MSU researchers test wetlands for treating Bridger Bowl’s wastewater

MSU researchers test wetlands for treating Bridger Bowl’s wastewater

Source: MSU News Service
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Marshall Swearingen, MSU News Service

BOZEMAN – When Shayla Woodhouse was offered a place on a Montana State University team researching innovative wastewater treatment methods, part of the deal was that she’d have to ski.

Woodhouse, a California native who had skied only a handful of times, embraced the opportunity. “It sounded awesome, skiing to collect samples,” she said.

The skiing was necessary because of an MSU experiment located mid-mountain at Bridger Bowl. There, a portion of the wastewater produced by the ski resort’s base lodges is diverted to an artificial wetland system designed by MSU engineers to treat the water.

During the past two winters, at least once per week, Woodhouse pulled off to the side of the Moose Meadows run to visit the site. After shoveling any new snow off several manhole covers, she took water samples that have been used to fine-tune the system and research its effectiveness. The results could change how Bridger Bowl and others – including residential subdivisions and even small towns in Montana – treat wastewater.

“It’s a relatively simple system when you look at it,” says Woodhouse, who is pursuing her master’s degree in environmental engineering in MSU’s College of Engineering. “We’re basically just putting wastewater on plants. But there’s so much more that goes on.”

The system, called a vertical flow treatment wetland, consists of two trenches roughly 16 feet by 32 feet. Each contains a rubber liner overlaid by drainage pipe and about 3 feet of gravel and sand in which sedges and rushes grow.

“These constructed wetlands are mimicking what would happen in a natural wetland,” Woodhouse said. “We’re applying that science to these man-made systems.”

The roots of the marsh-loving plants host microbes that break down the ammonia, organic carbon and other components of the wastewater, which is methodically pumped into the system and recirculated until clean. As a backup, the water then passes through the large, underground sand filter that treats the bulk of the wastewater after it is pumped uphill from settling tanks near the base lodges.

“It has exceeded my expectations about how well it would work,” said Otto Stein, a professor in MSU’s Department of Civil Engineering.

He conceived the pilot project around 2010 after studying constructed wetlands – which are widely used in Europe – for more than a decade. The project at Bridger Bowl offered an opportunity to test the technology in a harsh mountain environment.

“I thought, ‘If I can get it to work here, I can get it to work anywhere,’” he said.

In 2012, with Stein’s team providing the design and technical oversight, Bridger Bowl constructed the treatment wetland. Montana’s Department of Environmental Qualitypitched in $50,000 to cover materials and equipment for monitoring the water quality in the system, which became operational during the 2013-2014 ski season.

During the 2016-2017 season, the wetland treated an average of more than 2,000 gallons per day of the roughly 6,000 gallons of wastewater produced by the kitchens and bathrooms in the Jim Bridger and Saddle Peak lodges.

Woodhouse’s samples have shown that the system was removing nearly all the ammonia and other nitrogen-based nutrients in the effluent, “which is pretty difficult to do,” she said.

The MSU research team, funded with an additional $70,000 from Montana DEQ, has been able to achieve that by fine-tuning the system after experimenting with the timing and quantity of applying and recirculating the wastewater in the system.

According to Stein, the results show that even in the cold, high-elevation climate, constructed wetland technology performs nearly as well as expensive, energy-intensive mechanical wastewater treatment plants and better than other, lower-tech treatment methods such as sewage lagoons, which serve much of rural Montana.

“I’d like to see (constructed wetland technology) put into practice, because it could make a real difference in water quality in Montana,” Stein said.

“It’s been a good evolution, as students working on the project build on what others before them have done and move this technology closer to implementation” said Jerry Stephens, head of MSU’s Department of Civil Engineering.

Besides Woodhouse, five MSU students have contributed to the wastewater research at Bridger Bowl while earning their master’s degrees.

Stein has played a key role in bringing an important biennial conference dedicated to treatment wetlands to the U.S. for the first time. On Aug. 21-25, scientists and engineers from around the world will meet at Big Sky Resort for the Seventh International Symposium for Wetland Pollutant Dynamics and Control (WETPOL).

The pilot project at Bridger Bowl will be one stop on a tour that includes other experimental wastewater treatment systems, such as the constructed wetland at the Ennis National Fish Hatchery. Woodhouse, who plans to complete her master’s in the fall, will present her research at the conference.

“It would be awesome to keep working with wastewater,” she said as she reflected on her future plans during a recent visit to the Bridger Bowl research site.

Whatever form that takes, she admits somewhat wistfully, it’s not likely to require skiing.

Contact: Otto Stein,, (406) 994-6121.