Nutrient Mitigation and Fishery Enhancement With Floating Treatment Wetlands

Tuesday, September 10, 2013: 11:40 AM
Izard (Statehouse Convention Center)
Mark Reinsel , Apex Engineering, PLLC, Missoula, MT
Nutrient loading from anthropogenic activities can contribute to water body eutrophication and deplete oxygen levels within waterways.  Floating treatment wetlands (FTWs) are a new method for improving water quality where excess nutrients may otherwise deplete oxygen levels, or produce harmful algae blooms or other deleterious effects.  By combining biofilm surface area and circulation, FTWs cycle nutrients through the food web via biofilms/periphyton.  FTWs are essentially biofilm reactors with plants.

FTW-enhanced fishing and other biomass harvesting can be the primary method for transitioning excess nutrients from water, according to a recent study.  Critical FTW factors in transforming a eutrophic pond (Fish Fry Lake in Montana) to a productive fishery included improved water clarity, higher dissolved oxygen concentrations, lower water temperatures, more fish cover and an increased food source (biofilm/periphyton).

These findings are being explored at a larger scale in 2013.  Studies include:  1) a brush park at Fish Fry Lake, 2) a one-acre FTW installed for nutrient abatement in New Zealand, 3) large quantities of FTWs and aeration equipment proposed for the lower Susquehanna River (maximizing nutrient reduction by transitioning them into fish), and 4) a research study in Mississippi using FTWs with active circulation to improve water quality and fish habitat.