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| Author(s): |
Karina Aparecida de Abreu Tonani
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Escola de Enfermagem de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2011-06-21 |
| Examining board members: |
Susana Segura Muñoz;
Beatriz Rossetti Ferreira;
Elayse Maria Hachich;
Maria Tereza Pepe Razzolini;
Evandro Watanabe
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| Advisor: | Susana Segura Muñoz |
| Abstract | |
Sewage treatment is still precarious in many Brazilian cities, which has contributed to the emergence and re-emergence of waterborne diseases. This study analyzed Giardia spp. cysts and Cryptosporidium spp. oocysts, as well as cysts, eggs and larvae of other protozoa and helminthes. Also part of the study were total and thermotolerant coliforms, Rotavirus and Adenovirus in samples of raw and treated sewage of the Sewage Treatment Station (ETE) of Ribeirão Preto, SP, Brazil. Sewage samples were taken at the points of entry and exit of the ETE, Ribeirão Preto. Analyses of Giardia spp. cysts and Cryptosporidium spp. oocysts were performed through the EPA\'s method 1623. Eggs, cysts and larvae of other protozoa and helminthes were analyzed utilizing the method of sedimentation as proposed by CETESB (1989). Analyses of total and thermotolerant coliforms were performed using the Multiple Tube method (Colilert®). Viral analyses were performed through the RIDASCREEN® enzyme immunoassay ELISA test kit. The results revealed that the concentration of Giardia spp. in raw sewage varied from 120 to 2,200 cysts/L; this concentration varied from 0.45 to 3.5 cysts/L in treated sewage. The concentration of Cryptosporidium spp. oocysts in raw sewage varied from non-detectable to 28.9 oocysts/L and from non-detectable to 1.05 oocysts/L in treated sewage. The activated sludge process used in ETE promoted a partial removal of parasites such as: Endolimax nana, Entamoeba coli, Entamoeba hystolitica, Ancylostoma sp., Ascaris sp. Fasciola hepatica and Strongyloides stercoralis. Reduction factors varied from 18.2 to 100%. A statistically significant difference was observed between the most probable number of total and thermotolerant coliforms in raw and treated sewage, showing a reduction in the concentration of these indicators after the treatment of sewage in ETE, Ribeirão Preto. No statistically significant correlation was found between the concentrations of total and thermotolerant coliforms in relation to the concentration of Giardia cysts spp. and Cryptosporidium spp. oocysts. Analyzing viruses showed positive responses for Rotavirus and Adenovirus in all the studied samples (raw and treated sewage), with a smaller absorbance in the treated sewage. The results contribute to the identification and evaluation of the prevalence of waterborne microorganisms in treated sewage in ETE, Ribeirão Preto, providing useful data for the definition of public policies for sanitation concerning microbiological quality control in Brazil\'s sewage. (AU) | |