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

Autor(es)

Silva, Hugo Guilherme ^[1] ; Sabogal-Paz, Lyda Patricia ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Hydraul & Sanitat, Sao Carlos Sch Engn, Ave Trabalhador Sao Carlense 400, BR-13566590 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: WATER AIR AND SOIL POLLUTION; v. 231, n. 3 MAR 13 2020.
• Citações Web of Science: 0

Resumo

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)

• Processo FAPESP: 12/50522-0 - Contaminação ambiental pelos protozoários Giardia spp. e Cryptosporidium spp. e por Ascaris suum: desafios de detecção, remoção e inativação das formas infectantes
• Beneficiário: Regina Maura Bueno Franco
• Modalidade de apoio: Auxílio à Pesquisa - Temático