Avaliação de estações de tratamento de água do tipo ciclo completo em função da ocorrência de cistos de Giardia e Oocistos de Cryptosporidium

• Autor(a) principal: Silva, Débora Pereira da
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/00130000073jk
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/10340
• topic: Giardia; Cryptosporidium; Água; Ciclo completo; Filtração; Giardia; Cryptosporidium; Water; Conventional treatment; Filtration; ENGENHARIA SANITARIA::SANEAMENTO AMBIENTAL

The protozoa Giardia spp. and Cryptosporidium spp. are etiological agents responsible for the transmission of gastroenteritis mainly due to the consumption of contaminated water. The (oo)cysts are resistant to harsh environmental conditions, as well as to most of the physicochemical processes used at Water Treatment Plants (WTP). Thus, the objective of this work was to evaluate the seasonal occurrence and removal of these protozoa in WTPs with complete cycle technology of the State of Goiás. Among the 15 analyzed according to the variables: Escherichia coli in raw water; filtered water turbidity and pasture area in the catchment area; The Cerrado Stream was selected for the supply of Sanclerlândia (WTP I) and Santana Stream de São Luís de Montes Belos (WTP II), managed by the Saneago delegate, since the predominance of pasture indicates a risk of cryptosporidiosis outbreaks. These indicators (Cryptosporidium spp. and pasture area) showed a positive correlation (p = 0.0461). Six samples of raw and filtered water were collected for protozoan determination using the Membrane Filtration method and analysis of the physical parameters turbidity and pH in accordance with the Standard Methods for the Examination of Water and Wastewater. In the initial precision tests with ultrapure water, the tests met the USEPA (2012) criteria for Giardia (78.13% ± 0%) and Cryptosporidium (60.63% ± 32.65%), however, in raw water the recovery was lower due to turbidity. In the seasonal monitoring, the raw water from the superficial water source presented pathogen concentrations with maximum values of 50 cysts / L and 200 oocysts / L, and the maximum removal efficiency of Cryptosporidium was 99.69% and 98.75% in WTP I and II, respectively. The filter material of the quick filters of WTP I have well graded particle size (Tef = 0.60mm; Cu = 2.15), which promoted better filter performance in relation to the turbidity of the filtered effluent. WTP II quick filters made of uniform material (Tef = 0.61mm; Cu = 1.623) presented average turbidity parameter concentration of 0.35 NTU and 0.33 NTU in the dry and rainy season, thus the filtered water with lower Turbidity aims to prevent the spread of disease and can improve the efficiency of pathogen removal. In the mass balance, the influence of the steps preceding the filtration process was analyzed in relation to the physicochemical and microbiological parameters. The increase in raw water turbidity during the rainy season did not affect the filtered water, and this parameter ranged from 0.34 - 0.93 NTU in WTP I and 0.28 - 1.27 NTU in WTP II. The removal efficiency was higher than 99%, regarding turbidity, total coliforms and E. coli parameters. It can be concluded that WTP I and II presented pathogen removal efficiency below 99%, reported in the literature, which highlights the importance of studying the distribution of protozoa in the aquatic environment of the State of Goiás and the respective sources of contamination. , as well as the need to implement technologies to improve water treatment and ensure protozoa inactivation.