Evaluating native Phragmites as a wastewater treatment alternative

An obstacle to statewide control of invasive Phragmites australis (common reed) in Minnesota is its continued use for dewatering biosolids in wastewater treatment facilities, a “green technology” leveraging invasive Phragmites’ exceptional ability to take up water and transpire it to the atmosphere. Development of an alternative to invasive Phragmites is essential for eliminating wastewater treatment facility source populations that can drive reinvasion in Minnesota despite efforts to control it across the landscape. Native Phragmites (P. australis ssp. australis) is an obvious alternative, but its use in wastewater treatment facilities to date has produced mixed results.

1. Select native Phragmites source populations and controls for testing
2. Experimentally evaluate performance of native Phragmites
3. Disseminate results to wastewater treatment facility operators and other stakeholders

The goal of the project is to support wastewater treatment facilities’ transition away from invasive Phragmites by systematically seeking native Phragmites strains with high dewatering ability. Native Phragmites ideally suited for dewatering would exhibit a suite of traits that enable it to remove water at high rates. The project includes a series of measures and experiments spanning from the field to the lab to identify native Phragmites that has these qualities. Rather than attempting to define a precise benchmark (e.g., “native Phragmites must remove 80% as much water as invasive Phragmites”) as wastewater treatment facilities’ needs vary with their engineering, storage capacity, and the needs of the communities they serve, the project will instead estimate how close we can get to the benchmark of invasive Phragmites and provide this information to wastewater treatment facility operators and engineers to guide their transition planning. The study will begin by characterizing a relatively large number of candidate native genotypes and then select promising ones for further investigation of water removal at different growth stages. If successful, this research would benefit AIS control in Minnesota by advancing toward a safe alternative to invasive Phragmites in wastewater treatment facilities.

Project manager: Daniel Larkin

Funded by: Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources

Project start date: Jan. 2021

Project end date: Dec. 2022