In this study, the efficiency of centrifuge-concentration and membrane filtrated methods was evaluated in the detection of Cryptosporidium spp. oocysts and Giardia spp. cysts in raw or treated wastewater samples, from activated sludge systems (ETE - Samambaia, Campinas, in São Paulo). The samples were collected once a fortnight for two years: 53 samples of influent (AFL), 53 samples of treated effluent without ultraviolet disinfection (EFL), and 38 samples of treated effluent with ultraviolet disinfection (EFL+UV). Giardia spp. cysts were found in 90.5% of the AFL samples; in 96.2% of the samples, EFL; and in 94.7%, EFL+UV. Cryptosporidium spp. oocysts were detected in 6.4% of AFL samples and 2.6% of EFL+UV. Both methods showed efficiency when detecting protozoa in all types of samples, besides having low costs by analysis.
waterborne diseases; parasitoses; protozoa
