Manufactured wetlands use plants to remove nitrates

Wetlands have served as natural wastewater treatment for millennia. It's only been in the past few decades that their ability to meet water quality objectives has been seriously studied and implemented.

Ed Kleiner, a Douglas County resident who has been using a form of the natural method for five years, said constructed wetlands wastewater treatment systems could be one solution to the nitrate problem as residential density increases in the Carson Valley.

The gray water from Kleiner's septic tank is channeled into the system, a combination of microbes and water-loving plants in two plastic-lined collection cells specially designed to isolate and remove nitrates and other harmful elements.

Over time, the health of the environment and residents drawing their water from private wells can be impacted when nitrates filter into the water table from septic systems, a common problem in rural areas.

Kleiner lives on Highway 88 south of Douglas High School, a pastoral setting complete with a barn and winding driveway lined with green pastures.

His wetlands system is just feet from his backyard pond. Their proximity would be enough to curl the toes of almost any county official, but the system has been tested, and the results are impressive.

"There's no standing water, no odor, no vector problem," Kleiner said. "Landscape architects and engineers send their clients here to see the system."

He leaned against the rail of his back porch overlooking the pond. Muskrats swam from one end to the other while a pair of swallows swooped over the water to catch insects.

Dragonflies flew low over the pond. A chorus of buzzing insects mingled with the plaintive calls of red-winged blackbirds and killdeer.

In recent years, the systems have been used on a much grander scale with the technology expanded to treat municipal wastewater, storm water, industrial, mining and agricultural wastes, according to a report by the Environmental Protection Agency.

Kleiner said the technology has been used in the Leviathan Mine cleanup and to filter water flowing into Lake Tahoe.

The Arcata Marsh Project in Northern California's Humboldt County is an example of a city using the technology for wastewater treatment, according to the report.

The systems do require maintenance. Kleiner said he burns off the vegetation in his collection cells once a year, but he's never had to clean out his five-year-old septic tank.

His system is gravity-fed so it doesn't require energy, and it isn't centralized, he said.

"Governments believe in centralization so they can treat the water and put it back," Kleiner said. "This is decentralization. The system costs a little more, but there's no increase in water or sewer rates."

These systems require a steady flow of water to keep plants alive, so constructed wetlands aren't appropriate for seasonal homes. In colder climates, larger cells are needed for freeze-prevention design, according to Toolbase Services, an information resource for the home-building industry.

Constructed wetlands are an affordable solution in warm climates or where conventional absorption fields have failed. Collection cells can be designed in any shape to accommodate narrow or oddly shaped lots. The systems can also be used where there is a high water table or low soil percolation, which could prevent the use of conventional septics, according to Toolbase.

"These systems mostly involve conventional landscaping techniques - grading and planting plus some poured-in-place concrete," Toolbase said. "The remainder is similar to a regular on-site septic system. A properly constructed and maintained wetland can last much longer than conventional septic systems."

n Contact reporter Susie Vasquez at svasquez@recordcourier.com or 782-5121, ext. 211.