We recently started to test the newly developed pilot-scale cultivation systems for algae. This will be the basis for our study on how to improve the efficiency and productivity.
The main objective of the project part called work package 2 (WP2) is to maximize pilot-scale algal productivity in wastewater by combining efficient effluent treatment and carbon sequestration. This will remove nutrients (Nitrogen and Phosphorus) from the tertiary municipal wastewater from Veas that otherwise would end up in the Oslofjord.
Growing algae in the wastewater
One of the hypotheses of the ALGECO project is that a polyculture of filamentous algae can thrive in the treated wastewater. WP2 will perform pilot-scale phytobioremediation of the tertiary municipal wastewater. The remaining nutrients in the wastewater will be used by the algae polyculture to grow. The harvested algae biomass will be processed and then WP3 and WP4 will analyse its potential for new algae products, mainly biofertilizers.
Phytoextraction (or phytoaccumulation or phytosequestration) exploits the ability of plants or algae to remove contaminants from soil or water into harvestable plant biomass |
WP2 will also produce data for WP5 to complement the life cycle and techno-economic assessment of the entire bioremediation process. With more concerns on eutrophication in the Oslofjord, it is anticipated that our research work can provide a new insight to confront this growing environmental problem.
Trials started at research facility in Solbergstrand
In the first trial we primarily test our newly developed pilot-scale cultivation systems. The results from the trial will form the basis of our pilot study on how to simultaneously improve the bioremediation efficiency and biomass productivity.
The work of WP2 is conducted using flat panels reactors and “raceways” located at NIVA’s algae research and development facility in Solbergstrand outside of Drøbak. Raceway ponds for algae cultivation are a type of 'U' shaped closed circulation channel where the algae and cultivation medium (wastewater in our case) are mixed by circulation with the help of a paddle wheel.
The flat panels reactors produce high-quality inoculum or algae culture starter for raceway cultivation (the inoculum is the algae biomass we use to start the cultivation in any type of container). The raceways are under a greenhouse to guarantee relatively stable cultivation conditions with pH control and LED illumination.
The wastewater arrived at Solbergstrand at the beginning of April 2022. As the testing and development of optimal algae polycultures (WP1) is still ongoing, only one strain of algae (monoculture) was used for this first WP2 trial. Wastewater and highly concentrated algae inoculum were added to the raceway and the cultivation started. Periodic samples for nutrient concentration analysis are being taken for further research. After the nutrients are consumed, the algae will be harvested and the cleaned wastewater released to the Oslofjord.
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