Water pollution solution: build a marsh.
ALL THE WATER this planet has ever had and will ever have is now on earth--a fixed commodity that is constantly and naturally recycled. Most of the world is covered by water, but less than one percent of it is available for human use, and unfortunately, pollution from many sources has degraded much of that. The cleansing and recycling of our water resources will be one of the great challenges of the 21st century.
The federal Clean Water Act of 1965 and its 1972 amendments mandated reduction of point-source pollution (pollution generated at a specific site). In meeting these new standards, numerous communities and factories around the world have learned that huge treatment plants are not the only or best solutions. Nature provides its own highly effective water-cleansing system--it's called a marsh. According to a growing number of experts, marshes and wetlands can clean up almost anything we can throw in.
Arcata is a town of 15,000 on the northern California coast where citizens "flush with pride." The town, once known for its redwoods and more recently for the marijuana produced in logged-over forests nearby, has a new export--tangible proof that a constructed wetland system can provide cost-effective and environmentally sound treatment for municipal wastewater.
Back in 1979, Arcata's sewage-treatment plant was failing. Its discharge into Humboldt Bay did not meet the Clean Water Act's wastewater standards, and it was operating with a temporary pollution exemption from the state. Something had to change.
Guided by the fervent belief of Dr. George Allen, a fisheries professor at Humboldt State University, that wastewater is a resource and not a disposal problem, a coalition of academia, local politicians, concerned citizens, city bureaucrats, and environmental groups launched an attack against the conventional wisdom of sewage treatment. The town wanted to opt out of the county's expensive regional treatment plant and install a low-tech, low-cost system of marshes to treat its wastewater.
In what became known as the "Wastewater Wars," the town of Arcata ultimately triumphed over the state bureaucracy and local naysayers. Because the effluent (wastewater) would be released into Humboldt Bay rather than the Pacific Ocean, state law required Arcata to prove not only the system's ability to meet wastewater standards but that it would enhance the Bay. A three-year pilot project demonstrated the marsh system's effectiveness (see "Waste Not Wastewater," American Forests, June 1982).
The city proved enhancement in two ways. The first was George Allen's aquaculture research station, which utilized the effluent to raise anadromous fish. The second was the restoration of wetlands, which created additional wildlife habitat. Arcata opened its full-scale treatment process in 1986 for far less than the proposed $50 million regional treatment facility.
The Arcata Marsh and Wildlife Sanctuary adjoins Humboldt Bay, just three minutes from downtown. A primary treatment plant and oxidation ponds settle out solids and begin the biological breakdown of the sewage with micro-organisms. Effluent then moves through three 2-acre treatment marshes before going through three enhancement marshes in the Arcata Marsh and Wildlife Sanctuary.
Wetlands improve water quality with a mix of physical, chemical, and biological processes. Marsh vegetation obstructs water flow, enhancing sedimentation (settling of solids). The vegetation also provides an environment for algae, fungi, protozoa, and bacteria, the microbes that break down or remove substances from wastewater.
As early as 1970, Dr. George Allen demonstrated the value of effluent from Arcata's treatment ponds. He used it to establish an aquaculture research station to rear juvenile salmon in wastewater-sea-water ponds.
Standing beside dark pools, netted and fenced to keep out predators from the air and ground, he says modestly, "We killed every fish the first year. Our salinity and our temperatures were too high." With a smile he adds, "Now we have an 85 to 100 percent survival rate." Because of the high level of nutrients in the wastewater, Allen has substantially reduced the need for high-priced fish food.
Though coho salmon have been the most successful species raised, other species of anadromous salmonids like chinook salmon, steelhead, and coastal cutthroat trout have been raised. Allen's one-percent return (the rate of fish that return to the release site to spawn) betters or equals that of most commercial hatcheries.
The Arcata Marsh and Wildlife Sanctuary is much more than a wastewater-treatment system. According to Dr. Robert Gearheart, professor of environmental engineering at Humboldt State University and one of the key developers of the marsh concept, the marsh is only a tiny part of the water cycle, a connection between the rivers and streams and the bay and the ocean. "Our job is to restore the functions of the water system and help get the whole flow back in order," he says.
