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Drinking Water and Wastewater Treatment


Phosphorus Control and Management Using Biological Processes

The City of Logan has been mandated to lower the concentration of the chemical phosphorus that leaves the Water Reclamation Facility and enters Cutler Reservoir. Phosphorus causes algae to grow resulting in a green appearance of the water and reducing the oxygen content of the water at night. This results in fish kills and deterioration of water quality.

Current technology for reducing phosphorus concentration in water that has been estimated by the City of Logan to result in an increase of approximately $40 to $50 per month per household. This project is developing and testing inexpensive and natural biological processes that remove phosphorus through algae uptake at the Water Reclamation facility and then separation of the algae from the water before the water exists the facility and moves toward Cutler Reservoir.

Benefits to State:

Ability to reduce the pollutant phosphorus through the application of algae biotechnology will:

  • Enable other cities, towns, and communities in Utah to utilize this technology for the treatment of waters and wastewaters to ensure environmental health and protection at costs that are significantly lower than conventional technologies.
  • Enable State of Utah Department of Environmental Quality reduce the amount of loans and grants to community for upgrades to wastewater reclamation facilities, and redirect the financial support to other important projects.

Geographic Areas:

Study Areas: City of Logan Wastewater Reclamation Facility that treats the wastewater of six
towns, including Logan, Hyde Park, Smithfield, North Logan, Nibley, and Hyrum.

Areas Benefited: All areas of the State of Utah that utilize ponds or lagoons for the treatment of wastewater that includes Northern and Southern Utah.


Findings. A biotechnology process has been developed that reduces the phosphorus
concentration levels below those mandated by the state of Utah and the U.S. Environmental
Protection Agency. The process is applicable to other communities that utilize open ponds or
lagoons for wastewater treatment.

Results: Algae that grow and thrive in the Logan Lagoon system must be harvested before they die and release phosphorus back into the Lagoon water. As can be seen in the figure above, algae remove phosphorus from the water while they grow, and then release phosphorus back into the water (seen by the increase in concentration) when they die.

The Algae can be removed from the treated water using standard separation technology
(Dissolved Air Flotation) so that the treated water leaving the system meets state and federal
regulations for phosphorus concentration.

Informational Resources

Presentation: Sustainable Production of Biofuels from Algae. Institute of Biological Engineering
2009 Annual Conference, California (March). IBE wiki site:

Algae bioreactor in the laboratory

Algae Bioreactor in the Laboratory.

Effect of algae on phosphorus removal from Logan Lagoon water at temperatures representative of seasonal changes

Effect of algae on phosphorus removal from Logan Lagoon water at temperatures representative of seasonal changes.

March 10, 2011