The Maryland Port Administration algal flow-way pilot program evaluated attached-algae treatment in an urban, industrial marine terminal setting on the Patapsco River in Baltimore Harbor. The multi-year program examined nutrient and sediment reduction, algal biomass production, solids recovery, biomass dewatering, and potential integration of harvested algae with anaerobic digestion and renewable-energy production.
Maryland Port Administration algal flow-way pilot system at Dundalk Marine Terminal. The project evaluated attached-algae treatment as a potential best management practice for nutrient and sediment reduction in an urban port setting.
Facility Summary
Facility: Maryland Port Administration Algal Flow-Way Pilot
Location: Dundalk Marine Terminal, Baltimore, Maryland
Technology: Algal Turf Scrubber® / algal flow-way
Scale: Pilot-scale demonstration
Status: Pilot testing completed; Hawkins Point 30% design developed but not constructed
Initial Operation: 2013
Source Water: Patapsco River / Baltimore Harbor surface water
Operating Context: Urban, industrial marine terminal; brackish estuarine water; nutrient and sediment reduction evaluation
Application: Nutrient reduction, sediment reduction, biomass recovery, solids dewatering, and algae-to-energy evaluation
Owner / Sponsor: Maryland Department of Transportation Maryland Port Administration; later phases supported by U.S. DOT Maritime Administration
HydroMentia Role: Technical support, scale-up evaluation, ATSDEM modeling support, and participation in later pilot testing and design development
Operating Context
The Maryland Port Administration pilot program was located at Dundalk Marine Terminal, a working port facility adjacent to the Patapsco River in Baltimore Harbor. The project tested whether attached-algae treatment could be applied in a constrained urban waterfront setting where nutrient and sediment reductions may contribute to water-quality and regulatory objectives.
The pilot system used Patapsco River water as the source water. Water was pumped to the top of inclined floways and distributed across shallow treatment surfaces where naturally colonizing attached algae assimilated nitrogen and phosphorus into harvestable biomass. The harvested biomass also contained inorganic solids, allowing the project team to evaluate sediment-related benefits in addition to nutrient removal.
The project began in 2013 and continued through multiple phases. Early work evaluated algal productivity, nutrient content of harvested biomass, seasonal performance, hydraulic loading, and basic system operation. Later MARAD-supported phases refined design and operating details, including flow delivery, surge versus continuous flow, surface materials, harvest methods, solids recovery, biomass dewatering, and the use of harvested algae as feedstock for anaerobic digestion.
The Dundalk pilot work also supported evaluation of a potential larger facility at Hawkins Point. Although the Port has not advanced the Hawkins Point facility beyond initial design, the development of a 30% floway plan demonstrates that the pilot program progressed from field testing into site-specific scale-up planning.
Operational Significance
The Maryland Port Administration pilot is significant because it tested algal flow-way / ATS technology under conditions very different from HydroMentia’s large Florida surface-water systems. The Dundalk system operated in a brackish urban harbor environment, with variable salinity, seasonal temperature changes, industrial-site constraints, and practical challenges related to biomass recovery and dewatering.
The project generated useful performance data over multiple years. A 2016 performance synthesis estimated that a half-acre ATS facility, based on measured pilot performance, could produce approximately 12.9 dry tons of algal biomass per year while removing approximately 626 pounds of total nitrogen and 85 pounds of total phosphorus. The same analysis estimated meaningful sediment-related benefits based on inorganic ash recovered with the harvested biomass.
Later testing provided important design lessons for real-world implementation. Phase 3 and Phase 4 studies evaluated how flow delivery, surface materials, harvest configuration, dewatering channels, wedge-wire screening, and sand filtration affected operations and biomass handling. These details are important because full-scale ATS facilities must not only grow algae effectively, but also harvest, recover, dewater, and manage the resulting biomass reliably.
The 2019 Phase 4 testing also compared pulsed/surge flow with continuous/direct inflow and evaluated different floway surface materials, including liner with grid, concrete with grid, and concrete-only test sections. Under the Dundalk operating conditions, the surge system again showed negligible productivity benefit compared with direct discharge. These results are consistent with the broader design lesson that inflow velocity and hydraulic energy can influence productivity and algal community structure, while the specific method used to introduce that flow may be less important than maintaining effective hydraulic conditions across the floway. Surface-material testing indicated that roughened concrete provided productivity comparable to, and in some cases slightly higher than, liner/grid surfaces. Although roughened concrete is more expensive to construct, it offers important operations and maintenance advantages for larger facilities.
The project also explored the potential for harvested algal biomass to support anaerobic digestion and biogas production. While energy production was not the primary reason to consider ATS for water-quality treatment, the Maryland Port work provided a useful example of how nutrient recovery, biomass management, and renewable-energy concepts can be evaluated together in an industrial waterfront setting.
Photographs and Design Documents
Hawkins Point 30% Floway Plan. Pilot-scale performance and operating lessons from Dundalk Marine Terminal supported development of a site-specific scale-up concept for a potential larger algal flow-way facility at Hawkins Point.
Additional facility photographs are available in HydroMentia’s Facebook photo archive. Facebook may require visitors to sign in to view the complete gallery.
Reports and Publications
The Phase 4 Algal Flow-Way Pilot Testing Program at Dundalk Marine Terminal report is publicly available through the U.S. Maritime Administration and summarizes the final phase of the MARAD-supported pilot testing program.
Additional reports and publications related to Algal Turf Scrubber® technology and facility-scale applications are available in HydroMentia’s ATS Library.
Related Facilities
Related HydroMentia ATS facilities and demonstrations include Osprey Marsh ATS, Egret Marsh ATS, Taylor Creek ATS, S-154 ATS, and other full-scale and pilot-scale systems.