Algae biofilm based nutrient removal for energy efficient upgrades to small treatment plants
Tuesday, September 29, 2026 12:45 PM to 2:15 PM · 1 hr. 30 min. (US/Central)
New Orleans Convention Center
Technology Spotlight
Hall H Booth 7249
Information
Rising temperatures and elevated nutrient loadings are contributing to more frequent challenges with eutrophication and harmful algal blooms in receiving waters. As a result, nutrient discharge regulations are tightening. These constraints are particularly limiting for smaller wastewater treatment facilities, which often lack the financial and operational capacity required to implement advanced nutrient removal processes. Algae biofilm-based treatment systems represent an emerging technology which provides a low-energy, mechanically simple option for secondary or tertiary treatment to increase BOD, ammonia, and nutrient removal capacity.
The system consists of an array of cone shaped cloth carriers that support a mixed algae-bacteria biofilm. Wastewater is irrigated over the cone bed, where the biofilm community supports nutrient uptake, BOD reduction, and suspended solids removal without chemical addition. The cone shape optimizes solar radiation for optimal photosynthetic efficiency and maximizing available surface area for treatment. While algae can absorb significant quantities of nutrients, a major benefit of the process is the free oxygen, from algae respiration and air transfer, which can be used by bacteria to remove ammonia and organic carbon, avoiding the need for energy intensive mechanical aeration equipment.
The system has now been demonstrated at pilot and commercial scale in secondary and tertiary treatment applications for nearly 2 years, showing robust treatment, and in particular consistent ammonia removal through cold winter periods.
System startup consists of inoculation of the carrier media with algae, followed by introduction of wastewater. Biofilm establishment begins without further intervention and reaches steady state treatment performance after about 2 weeks. Key design considerations include light availability and seasonal temperature variability. In colder climates, greenhouses are required to maintain performance and prevent freezing. Biomass harvesting is carried out weekly to maintain active growth surfaces and limit excessive biofilm thickness. The system runs autonomously, but periodic operator attention is required to maintain optimal performance and conduct regulatory sampling/monitoring.
Findings indicate that algae biofilm-based systems offer a viable treatment option for small systems seeking lower-energy, mechanically and operationally simple systems. The Algae Forest also provides a modular, scalable framework that can be expanded as community needs evolve or regulatory requirements become more stringent.
The system consists of an array of cone shaped cloth carriers that support a mixed algae-bacteria biofilm. Wastewater is irrigated over the cone bed, where the biofilm community supports nutrient uptake, BOD reduction, and suspended solids removal without chemical addition. The cone shape optimizes solar radiation for optimal photosynthetic efficiency and maximizing available surface area for treatment. While algae can absorb significant quantities of nutrients, a major benefit of the process is the free oxygen, from algae respiration and air transfer, which can be used by bacteria to remove ammonia and organic carbon, avoiding the need for energy intensive mechanical aeration equipment.
The system has now been demonstrated at pilot and commercial scale in secondary and tertiary treatment applications for nearly 2 years, showing robust treatment, and in particular consistent ammonia removal through cold winter periods.
System startup consists of inoculation of the carrier media with algae, followed by introduction of wastewater. Biofilm establishment begins without further intervention and reaches steady state treatment performance after about 2 weeks. Key design considerations include light availability and seasonal temperature variability. In colder climates, greenhouses are required to maintain performance and prevent freezing. Biomass harvesting is carried out weekly to maintain active growth surfaces and limit excessive biofilm thickness. The system runs autonomously, but periodic operator attention is required to maintain optimal performance and conduct regulatory sampling/monitoring.
Findings indicate that algae biofilm-based systems offer a viable treatment option for small systems seeking lower-energy, mechanically and operationally simple systems. The Algae Forest also provides a modular, scalable framework that can be expanded as community needs evolve or regulatory requirements become more stringent.
