The Suwannee River Regional Algal Turf Scrubber® (ATS) Assessment was prepared by HydroMentia for the Suwannee River Water Management District as a conceptual engineering evaluation of ATS-based nutrient control for the Suwannee River in Florida. The assessment evaluated whether regional-scale ATS treatment systems could be used to reduce nitrate-nitrogen, total nitrogen, and total phosphorus loads from high-flow, nutrient-impaired surface waters.
Cover of HydroMentia’s 2006 preliminary engineering assessment for a regional Algal Turf Scrubber® nutrient-control program for the Suwannee River in Florida.
Unlike the individual pilot and full-scale ATS facilities described elsewhere in this archive, the Suwannee River assessment was not a constructed treatment facility. It was a regional planning and engineering concept intended to evaluate how multiple large-scale ATS treatment modules could be strategically located along the river system to support long-term nutrient-reduction goals.
Assessment Summary
Project: Suwannee River Regional Algal Turf Scrubber® Assessment
Location: Suwannee River Basin, Florida
Technology: Algal Turf Scrubber® / regional attached-algae treatment modules
Scale: 3,000 MGD conceptual treatment capacity; 120 treatment modules; 1,440 acres effective treatment area
Status: Conceptual engineering assessment completed
Assessment Date: 2006
Source Water: Suwannee River surface water
Operating Context: Regional nutrient control; nitrate-nitrogen loading from groundwater and spring discharges; Suwannee River and Gulf of Mexico water-quality protection
Application: Nitrate-nitrogen reduction, total nitrogen reduction, total phosphorus reduction, dissolved oxygen enhancement, regional treatment-site planning, and cost evaluation
Client / Requesting Entity: Suwannee River Water Management District
HydroMentia Role: Concept development, water-quality review, regional treatment-site evaluation, ATSDEM modeling, preliminary sizing, conceptual cost analysis, and engineering assessment
Planning Context
The Suwannee River is one of Florida’s largest and most important river systems. Water-quality monitoring had documented increased nitrate-nitrogen loading from groundwater and spring discharges, especially in portions of the river influenced by karst geology and artesian spring flow. These nutrient loads created management challenges for the Suwannee River, associated springs, downstream estuarine waters, and the Gulf of Mexico.
The Suwannee River Water Management District had already invested substantial effort in water-quality analysis and best management practices intended to reduce nutrient loading from the watershed. The regional ATS assessment was prepared to evaluate whether additional treatment infrastructure could complement watershed BMPs and provide a scalable method for recovering nutrient loads already present in river flow.
Regional Treatment Concept
The assessment evaluated an ATS-based regional treatment program using multiple 25 MGD treatment modules operated in parallel at strategic locations along the Suwannee River. The concept focused primarily on the Middle Suwannee River, where spring and groundwater contributions substantially influence flow and nutrient concentrations.
The conceptual program identified 11 regional treatment sites. Across those sites, the assessment evaluated 120 ATS treatment modules with a combined conceptual treatment capacity of 3,000 MGD and an effective treatment area of approximately 1,440 acres. The program was designed as a phased regional approach that could be implemented incrementally and coordinated with other nutrient-reduction programs.
Treatment Goal and Projected Performance
For the conceptual regional assessment, the nitrate-nitrogen reduction target was set at 30% of the Suwannee River nitrate load, or approximately 1,314 tons per year. The assessment also evaluated related water-quality benefits, including reductions in total nitrogen, total phosphorus, and increased dissolved oxygen associated with ATS treatment.
The 11-site regional treatment concept was projected to remove approximately 1,285 tons per year of nitrate-nitrogen, equal to 29.3% of the Suwannee River nitrate load and just below the 30% conceptual reduction target. The same concept was projected to remove approximately 1,922 tons per year of total nitrogen, equal to 23.0% of the total nitrogen load, and approximately 356 tons per year of total phosphorus, equal to 47.6% of the total phosphorus load.
These results were significant because they indicated that a phased, regional ATS treatment program could potentially approach basin-scale nitrate-reduction goals while also providing substantial total nitrogen and phosphorus reductions from high-flow, relatively low-concentration river water.
Engineering Significance
The Suwannee River assessment is significant because it evaluated ATS technology at a regional river-basin scale rather than as a single isolated treatment facility. The assessment addressed one of the most challenging nutrient-management problems in Florida: reducing nutrient loads in large, high-flow, relatively low-concentration river systems.
The assessment also demonstrated the value of modular planning. By using multiple treatment modules at multiple sites, the program could be phased, refined, and integrated with other basin-management efforts. This approach recognized that regional nutrient control would require a combination of source reduction, best management practices, and treatment of nutrient loads already present in surface waters.
Relationship to the Santa Fe ATS Pilot
The 2006 Suwannee River assessment provided the conceptual and engineering foundation for later field evaluation. The Santa Fe ATS pilot, operated from 2010 to 2011, was implemented to generate site-specific performance data for ATS treatment within the Suwannee River Basin.
The Santa Fe pilot tested ATS performance under low-nutrient, low-alkalinity river conditions and provided a conservative field evaluation of attached-algae treatment for the broader Suwannee River concept. Together, the 2006 assessment and the Santa Fe pilot form an important sequence: regional concept development followed by field-scale performance evaluation.
Figures and Planning Materials
The Suwannee River assessment includes conceptual treatment-site planning, preliminary module sizing, regional treatment layouts, and cost evaluation. Figures and maps from the assessment may be used to illustrate the scale and geographic logic of the proposed regional treatment approach.
Regional planning map from the 2006 Suwannee River ATS assessment showing the Florida section of the Suwannee River, monitoring stations, springs, and river segments considered in the conceptual nutrient-control program.
Reports and Publications
The Suwannee River regional ATS concept is documented in HydroMentia’s 2006 preliminary engineering assessment prepared for the Suwannee River Water Management District.
Related Facilities
Related HydroMentia ATS facilities, pilots, and assessments include Santa Fe ATS, PC-South/Osprey Marsh ATS, Osprey Marsh ATS, Egret Marsh ATS, S-154 ATS, Falls Lake ATS, NYCDEP Rockaway ATS, Maryland Port Administration Algal Flow-Way, and other full-scale and pilot-scale attached-algae treatment systems.