Remoção de microesferas de poliestireno, em substituição a oocitos de Crypstosporidium, por filtração direta ascendente no tratamento de água usando o coagulante quitosana

Méndez, Romero; Marcela, Ingrith

doi:10.26512/2014.11.d.17735

Cited by 2 publications

(2 citation statements)

References 32 publications

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“…As can be seen in Table 5 and Figure 2, the average residual turbidity remained consistently below 0.32 NTU in all experiments, a value that is below the limits established for filtered water by the Brazilian drinking water guidelines, less than or equal to 0.5 NTU in 95% of measurements [15]. Similar results were reported by Fagundes [26], Fernandes [27], Nascimento [28], and Méndez [29], authors who conducted their studies using raw water from the same source (Paranoá Lake) and similar filters. With turbidity values less than or equal to 0.3 NTU in 95% of measurements of filtered water, at least a 2.5 log removal of Cryptosporidium can be obtained in direct filtration plants [7,16].…”

Section: Turbidity and Head Loss Developmentsupporting

confidence: 85%

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 Cryptosporidium Oocyst Removal

Pereira,

Brandão,

Ginoris

et al. 2023

Water

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Monitoring the removal of Cryptosporidium 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 Cryptosporidium oocyst removal. Pilot filtration experiments were carried out with low turbidity Paranoá Lake water (average—3.7 NTU) with ASFB varying from 7 × 102 to 5.5 × 103 CFU/100 mL. In some experiments, water was spiked with microspheres, aiming for 105 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 Cryptosporidium.

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Section: Turbidity and Head Loss Developmentsupporting

confidence: 85%

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 Cryptosporidium Oocyst Removal

Pereira,

Brandão,

Ginoris

et al. 2023

Water

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“…The difference in the total particle counts in raw water was mainly due to the increase in the number of particles in the ranges 8-15 and 20-70 µm. This behavior is associated with the particle size distribution of the kaolinite suspension added to the water, whose granulometric analysis revealed that nearly 70% of kaolinite particles were greater than 7 µm [36].…”

Section: Particle Counts and Cryptosporidium Oocystsmentioning

confidence: 95%

Cryptosporidium Oocysts Removal by Upflow Direct Filtration: Pilot Scale Assessment

Nascimento

Ginoris

Brandão

2020

Water

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Studies on the removal of Cryptosporidium oocysts by direct filtration suggested that high removal efficiencies (>3.0 log) can be achieved, but the vast majority of the studies focused on the assessment of downflow direct filtration. However, in comparison with downflow direct filtration, filters in upflow direct filtration systems use lower filtration rates, deeper stratified bed, and water flows from coarse to fine sand grain, which may improve the removal of oocysts. In this context, we evaluated the removal of Cryptosporidium oocysts using upflow direct filtration, on a pilot scale, to treat Paranoá Lake water (Brazil) seeded with Cryptosporidium oocysts. The experiments were conducted with raw water with low turbidity (3.2–5.7 NTU) and induced higher turbidity (28–30 NTU). Non-parametric statistical analysis was used to verify correlations between the filtered water values and removal of oocysts, particles, and turbidity. In general, no correlation was observed between the parameters analyzed, nor between their removals. The exception was the correlation between residual values of Cryptosporidium oocysts and particles of 2 to 7 µm during ripening, an aspect that needs further evaluation. Under stable operation, average removal of Cryptosporidium oocysts by upflow direct filtration was >3.87 log. During ripening, removal of oocysts was around 1 log lower.

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Remoção de microesferas de poliestireno, em substituição a oocitos de Crypstosporidium, por filtração direta ascendente no tratamento de água usando o coagulante quitosana

Cited by 2 publications

References 32 publications

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 Cryptosporidium Oocyst Removal

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 Cryptosporidium Oocyst Removal

Cryptosporidium Oocysts Removal by Upflow Direct Filtration: Pilot Scale Assessment

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