Avaliação do risco microbiológico decorrente do reuso de águas cinza em uma edificação residencial de alto padrão

Abstract

Any activity of water reuse leads to considerations relating to health protection. In cases of reuse on a large scale a risk analysis can be applied to assess the risks involved. This work aims to promote the characterization physical-chemical and microbiological of the greywater produced in a high standard of residential building in the city of Vitória (ES), and evaluate the microbiological risk involved in the water reuse throughout the hydro-health system building’s. For this was done a monitoring physico-chemical and microbiological testing of different stages that make up the Greywater Treatment Plant (ETAC), whose process is based on the combination of a compartmentalised anaerobic reactor (RAC), a Submerged aerated biological filters (FBAS), a decanter (DEC), a tank of Equalization (TQE), a Tertiary Filter (TF) and chlorine-based disinfection. The treatment used had high efficiency in removing turbidity, color, BOD, COD and E. coli. and characteristics consistent with the various standards estabilished for the non-potable reuse. The presence of Salmonella spp. was not detected neither Eggs of helminths, Cryptosporidium sp. and Giardia spp. in the effluent from any stage of treatment. The risk analysis was conducted according to HASS (1999), using the model betapoison and variables described by WESTRELL (2004). The annual probability of infection of the water seal toilet filled with water of reuse behaves according to the reuse of water in the bottom reservoir of chlorination showing acceptable annual risk of 1 case of infection in 1000 for mild diarrhea (10-3).