Upflow Direct Filtration and Downflow Direct Filtration: A Comparison with Emphasis on the Removal of Aerobic Spore-Forming Bacteria and Fluorescent Microspheres as Surrogates for <i>Cryptosporidium</i> Oocyst Removal
Monitoring the removal of <i>Cryptosporidium</i> oocysts in water treatment plants is a challenge, particularly in developing countries, and the use of surrogates has proven necessary. Two surrogates already investigated and recognized by the scientific community are aerobic spore-formin...
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MDPI AG
2023-11-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/15/22/4012 |
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| author | Álef Luan de Souza Pereira Cristina Celia Silveira Brandão Yovanka Pérez Ginoris Carla Patrícia Pereira Alves |
| author_facet | Álef Luan de Souza Pereira Cristina Celia Silveira Brandão Yovanka Pérez Ginoris Carla Patrícia Pereira Alves |
| author_sort | Álef Luan de Souza Pereira |
| collection | DOAJ |
| description | Monitoring the removal of <i>Cryptosporidium</i> oocysts in water treatment plants is a challenge, particularly in developing countries, and the use of surrogates has proven necessary. Two surrogates already investigated and recognized by the scientific community are aerobic spore-forming bacteria (ASFB) and fluorescent polystyrene microspheres (ME). In this context, this study evaluates and compares the performance of upflow direct filtration and downflow direct filtration, with emphasis on the removal of ASFB and ME as a surrogate of <i>Cryptosporidium</i> oocyst removal. Pilot filtration experiments were carried out with low turbidity Paranoá Lake water (average—3.7 NTU) with ASFB varying from 7 × 10<sup>2</sup> to 5.5 × 10<sup>3</sup> CFU/100 mL. In some experiments, water was spiked with microspheres, aiming for 10<sup>5</sup> ME/L. Two operational conditions were evaluated: (1) filters operating with the same filtration rate (5 m/h); (2) filters operating with the same flow rate of 59.41 L/h. In general, the downflow filter presented a slightly higher removal efficiency than the upflow filter but the differences were not considered statistically significant in most cases. The removal efficiency of microspheres (3 to 5 log) was higher than that of ASFB (1.2 to 4 log) in both filters, corroborating that the removal of ASFB is a conservative surrogate of the removal of <i>Cryptosporidium</i>. |
| first_indexed | 2024-03-09T16:22:48Z |
| format | Article |
| id | doaj.art-8cf3410d6ed44492b70cd22155a3cdcb |
| institution | Directory Open Access Journal |
| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-03-09T16:22:48Z |
| publishDate | 2023-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Water |
| spelling | doaj.art-8cf3410d6ed44492b70cd22155a3cdcb2023-11-24T15:11:37ZengMDPI AGWater2073-44412023-11-011522401210.3390/w15224012Upflow Direct Filtration and Downflow Direct Filtration: A Comparison with Emphasis on the Removal of Aerobic Spore-Forming Bacteria and Fluorescent Microspheres as Surrogates for <i>Cryptosporidium</i> Oocyst RemovalÁlef Luan de Souza Pereira0Cristina Celia Silveira Brandão1Yovanka Pérez Ginoris2Carla Patrícia Pereira Alves3Department of Civil and Environmental Engineering, University of Brasilia, Brasilia 70910-900, DF, BrazilDepartment of Civil and Environmental Engineering, University of Brasilia, Brasilia 70910-900, DF, BrazilDepartment of Civil and Environmental Engineering, University of Brasilia, Brasilia 70910-900, DF, BrazilDepartment of Civil and Environmental Engineering, University of Brasilia, Brasilia 70910-900, DF, BrazilMonitoring the removal of <i>Cryptosporidium</i> oocysts in water treatment plants is a challenge, particularly in developing countries, and the use of surrogates has proven necessary. Two surrogates already investigated and recognized by the scientific community are aerobic spore-forming bacteria (ASFB) and fluorescent polystyrene microspheres (ME). In this context, this study evaluates and compares the performance of upflow direct filtration and downflow direct filtration, with emphasis on the removal of ASFB and ME as a surrogate of <i>Cryptosporidium</i> oocyst removal. Pilot filtration experiments were carried out with low turbidity Paranoá Lake water (average—3.7 NTU) with ASFB varying from 7 × 10<sup>2</sup> to 5.5 × 10<sup>3</sup> CFU/100 mL. In some experiments, water was spiked with microspheres, aiming for 10<sup>5</sup> ME/L. Two operational conditions were evaluated: (1) filters operating with the same filtration rate (5 m/h); (2) filters operating with the same flow rate of 59.41 L/h. In general, the downflow filter presented a slightly higher removal efficiency than the upflow filter but the differences were not considered statistically significant in most cases. The removal efficiency of microspheres (3 to 5 log) was higher than that of ASFB (1.2 to 4 log) in both filters, corroborating that the removal of ASFB is a conservative surrogate of the removal of <i>Cryptosporidium</i>.https://www.mdpi.com/2073-4441/15/22/4012aerobic spore-forming bacteria<i>Cryptosporidium</i> oocyst surrogatesdirect filtrationcontact filtrationgranular filtration performancedrinking water treatment |
| spellingShingle | Álef Luan de Souza Pereira Cristina Celia Silveira Brandão Yovanka Pérez Ginoris Carla Patrícia Pereira Alves Upflow Direct Filtration and Downflow Direct Filtration: A Comparison with Emphasis on the Removal of Aerobic Spore-Forming Bacteria and Fluorescent Microspheres as Surrogates for <i>Cryptosporidium</i> Oocyst Removal Water aerobic spore-forming bacteria <i>Cryptosporidium</i> oocyst surrogates direct filtration contact filtration granular filtration performance drinking water treatment |
| title | Upflow Direct Filtration and Downflow Direct Filtration: A Comparison with Emphasis on the Removal of Aerobic Spore-Forming Bacteria and Fluorescent Microspheres as Surrogates for <i>Cryptosporidium</i> Oocyst Removal |
| title_full | Upflow Direct Filtration and Downflow Direct Filtration: A Comparison with Emphasis on the Removal of Aerobic Spore-Forming Bacteria and Fluorescent Microspheres as Surrogates for <i>Cryptosporidium</i> Oocyst Removal |
| title_fullStr | Upflow Direct Filtration and Downflow Direct Filtration: A Comparison with Emphasis on the Removal of Aerobic Spore-Forming Bacteria and Fluorescent Microspheres as Surrogates for <i>Cryptosporidium</i> Oocyst Removal |
| title_full_unstemmed | Upflow Direct Filtration and Downflow Direct Filtration: A Comparison with Emphasis on the Removal of Aerobic Spore-Forming Bacteria and Fluorescent Microspheres as Surrogates for <i>Cryptosporidium</i> Oocyst Removal |
| title_short | Upflow Direct Filtration and Downflow Direct Filtration: A Comparison with Emphasis on the Removal of Aerobic Spore-Forming Bacteria and Fluorescent Microspheres as Surrogates for <i>Cryptosporidium</i> Oocyst Removal |
| title_sort | upflow direct filtration and downflow direct filtration a comparison with emphasis on the removal of aerobic spore forming bacteria and fluorescent microspheres as surrogates for i cryptosporidium i oocyst removal |
| topic | aerobic spore-forming bacteria <i>Cryptosporidium</i> oocyst surrogates direct filtration contact filtration granular filtration performance drinking water treatment |
| url | https://www.mdpi.com/2073-4441/15/22/4012 |
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