Free ammonia inhibition in microalgae and cyanobacteria grown in wastewaters: photo-respirometric evaluation and modelling
The inhibitory effects of free ammonia (FA) on microalgae/cyanobacteria in wastewater-treating photobioreactors (PBR) can strongly reduce their treatment efficiency, increasing the operational costs and undermining the stability of the system. Although FA-promoting conditions (high pH, temperature a...
| Authors: | , , , , , , |
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| Format: | article |
| Publication Date: | 2020 |
| Country: | España |
| Institution: | Universitat Politècnica de Catalunya (UPC) |
| Repository: | UPCommons. Portal del coneixement obert de la UPC |
| Language: | English |
| OAI Identifier: | oai:upcommons.upc.edu:2117/187079 |
| Online Access: | https://hdl.handle.net/2117/187079 https://dx.doi.org/10.1016/j.biortech.2020.123046 |
| Access Level: | Open access |
| Keyword: | Ammonia--Environmental aspects Microalgae -- Biotechnology Free ammonia inhibition Photosynthetic oxygenation modelling Wastewater treatment Microalgae and cyanobacteria Algae/bacteria consortia Microalgues -- Biotecnologia Amoniac -- Aspectes ambientals Àrees temàtiques de la UPC::Desenvolupament humà i sostenible::Enginyeria ambiental::Tractament de l'aigua |
| Summary: | The inhibitory effects of free ammonia (FA) on microalgae/cyanobacteria in wastewater-treating photobioreactors (PBR) can strongly reduce their treatment efficiency, increasing the operational costs and undermining the stability of the system. Although FA-promoting conditions (high pH, temperature and ammoniacal nitrogen concentration) are commonly met in outdoor PBRs, photosynthesis inhibition from FA has been scarcely explored and is rarely considered in microalgae-bacteria growth models. Two pilot systems and a series of lab-scale monocultures were tested using a photo-respirometry approach, to evaluate the effects of FA (8.5–136 mg NH3 L-1) on photosynthesis. Two mathematical inhibition models were compared, with the aim of selecting best-fitting equations to describe photo-respirometric experiments. A set of calibrated inhibition parameters was obtained for microalgae and cyanobacteria, growing in monocultures or in mixed algae-bacteria consortia. Cyanobacteria were more sensitive to FA than green microalgae and mixed phototrophs-bacteria consortia showed a higher resistance compared to monocultures. Estimated inhibition parameters were used to describe common operational/environmental conditions in algae-bacteria systems, demonstrating the potential drop in photosynthetic activity under those relevant operational conditions. |
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