chemicals.
"Children are so susceptible to indoor air pollution," Wolverton says. "The younger they are, the more susceptible they are to developing health problems from exposure to indoor air pollution. It is important to start with kindergartens first, because once children develop multiple chemical sensitivity, they are stuck with it the rest of their life. Children get multiple chemical sensitivity by being exposed to irritating chemicals that compromise the immune system, and the result is the children becoming allergic to nearly everything.
"We have erroneously blamed dust, mold and pollen for causing asthma in children, but approximately 90 percent of children with asthma, the disease is allergic in nature. This indicates that chemical contaminants in the indoor environment initially damage sensitive membranes surrounding the airways in lungs. Once these membranes have been damaged, children begin to develop allergic reactions to multiple substances."
Wolverton says plants systems for indoor air and wastewater simply bring nature indoors, simulating the kind of environment provided by nature.
"We're just getting back to the way nature intended us to live in a symbiotic or harmonious relationship with plants," he said. "We need what plants give off; plants need what we give off."
Wolverton recently participated in redesigning the Biohome, which is being renamed the Lunar One Module. It is being moved to the Visitor's Center at Stennis Space Center, which receives about 100,000 visitors per year.
Since a large number of teachers come to Stennis Space Center on class field trips and to participate in NASA's Teacher Resource System, Wolverton hopes that Lunar Module One will help stimulate schools to start considering using plants to prevent indoor air-quality problems at schools.
"We have the technology, simple and affordable, that creates healthy and efficient tightly closed schools," Wolverton said. "Now all we need is the will to use it."
"The marsh systems have spread all over the world. Indoor air is the next frontier. And most of the technology development on the indoor systems has been right here in Mississippi."
Dr. Wolverton will soon embark on a nationwide tour to promote his new book, How to Grow Fresh Air: Fifty Houseplants that Purify Your Home or Office, which is being published in the U.S., Canada, Europe, Australia by Penguin Books. Wolverton will leave April 20 to meet with media and do book signings in major U.S. cities.
Studies have shown that indoor air pollution is a major health problem in the U.S., and Wolverton's book offers a inexpensive, natural solution to the problem.
"Plants are the lungs of the Earth: they produce oxygen that makes life possible, add precious moisture, and filter toxins," the back cover of his book states. "Houseplants can perform these essential functions in your home or office with the same efficiency as a rainforest in our biosphere."
The book includes a chapter on the problem of indoor air pollution, a chapter on the living biosphere that is earth, and another on how houseplants purify the air. That is followed by a grower's guide to 50 houseplants that purify the indoor air, including information on which plants are most effective for specific toxic air pollutants.
Becky Gillette is a freelance writer in Biloxi, Mississippi.