HydroMentia’s managed aquatic plant systems can be designed to reduce nutrient pollutants to low receiving-water or natural background concentrations while maintaining competitive capital and operating costs. Algal Turf Scrubber® systems are especially suited for applications where high-rate nutrient removal, reduced land requirements, and recoverable biomass are important project objectives.
Passive wetland treatment systems have been widely used for regional stormwater treatment and nutrient reduction. These systems can provide valuable water quality and habitat benefits, but they may require large land areas and can face long-term sediment-management challenges when applied to higher pollutant loads. In settings where land is limited, expensive, or needed for other productive uses, high-rate treatment alternatives may offer important advantages.
ATS systems address these challenges by operating at higher hydraulic loading rates than many passive treatment wetlands and by routinely harvesting algal biomass from the treatment surface. This active harvesting process removes accumulated nutrients from the system, supports long-term nutrient accountability, and helps maintain the algal community in an active growth phase.
Algal Turf Scrubber® systems minimize these challenges through high hydraulic loading rate capabilities, and the regular recovery and recycling of algal biomass developed during decades of research and implementation.
A University of Florida economic analysis concluded that Algal Turf Scrubber® phosphorus treatment costs, expressed as dollars per kilogram of phosphorus removed, were 53–69% lower than costs estimated for wetland stormwater treatment areas proposed for the Lake Okeechobee watershed. This comparison included assigned value for water storage and recreational benefits associated with wetland stormwater treatment areas.
Because ATS systems combine high-rate treatment, active biomass recovery, and reduced land requirements, they can provide a cost-effective alternative or complement to passive wetland treatment systems for selected stormwater, surface-water restoration, agricultural runoff, and wastewater polishing applications.
[1] USACE, SFWMD, HDR. October 2003. Lake Okeechobee Watershed Project Draft PIR, Water Quality Treatment Ranking. TPIN = 261 ppb; TPOUT = 100 ppb; 61.6% removal; 97,500 AF/yr.
[2] HydroMentia. April 2005. Single Stage Algal Turf Scrubber Present Worth Cost & By-Product Market Analysis. TPIN = 200 ppb; TPOUT = 146 ppb; 27.0% removal; 56,000 AF/yr; pump costs included.