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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Filter Backwash Water and Floated Residue Containing Pathogenic Protozoa: Detection Method and Treatment Alternatives

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Author(s):
Silva, Hugo Guilherme [1] ; Sabogal-Paz, Lyda Patricia [1]
Total Authors: 2
Affiliation:
[1] Univ Sao Paulo, Dept Hydraul & Sanitat, Sao Carlos Sch Engn, Ave Trabalhador Sao Carlense 400, BR-13566590 Sao Carlos, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: WATER AIR AND SOIL POLLUTION; v. 231, n. 3 MAR 13 2020.
Web of Science Citations: 0
Abstract

Treatments using ozone for filter backwash water (FBW) and calcium oxide for floated residue (FR) were evaluated adopting bench-scale testing for the inactivation of Giardia spp. cysts and Cryptosporidium parvum oocysts. The protocol chosen for protozoa detection involved following the concentration step by direct centrifugation (adding ICN 7X cleaning solution at 1.0%) and purification by immunomagnetic separation (IMS). The FR treatment with calcium oxide (dosage of 23 mg CaO 100 mL(-1) and 3-day contact time at 25 degrees C) proved to be efficient, as no parasites were detected after the treatment. The reduction of calcium oxide dosage (16 mg CaO 100 mL(-1) and 3-day contact time at 25 degrees C) was insufficient to inactivate the protozoa, since potentially viable organisms were identified using propidium iodide (PI). Concerning the disinfection conditions with ozone (5-min and 10-min contact time and dosage of 10 mg O-3 L-1 and 7.5 mg O-3 L-1, respectively), there was complete removal of the target organisms, as no protozoa were detected after the FBW treatment. From the results obtained, the tested treatments can be considered promising alternatives for water treatment plants (WTPs). However, the costs incurred from these treatments have to be considered. (AU)

FAPESP's process: 12/50522-0 - Environmental contamination by protozoa Giardia spp. and Cryptosporidium spp. and Ascaris suum: challenges of detection, removal and inactivation of infective forms
Grantee:Regina Maura Bueno Franco
Support Opportunities: Research Projects - Thematic Grants