The impacts of replacing air bubbles with microspheres for the clarification of algae from low cell-density culture
| Autor: | Francesco Ometto, Andrea Gonzalez Torres, Raffaella Villa, Rachel Whitton, Bruce Jefferson, Carlo Pozza, Beatrice Smyth, Peter Jarvis, Rita K. Henderson |
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| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Environmental Engineering
Dissolved air flotation Chlorella vulgaris Chemie Microalgae harvesting Cyanobacteria 7. Clean energy Microsphere Water Purification Algae Cell density Floc structure Ballasted flotation Waste Management and Disposal Water Science and Technology Civil and Structural Engineering Aggregate (composite) Microbubbles biology Coagulants Ecological Modeling Air Environmental engineering Flocculation High cell Eutrophication Hydrogen-Ion Concentration biology.organism_classification Pulp and paper industry Pollution Carbon footprint 6. Clean water Microspheres Scenedesmus obliquus Scenedesmus |
| Popis: | Dissolved Air Flotation (DAF) is a well-known coagulation-flotation system applied at large scale for microalgae harvesting. Compared to conventional harvesting technologies DAF allows high cell recovery at lower energy demand. By replacing microbubbles with microspheres, the innovative Ballasted Dissolved Air Flotation (BDAF) technique has been reported to achieve the same algae cell removal efficiency, while saving up to 80% of the energy required for the conventional DAF unit. Using three different algae cultures (Scenedesmus obliquus, Chlorella vulgaris and Arthrospira maxima), the present work investigated the practical, economic and environmental advantages of the BDAF system compared to the DAF system. 99% cells separation was achieved with both systems, nevertheless, the BDAF technology allowed up to 95% coagulant reduction depending on the algae species and the pH conditions adopted. In terms of floc structure and strength, the inclusion of microspheres in the algae floc generated a looser aggregate, showing a more compact structure within single cell alga, than large and filamentous cells. Overall, BDAF appeared to be a more reliable and sustainable harvesting system than DAF, as it allowed equal cells recovery reducing energy inputs, coagulant demand and carbon emissions. |
| Databáze: | OpenAIRE |
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