Hybrid poplar trees are fast-growing with high absorption capacity for water, nutrients, and soil contaminants. They are therefore well-suited as a complement to wastewater treatment. Poplar can utilize approximately twice the mass of nitrogen per acre than grass crops, thereby doubling the capacity of farmland to apply nutrient-rich biosolids reclaimed from wastewater processing. Furthermore, growth rates improve with summer irrigation, which can be provided by recycled water from the treatment plant. Poplar irrigation provides further water quality benefits at the root zone and reduces direct discharge to streams, which may have restrictive water quality limitations during dry summer months. Within fairly short growth rotations of 10-12 years, the poplar reach harvest sizes suitable for sawlog and veneer milling as well as reaching suitable yields for chips and biomass markets. The MWMC in Eugene/Springfield, Oregon manages 400 acres of poplar for wastewater treatment and is one of the largest of its kind in the nation.
This project is supported by an Agriculture and Food Research Initiative Competitive Grant no. 2011-68005-30407 from the USDA National Institute of Food and Agriculture (NIFA).