Advanced HRT-Controller Aimed at Optimising Nitrogen Recovery by Microalgae: Application in an Outdoor Flat-Panel Membrane Photobioreactor
A fuzzy knowledge-based controller of hydraulic retention time (HRT) was designed and tested in an outdoor membrane photobioreactor (MPBR) to improve nitrogen recovery from a microalgae cultivation system, maintaining the algae as photosynthetically active as possible and limiting their competition...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-03-01
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| Series: | ChemEngineering |
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| Online Access: | https://www.mdpi.com/2305-7084/6/2/24 |
| _version_ | 1797436368428728320 |
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| author | Juan Francisco Mora-Sánchez Josué González-Camejo Aurora Seco María Victoria Ruano |
| author_facet | Juan Francisco Mora-Sánchez Josué González-Camejo Aurora Seco María Victoria Ruano |
| author_sort | Juan Francisco Mora-Sánchez |
| collection | DOAJ |
| description | A fuzzy knowledge-based controller of hydraulic retention time (HRT) was designed and tested in an outdoor membrane photobioreactor (MPBR) to improve nitrogen recovery from a microalgae cultivation system, maintaining the algae as photosynthetically active as possible and limiting their competition with other microorganisms. The hourly flow of the MPBR system was optimised by adjusting the influent flow rate to the outdoor environmental conditions which microalgae were exposed to at any moment and to the nitrogen uptake capacity of the culture. A semi-empirical photosynthetically active radiation (PAR) prediction model was calibrated using total cloud cover (TCC) forecast. Dissolved oxygen, standardised to 25 °C (DO25), was used as an on-line indicator of microalgae photosynthetic activity. Different indexes, based on suspended solids (SS), DO25, and predicted and real PAR, were used as input variables, while the initial HRT of each operating day (HRT0) and the variation of HRT (ΔHRT) served as output variables. The nitrogen recovery efficiency, measured as nitrogen recovery rate (NRR) per nitrogen loading rate (NLR) in pseudo-steady state conditions, was improved by 45% when the HRT-controller was set in comparison to fixed 1.25-d HRT. Consequently, the average effluent total soluble nitrogen (TSN) concentration in the MPBR was reduced by 47%, accomplishing the discharge requirements of the EU Directive 91/271/EEC. |
| first_indexed | 2024-03-09T11:01:37Z |
| format | Article |
| id | doaj.art-dfeadf05918c4a2bb78ce70f61b0114b |
| institution | Directory Open Access Journal |
| issn | 2305-7084 |
| language | English |
| last_indexed | 2024-03-09T11:01:37Z |
| publishDate | 2022-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | ChemEngineering |
| spelling | doaj.art-dfeadf05918c4a2bb78ce70f61b0114b2023-12-01T01:16:04ZengMDPI AGChemEngineering2305-70842022-03-01622410.3390/chemengineering6020024Advanced HRT-Controller Aimed at Optimising Nitrogen Recovery by Microalgae: Application in an Outdoor Flat-Panel Membrane PhotobioreactorJuan Francisco Mora-Sánchez0Josué González-Camejo1Aurora Seco2María Victoria Ruano3CALAGUA—Unidad Mixta UV-UPV, Departament d’Enginyeria Química, Universitat de València, Avinguda de la Universitat s/n, 46100 Valencia, SpainCALAGUA—Unidad Mixta UV-UPV, Departament d’Enginyeria Química, Universitat de València, Avinguda de la Universitat s/n, 46100 Valencia, SpainCALAGUA—Unidad Mixta UV-UPV, Departament d’Enginyeria Química, Universitat de València, Avinguda de la Universitat s/n, 46100 Valencia, SpainCALAGUA—Unidad Mixta UV-UPV, Departament d’Enginyeria Química, Universitat de València, Avinguda de la Universitat s/n, 46100 Valencia, SpainA fuzzy knowledge-based controller of hydraulic retention time (HRT) was designed and tested in an outdoor membrane photobioreactor (MPBR) to improve nitrogen recovery from a microalgae cultivation system, maintaining the algae as photosynthetically active as possible and limiting their competition with other microorganisms. The hourly flow of the MPBR system was optimised by adjusting the influent flow rate to the outdoor environmental conditions which microalgae were exposed to at any moment and to the nitrogen uptake capacity of the culture. A semi-empirical photosynthetically active radiation (PAR) prediction model was calibrated using total cloud cover (TCC) forecast. Dissolved oxygen, standardised to 25 °C (DO25), was used as an on-line indicator of microalgae photosynthetic activity. Different indexes, based on suspended solids (SS), DO25, and predicted and real PAR, were used as input variables, while the initial HRT of each operating day (HRT0) and the variation of HRT (ΔHRT) served as output variables. The nitrogen recovery efficiency, measured as nitrogen recovery rate (NRR) per nitrogen loading rate (NLR) in pseudo-steady state conditions, was improved by 45% when the HRT-controller was set in comparison to fixed 1.25-d HRT. Consequently, the average effluent total soluble nitrogen (TSN) concentration in the MPBR was reduced by 47%, accomplishing the discharge requirements of the EU Directive 91/271/EEC.https://www.mdpi.com/2305-7084/6/2/24fuzzy logichydraulic retention timemicroalgaenitrogen removalphotobioreactorwastewater |
| spellingShingle | Juan Francisco Mora-Sánchez Josué González-Camejo Aurora Seco María Victoria Ruano Advanced HRT-Controller Aimed at Optimising Nitrogen Recovery by Microalgae: Application in an Outdoor Flat-Panel Membrane Photobioreactor ChemEngineering fuzzy logic hydraulic retention time microalgae nitrogen removal photobioreactor wastewater |
| title | Advanced HRT-Controller Aimed at Optimising Nitrogen Recovery by Microalgae: Application in an Outdoor Flat-Panel Membrane Photobioreactor |
| title_full | Advanced HRT-Controller Aimed at Optimising Nitrogen Recovery by Microalgae: Application in an Outdoor Flat-Panel Membrane Photobioreactor |
| title_fullStr | Advanced HRT-Controller Aimed at Optimising Nitrogen Recovery by Microalgae: Application in an Outdoor Flat-Panel Membrane Photobioreactor |
| title_full_unstemmed | Advanced HRT-Controller Aimed at Optimising Nitrogen Recovery by Microalgae: Application in an Outdoor Flat-Panel Membrane Photobioreactor |
| title_short | Advanced HRT-Controller Aimed at Optimising Nitrogen Recovery by Microalgae: Application in an Outdoor Flat-Panel Membrane Photobioreactor |
| title_sort | advanced hrt controller aimed at optimising nitrogen recovery by microalgae application in an outdoor flat panel membrane photobioreactor |
| topic | fuzzy logic hydraulic retention time microalgae nitrogen removal photobioreactor wastewater |
| url | https://www.mdpi.com/2305-7084/6/2/24 |
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