The school paper forester Mark Vander Meer wrote years ago about watering poplar trees with effluent from the sewer plant got a B grade.
On the ground at the Wastewater Treatment Plant, though, the pilot project was successful enough for the city of Missoula to launch an expansion of 130 acres. Vander Meer, with Watershed Consulting, is part of the poplar implementation team, and on Thursday he and other city officials and scientists shared the benefits of the $1.375 million hybrid tree project underway near the Clark Fork River.
"We love poplar wood. It's good stuff," said Vander Meer, who hopes to purchase some of the harvest. "It's a good thing I live here."
In 2009, the city of Missoula launched a pilot poplar plantation of 1.6 acres, and it used effluent from the sewer plant to water the trees. Treated wastewater puts phosphorous and nitrogen back into the river; the nutrients feed algae and harm water quality, but they nourish the hybrid trees, adapted for the region.
In April, the Missoula City Council approved an expansion of the project to grow an estimated 72,500 poplars a half mile west of the sewer plant. Once the trees are mature, the sewer plant will be able to divert an estimated 10 percent of its effluent, or 1 million gallons a day, to the plantation, along with the phosphorous and nitrogen, according to the city.
"It just makes sense to put those compounds to growing a dense crop like those poplars here instead of algae in the river," said Chris Brick, science director of the Clark Fork Coalition.
The project will cost an estimated $1.375 million total, and the money will come out of sewer funds, said plant superintendent Starr Sullivan. The cost may seem high, he said, but it's 10 to 20 times cheaper than installing more equipment to meet tightening environmental standards for the levels of compounds going into the river.
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"I think in the future, we're going to see stricter and stricter requirements," Sullivan said.
If the project goes as planned, the harvest will take place in 2027, and will yield some $2 million, according to estimates from city officials.
Watershed Consulting and the Hybrid Energy Group of Missoula were hired to implement the project. Vice President Tom Platt, of the Hybrid Energy Group, said experimental programs are underway in several other states, including Idaho, Oregon and Washington, but the expansion locally is the first commercial-sized operation in Montana.
Together, Platt and Vander Meer will oversee the project, monitoring the health of the trees, maintaining equipment and the irrigation system, and controlling weeds. The goal is "straight, knot-free saw logs," and Vander Meer said he would like to purchase some of the crop.
A lease on the property is in place, and in January the city received a permit for the project from the Montana Department of Environmental Quality. In 2013, the implementation team will build a wildlife fence around the site, put in a pipe to deliver the effluent, construct a drip irrigation system, and prepare for planting.
Poplar "whips," or 12-inch cuttings, will be put in the ground next year, and in the first five years, the growth will be thinned to size, with extra biomass going to Eko Compost "as bulking material." The maintenance and watering plan for the pilot project will be used as a model for the larger plantation.
Brick, with the Clark Fork Coalition, said the project is a step in the right direction, and in the future she would like to see the plant use 100 percent of its effluent on the trees in the summer months. Sullivan agreed it was a good idea, but he said it's "a few years down the road" and would require 500 to 1,000 acres.