Floating Treatment Wetlands Mitigate Lake Eutrophication

Simple, cost-effective water treatment strategies are transforming agricultural effluent into world-class fish habitat in an ongoing study in Montana. An enhanced floating treatment wetland (FTW) that incorporates air diffuser technology is under evaluation. This latest-generation system lifts and circulates water through floating stream beds within the FTW. This combination of FTW and improved water circulation/aeration is called Leviathan™, and represents a cost-effective and novel approach to address nutrient loading. The primary objective of the study was to determine whether biofilmbased microbes can provide nutrient removal while increasing fish productivity.

The Leviathan™ system, which is a new type of constructed wetland, has been evaluated to treat agricultural effluent and municipal wastewater. Cost-effective treatment options for end users with limited funding will be its greatest utility. The enhanced system can provide treatment of agricultural-impacted waters, municipal wastewater, stormwater and polishing of tertiary wastewater, along with lake restoration.

Wetland areas have been reduced worldwide while human-caused nutrient loading has increased with growing human populations. Mass-production agriculture as practiced in many developed nations can contribute to hyper-eutrophication in water bodies that were previously low in nutrient concentrations. In fresh water, partly as a result of normal seasonal stratification, nutrient loading can deplete oxygen levels within the livable temperature zone for fish species.