The new wetlands enhance the entire Arcata waterfront, which heretofore had been nearly inaccessible to the public. Formerly the site of a sealed sanitary landfill, an abandoned log pond, and degraded pasture, the 154 acres that comprise the Arcata Marsh and Wildlife Sanctuary are now open to the public.
The marsh is an important wintering ground for migrating waterfowl and has become one of the best birding sites in northern California. More than 200 bird species have been identified, including the endangered peregrine falcon. River otters, rabbits, voles, and pocket gophers also live there.
The marsh is a human as well as a wildlife sanctuary. In 1987 the Ford Foundation recognized this wetlands project as an innovative local government project. The award included $100,000 to fund establishment of the Arcata Marsh and Wildlife Sanctuary Interpretive Center, which opened in spring 1993. Five miles of trails with educational displays and a freshwater lake facilitate public access.
As the morning vapors rise off the still waters, birdlovers with binoculars sweep the marshes. Then come the walkers, joggers, and bicyclists. Later in the day, school children and university students use the marsh for a variety of projects. Artists come to sketch. City workers flee downtown for a few moments of lunchtime calm. More than 150,000 people a year visit the marsh--not bad in a county of 100,000 population.
Julie Fulkerson, who represents the Arcata area on the Humboldt County Board of Supervisors, believes the project's success has had a beneficial impact on Arcata. "It made us aware of the entire watershed," she says, "of what happens when we turn on the tap or flush our toilets, and of what makes our planet healthy."
Steve Tyler, the town's director of environmental services, is confident that the marsh system can meet all the future demands placed on it. "It can do a lot more than we're asking it to do," he says. "We've got a cost-effective, environmentally sound response that uses less energy and fewer chemicals than conventional systems. I can't imagine an area in which it wouldn't work if you've got enough land."
Today the State Water Quality Control Board (SWQCB) cites the Arcata project as a model for others to emulate. According to Bill Rodriguez at SWQCB, "The treatment marshes seem to be doing what they were designed to do--meet the permit levels. However," he cautions, "this system may not meet the needs everywhere."
The Environmental Protection Agency (EPA) is enthusiastic about the use of constructed wetlands for wastewater treatment. It has provided construction grants for 17 successful projects in 10 states, says Bob Bastian, environmental scientist for EPA's Office of Water. "Each system is different; each is designed to perform specific tasks," he says. "This technology has great promise."
In central Florida, the Orlando Easterly Wetlands Reclamation Project protects the St. Johns River by removing nutrients from the already highly treated wastewater. Like Arcata, Orlando was faced with an effluent that did not meet state standards. In 1986 a 1,600-acre wetlands was built to perform advanced secondary treatment of effluent, removing both phosphorus and nitrogen.
According to JoAnn Jackson, an engineer and program manager with the firm that designed the marsh, "The Orlando wetland has been extremely successful at performing the function it was designed to do."
It also serves to restore wildlife habitat and as a park and recreation facility. The wetland supports more than 150 plant species, 141 species of birds, 22 reptiles, and 16 mammals. The estimated life-cycle costs of the Orlando project are 15 to 30 percent less than the city's other options.
"Twenty years ago," says Francesca Demgen, former wetlands manager for the Mt. View Sanitary District in Martinez, California, the general public didn't even use the word 'wetland.' Fifteen years of experience have proven the treatment marshes to be at least as reliable as conventional treatment methods. Wetland systems are so complex that if one part stops working, two or three elements are left to pick up the work."
If these systems are so great, why aren't there more of them? In the San Francisco Bay area, constructed wetlands are used for enhancement--habitat restoration and public access--rather than treatment. Demgen, who now works for the environmental consulting company Woodward-Clyde in Oakland, says, "Wetlands can do a lot more for treatment than they've been allowed to do up to now. But the conventional treatment plants in the San Francisco Bay area are very large, and a wetlands system for something that large requires a lot of land--a limited, expensive quantity here." Wetland experts estimate a minimum of two acres per 1,000 people are required.
