New Way Found to Recycle Wastewater
For years, Penn State University used its treated wastewater for irrigation, showering about 1 billion gallons per year on the state gamelands north of State College and on nearby university-owned farmland.
The idea originally was simply to find an environmentally friendly way to dispose of the university's wastewater. But after nearly 20 years of operation, university scientists now are trying to manage an environment that they have created.
"We know that having this much water just isn't natural here," said Todd Bowersox, professor of silviculture at Penn State, who manages the forestry aspect of the project. "So what we want to do is find out what native species that might grow in this region could make this a more sustainable place."
Penn State's main campus with more than 40,000 students and 10,000 employees gets its water from a series of wells, drawing from the water table under Centre County. After use in sinks, showers, toilets and drinking fountains on campus, the university collects and treats the water to stream-release standards in its own plant, just as a city would at a municipal water treatment plant.
But instead of feeding the water into a nearby waterway, the university pumps it out north of town, where an average of 2.7 million gallons per day are sprayed over 520 acres of farm and forest land, said John Gaudlip, utility systems engineer for the university. That would be the equivalent of 2 inches of rainfall per day.
The university began experimenting with treated wastewater in the 1960s, and by 1983 had developed a system to deliver that water to the gamelands and university farms north of town.
Although that water has been filtered through the university's plant, it still is higher in nutrients such as nitrogen and phosphorus than rainwater. Bowersox said that nutrient-rich environment might have been one reason that foresters saw fewer saplings from the native tree species, such as black oak, scarlet oak and red maple.
"The concern that I had was that we had a community here that had developed over a long period of time to around 40 to 45 inches of rainfall per year and was accustomed to growing on soils that were relatively low in fertility," Bowersox said. "By putting on all this irrigation, particularly of nutrient-rich water, we changed the game."
So a few years ago, the university began testing different species to see what would grow best in what Bowersox described as "sort of a northern rainforest." They found those species along the banks of Pennsylvania's rivers: sycamore (news - web sites), silver maple, green ash, river birch, black gum and Norway spruce. They also found that some of the native species, including quaking aspen and bigtooth aspen, did well despite the change in their environment.
Still, Bowersox and Lisa Kelso, a graduate student in forest resources, knew that any new trees they planted would have a hard time surviving the shade of the existing forest. So in 2000, they cleared a 20-acre area where the native trees were struggling and planted their river species.
Two years later, those trees are starting to come into their own. The quaking aspens are more than 12 feet tall. Kelso is doing experiments elsewhere in the forest to determine how best to encourage growth of the new species.
"I think people will be very pleased with what they see here in four or five years," Bowersox said. "It's definitely going to be a tree-dominated landscape, and I think it will do a good job sustaining wildlife."
That's important for the Pennsylvania Game Commission, which leases the land to the university. The gamelands are stocked with pheasant each fall, and university officials make sure the area is still accessible to hunters.
"The university has put the spraying on a schedule where there's minimal interference during hunting season, night spraying and not spraying on Saturdays, things like that," said Dennis Dusza, land management supervisor for the game commission's Northcentral Region.
But most important, the water is returned to the ground from which it came. Although some water is used by the vegetation and some lost to evaporation, about 90 percent of the water sprayed on the area is returned to the water table.
"This is really a wastewater recycling plan," Bowersox said. "The real goal is to discharge this water in a way that's environmentally friendly, and by putting it back into the ground here, maybe we can even use it again."