Concerns about protection of groundwater can also drive costs up. If the proposed wetland site sits above tight clay soils, protection may not be an issue. But if the soil beneath the site is loose and porous, a synthetic liner underneath the marsh might be required--a very expensive proposition.
Arcata has found its treatment facility relatively inexpensive to operate because of all the chemicals it doesn't have to buy. But maintenance costs can vary from project to project. JoAnn Jackson from Orlando points out that pumping costs can vary widely depending how far the treatment marshes are from the collection point.
Gearheart says engineers are partly to blame for constraining the growth of constructed wetlands: "They're not comfortable with passive, natural systems. They also don't have a lot of incentive to suggest this type of system. Engineers are paid a percentage of construction costs, not including land acquisition. Construction costs for constructed wetlands are relatively low."
Nonetheless, the development curve is upward. Ecologist Dr. Donald Hammer of the Tennessee Valley Authority says, "Five or six years ago, we kept track of all the projects on a database. Now the numbers are growing so fast we can't keep up with it." He estimates that more than 300 municipalities are now using natural treatment systems.
Pioneer projects around the U.S. and around the world have demonstrated that natural treatment systems work. In many cases, they not only treat wastewater but enhance wildlife habitat, recreation, and educational opportunities. Perhaps in the not-too-distant future, all of us--like Arcatans--will be able to flush with pride--or at least without guilt.
Industry Tries the Natural Approach
The American Crystal Sugar Company in Hillsboro, North Dakota, has constructed a 157-acre wetland to receive the partly treated wastewater from its sugar-beet factory. The wetland has produced a high-quality effluent for the last two years, and the company plans to build an additional wetland for its Drayton, North Dakota, facility.
Chevron Oil's refinery in Richmond, California, constructed a wetland beside San Pablo Bay. Source-control efforts upstream reduced the need for downstream oxidation ponds. As the old ponds dried up, a 90-acre eyesore was created. Project coordinator Peter Duda proposed restoring the devastated moonscape by developing a wetland. Though it is not used for wastewater treatment, the wetland has greatly improved wildlife habitat in a sensitive area by the bay.
For Duda, the wetland was a labor of love. He put in untold hours evenings and weekends planting much of the vegetation himself.
Duda praises both Chevron and environmental groups--traditional antagonists--for joining their efforts and resources to restore the 90-acre site. Today more than 100 species of birds have been identified at the site, and local universities use the wetland for research projects.
"Ecologic repair is possible." So states Dr. John Todd of Ocean Arks International of Falmouth, Massachusetts. "We can clean up the horrors of this planet with 'living machines.'"
His "living machines" use natural treatment processes similar to a wetland but in a more restricted space. Comprised of a series of distinct ecologies contained within a number of cylinders, the living machines are installed in a greenhouse to allow sunlight to serve as an energy source. As water moves between cylinders, each containing successively higher life forms, wastes created by the inhabitants of one cylinder become the food for the next cylinder.
In the first tank, bacteria consume suspended organic matter and thrive. In the next tank, algae consume the waste products of the bacteria. Next, snails consume the algae. Farther down the line of tanks, mollusks and fish join the natural process of consumption. Compounds are thus broken down without using chemicals and without creating hazardous byproducts.
In 1991 Todd's Solar Aquatic waste-treatment system received Discover Magazine's award for technological innovation in the environment. Todd is currently working with funding from the EPA on pilot projects in Maryland, California, and Vermont.
Says EPA environmental scientist Bob Bastian, "I have no doubt the technology will treat almost any type of wastewater. It has yet to demonstrate it is cost-effective."
Todd believes his living machines will prove cost-effective. "They use less energy and less chemicals than conventional treatment plants, and they require less land than the constructed wetlands."
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||includes related articles|
|Date:||Jul 1, 1994|
|Previous Article:||Green side up.|
|Next Article:||Salvaging Superior logs.|